Phytoconstituent Isolation and Cytotoxicity Evaluation of the Egyptian Cassia occidentalis L. Possessing Selective Activity against Lung Carcinoma

Abstract

Ethyl acetate fraction column chromatographic analysis was used to isolate eleven compounds (numerically tagged 1–10) from Cassia occidentalis L. in this study. Two unique metabolites, including a neolignan compound designated as occidentalignan I (9) and a flavonoidal glycoside, chrysin-7-O-α-L-rhamnopyranosyl (10), were identified, while silybin A (8) was the first flavonolignan to be isolated from the Fabaceae family. Four compounds, including β-sitosterol-3-O-β-D-glucopyranoside (1), stigmasterol-3-O-β-D-glucopyranoside (2), betulinic acid (3), and vanillic acid (4) were isolated from C. occidentalis for the first time. In addition, four known compounds, cinnamic acid (5), p-hydroxybenzoic acid (6), β- resorcylic acid (7), and citric acid (11), were also detected. The in-vitro cytotoxicity assessment of the methanolic extract of C. occidentalis on seven cancer cell lines, including A-549, Colo-205, Huh-7, HCT-116, PANC-1, SKOV-3, and BNL, demonstrated its selective potent cytotoxicity on lung cancer cells without affecting normal BNL cells. In contrast, the methanolic extract showed moderate activity on Colo-205 and Huh-7 and nearly no activity on HCT-116, PANC-1, and SKOV-3 cell lines. These results suggest that the methanolic extract of C. occidentalis is an excellent candidate with potential antiproliferative activity against lung cancer; however, further studies are necessary to clarify its mechanism of action.