(585b) Antioxidant Activity of Limnophila Aromatica Extracts

In recent years, the ingestion of fresh fruits and vegetables rich in natural antioxidants has been associated with the prevention of cancer and cardiovascular diseases. Many medicinal plants have been extensively studied for their antioxidant activity. Limnophila aromatica (Lamk.) Merr. (syn. L. gratissima Blume) is used as a spice and medicinal herb in Southeast Asia. Some studies on this species have found that L. aromatica (cited as L. gratissima) yielded 0.1% of an antibacterial, colourless essential oil, containing limonene and perillaldehyde as the principal constituents. Other minor constituents such as 7-desmethylartemetin (5,7-dihydroxy-3,6,30,40-tetramethoxyflavone, but later was revised as a mixture of nevadensin (5,7-dihydroxy-6,8,40-trimethoxy-flavone) and salvigenin (5-hydroxy-6,7,40-trimethoxyflavone)) and 8-oxygenated flavonoids were isolated from aerial parts of L. aromatica. Chlorogenic and caffeic acids were also reported as constituents of this species.

L. aromatica used in this study was bought at a Vietnamese store in Taiwan. In this study, water and various concentrations (50%, 75 % and 100%) of methanol, ethanol and acetone in water, were used as solvent in extraction of L. aromatica. The antioxidant activity, total phenolic content and total flavonoid content of the freeze dried L. aromatica extracts were investigated by using various in vitro assays. The extract obtained by 100% ethanol showed the highest total antioxidant activity, reducing power and DPPH radial scavenging activity. The same extract also exhibited the highest phenolic content (40.5 mg GAE/g DFLA) and the highest flavonoid content (31.11 mg QCE/g DFLA). The highest extraction yield was obtained by using 50% aqueous acetone. These results indicate that L. aromatica can be used in dietary applications with potential to reduce oxidative stress