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See detailChemical Constituents of the Leaves of Caloncoba welwitschii Gilg.
Douanla, Pascal D.; Tchuendem, Marguerite Hortence K.; Tchinda, Alembert T. et al

in Phytochemistry Letters (2018), 23(October 2017), 5--8

Two new compounds namely acetylcaloncobaside (1) and friedocaloncobic acid (2) were isolated from the leaves of Caloncoba welwitschii together with six known compounds. Their structures were determined by ... [more ▼]

Two new compounds namely acetylcaloncobaside (1) and friedocaloncobic acid (2) were isolated from the leaves of Caloncoba welwitschii together with six known compounds. Their structures were determined by standard spectroscopic methods including one- and two-dimensional NMR, EI-MS, and HRESIMS. The new compounds were established as kaempferol 4′,7-dimethoxy-3-O-(3″,4″,6″-O-triacetyl)-β-null-glucopyranoside (1) and 15β-hydroxy-3-oxo-28-friedelanoic acid (2). The isolated compounds were evaluated for their ability to inhibit the 3D7 strain of Plasmodium falciparum, using the semi-automated in vitro model with parasite lactate dehydrogenase assay. [less ▲]

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See detailPhenolic compounds from the roots of Ochna schweinfurthiana and their antioxidant and antiplasmodial activities
Messi, A. N.; Ngo Mbing, J.; Ndongo, J. T. et al

in Phytochemistry Letters (2016), 17

An investigation of compounds extracted from Ochna schweinfurthiana roots with ethyl acetate led to the isolation of three new compounds 4‴-methoxylophirone A (1), 4,4′,4‴–trimethoxylophirone A (2) and ... [more ▼]

An investigation of compounds extracted from Ochna schweinfurthiana roots with ethyl acetate led to the isolation of three new compounds 4‴-methoxylophirone A (1), 4,4′,4‴–trimethoxylophirone A (2) and (4E;7Z)-3,8-dicarboxy-1-(O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranosyl-2,9-dihydroxyhexeicosa-4,7-diene (3). Six known compounds were also identified, including Calodenone (4), Calodenine B (5), Lophirone A (6), Gerontoisoflavone A(7), 16α,17-dihydroxy-ent-kauran-19-oic acid (8) and 3β-O-D-glucopyranosyl-β-sitosterol (9). This report describes the first time that compounds 4-8 have been isolated from this plant, while 8 has never been identified in the genus Ochna. Some of the isolated compounds were evaluated for their antiplasmodial activity against the chloroquine-sensitive Plasmodium falciparum strain 3D7 and antioxidant activity using DPPH radical scavenging and Ferric reducing-antioxidant power (FRAP) assays. Compound 5 exhibited prominent radical scavenging and FRAP activities, while 7 had weak activity. Compound 1 showed good in vitro anti-plasmodial activity. The structures of the isolated compounds were elucidated by spectroscopic methods and comparisons with prior data in the literature. © 2016 Phytochemical Society of Europe [less ▲]

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See detailAntiplasmodial anthraquinones and hemisynthetic derivatives from the leaves of Tectona grandis (Verbenaceae)
Kopa, T.K.; Tchinda Tiabou, Alembert ULiege; Tala, M.F. et al

in Phytochemistry Letters (2014), 8

Chemical investigation of the methanol extract of the leaves of Tectona grandis led to the isolation of one new anthraquinone derivative, grandiquinone A (3-acetoxy-8-hydroxy-2-methylanthraquinone) (1 ... [more ▼]

Chemical investigation of the methanol extract of the leaves of Tectona grandis led to the isolation of one new anthraquinone derivative, grandiquinone A (3-acetoxy-8-hydroxy-2-methylanthraquinone) (1), along with nine known compounds: 5,8-dihydroxy-2-methylanthraquinone (2), hydroxysesamone (3), 3-hydroxy-2-methylanthraquinone (4), quinizarine (5), betulinic acid (6), ursolic acid (7), tectograndone (8), corosolic acid (9) and sitosterol 3-O-β-d-glucopyranoside (10). Compounds 2 and 3 were isolated for the first time from the leaves of this plant, while 5 has never been reported from the genus Tectona. Hydroxysesamone (3) and tectograndone (8) were subjected to cyclisation and acetylation reactions to afford two hemisynthetic derivatives, 6,9-dihydroxy-2,2-(dimethyldihydropyrano)-3,4-dihydro-2H-benzo[g]chromene-5,10-dione (11) and acetyltectograndone (12) respectively, which are reported here for the first time. The ethyl acetate-soluble portion, some of the isolated compounds and hemisynthetic derivatives were evaluated for their antiplasmodial activity against the multidrug-resistant Dd2 strain of Plasmodium falciparum. Compound 3 showed a prominent activity, while 2, 8, 9, 11 and 12 showed significant in vitro anti-malarial activity. Compound 1 was weakly active in this test. The structures of the compounds were elucidated by spectroscopic methods and comparison of the data with the literature. [less ▲]

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See detailAlkaloids from the stem bark of Strychnos icaja
Tchinda Tiabou, Alembert ULiege; Tamze, Victorine; Ngono, Annie R N et al

in Phytochemistry Letters (2012), 5(1), 108-113

A comprehensive phytochemical study of the stem bark of Strychnos icaja was done for the first time and led to the isolation of two new monoindole alkaloids 15-hydroxyvomicine (1) and 12-methoxyicajine (2 ... [more ▼]

A comprehensive phytochemical study of the stem bark of Strychnos icaja was done for the first time and led to the isolation of two new monoindole alkaloids 15-hydroxyvomicine (1) and 12-methoxyicajine (2) along with 13 known alkaloids: the monoindoles N-methyl-sec-iso-pseudostrychnine (3), vomicine (4), icajine (5), 19,20-α-epoxy-12-methoxyicajine (6), 19,20-α-epoxy-12,15-dihydroxy-11-methoxyicajine (7), 19,20-α-epoxy-15-hydroxynovacine (8), 15-hydroxyicajine (9), 12-hydroxystrychnine (10), strychnine (11) and the tertiary bisindoles sungucine (12), isosungucine (13), strychnogucine C (14) and bisnordihydrotoxiferine (15). Apart from 10 and 11, the other alkaloids were isolated for the first time from the stem bark of this plant. The hemisynthetic derivative, Nb-chloromethosungucine (16) and the previously reported synthetic compound 3 were isolated from a natural source for the first time. Fractions and some isolated compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. The bisindole alkaloids were most active with IC50 ranging from 0.72 to 3.41 μg/ml whilst the monomers 1 and 3 were slightly active (IC50 39.92 and 40.27 μg/ml respectively) and 6 inactive. The structures of the compounds were determined based on the analysis of their spectral data. The full 1H and 13C NMR data of compounds 3, 6 and 7 are also reported in the present work for the first time. [less ▲]

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See detailLC–SPE–NMR–MS analysis of Strychnos usambarensis fruits from Rwanda
Cao, Martine ULiege; Muganga, Raymond; Nistor, Iolanda ULiege et al

in Phytochemistry Letters (2012), 5(0), 170-173

The novelty of the present work lies in the characterization of akagerine and palicoside in Strychnos usambarensis fruits by a hyphenated analytical method combining high-performance liquid chromatography ... [more ▼]

The novelty of the present work lies in the characterization of akagerine and palicoside in Strychnos usambarensis fruits by a hyphenated analytical method combining high-performance liquid chromatography coupled with solid-phase extraction (SPE), mass spectrometry (HPLC–MS) and NMR spectroscopy. Akagerine was already known in S. usambarensis roots but palicoside is described for the first time in the species. [less ▲]

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See detailMoandaensine, a dimeric indole alkaloid from Strychnos moandaensis (Loganiaceae)
Verpoorte, Robert; Frederich, Michel ULiege; Delaude, Clément et al

in Phytochemistry Letters (2010), 3

Moandaensine contains a rare anhydronium base subunit. It presents a moderate antiplasmodial activity with IC values of 11.2 microM and 9.2 microM against , respectively, the chloroquino sensitive FCA 20 ... [more ▼]

Moandaensine contains a rare anhydronium base subunit. It presents a moderate antiplasmodial activity with IC values of 11.2 microM and 9.2 microM against , respectively, the chloroquino sensitive FCA 20 GHA and chloroquino resistant W2 strains of Plasmodium falciparum [less ▲]

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