A Comprehensive Review on the Botanical, Nutritional, Phytochemical and Pharmacological Aspects of Murraya koenigii

Presently, huge numbers of people in developing countries depend on medicinal plants for healthcare, skin care, economic benefits, and cultural development. For centuries, medicinal plants have been widely used in traditional medicine in countries like India, China, Germany, Thailand, etc.¹.

The World Health Organization (WHO) projected that 80 % of the population relies on traditional Medicine, which is clearly elucidated by the 19.4 billion USD global revenue for herbal remedies in 2010². Moreover, the demand for traditional medicinal plants is increasing; for instance, the market For medicinal plants is expanding at an annual rate of 20% in India. Likewise, in China, 30% to 50% of the total medicinal consumption is from preparations of traditional medicine³. Nearly 76.7% of the citizens of Thailand have reported mainly using traditional herbal medicine for their Primary healthcare⁴. Around 90% of the German population uses natural remedies for certain health Issues⁵. Therefore, the medicinal plants used in traditional medical treatments are significant in both developing and industrialized countries. This is clearly demonstrated by the worldwide market for traditional medicine. This market continues to gradually increase⁶.

Taxonomical Classification of Murraya koenigii (Curry leaves)

Table no. 1 describes taxonomical classification of Murraya koenigii plant, which includes its Kingdom, Subkingdom, Class, Family, Genus, Species and all other information.

Table 1 Taxonomical Classification of M. koenigii

Distribution of Murraya koeniigii plant all over India

Native to South Asia, curry plants can be found in many of these countries such as India, Sri Lanka, Myanmar, Indonesia, Hainan, And certain wet forests in China, Vietnam, Nepal, Laos, Bhutan, Pakistan, and Thailand. Although it is found all over India, it is Particularly easy to find in the Andaman Islands, Sikkim, Bengal, Assam, Western Ghats, and Garhwal.⁷ It propagates via seeds that spontaneously sprout in partially shaded environments. It is also found in various Asian regions, such As the humid forests of Guangdong, South Hainan, South Yunnan (Xishuangbanna), Bhutan, Laos, Nepal, Pakistan, Sri Lanka, Thailand, and Vietnam, which range in elevation from 500 to 1600 meters. Curry leaves travelled to Malaysia, South Africa, and the island of Réunion with immigrants from South India. Seldom do they exist outside of India’s area of influence.⁸

Various Names of Murraya koeniigii ⁹

Table 2 Names of Murraya koeniigii in various languages

Table 2 shows variety of synonyms or names that are available for Murraya koeniigii plant, means curry plant has number of names in various languages.

Phytochemical Constituents of Murraya koeniigii:- The constituents that have sparked the greatest attention are carotenoids, essential oils, and a variety of carbazole alkaloids. The Components of Murraya koeniigii are summed up in the following major group of bioactive compounds. This article provides a better Understanding of curry leave’s therapeutic and non-therapeutic characteristics by compiling a variety of ideas from the many studies that have been conducted on the subject.^10-11

Growing season of Murraya koeniigii:- Curry leaf plants produce bright green leaves and blossoms throughout the spring, summer, and fall. During the winter, when it is Resting, the leaves fall. They require fertilizer in the summer months and prefer full light and well-drained soil that is on the dry side. It was noted that the fruiting season lasted from the end of June to the end of August, with July being the peak fruiting season. In India, leaf harvesting began fifteen months after the plants were planted, and leaf gathering was repeated every two to three months.^12-13

Traditional uses of Murraya koeniigii ^14-16

To flavour soups, curries, and other food preparations, fresh leaves, dried leaf powder, and essential oils are frequently utilized. Additionally, the aromatherapy and soap industries use essential oils.

To make a fantastic hair tonic that preserves natural hair tone and promotes hair development, curry leaves are cooked with coconut oil until they are reduced to blanked residue. It has been used traditionally as a whole or in portions for bodily aches, kidney Pain, vomiting, antiemetics, antidiarrheal, febrifuge, blood purifier, and antifungal.

It contains large amounts of calcium, iron, and vitamins A, B, C, and B2. Both young and old benefit from its nutritional value. Curry leaves are a perfect natural calcium supplement for women who suffer from osteoporosis, calcium shortage, and other related conditions.

When combined with sugar and lime juice, fresh curry leaf juice works well as a medication for treating morning sickness, Nausea, and vomiting brought on by indigestion and overindulgence in lipids. In these circumstances, one or two tablespoons of the Leaf juice combined with a teaspoon of lime juice may be consumed.

Morphological Characteristics of Murraya koenigiiL.

Murraya koenigii L. is a deciduous shrub with a maximum height of 6 meters. Its bark peels off lengthwise, exposing white wood beneath the bark up to 16 centimetres in height.

a. Leaves- The flavour and smell of leaves are distinctive, and they are green in colour. With 24 lanceolate, 1.9 cm long, 1.8 cm broad, and 0.5 Cm long petioles, each exstipulate, bipinnately compound, 30 cm long leaflet has reticulate venation.

b. Stem- The main stem has many spots on it and is dark green to brownish in colour. Its white wood beneath can be seen by peeling off the bark longitudinally.

c. Flowers- Spherical to oval, 1.4–1.6 cm length, 1–1.2 cm in diameter; 880 mg in weight, 895μL in volume.

d. Fruits- Fruits are fully ripe, black, and have a glossy appearance. The pulp is wistaria blue, and there are anywhere from 32 to 80 fruits in each cluster.

e. Seeds- One spinach-green fruit, measuring 11 mm in length and 8 mm in diameter.

Nutrients Values of Murraya koenigii

Table 3 Nutrients Values of Murraya koenigii

Table 3 describes nutrient essentials of Murraya koenigii plant, as curry leaves are rich source of proteins, fats, carbohydrates, calcium, iron and β- carotene.

Pharmacognosy Murraya koenigii

Major phytochemicals found in the plant give it therapeutic value for a variety of ailments and enable the production of valuable human medications. Pharmacognostic factors can be quantitatively determined to assist create standards for crude medications. The Overall amount of ash is a crucial factor to consider when assessing the purity of medications. The plant’s pharmacognostic Invariants, diagnostic microscopic traits, and numerical standards are described; these are especially helpful in creating an Appropriate monograph for the plant’s appropriate identification. In addition to determining the amount of nutrients and leaf content, Pharmacognostic assessment, microscopic, and morphological characteristics were examined. Additionally, qualitative chemical Analyses were conducted as part of the phytochemical screening process. The leaf featured asymmetrical base venation with a dentate Border. On both sides, the stomata were dispersed. There are several phytochemicals such as volatile oils, flavonoids, alkaloids, Sterols, carbs, tannins, and anthraquinone glycosides. The colour, flavour, smell, and exterior features of Murraya koenigii’s bark were all noted as organoleptic qualities.

Phytochemistry Murraya Koenigii

The nutritional value of the matured curry leaves is 13.06% total ash, 1.15% nitrogen, 14.6% carbohydrates, and 63.2% moisture. Curry leaves contain oxalic acid, resin, and carbazole alkaloids as well as major bioactive substances like koenigine, Cyclomahanimbine, murrayastine, coumarin, bicyclomahanimbicine, koenidine, and pypaya foline-carbazole. These bioactive Compounds have been shown to have significant pharmacological activities, and the majority of the volatile oil is made up of bicycle-Mahanimbicine and mahanimbicine.

Pharmacological Activity of Murraya Koenigii ^18-30

Antifungal activity

The antifungal activity of Murraya koenigii has been reported in various studies. For example, the essential Oil of the leaves was reported to possess antifungal activity¹⁸. The antifungal activity of the leaves of Murraya koenigii is due to the presence of phytochemical constituents of complex molecular structures and diverse action mechanisms, viz. alkaloids, terpenoids, flavonoids, phenolics, tannins, and saponins, which are known for their antimicrobial properties. Different investigations support the traditional use of the plant as an antifungal agent. In vitro antifungal activity may explain the use of curry leaves for the treatment of diarrhea, dysentery, and skin eruptions in folklore medicines¹⁹. Bioactive Compounds of Murraya koenigii appreciably hold the ability of mycelial growth inhibition and thereby promote antifungal activity. The antifungal activity of Murraya koenigii against a wide range of pathogenic Fungi has been studied. Penicillium notatum, Aspergillus flavus, Aspergillus niger, Fusarium moniliforme, Mucor mucedo, Penicillium funiculosum etc., were isolated from infected saplings and spoiled foods Based on alterations of their growth characteristics, mycelial morphology, and spore morphology (Table 3)²⁰. The ethanolic extract of Murraya koenigii exhibited notable effects on the hyphal morphology; Namely, an increase in branching potential, which resulted in the development of short slender branches of hyphae with swollen tips. Such effects are usual for any antifungal compound. Bioactive compounds Like girinimbine, murrayanine, marmesin-1-O-beta D’galactopyranoside, mahanine, murrayacine, Mukoeic acid, murrayazolinine, girinimbilol, pyrafoline-D, and murrafoline-I are present in stem bark.Girinimbine, murrayanine, and marmesin-1-O-beta-D’galactopyranoside have notable anti-fungal activity.

Antibacterial Activity

The unsystematic use of antibiotics promotes the development of multiple drug-resistant Pathogenic strains of bacteria, which are very harmful, and there is a lack of proper treatment Procedures for these ailments. Therefore, the need to search for new antimicrobials remains. Currently, in addition to antibiotics and chemically-synthesized drugs, curiosity for alternative medicines, such as natural or herbal medicines, is increasing. They may have fewer side effects or toxicity owing to their natural sources. Combating microbial infections without side effects is always a tedious process. In this regard, in addition to classical antibiotics and synthetic drugs, there is an ongoing hunt for potent molecules from natural herbal medicines. Murraya koenigii extracts have demonstrated antibacterial effects on A wide variety of microorganisms. Methanol and ethanol extracts of Murraya koenigii leaves were found to be effective against the bacterial strains Escherichia coli, Staphylococcus, Streptococcus, and Proteus. Hence, its leaves could be efficiently used as a natural remedy in everyday meals for the prevention of several bacterial infections

Pyranocarbazoles isolated from Murraya koenigii exhibited antibacterial activity on bacterial strains of Staphylococcus aureus and Klebsiella pneumonia. Green synthesized silver nanoparticles (AGNPs) from Murraya koenigii exhibited therapeutic efficacy against Multidrug resistant MDR bacteria. Murraya koenigii essential oil showed antibiofilm activity against Pseudomonas aeruginosa and it was reported that Murraya koenigii essential oil treatment revealed an 80% reduction in biofilm formation by P. aeruginosa. Microscopic analyses confirmed the drop in biofilm formation in Pseudomonas aeruginosa when treated with Murraya koenigii essential oil. The presence of Antibiofilm substances like spathulenol (5.85%), cinnamaldehyde (0.37%), and linalool (0.04%) was reported in gas chromatography-mass spectrometry (GCMS) studies. Murraya koenigii counteraction on uropathogenic bacteria isolated from clinical samples was reported in a different study. Murraya koenigii was tested for its antibiotic action against Mycobacterium species, which was appreciable, like first-line Anti-tuberculosis drugs. Murraya koenigii half maximal inhibitory concentration ((IC₅₀) 400 µg/mL) was found to be more effective against Mycobacterium smegmatis compared to water extracts and petroleum Ether. An Murraya koenigii ethanol extract exhibited significant synergistic antibacterial activity against Mycobacterium smegmatis and Mycobacterium bovis bacillus calmette-guerin (BCG) in combination with the anti-tuberculosis drug rifampicin.

Hepatoprotective Effect

Liver diseases are a worldwide concern, and accessible medical treatments have an inadequate Efficacy. Since ancient times, herbs have been used when treating various disease conditions; plant Extracts and natural compounds have significant applications as hepatoprotective agents. The liver is the Site of drug metabolism and the detoxification site of toxic products, and so it is the organ most exposed to xenobiotics. Murraya koenigii extended hepatoprotective activity when crude aqueous extracts were Investigated against ethanol-induced hepatotoxicity in experimental animals. Murraya koenigii was reported to extend a protective effect in liver impairments in chronic alcoholism and was proved to be effective in maintaining the enzymatic oxidant status. Water extracts of carbazole alkaloids and tannin of Murraya koenigii were explored for their hepatoprotective activity against ethanol-induced hepatotoxicity in a HepG2 cell line model. They exhibited excellent hepatoprotective activity, maintaining the enzymatic and non-enzymatic antioxidant level at a near normal value and also maintaining the integrity of the Cells. An Murraya koenigii hydro-ethanolic leaf extract was reported to attenuate the CCl4 hepatotoxic Effects in rats. Murraya koenigii pretreated rats showed a significant decrement in activity levels of hepatic markers and also maintained the level of enzymatic antioxidants.

Immunomodulatory Activity

Immune system makes a network and regulates processes important for maintaining the health of an organism by hindering the entry and invasion of microbes. Impairments in the immune system lead to conditions from chronic inflammation to cancer^21-23.In an investigation on the humoraland cell-mediated immune response to ovalbumin, the immunomodulatory activity of a methanolic Extract of Murraya koenigii leaves was evaluated using a carbon clearance test. A considerable increase in the NO production indicated the increased phagocytic activity of macrophages. The Murraya koenigii extract Holds promise as an immunomodulatory agent, which acts by stimulating humoral immunity and the phagocytic function. The Murraya  koenigii leaf extracts were reported to have certain effects in regulating mice immunology related to oxidative stress metabolism. An Murraya koenigii leaf extract can exhibit an immunomodulatory effect through which it can regulate the oxidative stress metabolism in diabetic mice.

Nephroprotective Activity

Murraya koenigii has been used as a nephroprotective agent in a diabetic-induced rat model. The Murraya koenigii leaf extract was found to be efficient in maintaining normal levels of serum creatinine, Blood urea nitrogen, total serum protein, serum Na+, urine output, urinary creatinine, urinary urea, Total urinary protein, and urinary Na+. Furthermore, the extract maintained the standard pattern in in-vivo antioxidants, renal myeloperoxidase (MPO) activity, and histopathology of kidneys Against unilateral renal ischemia reperfusion injury. Therefore, the extract of was clearly demonstrated to be useful in treating kidney disorders in rats²⁴. The nephroprotective activity was elucidated in experimental investigations, which showed decreased levels of blood Urea nitrogen (BUN), serum creatinine (Cr), and lipid peroxidation (LPO). An extract is efficient against cyclophosphamide-induced nephrotoxicity, which was clearly revealed through the maintenance of high levels of glutathione (GSH) and superoxide dismutase (SOD) compared to the cyclophosphamide-treated group²⁵. M. koenigii protective activity has been shown to induce Significant dose-dependent decreases in serum urea and creatinine levels, as well as marked increases in the levels of plasma antioxidant capacity, in diabetic rats, compared to controls. More noteworthy is the histological integrity of kidneys, which showed comparable tissue regeneration induced by the aqueous extract.

Antidiabetic Activity

Most prominently in developing countries, medicinal plants play a helpful role in managing Diabetes mellitus due to their cost effectiveness. Diabetes mellitus, a metabolic disorder, is becoming A serious threat to human health. During the past few years, many phytochemicals responsible for Anti-diabetic effects have been isolated from plants. Alkaloids present in the leaves of Murraya koenigii have been explored and reported to have inhibitory effects on the aldose reductase enzyme, glucose Utilization, and other enzyme systems for extending anti-diabetic effects. It was tested for the α-glucosidase inhibitory property and was found to inhibit α glycosidase. Alpha-glucosidase Inhibitors are widely used in the treatment of patients with type 2 diabetes. A study reported that an ethanolic extract showed a significant reduction in blood glucose levels, and this effect of reducing blood glucose by Murraya koenigiiis mediated by antioxidant properties and insulin mimetic effects. In addition, it exhibited a profound antioxidant effect by reducing the malondialdehyde (MDA) level, increasing the GSH level, and significantly decreasing the homeostatic model assessment (HOMA)-insulin resistance index. On the whole, it is evident that possesses antidiabetic activity and has antioxidant effects in rats.

Anticancer Activity (In-Vivo and In-Vitro)

It possesses potential secondary metabolites that could be developed as anticancer agents. In one study, the cytotoxic activity was evaluated for three extracts: hexane, ethyl acetate, and methanol of Murraya koenigii leaves against the HeLa cell line. The extracts were reported as being potently cytotoxic in nature in HeLa cancer cells. These results established the potential anticancer agent in-vitro. Additional evidence for the anticancer activity has been obtained from rodent cancer cell lines, as well as different in-vivo cancer models. In an early study, histopathological evidence showed that extract treatment generated a decline in neoplasms in the colon. A methanolic extract was reported to have the ability to reduce proliferation in breast cancer cell lines. The total alkaloid extracted from Murraya koenigii leaves has been shown to have promising cytotoxic activity in breast cancer cells, with an IC50 of 14.4 µg/mL. The anticancer activity of mahanine and isomahanine in human oral squamous cell carcinoma CLS-354 has also been reported . Girinimbine, another Murraya koenigii-derived carbazole alkaloid, showed growth inhibitory activity in human hepatocellular carcinoma and lung cancer cells in-vitro. Rutin, quercetin, kaempferol, and apigenin, present in leaf extracts of Murraya koenigii, showed the dose-dependent inhibition of endogenous 26S proteasome activity in MDA-MB-231 cells²⁶. Therefore, it contains remarkable anticancer compounds, especially mahanine, which has been reported to show anticancer activity targeting different signaling pathways^27-30. Girinimbine, a carbazole alkaloid, has been found to have a good role in total leukocyte migration and result in an appreciable reduction in pro-inflammatory cytokine levels.

Phytochemical tests (Screening) of Curry leaves