Antioxidant, α-glucosidase, and nitric oxide inhibitory activities of Phyllanthus acidus and LC-MS/MS profile of the active extract

The inhibition of α-glucosidase and nitric oxide, and the antioxidant activities of two parts (leaf and fruit) of Phyllanthus acidus (an Asian gooseberry) extracted with various ethanol ratios (0%, 50% and 100%) were studied. The compounds that were associated with the three bioactivities in the P. acidus extracts were identified using ultra-high-performance liquid chromatography tandem mass spectrometry, UHPLC-MS/MS. The results showed that extraction of the leaves with 50% ethanol gave the most active extract with the lowest IC50 value for α-glucosidase at 1.5 µg/mL, moderate nitric oxide scavenging and inhibitory activities (IC50 =160 and 180 µg/mL, respectively), and the highest total phenolic content with 33 mg GAE/g extract. The 50% ethanol extract of the fruit showed the highest total phenolic content, DPPH free radical scavenging, nitric oxide scavenging, α-glucosidase and nitric oxide inhibitory activities with values of 9.4 mg GAE/g extract, 48%, 49%, 2.4 µg/mL and 43%, respectively. In total, 30 compounds were tentatively identified in the 50% ethanol extract of P. acidus leaf, which included derivatives of quercetin, kaempferol, epicatechin, coumaric, and cinnamic acids. Hence, P. acidus extracts that have antioxidant properties, α-glucosidase and nitric oxide inhibitory activities could be potential candidates for the treatment of diabetes and inflammation associated diseases.