The present work describes the isolation and anticancer activity of Tapinanthus sp. which is a hemi parasitic plant harvested on Combretum glutinosum, the host plant. Phytochemical study afforded a new flavonoid glycoside, tapinantoside (1) isolated for the first time from natural source, alongside six known compounds (2-7). Structure of compounds were elucidated by extensive spectroscopic analyses including 1 D and 2 D NMR, mass spectrometry and by comparison with literature data. The anticancer activity of extract and some isolated compounds were evaluated on glioblastoma (U87MG, C6) and prostate (PC-3) cancer cells. The methanol leaves extract showed good anticancer activity against U87 (IC₅₀ = 21.40 µg/mL) and PC-3 cells (IC₅₀ = 10.26 µg/mL). Compound 3 powerfully inhibits the proliferation of C6 (IC₅₀ = 38.84 µM) and PC-3 cells (IC₅₀ = 21.33 µM), while its effect was moderated on U87MG cells. Compound 1 and 7 were not active on all tested cancer cell lines. Graphical Abstract

A phytochemical study was carried out on stem bark of Combretum fragrans F. Hoffm., a medicinal plant belonging to the Combretaceae family and used traditionally in the treatment of various ailments. Column chromatography separation on silica gel of the crude methanol extract from stem barks of C. fragrans led to the isolation of a new pentacyclic triterpene acid, with a 3,6-epoxide bridge and trivially named as fragransinic acid (1), along with four known compounds: betulin (2), betulinic acid (3), bellericagenin B (4) and a mixture of β-sitosterol (5) and stigmasterol (6). Structures were elucidated by extensive spectroscopic analyses including 1D and 2D NMR, mass spectrometry as well as by comparison with literature data. The above compounds were isolated for the first time from C. adenogonium. Implications for chemosystematics and traditional medicine were briefly discussed. Graphical Abstract

This work concerns the isolation and structure elucidation of compounds obtained from the extract of leaves and stem bark of Combretum fragrans F. Hoffm. Both extracts and some isolated compounds were tested for antiproliferative activity on glioblastoma (U87MG and C6 cells) and prostate (PC-3 cells) cancer cell lines using XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt) assay. The dichloromethane/methanol (1:1) extract of the leaves led to the isolation of two new compounds such as fragransinate (1) and combretin C (2), alongside five known compounds such as combretin A (3), belamcanidin (4), cirsilineol (5), velutin (6), and a mixture of β-sitosterol-3-O-β-d-glucopyranoside (10a) and stigmasterol-3-O-β-d-glucopyranoside (10b), whereas the methanol extract of the stem bark led to the isolation of three known compounds betulinic acid (7), bellericagenin B (8), and a mixture of β-sitosterol (9a) and stigmasterol (9b). The structure of compounds was elucidated by nuclear magnetic resonance and mass spectrometry data. The methanol extract of the stem bark showed a powerful antiproliferative activity on all tested cells, as well as the extract of leaves which also showed important cytotoxicity effect. Compound (3) showed good antiproliferative activity particularly on U87MG and PC-3 cells, whereas compound (5) exhibits moderated activity. Compounds (2) and (8) were not active on all tested cells.

The present study reports the chemical constituents, antioxidant, anticonvulsant and α-amylase activities of the aerial part of Cyperus rotundus collected in Cameroon. Phytochemical study leads to the isolation of six known compounds alongwith lupeol (1), stigmasterol (2), tetracosanoic acid (3), a mixture of β-sitosterol (4a) and stigmasterol (4b), ursolic acid (5) and saikogenin F (6). Compounds 3, 5 and 6 were isolated for the first time from this species. The structures of these compounds were determined using spectroscopic analysis including 1D and 2D NMR, mass spectrometry and comparison with the literature data. Biological activities carried out on the extracts showed that the methanol extract exhibited good antiradical scavenging activity against DPPH radical (IC50 = 2.873 μg/mL) and very good ferric reducing antioxidant power (FRAP) (IC50 = 7.535 μg/mL). It appeared that the mixture of hexane and ethyl acetate extract at the dose 100 mg/kg protected 66% of mice against convulsion induced by the pentylenetetrazol and 50% of protection when using picrotoxin at the same dose. All the extracts and compounds from this plant showed no inhibition against α-amylase related to antidiabetic activity.