Grewia hirsuta Vahl Chemical Constituents and Biological Activities

Introduction

The term medicinal plants comprises of various types of plants that are used in the Herbalism and most of these plants possess medicinal properties. According to the World Health Organization (WHO), “a medicinal plant is any plant which, in one or more of its organs, contains substances that can be used for therapeutic purposes, or which are precursors for chemo pharmaceutical semi synthesis”.¹ Over the centuries, several ancient cultures and civilizations use plants as a medicinal agent and are used to treat the various ailments and health-related problems, ‘medicinal plants are the backbone of the traditional medicine’. These plants are rich resources of ingredients which play an important role in the drug discovery and development of human cultures across the world. Medicinal plants are a significant source of synthetic and herbal drugs. In less developed countries more than 3.3 billion people are consuming medicinal plants on a regular basis.² Indeed a majority of the world still relies heavily on natural products as herbal remedies for their primary health care. The man was dependent on the traditional herbal medicines for the prevention and treatment of diseases, before the synthetic drug availability. The use of herbal medicines for curing diseases and prevention has been documented in the history of all civilizations. The severe side effects are found to be in the use of allopathic drugs and are not cost effective, whereas herbal medicines are considered to be an excellent remedy due to their good efficacy, fewer side effects and relatively low costs of the diseases like hypertension, diabetes, brain disorders, liver disease.³ Grewia hirsuta is a shrub or small tree, with branchlets are coarsely gray brown hairy. It belongs to family Malvaceae (previously placed under Tiliaceae) is considered as Nagbala, Gudasharkara and Gangeruki by Ayurvedic Scholars. It’s also known as kukuebicha, Govli. The different parts of species of genus Grewia are used as folk medicine in the different part of globes.⁴

HABITAT

Grewia hirsute Vahl .is commonly found in countries like tropical Africa, Arabia, Madagascar, Himalaya, India, Srilanka, Vietnam, Pakistan, China, Bangladesh, Myanmar, Thailand, Malaysia, the pacific islands, and Northern Australia of the world. It is occurring throughout the greater parts of India, ascending to 4,500 feet in the Himalaya, generally found in mixed deciduous open and dry evergreen forests.⁵

Morphological description

Grewia hirsuta is a shrub of 5 feet in hEighT, branches slender with coarsely gray, brown colored hairy branches. Stalks of the leaves 2-3 mm long, tomentose. The leaves are of lance shaped with 6-14 cm length and 2-3.5 cm width, with base rounded. The lateral basal veins of the leaves are upto half as long as the leaf blade, and the lateral veins occur in 4 to 5 pairs base narrow, shallowly heart-shaped, margin teeth blunt, tip long pointed or rarely blunt..

These leaves are of black-brown color when dried and velvety. The flowers are white in color and are borne in cymes (3-4 flowers per cyme). Stalk of these flowers are 3-5 mm in length. Bracts are also 3-5 mm in length with lance shaped. Petals are narrowly ovate. The flowering period of this shrub is June to July. White colored flowers of this plant gradually turn into yellow color and then turn into brown color when fully grown. The buds of these flowers are globose. The fruits are small in size 7.5-10 mm diameter with hairy, more or less 2-4 lobed, 4 seeded, shining reddish purple , with scattered hair and a ring of hair at the top of the androgynophore. The fibrous roots are cylindrical in shape, with brown colored external surface.

Microscopic characters

The components present in the powder was stellate hairs with warty arms, mucilage cells of epidermis, palisade and spongy, fibres with phloem and cells containing prismatic crystals, mucilage cavities, vascular bundles, anisocytic stomata and multicellular glands.^7-8

Use in folk and tribal medicine

It is useful as nervine and brain tonic, demulcent, anti-acidic, expectorant, antipyretic, diuretic, carminative, aphrodisiac, cardiac tonic, abortifaciant, galactagogue, purgative, and anthelmintic. It is used in the treatment of nose, eye diseases, cholera, hydrophobia, kidney pain, piles, splenic enlargement, rheumatism pain in joints and breasts.^9-10 Drupe is given in diarrhoea and dysentery. A paste of dry root in water is applied to wounds to hasten suppuration and as a dressing. Acid fruit is much used for making sherbets. The plant extract is used as anti-fertility, ¹¹ anti-ulcer and aphrodisiac agent.¹²

Ayurvedic Description

Nagbala is an excellent Rasayana mentioned in Ayurveda useful in treatment of various diseases like tuberculosis, respiratory disorders. The powder of Nagbala root and Arjuna (bark of tree Terminalia arjuna) is mixed and used with milk for the management of heart disease. The recipe is given to a patient about a month. It eradicates heat, cough and dyspnoea. Powder with milk or ghee and honey or garlic is useful in weight gain. Dosage: Decoction: 50-100 ml; Root-bark powder: 3-6 gm

Rasa: Madhura, Kasaya

Guna: Guru, snigdha, pichil

Veerya: Sheeta

Vipak: Madhura

Actions and uses: Vata Pitta samak, raktstamvan, badanasamak, dahasamak, amltanask, anuloman, kaphanisark, mutral, rasayan

Phytochemistry

Phytochemical constituents such as aldehyde, alcoholic compound, α-curcumene, sesquiterpene, sesquiterpene alcohol, undecanoic acid, tetradecanoic acid, myristic acid, sesquiterpene oxide, n-hexadecanoic acid, palmitic acid, linoleic acid, oleic acid, gingerol and alkane are present.¹⁷ it contains ephedrine in large quantities. The flavonol present is 4’ methoxy kaempferol. The phenolic present is vanillic, syringic, cis and trans ferulic, cis and trans p- coumaric and gentisic acids. The mucilage has mannose and xylose as component sugars. In the stem ephedrine is the only alkaloid detected.

Flavonoids are present in traces. The plenty of phenolics present are vanillic, syringic, melilotic, p-hydroxy benzoic and protocatechuic acids. The mucilage has mannose; xylose and glucose.¹⁷ BiruduandPadmavathi5 havereported that the phytochemical investigation of ethanolic leaf extract shows saponins, tannins, cardiac glycosides, alkaloids, anthraquinones, steroids, carbohydrates, reducing sugars, amino acids, phenolic compounds and flavonoids. Phytochemically the genus Grewia has been found to possess mainly triterpenoids, fatty component, flavonoids, steroids, saponins and tannin. Abirami and Natarajan18isolated the compound(4Z, 12Z)-cyclopentadeca-4, 12-dienone from the Grewia hirsuta.¹⁸

Pharmacological Activities

Antiproliferative and Antioxidant Activity

AshanaEma and colleagues have evaluated the free radical scavenging potential of methanolic extract of leaves of Grewia hirsute by various in vitro assays such as DPPH, Phosphomolybdenum, metal chelating and hydroxyl radical scavenging assay. At a concentration of 200 µg the scavenging activity of methanol extract reached 95%. The extract is more powerful in scavenging free radicals, reducing phoshomolybdenum ions and in chelating metal ions. On the other hand methanol extract had a cytotoxic effect on HepG2 cell lines by MTT assay with IC50 values 15.6 µg/mL. Thus, the study revealed that Grewia hirsuta could be considered as a significant source of antioxidant and antiproliferative agents.¹⁹

Antidiabetic Activity

In 2014, Abirami and Natarajan worked on isolation and characterization of (4Z, 12Z)- cyclopentadeca-4, 12-dienone from the plant Grewia hirsute for the investigation of the potentials of hypoglycemic effect. The leaves were extracted, chemical components were separated by various chromatographic techniques (TLC and Column chromatography) and the fractions were tested for the hypoglycemic effect by in vitroα-amylase inhibitory assay. The fractions showed a significant α-amylase inhibitory action and are confirmed by various spectroscopic methods (UV, FTIR, 1H, and 13C NMR). In addition, the antidiabetic activity of the purified compound was evaluated on 3T3 and L6 cell line by MTT assay. The studies revealed that the percentage of cell viability was found to decrease as the concentration of this compound increases.¹⁸

Analgesic, Anti-Inflammatory, Anti-diarrhea and Anti-microbial Activities

Various examinations have been done to indicate analgesic, anti-inflammatory, anti-diarrheal and anti-microbial activity of crude ethanolic concentrate of Grewia hirsute in the rodents. The pain relieving action of leaf extract was assessed by acetic acid, hot plate and formalin induced writhing method. Hot plate method, swiss albino mice (sex-male) treated at different dosages of the concentrate of the extract (250 and 500 mg/kg bw), Ketorolac as a standard drug (10 mg/kg b.w) revealed higher percentage latency elongation. In acetic acid-induced analgesia, percentage of writhing inhibition for 250 and 500 mg/kg bw doses of plant extract and standard drug (Diclofenac sodium, 10 mg/kg bw) were 55%, 70% and 84% respectively. In formalin induced pain, extract of two doses and standard drug showed 66.01%, 76.3% and 82.608% writhing inhibition individually.

Anti-inflammatory action, at doses of 500 mg/ kg bw is noticeable inhibition (59.79%), than 250 mg/kg bw (48.18%) in xylin-induced ear edema. Whereas, in carrageenan method, extract disclosed significant inhibition activity as 40.67%, 53.11% and 62.03% for 250 and 500 mg/kg bw dose and standard drug respectively.

The crude ethanolic extract has anti-diarrheal impact of castor oil-induced diarrhea in rats, the percentage inhibition of defection for 250 and 500 mg/kg. bw dose was 41.67% and 59.72%, respectively. Whereas in gut motility test, 500 mg/ kg bw. dose showed remarkable (30.45%) depletion of BaSO4 transit

The crude ethanolic extract has anti-diarrheal impact of castor oil-induced diarrhea in rats, the percentage inhibition of defection for 250 and 500 mg/kg. bw dose was 41.67% and 59.72%, respectively. Whereas in gut motility test, 500 mg/ kg bw. dose showed remarkable (30.45%) depletion of BaSO4 transit In an examination the antimicrobial efficacy in various concentrations (25, 50 and 100 μg/ μl) of Grewia hirsute in comparison to four pathogenic bacterial strains and two fungal strains. Staphylococcus aureus and Streptococcus pyogenes as gram-positive bacteria; Escherichia coli and Pseudomonas aeruginosa as gramnegative bacteria; A. niger and A. clavatus as fungal strain were used in the assessment. The antibacterial and antifungal activities of the extract showed response depending on variation of doses while the standard (both amoxicillin and Griseofulvin) showed higher inhibition.²⁰

DISCUSSION

Grewia hirsute is one of the precious medicinal plants in Ayurveda. The plant has 35 genuses and species of 380. It is occurring throughout the greater parts of India, ascending to 4,500 feet. The plant has high medicinal values and is used for indigenous treatment of numerous diseases including nose, eye diseases, cholera, hydrophobia, kidney pain, piles, splenic enlargement, rheumatism pain in joints and breasts.The plant is rich in α-curcumene, sesquiterpene, undecanoic acid, tetradecanoic acid, myristic acid, sesquiterpene oxide, n-hexadecanoic acid, palmitic acid, linoleic acid, oleic acid, gingerol and alkane. Ephedrine was the only alkaloid detected in the stem and in large quantities, 4’methoxy kaempferol was the flavonol and phenolic acids was vanillic, syringic, cis and trans ferulic, cis and trans p- coumaric and gentisic acids, mucilage like mannose, xylose and glucose. Biruduand Padmavathihavereported the phytochemical investigation of ethanolic leaf extract shows saponins, tannins, cardiac glycosides, alkaloids, anthraquinones, steroids, carbohydrates, reducing sugars, amino acids, phenolic compounds and flavonoids. Abirami and Natarajanisolated the compound(4Z, 12Z)- cyclopentadeca-4, 12-dienone from the Grewia hirsuta.Many other Grewia species also have similar importance as well. G. asiatica, G. damine, G.lasiodiscus, G. optiva, G. biloba, G. bicolor, G. tiliaefolia, G. flavescensand many more species are well known medicinally and economically. These species are the part of trade of medicinal and aromatic plants. Various biological activities exhibited by the plant are antidiabetic, antiproliferative, antioxidant, analgesic, antiinflammatory and antimicrobial.

 CONCLUSION

Presence of secondary metabolites in the plant could serve as “lead” for development of novel agents for disorders in the coming years. This regard, further studies need to be carried out to explore for its potential in preventing and treating diseases. So, the present review gives a direction for future investigators to carry out research on the plant so that they could get some medically important drugs. This review furnishes the presence of several phytochemical components in Grewiahirsuta and its biological activities.

CONFLICT OF INTEREST

The authors declare there is no conflict of interest.