Phytochemical profiles, and antimicrobial and antioxidant activities of greater galangal [Alpinia galanga (Linn.) Swartz.] flowers

Previous studies of galangal (Alpinia galanga) have focussed mostly on rhizomes but seldom on flowers. A comprehensive look at galangal flowers could reveal additional benefits. The chemical composition of galangal flowers was significantly (p < 0.05) different from that of galangal rhizome. Pentadecane and α-humulene were identified as major compounds of galangal flower essential oil. 1′-acetoxyeugenol acetate was identified as the highest compound in flowers and exhibited the strongest antimicrobial activity among all fractions, with MIC50 values of 34 μg/ml against Staphylococcus aureus and 68 μg/ml against Listeria monocytogenes. Galangal flowers had a 3-fold higher total phenols content than had rhizomes (10.5 vs. 3.33 mg GAE/g powder). The antioxidant activities of different flower fractions varied from 2 to 4.45 mmol  trolox/g phenolics. These findings suggest that antimicrobial and antioxidant agents extracted from galangal flowers could potentially be utilized as natural food preservatives or as therapeutic agents.