The small-scale trial found that supplementation with the GS extract OSA for 60 days resulted in increased levels of insulin and C-peptide, together with lower levels of blood glucose.
According to Winconsin-based ingredient supplier Ayurvedic-Life International, which sponsored the study, the latest findings support the potential of its patented ingredient for addressing type 2 diabetes.
Gymnema sylvestre, grown primarily in the Indian sub-continent, has been used India for centuries as a traditional folk remedy to help maintain optimal health.
Ayurvedic-Life said its study also confirms previous findings that its isolate stimulates insulin secretion similar to sulphonylureas and meglitinide analogues that are currently used for the treatment of type 2 diabetes.
Published in Phytotherapy Research, the study involved seven female and four male participants from West Bengal, India. Their average age was 50, and their average weight was 59kg. They were all recently diagnosed with type 2 diabetes, or had previously received standard drug treatments for the condition.
All participants received 500mg of OSA twice daily, taken before food, for a duration of 60 days. There was no control group.
Blood samples were taken at the start and end of the trial, and blood glucose, insulin and C-peptide levels were measured.
Blood glucose reductions
The researchers from King's College London and Burdwan Medical College, J. B. Ayurveda College and Calcutta University, West Bengal, found that supplementation with OSA resulted in “significant improvements” in glycemic control in ten of the 11 participants.
Their findings recorded an average reduction in fasting blood glucose from 162 ± 23 to 119 ± 17 mg/dL. After eating, blood glucose levels were found to have reduced from 291 ±10 to 236 ±30 mg/dL. The researchers said it was “unclear” why one participant showed no reduction in glucose levels after OSA treatment.
A parallel in vitro test examined the effects of OSA on the pattern and rate of insulin secretion using human islets. Supplementation of the cells with 0.125mg/ml OSA resulted in a two-fold increase in insulin secretion. The secretion was sustained for the duration of exposure to OSA and rapidly reversible upon its withdrawal, said the researchers.
“This is the first report showing that OSA (…) is effective in reducing blood glucose and increasing plasma insulin and C-peptide levels in humans,” wrote the researchers.
“Our parallel in vitro studies suggest that at least some of these effects of OSA can be attributed to a direct stimulatory effect on insulin secretion from β-cells in the islets of Langerhans. OSA may therefore provide a potential alternative therapy for the hyperglycemia associated with T2DM (type 2 diabetes mellitus),” they concluded.
Source: A Novel Gymnema sylvestre Extract Stimulates Insulin Secretion from Human Islets In Vivo and In Vitro
Authors: A. Al-Romaiyan, B. Liu, H. Asare-Anane, C.R. Maity, S. K. Chatterjee, N. Koley, T. Biswas, A.K. Chatterji, G-C. Huang, S. A. Amiel, S. J. Persaud, P.M. Jones