Gymnema sylvestre (Sinhala: මස්බැද්ද / Masbadda)(Malayalam:ചക്കരക്കൊല്ലി ,Tamil:சிறுகுறிஞ்சா) is an herb native to the tropical forests of southern and central India and Sri Lanka. Chewing the leaves suppresses the sensation of sweet. This effect is attributed to the eponymous gymnemic acids. G. sylvestre has been used in herbal medicine as a treatment for diabetes for nearly two millennia, and though there is insufficient scientific evidence to draw definitive conclusions about its efficacy two small clinical trials have shown gymnema to reduce glycosylated hemoglobin levels. Common names include gymnema, cowplant, Australian cowplant, gurmari, gurmarbooti, gurmar, periploca of the woods, meshasringa (मेषशृंग), Bedki cha pala (बेडकीचा पाला) and miracle fruit(also a common name for two unrelated plants).
The major bioactive constituents of G. sylvestre are a group of oleanane-type triterpenoid saponins known as gymnemic acids. The latter contain several acylated (tigloyl, methylbutyroyl etc.,) derivatives of deacylgymnemic acid (DAGA) which is the 3-O-glucuronide of gymnemagenin (3,16,21,22,23,28-hexahydroxy-olean-12-ene). The individual gymnemic acids (saponins) include gymnemic acids I-VII, gymnemosides A-F, and gymnemasaponins.
G. sylvestre leaves contain triterpene saponins belonging to oleanane and dammarene classes. Oleanane saponins are gymnemic acids and gymnemasaponins, while dammarene saponins are gymnemasides. Besides this, other plant constituents are flavones, anthraquinones, hentriacontane, pentatriacontane, α and β-chlorophylls, phytin, resins, d-quercitol, tartaric acid, formic acid, butyric acid, lupeol, β-amyrin-related glycosides and stigmasterol. The plant extract also tests positive for alkaloids. Leaves of this species yield acidic glycosides and anthroquinones and their derivatives.
Use as herbal medicine
The effects of the herb are not entirely known. Gymnema reduces the taste of sugar when it is placed in the mouth. From extract of the leaves were isolated glycosides known as gymnemic acids, which exhibit anti-sweet activity. This effect lasts up to about 2 hours. Some postulate that the herb may block sugar receptors on the tongue. This effect was observed in isolated rat neurons.
The active ingredients are thought to be the family of compounds related to gymnemic acid: purified gymnemic acids are widely used as experimental reagents in taste physiology and have also an anti-diabetic effect in animal models, reduce intestinal transport of maltose in rats when combined with acarbose, and reduce absorption of free oleic acid in rats.
Historically, the leaves were used for stomach ailments, constipation, water retention, and liver disease; however, these claims are not supported by scientific studies.
A water-soluble extract of G. sylvestre caused reversible increases in intracellular calcium and insulin secretion in mouse and human β-cells when used at a concentration (0.125 mg/ml) without compromising cell viability. This in vitro data suggests that extracts derived from G. sylvestre may be useful as therapeutic agents for the stimulation of insulin secretion in individuals with type 2 diabetes. The rise in insulin levels may be due to regeneration of the cells in the pancreas. G. sylvestre can also help prevent adrenal hormones from stimulating the liver to produce glucose in mice, thereby reducing blood sugar levels. Clinical trials with type 2 diabetics in India have used 400 mg per day of water-soluble acidic fraction of the Gymnema leaves administered for 18–20 months as a supplement to the conventional oral drugs. During GS4 supplementation, the patients showed a significant reduction in blood glucose, glycosylated haemoglobin and glycosylated plasma proteins, and conventional drug dosage could be decreased. Five of the 22 diabetic patients were able to discontinue their conventional drug and maintain their blood glucose homeostasis with GS4 alone. These data suggest that the beta cells may be regenerated/repaired in Type 2 diabetic patients on GS4 supplementation. This is supported by the appearance of raised insulin levels in the serum of patients after GS4 supplementation. Though for the moment G. sylvestre cannot be used in place of insulin to control blood sugar by people with either type 1 or type 2 diabetes, further evidence of its positive effect is accumulating[unreliable source?]
Despite the part used being the leaf, one common name of this species is miracle fruit, a name shared by two other species: Synsepalum dulcificum and Thaumatococcus daniellii. Both species are used to alter the perceived sweetness of foods.
In English the species is also known as gymnema, cowplant, and Australian cowplant.
This species also goes under many other names such as; Gurmari, Gurmarbooti, Gurmar, periploca of the woods and Meshasringa. The Hindi word Gur-mar (Madhunaashini in Sanskrit, Chakkarakolli in Malayalam,Podapatri in Telugu), literally means sugar destroyer. Meshasringa (Sanskrit) translates as “ram’s horn”, a name given to the plant from the shape of its fruits. Gymnema derives from the Greek words “gymnos” (γυμνὀς) and “nēma” (νῆμα) meaning “naked” and “thread” respectively; the species epitheton sylvestre means “of the forest” in Latin.
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