Bioactive compounds from Euphorbia schimperiana with cytotoxic and antibacterial activities

Cytotoxicity and antibacterial activities of Euphorbia schimperiana total extract, fractions, and isolated secondary metabolites were investigated. The cytotoxicity assays were assessed against four human cancer cell lines HCT116, MCF7, HePG2, and PC3 as well as against normal cell line RPE1. The plant total extract, fractions, and pure compounds were more effective against PC3 and HepG2 cell lines than HCT116 and MCF7. Significant results were observed for ethyl acetate and n-hexane fractions against PC3 with IC50 of 4.7 mu g/ml for ethyl acetate, however, n-hexane exhibited 100% cytotoxicity up to 6.25 mu g/ml. The antibacterial potential activity was achieved on four pathogenic Gram-positive and four Gram-negative bacteria. The results showed that ethyl acetate and n-butanol fractions had more valuable results (p < 0.05) against the tested pathogenic bacteria than total extract and n-hexane fraction. The major components of n-hexane were determined by GCMS analysis and 14 compounds were tentatively identified. Chromatographic isolation of ethyl acetate and n-butanol afforded 7 secondary metabolites: Quercetin (1), quercetin-3-O-alpha-glucuronide (2), quercetin-3-O-beta-D-glucuronide-methyl ester (3), quercetin-3-O-alpha-L-rhamnoside (4), 3,3'-di-O-methylellagic acid (5), 3,3'-di-O-methyl-ellagic acid-4-beta-D-xylopyrnoside (6) and 4-O-ethylgallic acid (7). Structures of the obtained compounds were elucidated by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. The inhibition zones of pure compounds revealed that compounds 4,6 and 7 exhibited antibacterial efficiency against all tested strains. A significant inhibition for 4-O-ethylgallic acid (7) was recorded against Listeria monocytogenes (LM) and Staphylococcus aureus (SA). Promising cytotoxicity of pure compounds was observed for 3,30-di-O-methylellagic acid (5) against PC3 with IC50 of 5.5 mg/ml. (C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.