Isolation and characterisation of new bio-active compounds from Euphorbia cornigera: cytotoxic ingenol esters.

The aerial parts of Euphorbia cornigera Boiss., on extraction with MeOH, yielded new bio-active constituents (1, 2) and known compounds (3 and 4) after MTT cytotoxicity assay-guided fractionation and chromatographic separation were conducted. From the aerial parts of E. cornigera Boiss., new bio-active constituents were extracted in methanol. The extract was partitioned in different organic solvents and the ethylacetate-soluble portion was subjected to Craig's distribution. The MTT cytotoxicity assay-guided chromatographic separation yielded four (1-4), out of which two (1, 2) were new and two known (3, 4) bio-active compounds, and they are reported for the first time from this source. Their structure and relative stereochemistry were established by analysing spectroscopic and mass measurement data. The isolates were named as: 13-O-[(2Z ,4 E ,6 Z)]-deca-2,4,6-trienoylingenol (1), 13-O-( 2 Z ,4 E ,6 Z)-deca-2,4,6-trienoyl-20-O-angeloylingenol (2), 13-O-dodecanoyl-20-O-hexanoylingenol (3) and 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-hexadecanoylingenol (4). Literature revealed that compounds 1 and 2 are new metabolites, while 3 and 4 are known, and are reported for the first time from this source. Cytotoxicities of isolates were evaluated in terms of IC(50) against RAW and HT-29 cell lines through MTT assay using ambrucin hydrochloride as a control. Compound 3 showed more activity than control, while 1, 2 and 4 were moderate.

Isolation and characterization of cytotoxic compounds from Euphorbia cornigera Boiss.

Methanolic extract of Euphorbia cornigera shoots was separated using HPLC, affording compounds 1-4. Their structures and relative stereochemistry were established after obtaining their spectroscopic (IR, (1)H, (13)C NMR COSY-45°, HOHAHA, HSQC, HMBC, NOESY, and mass measurement) data. On the basis of these data, the compounds were characterized as 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-tetradecanoylingenol (1), 3-O-decanoyl-20-O-hexanoylingenol (2), 3-O-(2,3-dimethylbutanoyl)-13-O-dodecanoyl-20-O-hexadecanoylingenol (3), and 13-O-dodecanoyl-20-O-hexanoylingenol (4); among these compounds, two (1 and 2) were new metabolites while the rest (3 and 4) were known. The MTT cytotoxicity assay was carried out using amrubicin hydrochloride as a positive control. Compound 1 displayed IC(50) as 5.0 and 2.9 µM against RAW and HT-29 cell lines, respectively, which is 5- and 1.5-folds stronger than the control with IC(50) values of 25 and 4.36 µM, respectively.

Irritant and co-carcinogenic diterpene esters from the latex of Euphorbia cauducifolia L.

Ten (1-10) irritant and mild co-carcinogenic diterpene esters were isolated from the latex of Euphorbia cauducifolia L. using bioassay-guided countercurrent distribution and other chromatographic techniques. The isolated compounds were characterized on the basis of spectroscopic results and mass measurements. As an outcome, the ingenane-type esters were established with the following structures: 3-O-angeloyl-17-O-palmatoylingenol (1), 3-O-palmatoyl-5-O-angeloylingenol (2), 5-O-angeloyl-17-O-palmatoylingenol (3), 3-O-angeloyl-5-O-palmatoylingenol (4), 17-O-(2Z,4E,6Z)-2,4,6-tetradecatrienoyl-20-O-palmatoylingenol (5), 5-O-angeloyl-17-O-benzoylingenol (6), 5-O-angeloyl-17,20-diacetoxyingenol (7), 3-O-angeloyl-17-O-benzoyl-20-acetoxyingenol (8), 3-acetoxy-5-O-angeloyl-17-O-benzoylingenol (9), and 5-O-angeloyl-3,17,20-triacetoxyingenol (10). Their biological screening revealed that they are moderate irritants, and low to moderate tumor promoters compared to TPA, but hardly showed any solitary carcinogenic activity. The isolated esters represent new compounds and were not reported before from any source.

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.

Anti-tumor 12-deoxyphorbol esters from Euphorbia cornigera.

Nine (1-8 and 10) new and two (9 and 11) known compounds have been isolated from roots of Euphorbia cornigera Boiss. Their structure and relative stereochemistry were acquired through NMR ((1)H, (13)C, COSY-45, HOHAHA, HMQC, HMBC, NOE and HMBC) spectroscopic measurements. Compounds 1-10 were identified as diesters of 13,20-O-diacyl and 11 as 13-O-acetyl of 12-deoxyphorbol. Cytotoxic activity of the compounds was investigated on human KB cells by reduction of MTT. Compounds 8-10 displayed IC(50) of 0.8, 0.5, and 1.0 microg mL(-1), respectively, whereas the activity of rest of the compounds (1-7) was either very low or (11) zero even up to 1000 microg mL(-1). The inhibition of DNA synthesis through Trypan blue exclusion and Brd-U assay was investigation to figure out the role of compounds 8-10 and concluded that these were responsible for the death of KB cells. Significant correlation has been found between the cytotoxicity and DNA cross-link and DNA strand-break formation.

Cytotoxic macrocyclic diterpenoid esters from Euphorbia cornigera.

Root extract of Euphorbia cornigera Boiss. (Euphorbiaceae) was separated into seven (compound 1-7) isolates through multiple Craig's distributions and preparative HPLC. The structures and relative configuration of theses compounds were established via spectral analyses as 7,8,12- O-triacetyl-3- O-(2-methylbutanoyl)-ingol (1), 3,8,12- O-triacetyl-7- O-(2-methylbutanoyl = -ingol (2), 3,7,12- O-triacetyl-8- O-(2-methylbutanoyl)-ingol (3), 3,7,8- O-triacetyl-12- O-(2-methylbutanoyl)-ingol (4), 7,12- O-diacetyl-3- O-(2-methylbutanoyl)-8- O-methylingol (5), 3,12- O-diacetyl-7- O-(2-methylbutanoyl)-8- O-methylingol (6) and 3,7- O-diacetyl-12- O-(2-methylbutanoyl)-8- O-methylingol (7). All these compounds, except for 2, are novel metabolites and have not been reported earlier. It has further been demonstrated that all the compounds (1 - 7) are cytotoxic.