α-Glucosidase Inhibitory Activity and Safety Evaluation of Branch and Leaf Extracts of Phyllanthus acidus

To provide reference for the safety consumption of Phyllanthus acidus (PA) as food and its further medicinal development and utilization, a comparative study on acute and short-termtoxicity and α-glucosidase inhibitory ability of different components of its branches and leaves was conducted. The crude extract of PA, prepared under aqueous ethanol reflux extraction, was partitioned successively with petroleum ether, ethyl acetate and N-butanol according to the polarity. Furthermore, an alcohol-eluted and water-eluted fractions were obtained from water-soluble residue by column chromatography. The half inhibitory concentration (IC₅₀) of α-glucosidase was used as the evaluation index to compare the in vitro hypoglycemic activity of different extracts. The acute toxicity of these fractions was screened by maximum tolerated dose (MTD), median lethal dose (LD₅₀) values, and their subacute toxicity was evaluated by continuous oral administration of samples for 20 days. The results showed that each component of PA had a certain inhibitory ability to α-glucosidase. The MTD of crude extract of PA was 2.0 g/kg, and the order of acute toxicity for different fractions was ethanol-eluted fraction>water-eluted fraction>petroleum ether fraction>ethyl acetate fraction>N-butanol fraction>crude extract. The main acute toxicity symptoms were startle followed by idling, writhing, and shortness of breath. Subacute toxicity test showed no obvious toxicity and lesions. It was indicated that it was safe to take 2 g/kg/d (equivalent to 8.6 g/kg of dried branches and leaves) of the whole component of PA at oral ingestion. Thus, they have the potential to be developed as hypoglycemic, weight-loss food and medicine.