A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile.Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3enhanced its antimicrobial activities by up to 4-fold depending on the species.

A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile.Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3enhanced its antimicrobial activities by up to 4-fold depending on the species.

A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile.Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3enhanced its antimicrobial activities by up to 4-fold depending on the species.

A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile.Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3enhanced its antimicrobial activities by up to 4-fold depending on the species.

A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile.Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus.For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3enhanced its antimicrobial activities by up to 4-fold depending on the species.

A new dimer stilbene [Monalittorin (1)] and ten known compounds [engeletin (2), aurantiamide acetate (3), lupeol (4), friedelin (5), quercetin (6), tiliroside (7), rutoside (8), astragalin (9), isoquercitrin (10) and quercimeritroside (11)] have been isolated from the leaves of Monanthotaxis littoralis (Annonaceae). The structures of these compounds were established by interpretation of their data, mainly, HR-TOFESIMS, 1-D NMR ( 1H and 13C) and 2-D NMR ( 1H-1H COSY, HSQC, HMBC and NOESY) and by comparison with the literature. The evaluation of their antimicrobial activities against three bacteria (Staphylococcus aureus ATCC 25923, Escherichia coli S2 (1) and Pseudomonas aeruginosa PA01) and three fungal strains (Candida albicans ATCC10231, Candida tropicalis PK233 and Cryptococcus neoformans H99) using broth micro dilution method, showed the largest antimicrobial activities of EtOAc fraction and compounds 1, 5, 6, 8 and 11 (MIC = 8 - 64 μg/ mL). In addition, EtOAc fraction presented synergistic effect with Vancomycin and fluconazole against the tested microorganisms.

A new dimer stilbene [Monalittorin (1)] and ten known compounds [engeletin (2), aurantiamide acetate (3), lupeol (4), friedelin (5), quercetin (6), tiliroside (7), rutoside (8), astragalin (9), isoquercitrin (10) and quercimeritroside (11)] have been isolated from the leaves of Monanthotaxis littoralis (Annonaceae). The structures of these compounds were established by interpretation of their data, mainly, HR-TOFESIMS, 1-D NMR ( 1H and 13C) and 2-D NMR ( 1H-1H COSY, HSQC, HMBC and NOESY) and by comparison with the literature. The evaluation of their antimicrobial activities against three bacteria (Staphylococcus aureus ATCC 25923, Escherichia coli S2 (1) and Pseudomonas aeruginosa PA01) and three fungal strains (Candida albicans ATCC10231, Candida tropicalis PK233 and Cryptococcus neoformans H99) using broth micro dilution method, showed the largest antimicrobial activities of EtOAc fraction and compounds 1, 5, 6, 8 and 11 (MIC = 8 - 64 μg/ mL). In addition, EtOAc fraction presented synergistic effect with Vancomycin and fluconazole against the tested microorganisms.