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 (LC50 = 17.5 μg 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 1H, 13C NMR, 2-D NMR, HSQC, HMQC, HMBC, COSY-45°, 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 LC50) showed that all the compounds were 1.3–2.2 times more toxic than Bayluscide except 5 and 6.

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