Abstract

The radical scavenging activity using 1,1-diphenyl, 2-picrylhydrazyl (DPPH) and cytotoxicity using sulphorhodamine B (SRB) assay of the aqueous methanolic extract ofTamarix nilotica (Ehrenb.) Bunge (Tamaricaceae) flowers and its subextracts (CHCl₃, EtOAC and Pet.ether) were evaluated. Total phenolic and flavonoid contents were estimated using colorimetric assays. Ethyl acetate (EtOAc) showed the highest free radical scavenging activity with inhibitory concentration (IC₅₀) 7.25 ± 0.86 µg/ml in addition to potential cytotoxic effect on liver cell carcinoma (Huh-7) (IC₅₀ 49.1 ± 0.96 µg/ml) whereas effect on lung cell carcinoma (A-549) was much lower (IC_50: 137.9 ± 1.85 µg/ml). EtOAc had the highest flavonoid content (1.75 ± 1.5 mg/g QE) compared to other subextracts. These results indicated that ethyl acetate fraction contains bioactive compounds worthy of more sophisticated studies as free radical scavenger and cytotoxic agent.

Key words: Tamarix nilotica, cytotoxic activity, sulphorhodamine B (SRB) assay, scavenging activity, 1,1-diphenyl, 2-picrylhydrazyl (DPPH) assay, flavonoid, phenolic.