Abstract
•Euphorbia schimperiana is a rich natural source for bioactive secondary metabolites.•Ethyl acetate and n-hexane fractions are highly recommended to be used for further vivo study against PC3 cell line with no/low cytotoxicity against normal cell line.•4-O-ethylgallic acid (7) is reported from Euphorbia genus for the first time.•3,3′-di-O-methylellagic acid (5) has a selective cytotoxicity against PC3 as a pure compound with low cytotoxicity against the normal cell.•Antibacterial efficiency of 4-O-ethylgallic acid (7) has a significant against Gram-positive and Gram-negative bacteria.
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 μg/ml for ethyl acetate, however, n-hexane exhibited 100% cytotoxicity up to 6.25 μg/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-α-glucuronide (2), quercetin-3-O-β-D-glucuronide-methyl ester (3), quercetin-3-O- α-L-rhamnoside (4), 3,3′-di-O-methylellagic acid (5), 3,3′-di-O-methyl-ellagic acid-4-β-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 3,3′-di-O-methylellagic acid (5) against PC3 with IC50 of 5.5 μg/ml.