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DOI: 10.1055/s-0030-1264397
Evaluation of antioxidant and DNA protection activities in the extracts of the Terminalia catappa leaves
Terminalia catappa (Combretaceae) is used commonly as a folk medicine in Taiwan, and has been claimed to have therapeutic effects in hepatitis and liver related diseases [1, 2]. The leaves, bark and fruit of the Terminalia catappa have also been commonly used as a folk medicine for antidiarrheic, antipyretic and haemostatic purposes in India, Philippines, Malaysia and Indonesia [3]. The extracts from the Terminalia catappa leaves were used in this study. Antioxidant activities were measured by both 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging and 2, 2-azino-bis (3-ethylbenz- thiazoline-6-sulfonic acid) (ABTS·+) decolourisation methods. To further evaluate the effect of Terminalia catappa extracts on UV induced DNA damages, the DNA protection assay was employed. Terminalia catappa leaf extracts had effective DPPH bleaching activity and ABTS·+ radical scavenging activity in a concentration dependent manner. Furthermore, the Terminalia catappa leaf extracts to inhibit the oxidative DNA damages were assessed by measuring the conversion of supercoiled pUC119 plasmid DNA to the linear forms. UV irradiation of DNA with hydrogen peroxide resulted in the formation of linear forms of DNA, indicating double-strand DNA breaks. Addition of Terminalia catappa plant extracts to DNA resulted in a partial inhibition of the conversion of supercoiled DNA to linear forms, indicating that the Terminalia catappa plant extract was able to protect plasmid DNA against hydroxyl radical induced oxidative damage. The inhibition of hydroxyl radical induced DNA strand breaks by Terminalia catappa plant extracts exhibited a concentration dependent relationship.
Acknowledgements: Committee on Chinese Medicine and Pharmacy (Grant No. CCMP 98-RD-006), Chia Nan University of Pharmacy and Science.
References: 1. Chyau, CC. et al. (2002) Food Chemistry 78: 483–488.
2. Kinoshita, S. et al. (2007) Phytomedicine 14: 755–762.
3. Chyau, CC. et al. (2006) LWT 39:1099–1108.