Ecological and Phytochemical Studies on Euphorbia retusa (Forssk.) from Egyptian Habitat.

This study deals with the ecology, phytochemistry, and biological activity investigation of Euphorbia retusa, belonging to Euphorbiaceae family, obtained from Egypt. Ecologically, Euphorbia retusa secretes white sap inhibiting the growth of the other species, so Euphorbia retusa is forming complete patches. Phytochemical study of the plant was visualized intensively based on its extraction with a protic organic solvent, working up and purifying its entire bioactive compounds using a series of different chromatographic techniques. A broad range of diverse compounds were isolated, namely, 1-hexacosanol (1), 3ß-hydroxy-24-methylene-9,19-cyclolanostane; 24-methylenecycloartanol (2), 3ß-hydroxy-9,19-cyclolanostane; cyclolaudanol (3), 3ß,24S-Ergost-5-en-ol (4), and methyllinoleate. Additionally, GC-MS analysis of the unpolar fractions detected the existence of n-dodecane, methyllaurate, 6,10,14-trimethyl-pentadecan-2-one (5), 6,10-dimethyl-undecan-2-one (6), 2-methyl-hexadecanal (7), methylpalmitate, methyl-9,12,15-octadecatrienoate (8), and n-heneicosane (9). A full assignment for compounds 2 and 3 using 1 and 2 DNMR was carried out herein for the first time. The antimicrobial activity of the strain extract and obtained compounds was studied using a panel of pathogenic bacterial strains. The in vitro cytotoxicity of the compounds as well as the crude extract was studied against the human cervix carcinoma cell line (KB-3-1).

Indoline alkaloids from Tabernaemontana contorta with cancer chemopreventive activity.

Two bisindoline alkaloids, contortarine A, 16-epi-pleiomutinine and a reaction product of pleiomutinine, namely N4-chloromethyl-pleiomutinine, were isolated from the roots of Tabernaemontana contorta Stapf. together with five known compounds: pleiomutinine, 1-carbomethoxy-ß-carboline, strictosidine lactam, pleiocarpamine, and pleiocarpine. The structures and relative configuration of these alkaloids were determined by extensive 1D and 2D NMR, and MS measurements. The absolute configuration of these compounds was determined by comparison of experimental and calculated ECD spectra. Among the isolated compounds, contortarine A, 1-carbomethoxy-ß-carboline and strictosidine lactam presented cancer chemopreventive properties through either quinone reductase (QR) induction with CD values of 16.0 ± 2.5, 30.2 ± 6.1 and 23.1 ± 4.6 µM, respectively, while pleiomutinine and 16-epi-pleiomutinine displayed the inhibition of TNF-α induced NF-κB activity with IC50 at 11.7 ± 2.6 and 3.4 ± 1.1 µM, respectively.

The structure of antrocarine E, an ergostane isolated from Antrocaryon klaineanum Pierre (Anacardiaceae).

Eight compounds were isolated from the stem bark of Antrocaryon klaineanum, and their structures determined by chemical and spectroscopic methods. Among these compounds, the ergostane-type antrocarine E (1a) is a new compound, although the structure had already been published by mismatching the spectroscopic data with those of 2. In this paper, we are reporting the valid spectroscopic values for antrocarine E and X-ray diffraction results.

Phytochemical Analysis of a Cytotoxic Fraction of Quassia silvestris using LC-HR-ESI-MSn.

INTRODUCTION: The genus Quassia is a promising source of secondary metabolites with biological potential including antimalarial and cytotoxic activities. Limited data are available on the phytochemistry and pharmacology of Quassia silvestris Cheek & Jongkind, a Cameroonian medicinal plant used to treat various ailments. OBJECTIVES: To carry out the bioassay-guided fractionation and LC-HR-ESI-MS analyses of the leaves extract from Q. silvestris; to purify the active fractions and isolate the major compounds using different chromatographic and spectroscopic methods. The obtained compounds will be evaluated for their biological activity. MATERIAL AND METHODS: Following the cytotoxic screening and LC-HR-ESI-MS profiling of fractions obtained from partition of the methanolic extract of Q. silvestris leaves, the CH2 Cl2 -soluble fraction which exhibited the highest cytotoxicity was retained for further investigations. RESULTS: Sixteen squalene-derived metabolites were identified with oxasqualenoid derivatives being the most predominant. Among the isolates, structure elucidation of two new oxasqualenoids quassiols E (1) and F (2), were achieved by NMR (one-dimensional (1D) and two-dimensional (2D)) and MS methods. The newly characterised compounds 1 and 2, together with the known tetraol (3) and 3-oxo-oleanoic acid (16) displayed moderate cytotoxicity. CONCLUSION: The identification and structural characterisation of highly oxidised squalene derived metabolites from this plant may provide important insight data for further pharmacological investigations. The LC-HR-ESI-MSn method reported here could be developed as a rapid and efficient tool for the analyses of structurally related compounds in the genera Quassia, Simarouba, and Eurycoma of the subfamily Simarouboideae. Copyright © 2016 John Wiley & Sons, Ltd.

Antimicrobial and cytotoxic constituents from native Cameroonian medicinal plant Hypericum riparium.

Bioassay guided fractionation of Hypericum riparium leaves extract has resulted in the isolation and characterization of three new compounds namely chipericumin E (1), hyperenone C (3), and hyperixanthone (5), together with twenty known compounds. Their structures were elucidated based on comprehensive interpretation of spectroscopic and spectrometric data. Compounds 1-4, and 6-8 displayed moderate antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and cytotoxic effects on the human gastric cell line BGC-823 with IC50 values ranging from 6.54 to 18.50µM.

Labdane-type diterpenes and flavones from Dodonaea viscosa.

A new labdane diterpenoid, 2,18-dihydroxylabda-7,13(E)-dien-15-oic acid (1), together with two known labdane diterpenes (3, 4), a new flavone, 5,7-dihydroxy-3,6,4'-trimethoxy-3'-(4-hydroxy-3-methyl-but-2-enyl)flavone (2) with three known flavones (5-7) were isolated from the aerial parts of Dodonaea viscosa. Their structures were determined by extensive analysis of spectroscopic data (1D and 2D NMR, MS) and by comparison with literature data. The anti-inflammatory activity of five compounds (1-5) was evaluated with a flow cytometry TNF-α secretion assay on human THP-1 cell line.

Prenylated anthraquinones and other constituents from the seeds of Vismia laurentii.

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V(1) (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.