Antioxidant and anti-inflammatory properties of taiwanese yam (Dioscorea japonica Thunb. var. pseudojaponica (Hayata) Yamam.) and its reference compounds

• Ethanol extract of Dioscorea japonica Thunb. var. pseudojaponica (EDP) exhibits antioxidant activity in vitro.
• Fingerprint chromatogram from HPLC indicates that EDP contains gallic acid and vanillic acid.
• EDP decreased LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells.
• Anti-inflammatory activities of EDP were assessed in mouse paw oedema induced by λ-carrageenan.
• EDP might be a natural antioxidant and anti-inflammatory agent.

Dioscorea japonica Thunb. var. pseudojaponica (DP) is consumed as food and widely used in traditional Chinese medicine in Taiwan. The aims of this study are to investigate the antioxidant and anti-inflammatory effects of ethanol extract of DP (EDP) and its reference compounds. Fingerprint chromatogram from HPLC indicated that EDP contains gallic acid and vanillic acid. EDP was evaluated for its antioxidant effects and LPS-induced nitrite oxide (NO) production in RAW264.7 cells. EDP decreased the LPS-induced NO production and expressions of iNOS and COX-2 in RAW264.7 cells. In-vivo anti-inflammatory activities of EDP were assessed in mouse paw oedema induced by λ-carrageenan (Carr). We investigated the antioxidant mechanism of EDP via studies of the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) and the levels of malondialdehyde (MDA) in the oedematous paw. The results showed that EDP might be a natural antioxidant and anti-inflammatory agent.