Bio-active compounds from Euphorbia cornigera Boiss

Euphorbia cornigera Boiss. (Euphorbiaceae) roots extracted in various organic solvents were tested against Biomphalaria glabrata snails as molluscicide using Bayluscide as a control. Among these, acetone extract was found to be the most active (LC(50)=17.5 microg L(-1)) as compared to Bayluscide. The application of HPLC fractionation yielded ten (1-10) N-(2-aminobenzoyl)anthraniloy esters. Structure and the relative configuration of all the compounds were established through spectroscopic (UV, IR (1)H, (13)C NMR, 2-D NMR, HSQC, HMQC, HMBC, COSY-45 degrees , TOCSY, HOHAHA, HOESY, ROESY, NOESY, SECSY, NOE and mass measurements) techniques. On these basis the esters are named as: 3-O-[N-(2-aminobenzoyl)]-5-O-acetyl-20-O-angelylingenol (1), 3-O-[N-(2-aminobenzoyl)]anthraniloyl-5-O-angelyl-20-O-acetylingenol (2), 3-O-acetyl-5-O-[N-(2-aminobenzoyl)]anthraniloyl-20-O-angelylingenol (3), 3-O-acetyl-5-O-angelyl-20-O-[N-(2-aminobenzoyl)]anthraniloylingenol (4), 3-O-angelyl-5-O-acetyl-20-O-[N-(2-aminobenzoyl)]-anthraniloylingenol (5), 3-O-angelyl-5-O-[N-(2-aminobenzoyl)]anthraniloyl-20-O-acetylingenol (6), 3,20-O-diacetyl-5-O-[N-(2-aminobenzoyl)]anthraniloylingenol (7), 5,20-O-diacetyl-3-O-[N-(2-aminobenzoyl)]anthraniloylingenol (8), 3-O-[N-(2-aminobenzoyl)]anthraniloyl-20-O-acetylingenol (9) and 20-O-[N-(2-aminobenzoyl)]anthraniloyl-3-O-acetylingenol (10). The literature reveals that compounds 1-8 are new from plant kingdom, whereas 9 and 10 are known but not reported from this source earlier. Their molluscicidal activity (in terms of LC(50)) showed that all the compounds were 1.3-2.2 times more toxic than Bayluscide except 5 and 6.