Total Phenolic Contents and Free Radical Scavenging Activity of Guaiacum officinale L. Extracts

Backgound: Guaiacum officinale L. is an alien species to Thailand. It is used as anti-arthritis and anti-rheumatoid agents in Indian folklore medicine. Objective: The present study was aimed to investigate total phenolic contents and free radical scavenging activity of the extracts from Guaiacum officinale L. (Zygophyllaceae). Methods: The plant parts including bark, twig and leaf were extracted using different solvents (ethyl acetate, water and ethanol). Total phenolic contents were determined by Folin-Ciocalteu Colorimetry method while free radical scavenging activity of the extracts was investigated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay. Results: The results show that the highest total phenolic content is found in the ethyl acetate twig extracts (20.3±0.0031 μg GAE/1 μg extracts). The ethanolic twig extracts had the highest free radical scavenging activity with IC50 of 0.45±0.0188 mg/ml. Conclusion: The extracts from Guaiacum officinale L. exhibit good anti-oxidant activity and may be suitable for development as drugs and supplementary food.