Isolation and characterisation of cytotoxic compounds from Euphorbia clementei Boiss.

A new phorbol-type diterpene ester, 4,20-dideoxy-4α-phorbol-12ß-acetate-13α-isobutyrate, in addition to 11 known compounds were isolated from the latex and roots of Euphorbia clementei Boiss. Structure elucidation was performed by comprehensive 1D and 2D NMR analyses (1H and 13C NMR, COSY, ROESY, HSQC and HMBC experiments), mass spectrometry (HR-ESI-MS) and by comparison with literature data. The inhibitory activity of all isolated compounds was evaluated against promyelocytic leukemia HL60 and human erythromyeloblastoid leukemia K562 cell lines and seven of these compounds exhibited a weak cytotoxicity with IC50 values ranging from 40 to 97 µM.

Compounds from the pods of Astragalus armatus with antioxidant, anticholinesterase, antibacterial and phagocytic activities.

CONTEXT: The phytochemical study and biological activities of Astragalus armatus Willd. subsp. numidicus (Fabaceae) pods, an endemic shrub of Maghreb, are reported. OBJECTIVE: This study isolates the secondary metabolites and determines the bioactivities of Astragalus armatus pods. MATERIALS AND METHODS: The chloroform, ethyl acetate and n-butanol extracts of hydro-ethanolic extracts were studied. Antioxidant activity was investigated using DPPH and ABTS radical scavenging, CUPRAC and ferrous chelating assays at concentrations ranging from 3 to 200 µg/mL. Anticholinesterase activity was determined against acetylcholinesterase and butyrylcholinesterase enzymes at 50, 100 and 200 µg/mL. Antibacterial activity was performed according to minimum inhibitory concentration (MIC) method. Carbon clearance method in albino mice was used for the phagocytic activity at concentrations 50, 70 and 100 mg/kg body weight. Spectroscopic techniques were used to elucidate the compounds. RESULTS: Ethyl acetate extract afforded a flavonoid (1) while the n-butanol extract gave four flavonoids (2-5), a cyclitol (6) and a cycloartane-type saponin (7). The ethyl acetate extract exhibited highest antioxidant activity in DPPH (IC50: 67.90 ± 0.57 µg/mL), ABTS (IC50: 11.30 ± 0.09 µg/mL) and CUPRAC (A0.50: 50.60 ± 0.9 µg/mL) assays. The chloroform extract exhibited the best antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, each with 80 µg/mL MIC values. The n-butanol extract enhanced phagocytic activity. DISCUSSION AND CONCLUSION: Isorhamnetin (1), isorhamnetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-ß-d-galactopyranoside (2), isorhamnetin-3-O-ß-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-ß-d-galactopyranoside (3), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-ß-d-galactopyranoside (4), kaempferol-3-O-(2,6-di-O-α-l-rhamnopyranosyl)-ß-d-glucopyranoside (5), pinitol (6) and cyclomacroside D (7) were isolated whereas 1, 2, 6 and 7 are reported for the first time from A. armatus.