First report of compounds from an Ancistrocarpus species: Triterpenoids from A. densispinosus Oliv. (Malvaceae).

The stem bark of Ancistrocarpus densispinosus Oliv. exhibited triterpenoids, including the rare fernane-type, fern-9(11)-ene-2α,3ß-diol (1) a possible chemotaxonomically distinct biomolecule for the genus. Other triterpenoids that were isolated from this plant include the ursane-type ursolic acid (2) and corosolic acid (3), friedelane-type friedelin (4) and canophyllol (5), lupane-type lupeol (6), betulin (7), betulinic acid (8) and hennadiol (9), oleanoic acid (10), maslinic acid (11) and taraxerol (12) and three sterols. This is the first report of the chemistry of a plant of the Ancistrocarpus. The structures of the compounds were elucidated based on their NMR, IR and MS techniques and by comparisons of their experimental data with those reported. The twelve triterpenoids 1-12 were found to be inactive against five bacterial strains Escherichia coli, Bacillus subtilis, Pseudomonas agarici, Micrococcus luteus and Staphylococcus warneri; inactive against KB-3-1 cervix carcinoma cancer cell line and inactive as antioxidants in the DPPH assay.

Preliminary study of black carbon content in airborne particulate matters from an open site in the city of Yaoundé, Cameroon.

A light absorbing reflectometer was used to calculate black carbon (BC) mass concentrations contained in both fine and coarse particulate matters (PM2.5 and PM2.5-10) collected in an urban area of Yaoundé from 1st March 2018 to 26th February 2019 to highlight BC fluctuation and determine its potential predominant sources. The highest BC concentrations were obtained on 14/02/2019 (5.37 µg/m3) and 17/01/2019 (3.90 µg/m3) whereas the cleanest days were 28/06/2018 (0.01 µg/m3) and 30/06/2018 (0.21 µg/m3) for BC content of PM2.5 and PM2.5-10, respectively. While BC values for BC2.5-10 were only obtained from November 2018 to February 2019 and in the long dry season, those of BC2.5 were obtained for all the seasons. Months, which were most polluted with BC, were January with an average value of 2.34 ± 1.71 µg/m3 and December with 1.65 ± 0.82 µg/m3 whilst the least polluted were September with 0.54 ± 0.33 µg/m3 and August with 0.21 ± 0.10 µg/m3 for BC2.5 and BC2.5-10, respectively. The BC2.5 and BC2.5-10 annual average values were 1.18 ± 0.98 µg/m3 and 0.66 ± 0.39 µg/m3. The annual mean BC contributions were 8.27 ± 5.00% and 6.63 ± 4.49%, respectively, in PM2.5 and PM2.5-10. The BC2.5/PM2.5 percentages varied widely; thus, a complete identification of potential sources of BC was very complex. However, by analogy with other studies, predominant sources were agricultural burn, light-duty gasoline, household wood and charcoal burning sources.

A New Aromatic Amide from the Roots of Zanthoxylum tessmannii (Rutaceae).

Phytochemical investigation of the methanolic extract of the roots of Zanthoxylum tessmannii Zepernick and Timler (Rutaceae) led to the isolation and characterization of one new aromatic amide named tessmamide (1) along with twelve known compounds, N-benzoyltyramine methyl ether (2), 7,8,9-trimethoxycoumarin (3), 7,8-dimethoxycoumarin (4), integrifoliodiol (5), robustin (6), skimmianine (7), lupeol (8), lupenone (9), a mixture of stigmasterol and ß-sitosterol, and a mixture of their glucosides. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D- and 2D-NMR, EI-MS, and ESI-MS) and comparison with known analogs. The determination of the radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay gave moderate antioxidant values for the crude extracts of the roots of Zanthoxylum tessmannii (IC50 0.8 mg/mL), tessmamide (1; IC50 31.8 µm), and 7,8,9-trimethoxycoumarin (3; IC50 29.3 µm), compared to the standard ascorbic acid (IC50 11.6 µm).

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.

Antiplasmodial activity of some phenolic compounds from Cameroonians Allanblackia.

BACKGROUND: Plasmodium falciparum, one of the causative agents of malaria, has high adaptability through mutation and is resistant to many types of anti-malarial drugs. This study presents an in vitro assessment of the antiplasmodial activity of some phenolic compounds isolated from plants of the genus Allanblackia. METHODS: Tests were performed on well plates filled with a fixed parasitized erythrocytes volume. Compounds to be tested were then added in wells. After incubation, tritiated hypoxanthine is added and the plates were returned to the incubator. After thawing, the nucleic acids are collected. Inhibitory Concentration 50 (IC50) was determined by linear interpolation. RESULTS: From Allanblackia floribunda, have been isolated and characterized 1,7-dihydroxyxanthone 1, macluraxanthone 4, morelloflavone 9, Volkensiflavone 10 and morelloflavone 7-O-glucoside 11; from Allanblackia monticola, α-mangosine 2, rubraxanthone 3, allaxanthone C 5, norcowanine 6, tovophiline A 7, allaxanthone B 8 and from Allanblackia gabonensis, 1,7-dihydroxyxanthone 1. Six of them were evaluated for their antimalarial properties. The most active compound, macluraxanthone, presented a very interesting activity, with an IC50 of 0.36 and 0.27 µg/mL with the F32 and FcM29 strains respectively. CONCLUSION: This work confirms that species of Allanblackia genus are medicinally important plants containing many biologically active compounds that can be used effectively as antiplasmodial.

Urease inhibitory isoflavonoids from different parts of Calopogonium mucunoides (Fabaceae).

The dichloromethane-methanol (1:1) soluble part of Calopogonium mucunoides (Fabaceae) resulted in the isolation of 10 isoflavones (4'-O-methylalpinumisoflavone, 4'-O-methylderrone, alpinumisoflavone, daidzeine, Calopogonium isoflavone A, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin, cabreuvin and 7-O-methylpseudobaptigenin) and a rotenoid (6a,12a-dehydroxydegueline). Among these, daidzeine, 7-O-methylcuneantin, atalantoflavone and 6a, 12a-dehydroxydegueline have been isolated for the first time from C. mucunoides while remaining are already reported from this source. Structures of all the isolated constituents were elucidated with the aid of NMR spectroscopic and mass spectrometric techniques. Among all the isolated constituents, nine were evaluated for their urease inhibitory potential. However, six were found potent. These include 4'-O-methylderrone, daidzeine, atalantoflavone, 2',4',5',7-tetramethoxyisoflavone, 7-O-methylcuneantin and 6a, 12a-dehydroxydegueline.

Terpenoids from Turraeanthus species.

Chemical investigation of the root bark of Turraeanthus mannii and the stem of T. longipes resulted in the isolation of two new diterpenes, 13-methyl-labda-8(17)-en-15-oic acid (1) and 13-(hydroxymethyl)-14-hydroxy-ent-labda-8(17)-en-15-oic acid (2), along with two known diterpenes, 19-hydroxy-ent-labda-8(17),13-dien-15,16-olide (3) and 19-acetoxy-ent-labda-8(17),13-dien-15,16-olide (4), and the phytosterol, stigmasterol. The structure elucidation of the new compounds has been achieved using spectroscopic techniques.

Diterpenoids from Turraeanthus mannii.

Three new compounds, 15-acetoxy-12-hydroxy-16-methyl-labda-8(17),13E-diene (1), ent-labda-8(17),13-dien-15,16-olid-19-oic acid methyl ester (2), and 12-hydroxy-labda-8(17),13-dien-15,16-olide (3), together with two known compounds, 19-acetoxy-ent-labda-8(17),13-dien-15,16-olide (4), and 16-acetoxy-12,15-epoxy-15beta-hydroxy-labda-8(17),13(16)-diene (5) were isolated from the stem bark of Turraeanthus mannii (Meliaceae). The structures of compounds 1 - 3 were elucidated by analysis of the spectroscopic data. The crude methanol extract and compound 5 exhibited weak antibacterial and antifungal activity.

Alkaloids from the stem bark of Turraeanthus africanus (Meliaceae).

Fractionation of the methanol extract of the stem bark of Turraeanthus africanus led to the isolation of two new alkaloids designated turraeanthin A and B, together with two known alkaloids. The structures of the new alkaloids were elucidated by means of spectroscopic analysis and characterized as 10-O-demethyl-17-O-methyl isoarnottianamide and 11-demethoxyl-12-methoxyl oxynitidine respectively.