A Systemic Review on Herbal Medicines and Advances in Standardization of Herbal Drug and Herbal Drug Technology

Herbal medicine is experiencing a renaissance driven by global demand for natural remedies, backed by scientific validation. Key review areas include efficacy/safety profiles, advanced delivery systems like nanotechnology, standardization challenges, and integration of traditional knowledge with modern tech. In India, systems like Ayurveda, Siddha, and Unani emphasize holistic balance via herbs, diet, yoga, and therapies such as Panchakarma.

INDIA'S TRADITIONAL MEDICINE SYSTEMS

India's AYUSH framework (Ayurveda, Yoga, Unani, Siddha, Homeopathy, Naturopathy) prioritizes constitution-based diagnosis and treatment.

• • Ayurveda: Balances doshas (vata, pitta, kapha) using herbs, diet, and detoxification.
  • Siddha: Focuses on five elements and 96 principles for Tamil-region practices.
  • Unani: Harmonizes four humors (blood, phlegm, yellow/black bile) rooted in Greco- Arabic traditions.
  • Yoga & Naturopathy: Promote self-healing through postures, breathwork, and natural elements.
  • Homeopathy: Applies "like cures like" with diluted remedies.

Diagnosis relies on pulse reading (nabz), urine/stool analysis, case history, and physical exams. Treatments feature herbal extracts, lifestyle tweaks, and targeted therapies.

DRUG STANDARDIZATION FUNDAMENTALS

Standardization ensures consistent quality, purity, potency, and safety in pharmaceuticals, especially herbs where variability arises from plant sourcing, growth, and processing.

Core Concepts

Drug Standardization: Defines parameters like bioavailability and contaminants via pharmacopoeias (e.g., USP, IP) and reference standards.

Importance: Prevents batch inconsistencies, builds trust, aids regulatory compliance (FDA, WHO, ICH), and supports R&D reproducibility.

Principles

For herbals, it addresses phytochemical variability, adulteration, and interactions, using macroscopic/microscopic exams, chromatography, and DNA fingerprinting (e.g., ISSR, SCAR markers).

• Herbal-Specific Standardization

Steps:

Authentication, profiling (TLC/HPTLC), biological assays, toxicity checks (pesticides, microbes, heavy metals).

Polyherbal Examples: Madhumehari Churna (antidiabetic), Dashamularishta (postpartum), standardized via markers and fingerprints.

WHO Guidelines: Cover botany, chemistry, biology, toxicity, and contaminants.

DNA techniques distinguish genuine plants from adulterants, even in processed forms, as genomes remain stable unlike varying phytochemicals.

• Advanced Delivery Systems

Phytosomes/ Pharmacosomes

Phospholipid complexes boost bioavailability of polyphenols/flavonoids (e.g., from milk thistle, ginseng). Forms include capsules, gels; benefits: higher absorption, reduced toxicity for liver, cancer, skin issues.

Herbal Nanomedicines

Nanoforms (liposomes, nanoparticles) enhance solubility/stability:

Examples: Silver nanoparticles from Ocimum sanctum for antibacterials; nanoemulsions for green tea extracts.

Bhasmas: Ayurvedic nano-metallics (e.g., Swarna bhasma ~56nm gold particles) as carriers, characterized by TEM/SEM/XRD. Table 1.2 lists marketed ones like those with iron, mercury (detoxified via ghee/milk).

EXTRACTION PROCESSES

Extraction isolates bioactives for formulations, crucial for standardization.

Steps

• Select/wash/grind plant part.
• Choose solvent (water, ethanol).
• Extract, filter, concentrate (evaporate), purify, store.

TRADITIONAL METHODS

• Maceration: Soak 3-7 days with agitation.  
• Digestion: Gentle heat maceration.
• Infusion/Decoction: Cold/hot water for leaves (short) vs. roots (boil 10-15 min).  
• Percolation/Soxhlet: Continuous solvent flow for exhaustive extraction.

MODERN METHODS

• Supercritical Fluid (SFE): CO? for oils, no residues.  
• Ultrasound/Microwave: Faster, greener.
• Others: Enzyme/Pulsed Electric Field for targeted yields.

Quality checks post-extraction: Pharmacopoeial tests, contaminant screening, bioactive quantification.

STANDARDIZATION TECHNIQUES

Table. No 1. Techniques of standardization

THIN-LAYER CHROMATOGRAPHY (TLC)

Thin-layer chromatography (TLC) is a versatile, widely used method for herbal medicine analysis, featured in global pharmacopeias, serving as a simple initial screening tool with semi-qualitative evaluation alongside advanced techniques like HPLC. It involves solute distribution between a thin adsorbent stationary phase on glass plates and a liquid mobile phase, enabling separation via adsorption or partition, with identification by matching Rf values, spot sizes, and intensities for semi-quantitative estimates. TLC offers high throughput (over 30 samples per plate), minimal cleanup, versatile detection, and advanced imaging for qualitative/quantitative insights, such as cordycepin levels in Cordyceps sinensis, making it ideal for rapid herbal extract analysis.

Fig.No.1 Thin layer chromatography

GAS CHROMATOGRAPHY (GC)

Gas chromatography (GC), or gas-liquid chromatography, separates volatile mixtures by redistributing components between a stationary phase (liquid, solid, or both) and a gaseous mobile phase, making it essential for analyzing volatile pharmacologically active compounds in herbal medicines. It provides a characteristic "fingerprint" of volatile oils for plant identification, detects impurities, and supports authentication/quality control with high- selectivity capillary columns enabling rapid, simultaneous separations—though tedious sample prep like derivatization may be needed. Early innovations like the automated GC-IR system by Scott et al. integrated IR and mass spectra for detailed solute analysis, complementing liquid chromatography for comprehensive herbal evaluations.

Fig.No.2.Gas Chromatography

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC)

High-performance liquid chromatography (HPLC), also called high-pressure liquid chromatography, uses small-particle (3-50 μm) stationary phases in columns with pressurized liquid mobile phases, employing ion exchange, partition, or adsorption modes. It's a popular, user-friendly method for herbal medicine analysis, applicable to nearly all compounds regardless of volatility or stability, with reversed-phase (RP) columns being the most common. Optimal separations require careful design of factors like mobile phase composition, pH, and pump pressure, driving recent innovations in liquid chromatography techniques for enhanced results.

Fig.No.3. High-performance liquid chromatography

CHROMATOGRAPHIC FINGERPRINTING

Chromatographic fingerprinting is the most effective quality control method for herbal medicines, creating a pattern from extracts of key chemical components (pharmacologically active or characteristic) that captures integrity, fuzziness, sameness, and differences to represent the medicine chemically. This enables accurate authentication and identification of samples, even with varying numbers or concentrations of constituents. It employs techniques like TLC, HPTLC, HPLC, GC, and hyphenated methods.

Fig.No.4 Chromatographic fingerprinting

OBJECTIVES

Objectives in Herbal Medicine

1. Preserve and scientifically validate traditional uses of medicinal plants across cultures.
2. Establish efficacy and safety profiles through rigorous research.
3. Promote sustainable cultivation and conservation to prevent overharvesting.
4. Integrate herbal remedies into modern healthcare with evidence-based protocols.
5. Educate practitioners and public on proper use, benefits, and risks.

Advances in Standardization and Technology

1. Develop standardized extracts ensuring consistent quality, potency, and purity.
2. Implement advanced QC techniques like HPLC, GC-MS, FTIR for authentication.
3. Achieve batch-to-batch consistency via improved GMP practices.
4. Eliminate adulteration and contamination through detection methods.
5. Enhance bioavailability and stability using nanoparticles and phytosomes.
6. Comply with global regulations (WHO, AYUSH, FDA).
7. Facilitate international market access via quality standards.

RESULT AND DISCUSSION

Herbal medicine standardization research encompasses around 100 peer-reviewed studies, including reviews, RCTs, observational trials, methodological surveys, contaminant analyses, and formulation standardization, predominantly from Asia (India, China), the Middle East, and Africa, with fewer from Europe and the Americas outside traditional systems like Ayurveda, TCM, and Unani.

Standardization parameters span botanical authentication via morphological/microscopic exams and DNA barcoding, chemical profiling with HPLC/GC- MS/LC-MS for markers, physicochemical tests (moisture, ash, extractives), and purity checks for heavy metals, pesticides, microbes, and adulterants, aiming for consistent extracts with defined active percentages. Advances feature hyphenated techniques (LC-MS/MS, UPLC, HPTLC), spectroscopy (NMR/IR/UV-Vis) with chemometrics, DNA sequencing, nanotechnology (nanoemulsions with particle standardization), and novel tools like electronic noses plus ML for quality/origin detection.

Clinical RCTs highlight efficacy in areas like COVID-19 recovery and metabolic disorders, though many suffer from bias and poor reporting (low AMSTAR-2 scores); contamination remains prevalent (bacteria, metals). Key progress includes market growth to over $500B by 2025, GMP reductions in variability, turmeric’s anti-inflammatory validation, and curcumin nanoformulations boosting bioavailability 10-fold, yet challenges persist in environmental/genetic variability, regulatory disharmony, and safety gaps, pointing to needs for rigorous RCTs, omics, WHO-harmonized standards, and fingerprinting over single markers.

STANDARDIZATION METHODS FOR HERBAL DRUGS

Standardization of herbal drugs employs a multi-tiered approach to ensure identity, purity, potency, and safety amid natural variability. Core conventional methods include macroscopic and microscopic evaluation for botanical authentication (shape, texture, cellular features like stomata via light/SEM microscopy), physicochemical tests (moisture content, ash values, extractive values, pH, solubility), and organoleptic assessment (odor, taste, color).

Chemical profiling dominates advanced techniques: chromatography such as TLC/HPTLC for fingerprints and semi-quantitation, HPLC/GC-MS/LC-MS for marker compound quantification (e.g., alkaloids, flavonoids via qualitative screens like Mayer’s or quantitative UV-Vis), and hyphenated methods (UPLC-MS/MS) for multi-component analysis. Spectroscopic tools like NMR, FTIR, IR, UV-Vis with chemometrics enable non- destructive profiling and structural elucidation.

Safety and purity checks cover microbial contamination, heavy metals (ICP-MS), pesticides, aflatoxins, alongside DNA-based methods (barcoding, ISSR/SCAR markers, PCR sequencing) for species verification against adulterants, even in processed forms. Biological assays assess activity, stability, and toxicity, supported by GMP, WHO guidelines, and fingerprinting for batch consistency in polyherbals

Chromatographic Techniques Overview

Chromatography separates mixtures by differential partitioning between a stationary phase and mobile phase. Key types for herbal drug analysis include planar, column-based, gas, and liquid variants, selected based on compound volatility, polarity, size, and complexity.

Planar Chromatography

Paper Chromatography: Uses absorbent paper as stationary phase; mobile phase (solvent) rises via capillary action. Ideal for simple mixtures like plant pigments, amino acids, or inks; low-cost, qualitative screening.

Thin-Layer Chromatography (TLC/HPTLC): Silica/alumina-coated plates; faster/higher resolution than paper. Best for rapid herbal fingerprinting, purity checks, and semi- quantitative marker detection (e.g., flavonoids via color changes).

Column Chromatography

Classical Column: Gravity-fed stationary phase (silica/gel) in a tube. Suited for preparative purification of larger quantities, like isolating herbals pre-HPLC.

High-Performance Liquid Chromatography (HPLC/UPLC): Pressurized liquid mobile phase through small-particle columns (reversed-phase common). Versatile for non-volatiles like polyphenols, alkaloids in herbals; quantitative analysis with UV/MS detection; UPLC for higher speed/resolution.

Gas Chromatography (GC/GC-MS)

Inert gas (helium) mobile phase; liquid/solid stationary in capillary columns. Optimal for volatile/semivolatile herbals (essential oils, terpenoids); pair with MS for identification. Not for thermolabile compounds.

Specialized Types

Ion-Exchange: Charged resins separate by charge (anion/cation). For ionic herbals or proteins.

Size-Exclusion: Pores separate by molecular size. For polymers or cleanup.

Affinity: Ligand-specific binding. For targeted purification (e.g., enzyme inhibitors).

Choose based on sample: TLC for quick screens, HPLC for precision quantitation, GC for volatiles in herbal standardization

HPLC Advantages and Limitations

High-Performance Liquid Chromatography (HPLC) excels in versatility for non-volatile, polar, and thermally labile compounds like polyphenols, alkaloids, and proteins in herbals. Advantages include high resolution via pressurized small-particle columns, quantitative precision with UV/MS detectors, easy sample recovery, and broad applicability without vaporization. Limitations: Slower analysis (10-60 min), higher costs from solvents/pumps, complex operation, and lower efficiency for volatiles compared to GC.

GC Advantages and Limitations

Gas Chromatography (GC/GC-MS) shines for volatile/semivolatile herbals (essential oils, terpenoids) with inert gas mobile phase. Strengths: Superior speed (minutes), high sensitivity (pg levels), sharp peaks, cost-effective operation via cheap gases, and excellent separation efficiency. Drawbacks: Restricted to heat-stable/volatiles (requires derivatization otherwise), challenging sample recovery, strict temperature/gas purity needs, and unsuitable for large biomolecules.

TLC Advantages and Limitations

Thin-Layer Chromatography (TLC/HPTLC) offers rapid, low-cost planar screening on silica plates for herbal fingerprints. Pros: Simple setup, multiple samples per plate (>30), qualitative/semi-quantitative via Rf spots/color, minimal cleanup, and versatile detection (UV, stains). Cons: Lower resolution/quantitation than HPLC/GC, labor-intensive (manual), poor reproducibility without HPTLC automation, and limited sensitivity for trace analysis.

Table.No.2 Advantages & limitations of techniques