Phytochemical, cytotoxicity and antioxidant investigation of Cassia alata leaves growing in Egypt

Abstract

Leaf extracts of Cassia alata L traditionally used for treatment of a variety of diseases. Chloroform fraction of leaves was evaluated for its potential antitumor properties in vitro. MTT assay was used to examine the cytotoxic effect on three human cancer cell lines namely HepG2, MDA-MB-231 and Caco2. Chloroform fraction showed remarkable cytotoxicity against HepG2 cells with IC₅₀ = 37.4 µg/ml at exposure time 48 h. This observation was confirmed by morphological investigation. The fraction exhibited weak anti-proliferative effect on Caco2 and MDA-MB-231 cells (8.2% and 11.6% respectively), with IC₅₀ values >100 µg/ml. DPPH free radical scavenging activity of the fraction (100 µg/ml) revealed weak antioxidant activity (7.8%). Further bioassay-guided fractionation of the cytotoxic fraction led to the isolation and characterization of three anthraquinones (rhein, aloe-emodin and emodin). On the other hand, n-hexane fraction was saponified into unsaponifiable and saponifiable matters. GC/MS of the fatty acid methyl esters revealed that the major fatty acids were palmitic (37.02%), linolenic (24.27%), linoleic (15.22%) and stearic (14.18%) acid which composed 90.69% of the total fatty acids. GC/MS analysis of the unsaponifiable matter showed that phytol was the major constituent (74.59%) and β-sitosterol (17.45%) was the second abundant one. The cytotoxicity profile might represent new promising compounds with potential for development as an anticancer drug with low or no toxicity to non-cancer cells