Myrsinane-type diterpenes from Euphorbia gedrosiaca with cell growth inhibitory activity and apoptotic effects on melanoma cancer cells.

Phytochemical analysis of Euphorbia gedrosiaca Rech.f., Aellen & Esfand., an Iranian endemic spurge, afforded the isolation of four myrsinane types diterpene polyesters. Two new compounds (1-2) were based on a myrsinane skeleton while the others (3-4) were known diterpenes based on a cyclomyrsinane backbone. Their chemical structures were elucidated by spectroscopic methods, including 1D and 2D NMR and HRESIMS. The isolated compounds were tested to evaluate their cell growth inhibitory activity and apoptotic effects on melanoma cell lines, B16F10 and A375. The IC50 values for compounds 1-4 were 58.45, 55.43, 86.52 and 82.27 µM, respectively, on B16F10, and 20.66, 21.88, 36.21 and 39.87 µM, respectively, on A375 cells. Non-treated cells were used as negative control (100% cell growth) and 5 nM Taxol were considered as a positive control.

Cinnamic acid derivatives from welsh onion (Allium fistulosum) and their antibacterial and cytotoxic activities.

INTRODUCTION: Cinnamic acids are a class of compounds based on phenyl propanoid backbone (C6-C3) isolated from plants and microorganisms, exhibiting interesting biological activities. OBJECTIVE: To characterise cinnamic acids through the phytochemical study of welsh onion, Allium fistulosum, and to evaluate their antibacterial and cytotoxic properties. MATERIAL AND METHODS: The phytochemical study of A. fistulosum was performed through chromatographic techniques, including reversed phase medium-pressure liquid chromatography (MPLC) and high-pressure liquid chromatography (HPLC). Preliminary analysis of crude chromatographic fractions from the organic extracts was carried out by proton nuclear magnetic resonance (1 H-NMR) in order to prioritise the study of those having phenyl propanoid skeleton. The structural identification of the isolated compounds was performed through analysis of spectroscopic data, mainly one-dimensional (1D) and two-dimensional (2D) NMR. The antibacterial activity was assessed against gram negative (Escherichia coli) and gram positive (Staphylococcus aureus) bacteria while the cytotoxic property was evaluated on breast cancer cell line (MCF-7). RESULTS: The 1 H-NMR study of crude fractions and application of a straightforward method to purify the phenyl propanoid compounds by reversed phase MPLC and HPLC, allowed the effortless isolation of several cinnamic acids, including two new rare phenolic imidates (1 and 2). The use of an entirely NMR approach for structural elucidation of the isolated metabolites allowed the isolated material to be kept for further pharmacological tests. CONCLUSION: These results corroborate the importance of the use of 1D and 2D NMR to the identification of new phenyl propanoids, potential lead compounds against bacteria and cancer cells.

Furostanol Saponins from the Bulbs of Welsh Onion, Allium fistulosum L.

An extensive phytochemical analysis of the polar extracts from bulbs of Welsh onion Allium fistulosum L. led to the isolation of nine saponins, four of them, named fistulosaponins G (1a/1b), H (2), I (3a/3b), and J (4), have never been reported previously. Fistulosaponins G and I were isolated as a couple of isomers in equilibrium. On the basis of 2D NMR and mass spectrometry data, the structure of the novel compounds were elucidated as (25R)-26-[(ß-D-glucopyranosyl)oxy]-3ß,22ß-dihydroxyfurost-5-en-1ß-yl O-α-L-rhamnopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 4)-ß-D-glucopyranoside (1a) with its 22α epimer (1b), (25R)-26-[(ß-D-glucopyranosyl)oxy]-3ß-hydroxyfurost-5,20-dien-1ß-yl O-α-L-rhamnopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 4)-ß-D-glucopyranoside (2), (25R)-26-[(ß-D-glucopyranosyl)oxy]-3ß,22ß-dihydroxyfurost-5-en-1ß-yl O-α-L-rhamnopyranosyl-(1 → 4)-ß-D-glucopyranoside (3a) with its 22α epimer (3b), and (25R)-26-[(ß-D-glucopyranosyl)oxy]-3ß-hydroxyfurost-5,20-dien-1ß-yl O-α-L-rhamnopyranosyl-(1 → 4)-ß-D-glucopyranoside (4). This is the first report of furostanol saponins in A. fistulosum bulbs. In addition, data on the antibacterial tests of the isolated saponins against Escherichia coli and Enterococcus faecalis are reported.

6(17)-Epoxylathyrane diterpenes from Euphorbia sogdiana Popov with cytotoxic activity.

Phytochemical analysis of Euphorbia sogdiana Popov, Euphorbiaceae, afforded the isolation of three new diterpenes based on the rare 6(17)-epoxylathyrane skeleton (1-3), along with a lathyrane (4), a myrsinane (5) and a tigliane (6) diterpenoids, previously isolated from Euphorbia aellenii. Their chemical structures were established through a combination of nuclear magnetic resonance spectroscopy and mass spectrometric methods. The epoxylathyranes 1-4 were tested to evaluate their cytotoxic activity against Jurkat T-leukemia and EJ-138 bladder cancer cells and their chemical analogy allowed to propose some structure activity relationships.