LC-QTOF-MS profiling, extraction optimization, biological evaluation, and preliminary phytochemical screening of stingless bee ( <i>Tetragonula pagdeni</i> 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.