Microwave-assisted extraction of Trang peppercorn (<i>Piper nigrum</i> Linn.) and its α-glucosidase inhibitory activity and immune-stimulation

Diabetes is a chronic condition that causes insulin production problems and excessive blood sugar. Patients who cannot control their sugar are more susceptible to infection. The objective of this study is to explore the phytochemical contents, α-glucosidase inhibitory effects, and immune stimulation of three Trang peppercorn (<i>Piper nigrum</i> Linn.): black (BP), red (RP), and white (WP). The study uses DI water as a solvent and employs MAE at 500 and 300 Watts (W) of power, with extraction times of 30 and 50 seconds (sec), respectively. The MAE extracts made with 500 W of power for 30 sec had higher amounts of extraction yields (%), TPC, TFC, piperine (%), fatty acids, and α-glucosidase inhibitory than the extracts made with 300 W of power for 50 sec (p < 0.05). The BP and WP extract exhibited the highest inhibitory effects against baker's yeast and maltase α-glucosidase with IC<sub>50</sub> values of 2.09±0.75 mg/mL and 1.70±0.05 mg/mL, respectively, while the RP extracts showed an inhibitory effect against sucrase with an IC<sub>50</sub> value of 3.02±0.04 mg/mL. Interestingly, the BP, RP, and WB extracts with 500 W for 30 sec and 300 W for 50 sec at a concentration range of 1.00-200 µg/mL can stimulate the macrophage cell's process of taking up foreign substances and increase the creation of NO. This study revealed that MAE promotes Trang peppercorn phytochemical yields and biological activities, which may be used to make traditional diabetic medication and boost the immune system.