Optimization of ultrasonic-assisted extraction parameters of Garcinia Cambogia and the biological activities of the extract

Abstract

Garcinia cambogia (G.cambogia) which is known locally as asam gelugur has been recognized in many Asian countries for its benefits to treat constipation piles, rheumatism, irregular menstruation, and intestinal parasites. The previous study reported that the main extract of G.cambogia,(-)-hydroxycitric acid ((-)-HCA), an organic acid component of the fruit, exhibited anti-obesity activity. Most of the products available in the market nowadays contain a low percentage of this active ingredient, (-)-HCA while and some of the products contain a combination of different active ingredients. Thus, optimization of ultrasonic-assisted extraction (UAE) of G.cambogia and the biological activities; antioxidant activity, antimicrobial and in vitro inhibitory activity of a G.cambogia extract on pancreatic lipase activity was studied. Response surface methodology (RSM) involving central composite design was employed to study the effect of ultrasound-assisted extraction parameters namely sonication amplitude (10–70 %), solid-liquid ratio (4–12 %w/v) and extraction time (10-40 min) on the yield of (-)-hyrdroxycitric acid and total organic acid. The significant (p < 0.05) response surface models with high coefficients of determination values (R2) of 0.9297 and 0.9438 for the yield of (-)-HCA and total organic acid, respectively were obtained. The high R2 values indicated that these polynomial response models are well fitted for describing the extraction efficiencies of the responses. Based on the RSM result, the optimal condition for obtaining higher extraction was at extraction time of 21 min, percentage amplitude of 22 %, and solid-liquid ratio of 6 % w/v. Under this optimal condition, the G.cambogia extract obtained contain 36.916 g/100 g dry weight of (-)-HCA and 69.251 g/100 g dry weight of total organic acid. Meanwhile, G.cambogia extract shows that it exhibited antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) with IC50 value 46.57 ? 0.93 ?g/ml. For antimicrobial activity, maximum inhibition zone was recorded against S. aureus (19.3 ± 2.3 mm) and E.coli (15.3 ± 2.3 mm) at concentration 0.5 g/ml crude extract of G.cambogia. The result from in vitro inhibitory pancreatic lipase study indicated the inhibitory effect of optimized G.cambogia which the lipolysis on tributyrin was reduced by 11.81 %. The study showed that the extraction using UAE of G.cambogia with controlled parameters produce a high yield of G.cambogia extracts with high biological activities. Thus, G.cambogia extracted using this process has the potential to enhance the quality of herbal products in the market.