Antimicrobial activity of some edible flowers in Thailand

In Thailand, many flowers were used for long time as vegetable, tea, dye and also Thai traditional medicine. However, biological activity of some flowers have never been reported. In this study, some of Thai edible flowers were investigated in their anti-microbial activities. The methanolic extracts were screened using agar disc diffusion method at 1mg/disc and only extracts that generated the clear zone were selected to determine the minimum inhibitory concentration (MIC) using microdilution plate method. Antimicrobial activities against Staphylococcus aureus with MIC at 50–800µg/ml were found in five of 19 flowers, Mesua ferrea L., Sonneratia caseolaris Gaerth, Quisqualis indica L., Saraca indica L. and Antigonon leptopus Hook. Candida albicans were inhibited by flower extracts from Sonneratia caseolaris Gaerth and Quisqualis indica L., with MIC at 50 and 800µg/ml, respectively. However all extracts had no inhibitory effect on E. coli. Total phenolic content, using Folin-Ciocalteu colorimetric method, in all extracts was 1.27–31.49%. All flower extracts with antimicrobial activity in this study, except Seraca indica L., also generated antioxidant activity in ABTS assay with the trolox equivalent antioxidant capacity (TEAC) of 0.15–0.70. These results implied that some flowers have potential to be further developed as medicinal food or pharmaceutical products, however it needs more investigation.

Acknowledgements: Faculty of Pharmacy, Silpakorn University

References: [1] Hutapatt, K. (2004) Edible flowers. Greenmedia and Product. Bangkok. Thailand. (Thai). [2] Casey, JT. (2004) J Microb Methods 58: 327–334.