The constituents that effectively work on diabetes in gymnema are the gymnemic acids and conduritol. Gymnemic acids are triterpenoid saponins; more than 10 gymnemic acids have been isolated. Gurmarin, a polypeptide of 35 amino acids, is the other active constituent.

Of the currently available therapies for NIDDM, only the sulfonylureas are used to stimulate β -cells to secrete more insulin. They act at a proximal stage in the β -cell stimulus-secretion coupling cascade – they close the plasma membrane ATP-sensitive K + channels and the subsequent decrease in K + efflux depolarises the cells, leading to Ca 2+ channels. Increases in intracellular Ca 2+ are sufficient to stimulate insulin release from β -cell secretory granules. Agents that act at downstream sites, perhaps diresctly on the exocytotic release of insulin, would be more useful adjuncts to sulfonylureas in the treatment of NIDDM. The stimulatory effect of Gymnema differed from other insulin secretagogues in that it was able to stimulate insulin release at temperatures as low as 4 0C in a variety of β -cell lines whereas physiological insulin secretion occurs at temperaaures above 30 0 C. Gymnema may act by increasing the cell permeaability rather than by stimulating exocytosis by regulated pathways, according to a paper appearing in Journal of Endocrinology.

Gurmarin, a peptide consisting of 35 amino acids present gymnema, effectively suppresses integrated nerve response to sweet-tasting substances (sugar, sodium saccharin and sweet-tasting amino acids) without affecting responses to salty, sour or bitter substances. The inhibitory effect of gurmarin was highly specific and lasted more than a few hours.

Gymnema is safe without any side effects. A 52 week study on rats showed that the no-observable-effect level was 504 mg/kg/day for male and 563 mg/kg/day for female as mean daily intake, for 52 weeks.