LC-QTOF-MS profiling, extraction optimization, biological evaluation, and preliminary phytochemical screening of stingless bee (Tetragonula pagdeni Schwarz) propolis from Thailand.

This study explored optimal extraction conditions, bioactivities, and phytochemical profiles of stingless bee (Tetragonula pagdeni Schwarz) propolis using LC-QTOF MS. The best extraction was achieved using 75% ethanol, a 30 mL/g solvent-to-propolis ratio, and a 50-minute extraction time. Maceration for 7 days without dewaxing yielded the highest total phenolic (59.1 ± 6.4 µg GAE/mg) and flavonoid (13.6 ± 0.6 µg catechin/mg) contents. A total of 60 compounds were tentatively identified. The extract exhibited antimicrobial activity against S. pyogenes, and exhibits antioxidant activity, with IC50 values of 41.9 ± 6.3 µg/mL (DPPH•) and 22.6 ± 0.3% at 1.0 mg/mL (ABTS•+). It also showed potent anti-inflammatory activity (IC50 = 19.1 ± 1.00 µg/mL) without cytotoxicity towards RAW 264.7 cells. These findings highlight the potential of stingless bee propolis as a natural source of bioactive compounds for future commercial applications.