Antioxidant and Hepatoprotective Effects of Orthosiphon aristatus on

Liver Damage Induced by CCl₄ in Mice

Orthosiphon aristatus Blume, is a popular medicinal herb in Vietnam. The extract of this plant have been proven to exert a diuretic, anti-diabetic and lipid lowering activities. In this study, fractions obtained by liquid-liquid distribution between water and chloroform (CHCl₃-F), ethyl acetate (Et-F) and n-butanol (Bu-F) of the ethanol extract of Orthosiphon aristatus Blume were tested for their antioxidative activity on in vitro (FRAP and DPPH assays), ex vivo (mouse liver cells intoxicated by CCl₄) and in vivo (mice intoxicated by CCl₄) tests. The results showed that Bu-F fraction had higher FRAP  than those of other fractions while Et-F had higher antioxidative ability than those of the others in DPPH, ex vivo and in vivo assays. The IC₅₀ (2.80 mg/ml) of DPPH^• radical scavenging assay of Et-F was better antioxidative activity than the pure natural antioxidant ascorbic acid (IC₅₀ = 3.24 mg/ml). In vivo hepatoprotective activity of Et-F on liver injury induced by CCl₄ in mice was dose dependent and comparable to Silymarin at dose 16 mg/kg but weaker than Silymarin at dose 8 mg/ml. The results obtained in the present study demonstrated that O. aristatus is a potential source of natural antioxidants and hepatoprotective agents.