Phytochemical and Pharmacological Insights into Croton tiglium Linn: A Promising Herbal Remedy for Hair Growth and Beyond

1.1 The Genus Croton and Its Ethnobotanical Significance

The genus Croton is one of the largest and most chemically diverse groups within the family Euphorbiaceae, comprising over 1,200 species distributed across tropical and subtropical regions worldwide (Salatino & Salatino, 2020). Members of this genus have been widely recognized for their diverse phytochemical profiles, including terpenoids, alkaloids, flavonoids, and phenolic compounds that contribute to their broad pharmacological spectrum. Species such as Croton lechleri (source of the medicinal resin “Dragon’s blood”), C. tiglium, C. zambesicus, and C. oblongifolius have been utilized for centuries in folk and traditional medicine systems for ailments ranging from gastrointestinal disorders to infections and inflammatory diseases (de Souza et al., 2019).

Among these, Croton tiglium Linn., commonly known as Jamalgota or Purging Croton, has gained particular attention for its potent biological activity and complex phytochemical makeup. The plant was first described by Carl Linnaeus in Species Plantarum (1753) and remains one of the earliest botanically classified Euphorbiaceae members with medicinal relevance. In Ayurvedic literature, C. tiglium is referred to as “Jayapala,” and it is recognized as a strong purgative herb used traditionally after specific detoxification (Shodhana) processes to mitigate toxicity (Sharma et al., 2021). Its seeds, though toxic, are valued for their oil, which exhibits both medicinal and industrial utility.

1.2 Botanical Classification and Distribution

Croton tiglium is a small deciduous shrub or tree that typically grows up to 6 meters in height. Taxonomically, it is classified as follows:

Table 1: Taxonomical classification of Croton tiglium Linn. (Family: Euphorbiaceae).

The plant is indigenous to Southeast Asia, including India, Myanmar, Indonesia, Malaysia, and southern China, but it is now cultivated in tropical regions worldwide. In India, it thrives in the warmer parts of the subcontinent, particularly in Bengal and Assam, where it is cultivated primarily for its seeds and oil (Patra et al., 2019). The species prefers well-drained soils and grows in humid, tropical climates. Its leaves are ovate and glabrous, and its seeds are brownish, oval, and enclosed in a three-lobed capsule—features that have been historically used for plant identification.

Fig no. 1: Photographs of C. tiglium L., leaves (A), flowers (B), fresh fruits (C), and dry fruits and seeds (D).

1.3 Traditional and Ethnomedicinal Uses

The medicinal use of C. tiglium dates back thousands of years. In Ayurveda, the seed oil (Jayapala Taila) is classified under “Ushna” (hot) and “Tikshna” (sharp) drugs and is primarily employed as a strong purgative, anthelminthic, and counter-irritant (Tripathi et al., 2020). However, because of its potent toxicity, traditional healers devised purification techniques known as Shodhana, which involve processing the seeds with cow’s milk, ginger juice, or tamarind extract to neutralize toxic phorbol esters and proteins (Jain et al., 2022).

In Traditional Chinese Medicine (TCM), C. tiglium (known as Ba Dou) has been used as a drastic purgative, expectorant, and topical treatment for sores and ulcers. It is listed in the Chinese Pharmacopoeia under strict dosage limitations, emphasizing its dual nature as a medicine and poison (Li et al., 2018). Southeast Asian folk practitioners have employed the seed oil externally to treat rheumatism, neuralgia, and scabies, while diluted preparations are used for constipation and bronchial congestion (Nguyen et al., 2017). Despite its harsh purgative nature, its external use in minute, processed doses remains valued in traditional dermatological and hair formulations, where it is often blended with other herbal agents.

1.4 Toxicological Concerns and Scientific Reappraisal

The historical reputation of C. tiglium as both a healing and hazardous plant has led to polarized perceptions in pharmacognosy. The plant’s seed oil contains potent phorbol esters, a group of tigliane diterpenoids known for their irritant and tumor-promoting activities via activation of protein kinase C (PKC) (Blumberg & Kedei, 2019). Additionally, toxic proteins such as crotin and crotonalbumin are reported to exhibit hemagglutinating and cytotoxic properties (Ghosh et al., 2020).

Despite these toxic attributes, recent pharmacological investigations have begun to isolate and structurally modify these compounds to harness their therapeutic potential. For instance, semi-synthetic analogs of phorbol esters have shown antitumor, antiviral, and immune-modulatory effects when used at controlled doses (Azhari et al., 2021). The renewed interest in C. tiglium thus stems from its dualistic pharmacology—where toxic principles, when modulated or detoxified, may provide novel pharmacotherapeutic opportunities.

1.5 Rationale for Phytochemical and Pharmacological Investigation

The pharmacological significance of C. tiglium arises from its rich and complex array of secondary metabolites. Diterpenoids, particularly tigliane derivatives, play a central role in modulating intracellular signaling cascades, including PKC activation, reactive oxygen species (ROS) generation, and inflammatory mediators (Liu et al., 2020). These molecular pathways are not only relevant to inflammation, cancer, and viral replication but also overlap with the mechanisms underlying hair follicle cycling and dermal papilla cell activation an emerging field of interest in cosmetic dermatology and trichology (Zhao et al., 2023).

Furthermore, the traditional topical use of C. tiglium in herbal oils for scalp stimulation suggests empirical recognition of its circulatory and irritant effects, which may enhance local blood flow and follicular metabolism. Such observations justify modern scientific exploration into its hair-growth-promoting potential, especially after detoxification to remove harmful phorbol esters and protein toxins. The plant therefore represents a unique case of a historically toxic herb undergoing scientific reevaluation for controlled therapeutic and cosmeceutical use.

1.6 Current Knowledge Gaps and Need for Standardization

Despite the extensive ethnomedicinal documentation, scientific research on C. tiglium remains fragmented and primarily descriptive. Most studies have focused on its purgative activity or cytotoxic constituents, while only a few have explored its broader pharmacological spectrum. Quantitative and qualitative variations in phytochemical composition due to geography, processing, and extraction methods further complicate reproducibility (Gad et al., 2022).

Additionally, the lack of standardized detoxification protocols (Shodhana) and validated safety evaluations limits its clinical and cosmetic applications. No systematic studies have yet elucidated optimal extraction conditions, safe topical concentrations, or formulation compatibilities for dermal use. Therefore, a comprehensive review integrating phytochemical, pharmacological, toxicological, and mechanistic data is warranted to establish a foundation for evidence-based utilization of C. tiglium.

1.7 Objectives and Scope of the Review

This review aims to synthesize and critically analyze the current literature on Croton tiglium Linn. with emphasis on its phytochemical composition, pharmacological activities, toxicology, and potential hair-growth mechanisms. Specifically, it seeks to:

1. Summarize and classify the known phytoconstituents, including diterpenoids, alkaloids, fatty acids, and proteins.
2. Evaluate experimentally validated pharmacological effects such as anticancer, anti-inflammatory, antimicrobial, and neuroprotective activities.
3. Examine traditional detoxification approaches and their impact on reducing toxicity.
4. Discuss plausible molecular mechanisms underlying its hair-growth potential.
5. Identify existing research gaps, challenges, and future prospects for safe therapeutic or cosmetic applications.

By integrating classical ethnomedicinal insights with contemporary biochemical evidence, this review provides a balanced scientific perspective on C. tiglium a plant that epitomizes the delicate boundary between poison and medicine.

2. Botanical Description and Traditional Uses

2.1 Morphological and Taxonomic Features

Croton tiglium Linn. is a deciduous, glabrous shrub or small tree belonging to the Euphorbiaceae family a group well-known for its chemically rich members that produce latex and various secondary metabolites. The plant typically grows between 3–6 meters in height, with a short trunk and numerous spreading branches (Patra et al., 2019). The bark is thin and grayish-brown, exuding a yellowish sap when cut. The leaves are simple, alternate, and ovate to elliptic, measuring approximately 5–10 cm in length and 3–6 cm in width. Each leaf displays a smooth texture with entire or slightly serrated margins, acuminate apex, and prominent venation. The petiole is slender and often exhibits two small glands near the base.

The plant bears small, unisexual flowers arranged in terminal racemes or panicles. Male flowers are numerous and possess five white petals with many stamens, while female flowers are fewer, lacking petals, and have a superior, three-lobed ovary. The fruit is a three-seeded capsule, approximately 8–10 mm in diameter, which dehisces upon maturation to release smooth, oval, brownish-gray seeds. Each seed contains an oily endosperm that constitutes the source of croton oil, one of the most pharmacologically active and toxic plant oils known (Sharma et al., 2021).

Taxonomically, C. tiglium is characterized by its distinctive glandular structures and the presence of unique tigliane diterpenoids, which differentiate it chemotaxonomically from other Euphorbiaceae members (Salatino & Salatino, 2020). The following summarizes its botanical classification:

? Kingdom: Plantae

? Division: Magnoliophyta

? Class: Magnoliopsida

? Order: Malpighiales

? Family: Euphorbiaceae

? Genus: Croton

? Species: C. tiglium Linn.

This taxonomic clarity is crucial, as several Croton species share morphological similarities but differ in phytochemical content and toxicity, often leading to misidentification in ethnomedicinal contexts (Nguyen et al., 2017).

2.2 Geographical Distribution and Cultivation

Croton tiglium is native to tropical and subtropical regions of Southeast Asia, particularly India, Sri Lanka, Indonesia, the Philippines, and southern China (Li et al., 2018). It thrives in humid, lowland regions and is commonly found in coastal forests, open fields, and secondary growth areas. In India, it is predominantly cultivated in Bengal, Assam, Tamil Nadu, and Kerala, where it is valued for medicinal, horticultural, and research purposes (Gad et al., 2022).

The plant requires well-drained sandy or loamy soil and prefers a warm, humid climate with moderate rainfall. Propagation is achieved through seeds or stem cuttings, though germination rates are low due to the hard seed coat. Cultivation for medicinal purposes involves careful post-harvest processing to ensure detoxification of the seeds before any therapeutic use. The seeds are collected when ripe, dried, and stored in airtight containers away from light and moisture to preserve the oil content.

2.3 Traditional Medicinal Applications

Historically, C. tiglium has been a significant medicinal plant across multiple cultural systems, though its potent purgative and irritant nature has restricted its use to experienced practitioners.

In Ayurveda:

In Ayurvedic medicine, C. tiglium is classified under the “Tikshna Dravya” category substances of penetrating and potent nature. The seed oil, known as Jayapala Taila, is primarily used as a powerful purgative (Virechaka) for the elimination of doshas, particularly “Kapha” and “Vata” (Tripathi et al., 2020). Traditional texts such as Charaka Samhita and Sushruta Samhita describe its use in minute doses (after purification) to treat constipation, ascites, worm infestation, and skin diseases (Sharma et al., 2021). Topically, it is used in combination with other herbal oils for localized inflammation, joint pain, and chronic skin ailments.

In Siddha and Unani Systems:

In Siddha medicine, C. tiglium is incorporated in formulations for treating dropsy, bronchitis, and leprosy. The Unani system employs the oil as a drastic purgative under strict regulation and in externally applied liniments for neuralgia and rheumatism (Patra et al., 2019).

In Traditional Chinese Medicine (TCM):

Known as Ba Dou in TCM, C. tiglium seeds are used as a powerful cathartic agent to relieve severe constipation, phlegm retention, and edema. The Chinese Pharmacopoeia specifies a highly restricted dosage range (0.03–0.1 g of seed powder) and mandates prior processing to reduce toxicity (Li et al., 2018). The oil is sometimes used in minute external applications for skin ulceration and alopecia areata, reflecting its longstanding empirical association with skin and hair conditions.

In Southeast Asian and Folk Traditions:

Local healers in Indonesia, Malaysia, and the Philippines employ diluted croton oil as a rubefacient and counter-irritant in treating muscle pain, paralysis, and rheumatism (Nguyen et al., 2017). In some regions, finely powdered seeds are mixed with coconut oil for topical application on the scalp to stimulate hair growth—a practice that inspired scientific hypotheses regarding its potential role in trichogenesis (Zhao et al., 2023).

2.4 Shodhana (Ayurvedic Detoxification) Process

The Ayurvedic purification process, or Shodhana, plays a pivotal role in rendering C. tiglium therapeutically usable. The classical Rasatarangini and Bhaishajya Ratnavali prescribe several Shodhana methods to detoxify Jayapala seeds. Common procedures include:

• Boiling in cow’s milk or goat’s milk for 3–6 hours to denature toxic proteins such as crotin and crotonalbumin.
• Soaking in tamarind extract or ginger juice for 24 hours to reduce the concentration of phorbol esters and neutralize irritant compounds.
• Roasting in castor oil or ghee to remove volatile toxins and improve stability (Jain et al., 2022).

Post-detoxification, the seeds lose much of their drastic purgative potency and become safer for both internal and external medicinal applications. Analytical studies have demonstrated that Shodhana reduces total phorbol ester concentration by over 60–80%, thereby mitigating the plant’s irritant and genotoxic potential (Rathi et al., 2022).

2.5 Ethnopharmacological Relevance

The widespread use of C. tiglium across diverse traditional systems underscores its ethnopharmacological importance. The plant’s purgative and counter-irritant activities are consistent with its high diterpenoid and fatty acid content, particularly the presence of crotonic acid, myristic acid, and phorbol esters that induce gastrointestinal and dermal responses (Blumberg & Kedei, 2019). Ethnobotanical documentation further reveals its usage in small, topical doses for stimulating circulation and treating alopecia, eczema, and scabies (Nguyen et al., 2017).

The convergence of these traditional applications with emerging pharmacological findings such as anti-inflammatory, immunomodulatory, and pro-regenerative properties supports a re-evaluation of C. tiglium as a complex therapeutic resource. While its toxicity cannot be ignored, detoxification practices validated by modern analytical chemistry have opened avenues for safer exploration of its bioactive compounds in regulated formulations (Gad et al., 2022).

2.6 Summary

In summary, Croton tiglium is a botanically well-characterized yet pharmacologically paradoxical plant. Its seeds and oil are the most utilized parts, serving as both potent medicines and sources of toxicity. Traditional medical systems across Asia have long recognized its power and have developed detoxification methods to mitigate its dangers. The plant’s documented topical use for scalp and hair conditions, combined with recent pharmacological evidence, suggests it may possess mechanistically relevant bioactivities for promoting hair growth and enhancing dermal regeneration.

Thus, understanding the plant’s traditional context and botanical intricacies provides a necessary foundation for the subsequent scientific evaluation of its phytochemical and pharmacological dimensions.

3. Phytochemical Composition

3.1 Overview of Phytochemical Diversity

Croton tiglium Linn. exhibits remarkable phytochemical diversity, contributing to its broad pharmacological profile and historical medicinal use. The seeds, leaves, stem bark, and root contain various classes of bioactive compounds such as diterpenoids, fatty acids, alkaloids, flavonoids, phenolics, and proteins (Patra et al., 2019). Among these, tiglane diterpenoids especially phorbol esters are considered the principal bioactive and toxic constituents. Other key components, including crotonic acid, myristic acid, crotin, and crotonalbumin, contribute to its purgative, irritant, and immunomodulatory activities (Ghosh et al., 2020).

The chemical complexity of C. tiglium has made it both pharmacologically valuable and toxicologically challenging. Advances in chromatographic and spectroscopic techniques such as GC–MS, LC–MS, NMR, and HPLC have facilitated identification of over 100 distinct compounds from different plant parts (Liu et al., 2020). Recent investigations also highlight the presence of minor secondary metabolites like volatile terpenes, sterols, and phenolic acids that may synergize with major constituents in biological activities (Azhari et al., 2021).

3.2 Tigliane Diterpenoids and Phorbol Esters

Diterpenoids constitute the most characteristic and biologically active class of compounds in C. tiglium. They primarily belong to the tigliane and daphnane skeleton types, often esterified to form complex phorbol esters (Blumberg & Kedei, 2019). These compounds are known to activate protein kinase C (PKC), modulating cellular signaling involved in inflammation, apoptosis, and proliferation.

Key diterpenoids identified from C. tiglium seeds and oil include 12-O-tetradecanoylphorbol-13-acetate (TPA), phorbol-12,13-didecanoate, phorbol-12,13-dibutyrate, and crotonin (Liu et al., 2020). The structure–activity relationship of these esters indicates that the length and saturation of acyl side chains influence their biological potency.

Although phorbol esters are tumor-promoting at high doses, several analogs have demonstrated potential therapeutic uses at subtoxic levels. For instance, modified phorbol derivatives have exhibited anti-HIV latency reversal, antitumor cytotoxicity, and immunomodulatory effects (Azhari et al., 2021). These findings highlight the dual pharmacology of tigliane diterpenoids—acting as both therapeutic leads and toxic irritants depending on concentration and molecular configuration.

3.3 Fatty Acids and Lipid Constituents

Croton oil, extracted from the seeds of C. tiglium, is a rich source of fatty acids, which constitute approximately 30–50% of the seed weight. The predominant fatty acids include oleic acid (C18:1), linoleic acid (C18:2), myristic acid (C14:0), stearic acid (C18:0), and crotonic acid (C4:1) (Patra et al., 2019).

These fatty acids, apart from serving as solvents for diterpenoids, possess independent pharmacological activities. Linoleic acid and oleic acid are known to enhance skin permeability and stimulate dermal repair, suggesting a role in topical applications (Tripathi et al., 2020). Additionally, crotonic acid, a short-chain unsaturated acid unique to this species, contributes to the irritant and purgative activity by stimulating intestinal mucosa and promoting peristalsis (Li et al., 2018).

Recent lipidomic analyses have identified minor lipophilic compounds such as glycerides, sterols (β-sitosterol, stigmasterol), and tocopherols, which may add antioxidant properties to detoxified extracts (Rathi et al., 2022).

3.4 Alkaloids

Although diterpenoids dominate the chemistry of C. tiglium, the plant also contains a number of nitrogenous alkaloids. Alkaloids such as crotonine, tiglinine, and crotonosine have been isolated from seeds and leaves (Nguyen et al., 2017).

These compounds exhibit mild spasmolytic and antimicrobial activities and may modulate neurotransmission through cholinergic pathways (Gad et al., 2022). However, their concentrations are relatively low compared to diterpenoids, and limited studies have explored their pharmacological significance.

Recent chromatographic fractionation has revealed that alkaloid-rich fractions from detoxified seeds exhibit reduced cytotoxicity and may contribute synergistically to anti-inflammatory effects observed in ethanolic extracts (Jain et al., 2022).

3.5 Proteins, Lectins, and Toxins

The protein fraction of C. tiglium contains several bioactive and toxic components, including crotin, crotonalbumin, and crotonin A and B. These are ribosome-inactivating proteins (RIPs) that inhibit protein synthesis by depurinating 28S rRNA, leading to cytotoxic and inflammatory responses (Ghosh et al., 2020).

• Crotin is a Type I RIP, structurally similar to ricin, and responsible for severe gastrointestinal and systemic toxicity when ingested.
• Crotonalbumin is a hemagglutinating lectin capable of binding to cell membranes and inducing immune responses.

Interestingly, controlled hydrolysis or Shodhana significantly decreases the concentration of these proteins, correlating with a reduction in hemagglutination and cytotoxicity (Rathi et al., 2022). Some detoxified protein fractions also show immunostimulatory effects at low doses, suggesting potential use in immunotherapy after safety validation.

3.6 Phenolic Compounds and Flavonoids

Although not abundant, C. tiglium contains several phenolic acids and flavonoids that contribute antioxidant properties. Identified compounds include gallic acid, ferulic acid, vanillic acid, and quercetin, mostly in the leaf and bark extracts (Salatino & Salatino, 2020).

These compounds may play a role in counteracting oxidative stress induced by diterpenoid metabolism, potentially balancing the plant’s pro-oxidant toxicity with antioxidant defense mechanisms. Extracts rich in phenolics have shown free radical scavenging and lipid peroxidation inhibition, which are particularly relevant for dermal and hair follicle protection (Zhao et al., 2023).

3.7 Volatile and Minor Constituents

GC–MS analysis of C. tiglium essential oil has identified monoterpenes and sesquiterpenes such as α-pinene, β-caryophyllene, and limonene, contributing to its aromatic and possibly antimicrobial profile (Nguyen et al., 2017). Additionally, traces of saponins and tannins have been detected, which may assist in stabilizing emulsified formulations used for topical applications.

3.8 Impact of Detoxification (Shodhana) on Phytochemical Profile

The Ayurvedic detoxification process (Shodhana) significantly alters the chemical composition of C. tiglium seeds and oil. Studies using HPTLC and HPLC fingerprinting show that Shodhana with cow’s milk or ginger juice reduces phorbol ester content by up to 80–90%, while preserving beneficial fatty acids and minor diterpenoids (Jain et al., 2022).

Similarly, protein denaturation during boiling or roasting decreases crotin and crotonalbumin levels, resulting in markedly lower cytotoxicity and irritation potential. Interestingly, detoxification can also enhance the relative concentration of certain antioxidants like tocopherols and phenolic acids, suggesting that detoxified C. tiglium extracts may retain therapeutic benefits with improved safety profiles (Rathi et al., 2022).

Table 1. Major Phytochemicals Identified in Croton tiglium Linn.

4. Pharmacological Activities

4.1 Overview

Croton tiglium Linn. possesses a wide range of pharmacological properties, attributed to its diverse phytoconstituents particularly tigliane diterpenoids, fatty acids, alkaloids, and proteins. Although many of these compounds exhibit dual activity (therapeutic and toxic), controlled extraction, detoxification, and dosage optimization have revealed significant biological effects, including laxative, anticancer, antiviral, anti-inflammatory, analgesic, antimicrobial, metabolic, and neuroprotective actions (Patra et al., 2019; Azhari et al., 2021).

The following subsections review the major pharmacological categories associated with C. tiglium, integrating in vitro and in vivo findings, mechanistic insights, and clinical relevance.

4.2 Laxative and Gastrointestinal Effects

The laxative property of C. tiglium is among its most anciently recognized therapeutic uses. The croton oil extracted from its seeds acts as a powerful purgative due to the presence of phorbol esters and crotonic acid, which stimulate intestinal mucosa, increase peristaltic contractions, and promote secretion of intestinal fluids (Li et al., 2018).

In animal studies, administration of croton oil at doses of 0.1–0.5 mg/kg induced strong cathartic activity, characterized by enhanced fecal output and intestinal motility within 2–3 hours (Tripathi et al., 2020). The mechanism involves activation of PKC in smooth muscle cells, leading to calcium-dependent contractility and prostaglandin-mediated intestinal secretion (Blumberg & Kedei, 2019).

While traditionally exploited for its purgative effect, modern studies emphasize dose standardization to minimize gastrointestinal irritation and dehydration. Detoxified preparations (post-Shodhana) have demonstrated milder laxative effects without mucosal damage, confirming the safety enhancement achieved through purification (Rathi et al., 2022).

4.3 Anticancer and Cytotoxic Activities

Several diterpenoids isolated from C. tiglium notably 12-O-tetradecanoylphorbol-13-acetate (TPA), phorbol-12,13-didecanoate, and crotonin exhibit significant cytotoxic and antiproliferative activities in diverse cancer cell lines (Liu et al., 2020). Despite TPA’s known tumor-promoting activity in chronic exposure, low or modified doses have shown potential in inducing apoptosis and differentiation in certain malignancies.

In vitro studies demonstrated that TPA at nanomolar concentrations activates PKC-δ, resulting in apoptosis in HL-60 leukemia and HeLa cells (Azhari et al., 2021). Additionally, crotonin derivatives suppressed tumor cell migration through inhibition of the NF-κB signaling pathway and downregulation of MMP-9 expression (Ghosh et al., 2020).

Interestingly, semi-synthetic analogs of phorbol esters, such as prostratin (a non-tumor-promoting phorbol analog derived from C. tiglium precursors), are under investigation for HIV latency reversal and anticancer drug development (Kedei et al., 2019). The dualistic behavior of these compounds underscores the importance of structural modification and precise dose control in harnessing their anticancer potential.

4.4 Antiviral and Anti-HIV Activity

Phorbol esters derived from C. tiglium exhibit potent antiviral properties, primarily mediated through PKC activation and modulation of viral transcription factors. Notably, the phorbol ester analog 12-deoxyphorbol-13-decanoate has demonstrated anti-HIV latency-reversing activity by reactivating dormant proviruses within latent reservoirs, thereby facilitating their elimination by antiretroviral therapy (Azhari et al., 2021).

In vitro studies have shown that treatment with submicromolar concentrations of C. tiglium-derived phorbol esters induces expression of HIV-1 LTR-driven genes in chronically infected T cells via PKC-NF-κB activation, suggesting therapeutic potential in latency-reversing strategies (Kedei et al., 2019).

Beyond HIV, C. tiglium extracts have demonstrated inhibitory activity against hepatitis B virus (HBV) and herpes simplex virus (HSV-1) in vitro, with IC?? values ranging from 25–40 μg/mL (Nguyen et al., 2017). Mechanisms involve suppression of viral DNA replication and interference with viral protein synthesis. These findings position detoxified C. tiglium fractions as potential antiviral agents pending comprehensive toxicity evaluation.

4.5 Anti-inflammatory and Analgesic Activities

Inflammation is one of the most well-characterized pharmacological targets of C. tiglium constituents. Although croton oil is classically used in mouse ear edema assays as an irritant to induce inflammation for drug testing, paradoxically, detoxified and fractionated extracts of C. tiglium have demonstrated anti-inflammatory effects in both in vitro and in vivo models (Patra et al., 2019).

In one study, ethanolic seed extracts (after Shodhana) inhibited carrageenan-induced paw edema in rats by 47% at 200 mg/kg, comparable to indomethacin (Tripathi et al., 2020). Mechanistically, these effects were associated with suppression of COX-2, TNF-α, and IL-6 expression. Additionally, diterpenoid fractions inhibited nitric oxide (NO) production in LPS-stimulated macrophages via NF-κB inhibition (Liu et al., 2020).

The dual role of phorbol esters in inflammation acting as irritants in crude form but anti-inflammatory in regulated concentrations reflects their ability to desensitize PKC-mediated inflammatory signaling after repeated exposure (Blumberg & Kedei, 2019). Such controlled modulation could have implications in treating chronic inflammatory or autoimmune conditions.

4.6 Antibacterial and Antifungal Properties

Extracts of C. tiglium have shown broad-spectrum antimicrobial activity, particularly against Gram-positive bacteria and pathogenic fungi. Ethanol and methanol extracts of detoxified seeds demonstrated significant inhibition against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Candida albicans, with MIC values ranging between 100–250 μg/mL (Nguyen et al., 2017).

The antimicrobial activity is largely attributed to crotonic acid, phorbol derivatives, and phenolic compounds, which disrupt microbial membranes and interfere with protein synthesis (Gad et al., 2022). Additionally, essential oils containing β-caryophyllene and limonene contribute to antifungal activity by compromising fungal cell wall integrity (Salatino & Salatino, 2020).

Topical applications of C. tiglium extracts have been used traditionally for treating dermatophytosis, scabies, and bacterial skin infections, consistent with its observed antimicrobial profile. However, standardization of concentration remains critical to prevent irritant reactions.

4.7 Metabolic and Cardiovascular Effects

Several fatty acids and diterpenoids from C. tiglium exhibit metabolic and cardiovascular effects. Oleic and linoleic acids, predominant in croton oil, modulate lipid metabolism and improve endothelial function by enhancing nitric oxide bioavailability (Tripathi et al., 2020).

Experimental studies have demonstrated that low doses of detoxified C. tiglium oil promote lipolysis in adipocytes via PKC activation, potentially contributing to anti-obesity effects (Azhari et al., 2021). However, higher doses may produce oxidative stress and lipid peroxidation, emphasizing the narrow therapeutic index.

Furthermore, isolated phorbol derivatives have demonstrated vasodilatory and antiplatelet properties through endothelium-dependent relaxation and inhibition of thromboxane synthesis (Ghosh et al., 2020). These findings suggest potential cardioprotective benefits of detoxified extracts under controlled use.

4.8 Neuroprotective and Antioxidant Activities

Emerging studies indicate that detoxified extracts of C. tiglium exhibit neuroprotective potential, attributed to their antioxidant, anti-inflammatory, and PKC-modulatory effects. In neuronal cell cultures, low-dose phorbol esters enhanced neurite outgrowth and synaptic plasticity by stimulating PKC-ε, which plays a role in memory and neuroprotection (Zhao et al., 2023).

Methanolic leaf extracts have shown significant free radical scavenging capacity with DPPH inhibition up to 70% at 200 μg/mL, correlating with their phenolic and flavonoid content (Salatino & Salatino, 2020). Additionally, detoxified oil fractions protected SH-SY5Y neuroblastoma cells from oxidative injury by reducing ROS accumulation and upregulating antioxidant enzymes such as SOD and catalase (Rathi et al., 2022).

Such findings suggest that, beyond traditional gastrointestinal uses, C. tiglium holds promise as a source of neuroprotective agents, pending toxicological validation.

4.9 Immunomodulatory and Antioxidant Effects

Protein and diterpenoid fractions of C. tiglium have been shown to modulate immune responses through activation of PKC and MAPK pathways. Croton protein fractions stimulated macrophage phagocytosis and nitric oxide production at low doses, while higher concentrations induced cytotoxicity (Ghosh et al., 2020).

In vivo, detoxified seed extracts enhanced antibody titers and delayed-type hypersensitivity (DTH) reactions in murine models, indicating immunostimulatory potential (Patra et al., 2019). Additionally, the phenolic components contribute to antioxidant defense by scavenging reactive oxygen species and preventing lipid peroxidation (Zhao et al., 2023).

The overall pharmacological evidence underscores the importance of dosage and purification in determining whether C. tiglium acts as an immunomodulator or a toxin.

5. Toxicology and Safety Considerations

5.1 Overview of Toxic Constituents

The toxicity of Croton tiglium Linn. is primarily attributed to its phorbol ester-rich oil and protein toxins, which are concentrated in the seeds. These compounds exhibit potent irritant, genotoxic, and cytotoxic properties, posing significant risks when ingested or applied topically without proper detoxification (Li et al., 2018). The major toxic constituents include:

• Phorbol esters: Highly lipophilic tigliane diterpenoids such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and phorbol-12,13-didecanoate, known for PKC overactivation and tumor-promoting activity (Blumberg & Kedei, 2019).
• Crotin: A Type I ribosome-inactivating protein (RIP), structurally analogous to ricin, which inhibits protein synthesis by depurinating rRNA (Ghosh et al., 2020).
• Croton albumin: A hemagglutinating lectin that induces inflammation and hemolysis.
• Crotonic acid: A short-chain fatty acid responsible for local irritation and purgative effects.

Although these compounds contribute to the plant’s pharmacological actions at sub-toxic levels, their unprocessed forms are associated with severe toxicity, including dermal inflammation, gastrointestinal distress, and systemic organ damage (Patra et al., 2019).

5.2 Mechanisms of Toxicity

5.2.1 Phorbol Ester-Induced PKC Overactivation

Phorbol esters act as structural analogs of diacylglycerol (DAG), a natural activator of protein kinase C (PKC). When administered in unregulated doses, they induce sustained PKC activation, leading to aberrant signal transduction cascades, oxidative stress, and uncontrolled cell proliferation (Blumberg & Kedei, 2019).

Chronic PKC activation triggers expression of proto-oncogenes (c-fos, c-jun) and inflammatory mediators, contributing to tumor promotion in skin and gastrointestinal tissues. In murine models, topical application of 2 µg of croton oil twice weekly for 20 weeks induced papilloma formation in over 80% of animals previously initiated with carcinogens (Azhari et al., 2021). This tumor-promoting effect is dose- and duration-dependent, highlighting the need for detoxification before medicinal use.

5.2.2 Protein Toxins and Cytotoxicity

Crotin and crotonalbumin exert their toxicity via inhibition of protein synthesis and membrane disruption. In cell-free systems, crotin inhibits protein translation with an IC?? of 0.05 µg/mL, indicating high potency (Ghosh et al., 2020). In animal studies, subcutaneous administration of crotonalbumin (5 mg/kg) produced edema, leukocytosis, and hepatic necrosis, confirming its systemic toxicity.

These protein toxins are thermolabile; therefore, heat-based Shodhana (boiling or roasting) denatures them, resulting in reduced cytotoxicity and elimination of hemagglutinating activity (Jain et al., 2022).

5.2.3 Oxidative and Genotoxic Effects

Croton oil and phorbol esters induce reactive oxygen species (ROS) generation, leading to lipid peroxidation and DNA damage (Rathi et al., 2022). Comet assay and micronucleus studies have demonstrated increased genotoxicity in rodent liver and skin cells following high-dose exposure to crude croton oil.

However, detoxified preparations exhibit a significant reduction in genotoxic markers, suggesting that removal or degradation of phorbol esters and toxic proteins through Shodhana substantially mitigates oxidative stress and DNA damage potential.

5.3 Acute and Chronic Toxicity Data

5.3.1 Animal Toxicity Studies

Experimental studies reveal high acute toxicity for C. tiglium seed oil when administered orally. The LD?? in rats ranges from 0.2–0.5 mL/kg, while for purified phorbol esters, the LD?? is approximately 10 µg/kg (i.p.) (Li et al., 2018). Symptoms of toxicity include profuse diarrhea, abdominal pain, dehydration, and convulsions.

Topical application of undiluted croton oil causes erythema, blistering, and edema in both humans and animals within minutes. Repeated exposure can result in chronic dermatitis and carcinogenic changes (Azhari et al., 2021).

Detoxified oil, however, exhibits significantly higher safety margins. In rats, orally administered detoxified oil at doses up to 100 mg/kg for 14 days showed no mortality or organ histopathology, confirming effective toxin removal (Rathi et al., 2022).

5.3.2 Human Toxicity and Case Reports

Accidental ingestion of croton seeds or oil has been documented in several clinical case studies. Ingestion of a single seed may cause severe vomiting, purging, and circulatory collapse, while larger doses can be fatal (Patra et al., 2019). Topical misuse in folk medicine has led to cases of chemical burns and severe dermatitis, particularly when used undiluted.

Historical records from Ayurvedic texts emphasize that unpurified Jayapala Taila is “Vishadravya” (toxic substance) and should never be used internally without purification (Sharma et al., 2021). Modern toxicological assessments corroborate these traditional warnings, reinforcing the critical role of detoxification.

5.4 Impact of Shodhana (Detoxification) on Toxicity

Ayurvedic Shodhana methods, such as boiling seeds in cow’s milk or ginger juice, significantly reduce toxicity by degrading phorbol esters and denaturing toxic proteins (Jain et al., 2022). Analytical studies using HPTLC and LC–MS confirm a 70–90% reduction in phorbol ester content after Shodhana, along with the elimination of hemagglutination activity.

In vivo safety evaluation of detoxified C. tiglium extract revealed no signs of gastrointestinal irritation or systemic toxicity at doses up to 500 mg/kg in rats. Histopathological examination of liver and kidney tissues showed normal architecture, further validating detoxification efficacy (Rathi et al., 2022).

Additionally, Shodhana improves the physicochemical stability and skin compatibility of the oil, making it suitable for topical formulations. This detoxified oil retains beneficial fatty acids (oleic, linoleic) and minor diterpenoids that contribute to therapeutic effects without inducing irritation.

5.5 Carcinogenic and Mutagenic Potential

Croton oil has historically been used in carcinogenesis research as a tumor promoter when applied to mouse skin pre-treated with initiators like DMBA (7,12-dimethylbenz[a]anthracene). The tumorigenic activity is linked to chronic PKC overactivation and oxidative DNA damage (Blumberg & Kedei, 2019).

However, these effects are promotion-dependent, meaning croton oil alone does not initiate tumor formation but amplifies proliferation in pre-mutated cells. Importantly, detoxified preparations, lacking significant phorbol esters, show no tumorigenic effects even after long-term dermal application (Azhari et al., 2021).

In Ames mutagenicity assays, crude seed oil was mutagenic at concentrations above 50 µg/mL, while detoxified oil was non-mutagenic up to 500 µg/mL (Gad et al., 2022). These findings confirm that detoxification effectively neutralizes the plant’s carcinogenic potential.

5.6 Dermal and Ocular Toxicity

Topical exposure to croton oil causes immediate erythema and blistering, resulting from phorbol ester-induced inflammatory cascades and vasodilation. The reaction involves massive leukocyte infiltration and histamine release (Tripathi et al., 2020).

Ocular contact leads to conjunctivitis, lacrimation, and temporary vision impairment. Hence, crude croton oil is contraindicated for use near mucosal or ocular surfaces. In contrast, Shodhana-processed oil, when tested on rabbit skin, exhibited only mild transient irritation with no histopathological damage (Rathi et al., 2022).

These findings suggest that detoxified croton oil, when formulated at low concentrations (<1%), can be safe for controlled external use in topical or trichological applications.

5.7 Regulatory and Safety Perspectives

Due to its potent toxicity, C. tiglium is regulated under multiple pharmacopoeial frameworks:

• The Chinese Pharmacopoeia restricts internal dosage to 0.03–0.1 g of processed seed powder and prohibits unprocessed forms.
• The Ayurvedic Pharmacopoeia of India (API) lists Jayapala Taila as a “Shodhita dravya” (purified substance) suitable for external or internal use only after detoxification (Patra et al., 2019).
• Modern toxicological guidelines recommend standardized detoxification, chromatographic verification of phorbol ester removal, and patch testing for dermal applications.

The World Health Organization (WHO) emphasizes the need for toxicological standardization of traditional herbal medicines before clinical use, which is especially relevant for potent herbs like C. tiglium.

6. Mechanistic Insights for Hair-Growth Potential

6.1 Introduction

Hair loss (alopecia) is a common condition influenced by hormonal, genetic, and environmental factors. Many herbal plants have been studied for their ability to promote hair growth by improving blood circulation, reducing inflammation, and stimulating hair follicle cells.
Croton tiglium Linn., though best known for its strong purgative properties, has also been mentioned in traditional medicine for external use on the scalp to stimulate hair growth and treat scalp infections (Tripathi et al., 2020). Modern studies suggest that certain bioactive compounds from this plant, especially after detoxification, may help in hair follicle regeneration and dermal papilla stimulation.

Fig no 2: Mechanistic Insights for Hair-Growth Potential (Hair follicle structure and hair aging phenotypes. HF accommodates multiple tissues and cells, and their malfunction leads to hair aging.

Causes of hair aging are listed in the red box. Hair aging is largely manifested by hair graying, hair loss, hair thinning, and hair shaft structural change.)

6.2 Role of Protein Kinase C (PKC) in Hair Follicle Regulation

Protein kinase C (PKC) plays an important role in hair growth by regulating the hair follicle cycle from resting (telogen) to active growth (anagen) and regression (catagen). Moderate PKC activation stimulates cell division in hair follicle keratinocytes and dermal papilla cells (Zhao et al., 2023).

Phorbol esters from C. tiglium, such as phorbol-12,13-didecanoate, are known to activate PKC. While high doses are toxic, detoxified and diluted extracts may gently trigger PKC signaling, promoting hair follicle cell proliferation. This controlled activation may help shift follicles from the resting to growing phase, similar to the mechanism of herbal PKC modulators like Eclipta alba (Bhringraj) (Zhao et al., 2023).

6.3 Anti-Inflammatory and Microcirculatory Effects

Inflammation around hair follicles is a common cause of hair loss. C. tiglium contains linoleic acid, oleic acid, and minor diterpenoids that show anti-inflammatory properties when used in detoxified form.
Studies show these compounds can reduce cytokines like TNF-α and IL-6 and improve microcirculation around the follicle (Patra et al., 2019). Better blood flow means more oxygen and nutrients reach the roots, supporting healthy hair growth.

In traditional oils, C. tiglium was often blended with coconut or sesame oil to reduce irritation and improve absorption. The mild heating effect after topical application may further enhance scalp circulation, helping follicles receive essential nutrients.

6.4 Antioxidant and Regenerative Potential

Oxidative stress damages hair follicles and shortens the anagen (growth) phase. C. tiglium leaves and bark contain phenolic compounds like gallic acid and quercetin, which are strong antioxidants (Salatino & Salatino, 2020).
These antioxidants neutralize free radicals, protect dermal papilla cells from oxidative injury, and may help maintain the natural hair cycle balance. In laboratory studies, detoxified C. tiglium extracts reduced ROS (reactive oxygen species) levels in skin and neuronal cell models (Rathi et al., 2022). This antioxidant activity can support scalp health and follicular longevity.

6.5 Stimulation of Dermal Papilla and Growth Factors

The dermal papilla at the base of each follicle controls hair formation and growth. Phytochemicals that stimulate these cells often improve hair density and thickness.
Detoxified C. tiglium extracts contain minor diterpenoids and lipids that may increase VEGF (vascular endothelial growth factor) and IGF-1 (insulin-like growth factor) expression, both essential for new hair growth (Zhao et al., 2023).

By enhancing these growth factors and improving circulation, C. tiglium may encourage follicular regeneration similar to other natural stimulants like Rosmarinus officinalis (rosemary) or Nigella sativa (black seed oil).