Different wavelengths light to induce physiological changes callus for the biosynthesis of gymnemic acid in Gymnema sylvestre
A callus culture of Gymnema sylvestre was cultivated under different light conditions (blue, white, red and green light). Green coloured callus extracts containing the gymnemic acid, which was increased under blue light respectively. The phytohormone kinetin enhanced the gymnemic acid formation in blue light, but was unable to induce gymnemic acid in darkness. The phytohormone 2,4-D induced the formation gymnemic acid under all light conditions studied. Analysis of the callus growth phase under all treatments revealed that gymnemic acid accumulation was maximum (12.22 mg/g d.w) in the callus during stationary phase of 45 days, grown in MS medium with 2,4-D (1.5 mg/l) and KN 0.5 mg/l under white fluorescent light. Blue light enhanced the gymnemic acid accumulation up to 4.4 fold of that found under white fluorescent light and 2.8 fold of that found in intact leaves. Present findings concluded that blue light can be used as tool for enhancing pentacyclic tri-terpenoids in batch culture of G. sylvestre.
Gymnema sylvestre (Retz) R.Br. Ex Roemer & Schultes is a woody climber belonging to the family Asclepiadaceae. It is distributed in Deccan peninsula parts of northern, western India, tropical Africa, Vietnam, Malaysia, Sri Lanka and it is available in Japan, Germany and USA as health food. It is a traditional medicine in India for diabetes mellitus, and used as a stomachic and as a diuretic (1). In Japan, there are Gymnema Teas and Gymnema chewing gum made from G. sylvestre leaves which are promoted as a natural method for controlling obesity, insulin secretion, diabetes and inhibiting the taste of sweetness (2). It helps to maintain blood glucose homeostasis through increased serum insulin levels provided by repair or regeneration of the endocrine pancreas (3). Several products are marketed under brand names such as Body Slatto Tea®, Gymnema®, Gymnema Tea®, Gymnema Diet®, Sugar Off®, GlucosetTM, Cinndrome XTM, and PilisoftTM. Gymnema sylvestre was propagated in vitro using axillary node and inter nodal explants; among that axillary node explants showed higher multiple shoots (57.2 shoots/ explant) than inter nodal explants (4). Fur ...