Effect of microwave and ultrasound-assisted extraction methods on phytochemical extraction of bee propolis of Indian origin and its antibacterial activity

The propolis is a natural resinous product of bee hive and its composition majorly depends on the flora and geographical region. This study evaluated the propolis extracts collected from two different phytogeographical regions of India: Jammu & Kashmir (JKP) and Rajasthan (RP) obtained through maceration, ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). Phytochemical composition and antibacterial effect of bee propolis against Staphylococcus aureus and Escherichia coli bacteria by the minimum inhibitory concentration assay were performed. The best results were obtained for JKP propolis and UAE was more efficient provided the highest extraction yield (46.76-62.44 g), phenols (137.17-355.58 GAE per g propolis), flavonoids (20.66-60.23 Q per g propolis) and antioxidant activity (76.04-64.24%) for both samples. The JKP and RP samples exhibited maximum inhibitory effect on gram - positive bacteria S. aureus with MIC value of 5 mg mL(-1) compared to gram - negative bacteria E. coli.