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Investigation of the leaves of Bauhinia thonningii Schum led to the isolation and identification of a new flavonol derivative, 6-C-methylquercetin-3,4'-dimethyl ether (1) together with eleven known compounds (2–13), with two of them (10 and 11) obtained as a mixture. Their structures were established by extensive spectroscopic analyses. Antibacterial activity of compound 1 as well as the reference antibiotic, ciprofloxacin was tested on Gram-negative multidrug-resistant bacteria overexpressing active efflux pumps, and against methicillin-resistant strains of Staphylococcus aureus (MRSA). Samples were tested alone and in combination with an efflux pump inhibitor (EPI), phenylalanine-arginine-β-naphthylamide (PAßN). Results show that when compound 1 was tested alone, its inhibitory effects were obtained on 7/10 tested bacteria with the highest MIC value of 128 µg/mL whilst in the presence of EPI, this activity significantly increase in all the 10 bacteria. An interesting antibacterial activity was obtained with compound 1 against Klebsiella pneumoniae ATCC11296 (MIC of 4 µg/mL), KP55 and Staphylococcus aureus MRSA6 in the presence of the PaßN. [ABSTRACT FROM AUTHOR]

The phytochemical investigation of the methanol extract of the stem bark of Chrysophyllum lacourtianum led to the isolation and characterization of one new secondary metabolite, lacourtianal (1), together with eight known compounds. Compounds 2; 3; 5; 6; 7 and 9 were reported for the first time from Chrysophyllum genus. The structures of compounds 1–9 were elucidated on the basis of 1 D and 2 D NMR spectroscopic and mass spectrometric data as well as comparison with the literature. The antibacterial activity of the methanol extract, fractions and compounds 1–9 were evaluated against bacterial strains. The methanol extract exhibited moderate activity against Staphylococcus aureus NR4674 with MIC values of 500 µg/mL. The n-hexane fraction showed moderate activity against Staphylococcus aureus (ATCC 43300 and ATCC 25923) with MIC values of 125 µg/mL and ursolic acid (5) exhibited strong activity against Enterobacter aerogenes CPC and Escherichia coli ATCC 25322 with MIC values of 7.8 and 3.9 µg/mL respectively. [ABSTRACT FROM AUTHOR]

Stem barks of Boswellia dalzielii are used traditionally for the treatment of various bacterial infections. A bioassay guided fractionation of the MeOH-CH2Cl2 (1/1, v/v) stem barks extract led to the isolation of fourteen compounds 1–14, identified based on spectroscopic data. Dalzienoside (1) is reported here for the first time. The broth microdilution method was used to evaluate the antibacterial activity of the crude extract, fractions and compounds against six bacterial strains. The crude extract exhibited moderate antibacterial activity with MIC of 250 μL/ml; two fractions showed significant activities with MICs ranging from 7.8 to 125 μg/ml, while α-boswellic acid (2), β-boswellic acid (3), acetyl-11-keto-β-boswellic acid (4) from these fractions exhibited strong activities with MIC value of 3.125 µg/mL against Staphylococcus aureus, Salmonella typhi, Enterobacter cloacae, Streptococcus pneumonia and Pseudomonia aeruginosa. This study gives insight into the antibacterial constituents of the stem bark of B. dalzielii and justifies its use in ethnomedicine. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the stem bark of Stereospermum acuminatissimum resulted in the isolation of seventeen compounds, including four tirucallanes (1 – 4), three hopanes (5 – 7), one oleanane (8), three sterols (9 – 11), three saponins (12 – 14), two cinnamic acids (15 – 16), and one iridoid (17). The dehydration of compound 5 led to compound 5a. The structures of all compounds were elucidated by analysis of spectroscopic and mass spectrometric data. Compounds 1 , 6 and 7 are reported from the Bignoniaceae family for the first time, while compounds 11 – 14 and 16 are reported from S. acuminatissimum for the first time. The in vitro antibacterial activities of some compounds (1 – 5 , 8 , 5a), the crude extract and the ethyl acetate fraction were assessed. The crude extract showed significant antibacterial activity against Staphylococcus aureus , Salmonea pneumonia and Klebsiella pneumoniae with MIC values of 62 μg/mL. Compound 1 revealed moderate antibacterial activities against K. pneumoniae , Shigella flexneri and Methycillin resistant S. aureus with MIC values of 62, 62 and 31 μg/mL respectively. [Display omitted] • Phytochemical investigation of Stereospermum acuminatissimum K. Schum. • Dehydration of one of the isolated compound. • Chemophenetic significance of the isolated compounds. • Antibacterial activities of crude extract, fractions and compounds. [ABSTRACT FROM AUTHOR]

The phytochemical study was done on the leaves of Gambeya lacourtiana. This plant has been used in traditional medicine to treat of different ailments such as uterine heamorrhage, metritis and other vaginal infections. Chromatographic fractionation and purification on the leaves crude extract afforded lupeol acetate (1), lupenone (2), lupeol (3), taraxerol (4) stigmasterol (5), erythrodiol (6), chamaedrydiol (7), methyl pheophorbide-a (8), corosolic acid (9), tormentic acid (10), epicatechin (11) and 22-dihydrospinasterol 3- O - β - D -glucopyranoside (12). The structures of compounds 1 – 12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. Compounds 4 , 7 – 10 and 12 were isolated for the first time from Gambeya genus. Crude extract, fractions and compounds 6–12 were evaluated for their antibacterial activity. Methyl pheophorbide-a (8) demonstrated moderate activity against Salmonella typhi CPC with MIC values of 62.5 μg/mL. The chemophenetic significance of these compounds is also discussed. [Display omitted] • Isolation of 12 compounds from the leaves of Gambeya lacourtiana (Sapotaceae). • First report of a chlorophyll type skeleton in the genus Gambeya. • First antibacterial report of the leaves of Gambeya lacourtiana. [ABSTRACT FROM AUTHOR]