Free radical scavengers from dendrobium virgineum

Abstract

Free radicals are unstable, highly reactive, molecules which can cause several degenerative diseases such as mutagenesis and carcinogenesis. This research aims to study the chemical constitutents of Dendrobium virgineum and their antioxidant activity in 3 different test models including DPPH radical scavenging assay, superoxide radical scavenging activity assay and oxygen radical absorbance capacity assay. Nine compounds were isolated and determined to be two new compounds named 2,8-dimethoxy-9,10-dihydro-4,5-phenanthrenediol and 2,5-dimethoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone, together with seven known compounds, which are 2-methoxy-9,10-dihydro-4,5-phenanthrenediol, gigantol, 5-methoxy-7-hydroxy-9,10-dihydro-1,4-phenanthrenequinone, p-coumaric acid, tristin, 2,5,7-trihydroxy-4-methoxy-9,10-dihydrophenanthrene and 9,10-dihydro-2,4,7-phenanthrenetriol. The result obtained from the three testing models revealed that 2,5,7-trihydroxy-4-methoxy-9,10-dihydrophenanthrene showed strongest antioxidant activity. This compound has potential for further development as a preventive agent for free radical-related diseases.