Process optimization to high gymnemic acid content from Gymnema inodorum (Lour.) Decne. leaves

Abstract

Abstract Gymnema inodorum or Phak Chiang Da (PCD) vegetable is an indigenous medicinal plant used in Northern Thailand for diabetic treatment since ancient times. However, the low concentration of an active molecule, gymnemic acid (GA) in the leaves limit its applications among the large population. Therefore, the present study aimed to maximize the extraction of GA from PCD leaves using the solvent extraction method. The effect of concentration of ethanol and extraction temperature were investigated for the determination of optimum extraction conditions. A process was developed for the production of GA-enriched PCD extract powder and characterized. Results showed that a concentration of 50% (v/v) ethanol at 70°C for 2 h was appropriate to extract a higher GA concentration of 8,307 mg/kg from dried PCD leaves. During the drying process, maltodextrin with a concentration of 0.5% (w/v) was appropriate to produce PCD extract powder with maximum GA concentration. The color analysis (L*, a* and b*) revealed that the overall appearance of the PCD extract powder was a dark greenish tint mixed with yellow. The antioxidant activity assay showed that PCD extract powder at 0.1 g was able to neutralize 75.8% of DPPH free radicals. The results suggested that PCD extract powder rich in GA could be used as a possible source of nutraceuticals or as a functional food ingredient.