Bioactivity Evaluation of Leucas zeylanica and its Phytochemicals

Abstract

Leucas zeylanica belongs to the Lamiaceae family has high medicinal value. Present study focused on the isolation and bioactivities of aerial part of L. zeylanica. The phytochemicals screening results showed that terpenoids, flavonoids, tannins, saponins, phenols and alkaloids are present in aerials part of L. zeylanica. Vacuum liquid chromatography (VLC) and column chromatography (CC) techniques were used in fractionation and purification of the crude extracts. The structure of isolated compound was elucidated by Infrared (IR) and Nuclear Magnetic Resonance (1H, 13C NMR) spectroscopies. A compound was successfully isolated from the chloroform extract and identified as vanillin. Hexane crude extract contained abundance of terpenoids while methanol crude extract was abundance in phenols, tannins and flavonoids. The antioxidant activity of the crude extracts was determined by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. Methanol extract was found to show good scavenging activity with IC50 value of 145.9 µg/mL. This is in accordance to the results showing that methanol extract showed the highest total phenolic content and total flavonoid content which were 133.0 mg GAE/g and 238.0 mg QE/g, respectively. The anthelmintic activity of the crude extracts was also tested by using adult earthworms Lumbricus rubellus and it was found that the activity is dose dependent for methanol and chloroform extracts. The result showed that methanol extract at concentration of 50 mg/mL exhibited better activity than other extracts but not comparable with the reference drug Albendazole.