In vitro antitubercular activity of extract and constituents from the stem bark of Disthemonanthus benthamianus

A new C-glycosylflavone, apigenin 7-methyl ether 6-C-[β-xylopyranosyl-(1→3)-β- glucopyranoside] named distemonanthoside was isolated from the stem bark of Distemonanthus benthamianus Baill., Fabaceae, along with six known compounds, sitosterol 3-O-β-d-glucopyranoside, 4-methoxygallic acid, syringic acid, quercetin, 6″- O-acetylvitexin, quercetin 3-O-β-d-glucopyranoside. The structures of those compounds and others were determined through spectral analyses. Compounds distemonanthoside, sitosterol 3-O-β-d-glucopyranoside, 4-methoxygallic acid and quercetin were tested against a clinical isolate strain of Mycobacterium tuberculosis AC 45; they exhibited good to moderate antitubercular activities with MIC values ranged from 31.25 to 125μg/ml

Secondary metabolites from Triclisia gilletii (De Wild) Staner (Menispermaceae) with antimycobacterial activity against Mycobacterium tuberculosis

Triclisinone (2), a new ochnaflavone derivative, was isolated from the aerial parts of Triclisia gilletii, along with known drypemolundein B (1) and eight other known compounds. The chemical shifts of drypemolundein B (1) have been partially revised based on reinterpretation of NMR spectroscopic data. The eight other secondary metabolites are composed of: (+)-nonacosan-10-ol (3); stigmasterol (4), 3-O-β-D- glucopyranosylsitosterol (5), 3-O-β-D-glucopyranosylstigmasterol (6); oleanic acid (7); myricetin (8), quercetin (9) and 3-methoxyquercetin (10). Their structures were elucidated using IR, MS, NMR 1D and 2D, 1H and 13C and comparison with literature data. Furthermore, compounds 1, 2, 5, 6, 8, 9 and the crude extract were tested against Mycobacterium tuberculosis. Compounds 1, 2, 8 and 9 displayed moderate to very good activity against resistant strain (codified AC 45) of M. tuberculosis with minimum inhibitory concentrations MICs ranging from 3.90 to 62.5 μg/mL

Rauvolfianine, a new antimycobacterial glyceroglycolipid and other constituents from Rauvolfia caffra. Sond (Apocynaceae)

The chemical investigation of the extract of the dried leaves of Rauvolfia caffra (Sond) (synonym Rauvolfia macrophylla) (Apocynaceae) led to isolation of a new glycoside derivative, rauvolfianine (1) as well as six known compounds: oleanolic acid (2), sitosterol-3-O-β-D-glucopyranoside (3), betulinic acid (4), vellosimine (5), sarpagine (6) and D-fructofuranosyl-β-(2→1)-α-D-glucopyranoside (7). Compounds 1, 2, 3, 4 and 7 were evaluated for antitubercular activity. Compounds 1 and 2 were the most active (MIC = 7.8125 and 31.25 μg/mL) towards the Isoniazid resistant strain of Mycobacterium tuberculosis AC45. Their structures and relative stereochemistry were elucidated by spectroscopic methods

Phytochemical Study of Aqueous Extract of Ochna schweinfurthiana F. Hoffm Powder Bark and Evaluation of Their Anti-Inflammatory, Cytotoxic, and Genotoxic Properties

Ochna schweinfurthiana has been used in traditional medicine to treat pain, inflammation, and arthritis. It is a rich source of complex dimers of flavonoids with potential use as templates for the development of therapeutic drugs. Hence, the aim of this study was to study the phytochemical content and evaluate the in vitro cytotoxic, genotoxic, and anti-inflammatory activities of the aqueous extract of Ochna schweinfurthiana bark (OSE). Phytochemical study was carried out according to LC-MS procedures, while isolation was carried out using thin layer and column chromatographies. Cytotoxicity was investigated by the mitochondrial viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) method while genotoxicity potential of the extract was ascertained using the Salmonella typhimurium test strains TA98 and TA100. The anti-inflammatory effect of OSE was evaluated by the in vitro inhibition of 15-lipooxygenase enzyme and bovine serum albumin denaturation (BSA) assays. The investigation of compounds extracted from OSE led to the identification and isolation of six known compounds, namely, hemerocallone (9), 6,7-dimethoxy-3’-4’-dimethoxyisoflavone (10), lithospermoside (13), amentoflavone (14), agathisflavone (15), and β-D-fructofuranosyl-α-D-glucopyranoside (17). In the anti-inflammatory assay, aqueous extracts of the bark showed selective inhibition of 15-lipooxygenase with IC50 value of 32.2±0.36  μg/mL and the result of the bovine serum albumin denaturation assay with IC50 value of 130± 5.78 μg/mL showed moderate activity. The toxicity assay indicated that OSE are noncytotoxic on Vero cell line with LC50 value of 50 mg/mL and nongenotoxic toward Salmonella typhimurium tester strain TA98 and TA100. Result from this study supports the traditional use of the selected medicinal plants in Cameroon for the treatment of inflammatory conditions. Noncytotoxicity and nongenotoxicity of OSE suggest that this plant is safe for use

The Chemical Composition and Antibacterial Activities of the Essential Oils from Three Aframomum Species from Cameroon, and Their Potential as Sources of (E)-(R)-Nerolidol

International audienceEssential oils obtained by hydrodistillation of seeds, pericarps, leaves and rhizomes of Aframomum dalzielii, A. letestuianum and A. pruinosum grown in Cameroon were analyzed by GC-FID and GC-MS. The seed oils of the three species were characterized by a high content of (E)-(R)-nerolidol (>88.0 %), which was fully characterized by NMR spectroscopy and chiral GC analysis. The main constituents of the pericarp and rhizome oils were monoterpene hydrocarbons, mainly beta-pinene (0.8%-22.9%) and sabinene (29.0%-42.3%), along with 1,8-cineole (4.5%-23.7%); leaf oils were characterized by sesquiterpenes, namely (E)-beta-caryophyllene (18.4%-82.4%) and caryophyllene oxide (4.5%-23.7%). The antibacterial activities of these essential oils and of nine pure compounds (sabirtene, beta-pinene, 1,8-cineole, linalool, racemic (E)-nerolidol, (E)-(R)-nerolidol, (E)-beta-caryophyllene, a-humulene and caryophyllene oxide) were assessed against Micrococcus luteus and Escherichia coli. The strongest activities were observed against E. coli. The seed essential oils and their major component, (E)-(R)-nerolidol, exhibited the lowest MIC values (0.19-0.39 mu L/mL), justifying their traditional use and their potential application as natural food preservatives

Relative abundance and diversity of extended-spectrum beta-lactamase-producing Enterobacteria in some aquatic environments in an urbanized area in DR Congo

ESBL-producing enterobacteria have a significant impact on public health as they provide antibiotic resistance. Little is known about the relative diversity in various types of biotopes in the same geographical area. This study aimed to determine their diversity and abundance in 3 different aquatic environments. Samples from wells, river water, and hospital wastewater were analyzed. ESBL-producing enterobacteria isolated were identified using double-disk synergy test method based on enzymatic tests. Results showed that the abundance of total enterobacteria in log (CFU/100 µL) varied from 0.60 to 2.10 in wells, from 0.79 to 5.73 in rivers, and from 1.58 to 6.52 in hospital wastewater. That of ESBL-producing enterobacteria reached 6.23 in hospital wastewater, 3.08 in river samples and 2.04 in wells. Their relative abundances compared to all of the isolated enterobacteria varied from 0.34 to 4.55% in wells, from 0 to 97.5% in rivers and from 0.73 to 61.29% in hospital wastewater. Their abundances and diversity varied significantly between hospital wastewater and the 2 other types of samples analyzed (P<0.05). ESBL-producing enterobacteria identified include

The Chemical Composition and Antibacterial Activities of the Essential Oils from Three Aframomum Species from Cameroon, and Their Potential as Sources of (E)-(R)-Nerolidol

Essential oils obtained by hydrodistillation of seeds, pericarps, leaves and rhizomes of Aframomum dalzielii, A. letestuianum and A. pruinosum grown in Cameroon were analyzed by GC-FID and GC-MS. The seed oils of the three species were characterized by a high content of (E)-(R)-nerolidol (>88.0 %), which was fully characterized by NMR spectroscopy and chiral GC analysis. The main constituents of the pericarp and rhizome oils were monoterpene hydrocarbons, mainly beta-pinene (0.8%-22.9%) and sabinene (29.0%-42.3%), along with 1,8-cineole (4.5%-23.7%); leaf oils were characterized by sesquiterpenes, namely (E)-beta-caryophyllene (18.4%-82.4%) and caryophyllene oxide (4.5%-23.7%). The antibacterial activities of these essential oils and of nine pure compounds (sabirtene, beta-pinene, 1,8-cineole, linalool, racemic (E)-nerolidol, (E)-(R)-nerolidol, (E)-beta-caryophyllene, a-humulene and caryophyllene oxide) were assessed against Micrococcus luteus and Escherichia coli. The strongest activities were observed against E. coli. The seed essential oils and their major component, (E)-(R)-nerolidol, exhibited the lowest MIC values (0.19-0.39 mu L/mL), justifying their traditional use and their potential application as natural food preservatives