Endocrine Abstracts

Aim: Ocimum basilicum extract is used traditionally for type 2 diabetes treatment in developing countries. Studies have reported antidiabetic properties of aqueous and methanolic extracts of O. basilicum but mechanisms underlying these actions are not fully understood.

Methods: Insulin-releasing effect of O. basilicum extract (0.1 – 1000µg/ml) were investigated using BRIN-BD11 cells. Effects of the extract (100µg/ml) on insulin secretion at various glucose concentration, presence of established modulators of insulin secretion and in the absence of extracellular calcium were also investigated. Insulin concentrations were measured by ELISA. Total flavonoids and phenolics content, phytochemicals, Cytotoxicity, protein glycation and intracellular calcium concentration were investigated.

Results: O. basilicum extracts stimulated non-toxic insulin secretion at concentration ≥0.1 mg/ml in a dose-dependent manner. Insulin secretion increased by 2.95-fold at 1000 µg/ml and the lowest stimulation of insulin was observed at 10 µg/ml (0.5-fold, P < 0.001) compared to glucose (5.6mM) control. Insulin-release increase with increasing glucose concentration (1.1mM to 5.6mM, 10%, P < 0.05, and 5.6mM to 16.7mM, 13%, P < 0.05). Actions of the extract was reduced in the presence of diazoxide (300µM, 30%, P < 0.01), verapamil (50 µM, 29%, P < 0.01) and in the absence of extracellular calcium (29%, P < 0.05). Enhanced insulin secretion was observed in incubations containing KCl (30mM, 3.2-fold, P < 0.001) and IBMX (200μM, 2.1-fold, P < 0.01). Intracellular calcium concentration significantly improved on exposure to O. basilicum by 24% (P < 0.01). Preliminary screening of phytochemicals shows presence of alkaloids, flavonoids, tannins and saponins. O. basilicum shows significant concentration of both total flavonoids and phenolics content, improved protein glycation.

Conclusions: These results suggest that the anti-diabetic properties of O. basilicum extract may involve the K_{AT P} -dependent pathway and motivate future investigation of its in vivo effects.