Abstract

Free radicals, with their single electrons and reactive nature, could easily interact with different cellular compartments and cause oxidative damage. Prolonged oxidative stress could lead to DNA mutations, neurodegenerative diseases and heart disorders. These disorders could deteriorate our overall well-being and prove to be fatal. Medicinal herbs, rich in their secondary metabolites, could provide the antioxidants and scavengers needed to eliminate the free radicals. In this study, we tested six medicinal herbs used in Malaysia for their scavenging activities, in three different radical scavenging assays. We also tested their total phenolic and flavonoid levels. Among the herbs tested, Scutellaria barbata, Prunellavulgaris and Lophatherum gracile consistently demonstrated the highest activities in all three radical scavenging assays and trolox equivalent antioxidant capacity. Higher levels of total phenolic and flavonoid contents were also detected in these three herbs. Additionally, brine shrimp lethality assays also indicated low cytotoxicity in these herbs. In short, our results provided evidence for the safe use of these herbs as treatment for ailment in which free radical damage is implicated.

Key words: Cytotoxicity, flavonoid, free radical scavenging activities, medicinal herbs,phenolic, trolox equivalent antioxidant capacity.

Abbreviation

ABTS, 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid); DPPH, 1,1-diphenyl-2-picrylhydrazyl; NO, nitric oxide; TEAC, trolox equivalent antioxidant capacity.