Isolation of Secondary Metabolites from Pulicaria gnaphalodes (Vent.) Boiss. and Evaluation of Their anti-Proliferative Activity

A bioassay-guided study of Pulicaria gnaphalodes from the Asteraceae (Compositae) family led to the isolation of luteolin (1), quercetin (2), 4 - methoxy benzoic acid (3), and quercetin-3-O-beta-D-glucuronide (4). Their structures were recognized based on spectroscopic analyses. The cytotoxicity of methanol extract of aerial parts and five fractions (n-hexane, CHCl3, EtOAc, n-BuOH, and H2O) of the plant was tested against MCF-7 and DU-145 by MTT assay. Also, the ability of extract and fractions to act as free radical scavengers were measured by DPPH radical scavenging assay. As a result, the EtOAc fraction was selected for phytochemical analysis based on the half-maximal inhibitory concentration (IC50 = 107.99 +/- 2.89 mu g/ml) and antioxidant activity (IC50 = 10.64 +/- 1.45 mu g/ml). Finally, three flavonoid compounds 1, 2, 4, and one phenolic compound 3 were isolated from the EtOAc fraction and all isolated compounds were tested for their cytotoxicity. Both compounds 1 and 2 exhibited remarkable inhibitory activity on MCF-7 and DU-145 cell lines. Regarded to the above results, it could be concluded that Pulicaria gnaphalodes can be considered a natural source of biological compounds for further research.

Automated summary

A bioassay-guided study of Pulicaria gnaphalodes led to the isolation of four compounds, which were tested for their cytotoxicity and antioxidant activity. The EtOAc fraction showed significant inhibitory activity on cancer cell lines, suggesting that Pulicaria gnaphalodes may serve as a natural source of bioactive compounds.