Disruption of Biofilm Formation and Quorum Sensing in Pathogenic Bacteria by Compounds from Zanthoxylum Gilletti (De Wild) P.G. Waterman.

Microbial resistance is facilitated by biofilm formation and quorum-sensing mediated processes. In this work, the stem bark (ZM) and fruit extracts (ZMFT) of Zanthoxylum gilletii were subjected to column chromatography and afforded lupeol (1), 2,3-epoxy-6,7-methylenedioxyconiferyl alcohol (3), nitidine chloride (4), nitidine (7), sucrose (6) and sitosterol-ß-D-glucopyranoside (2). The compounds were characterized using MS and NMR spectral data. The samples were evaluated for antimicrobial, antibiofilm and anti-quorum sensing activities. Highest antimicrobial activity was exhibited by compounds 3, 4 and 7 against Staphylococcus aureus (MIC 200 µg/mL), compounds 3 and 4 against Escherichia coli (MIC = 100 µg/mL) and compounds 4 and 7 against Candida albicans (MIC = 50 µg/mL). At MIC and sub-MIC concentrations, all samples inhibited biofilm formation by pathogens and violacein production in C. violaceum CV12472 except compound 6. Good disruption of QS-sensing in C. violaceum revealed by inhibition zone diameters were exhibited by compounds 3 (11.5 ± 0.5 mm), 4 (12.5 ± 1.5 mm), 5 (15.0 ± 0.8 mm), 7 (12.0 ± 1.5 mm) as well as the crude extracts from stem barks (16.5 ± 1.2 mm) and seeds (13.0 ± 1.4 mm). The profound inhibition of quorum sensing mediated processes in test pathogens by compounds 3, 4, 5 and 7 suggests the methylenedioxy- group that these compounds possess as the possible pharmacophore.

Curative anti-typhoid effect of Detarium microcarpum Guill. & Perr. (Leguminosae) hydroethanolic extract root bark based-on in vivo and molecular docking analyses.

ETHNOPHARMACOLOGICAL RELEVANCE: Detarium microcarpum is used to treat typhoid fever, a major public health problem, by indigenous population in Africa. Though its preventive activities have been documented, the curative effect is still to be confirmed. AIM OF THE STUDY: This study aimed at evaluating the curative effects of the hydroethanolic extract of Detarium microcarpum root bark on Salmonella typhimurium-induced typhoid in rat and exploring the in-silico inhibition of some bacterial key enzymes. STUDY DESIGN: In vitro antioxydant, in vivo antisalmonella of the extract and in silico molecular docking assay on the isolated compounds were carried out to explore the anti-salmonella effects of Detarium microcarpum. MATERIAL AND METHODS: The in vitro antioxidant properties of the extract were evaluated using DPPH, ABTS and FRAP tests. The anti-salmonella activity of the extract was assessed through feacal sample from Salmonella typhimurium-infected rat cultured in Salmonella-Shigella agar (SS agar) medium. The affinity of isolated compounds (Rhinocerotinoic acid and Microcarposide) from the extract were performed on four key enzymes (Adenylosuccinate lyase, Acetyl coenzyme A synthetase, Thymidine phosphorylase and LuxS-Quorum sensor) using molecular docking simulation to elucidate the molecular level inhibition mechanism. RESULTS: Crude extract of D. microcarpum root bark showed variable activities on DPPH (RSa50: 6.09 ± 1.04 µg/mL), ABTS (RSa50: 24.46 ± 0.27), and FRAP (RSa50: 23.30 ± 0.23). The extract at all the doses exhibited significant healing effect of infected rats, with the complete clearance. The extract restored hematological, biochemical and histological parameters closed to the normal control. The molecular docking results indicates that rhinocerotinoic acid and microcarposide present more affinity to the LuxS-Quorum sensor and Acetyl coenzyme A synthetase protein as compared to the others. CONCLUSION: These results demonstrate potent anti-typhoid activities of the hydroethanolic of Detarium microcarpum root bark extract through antioxidant properties and high inhibitory affinity of its compounds on some bacterial key enzymes that justify its use as traditional medicine to typhoid fever.

A new flavone and a newly synthesized alkaloid from Lippia rugosa A. Chev (Verbenaceae).

The chemical investigation of the leaf extract of a Cameroonian medicinal plant, Lippia rugosa A Chev (Verbenaceae) led to the isolation of a new flavonoid derivative flavolippia (1), alongside eleven known compounds: 2,4-dimethylpyridin-3,5-diol (2), 5-hydroxy-6,7,4'-trimethoxylflavone (3), 5-hydroxy-3,7,4'-trimethoxyflavone (4), 7-hydroxy-5,6,4'-trimethoxyflavone (5), 3ß-hydroxy-urs-12-en-3-ol (α-amyrin) (6), lupeol acetate (7), lup-20(29)-en-3ß-ol (lupeol) (8), lup-20(29)-en-3ß,28-diol (betulin) (9), fridelan-3-one (fridelan) (10), saccharose (11), cosanol (12). In addition, a new semi-synthetic alkaloid derivative named lippiamicin (13) was prepared from 2,4-dimethylpyridin-3,5-diol (2). Their structures were established on the basis of their spectroscopic data, as well as 1 D and 2 D NMR. Compounds 1-13 were evaluated for their antioxidant activities. The results obtained showed that compounds 2 and 12 were the most active with IC50 values of 0.145 ± 0.011 and 0.195 ± 0.017 µM/mL respectively (for DPPH•) and 0.241 ± 0.027 and 0.223 ± 0.024 µM/mL respectively (for FRAP) compared to butylated hydroxyltoluene used as positive control.

Secondary metabolites from Detarium microcarpum Guill. and Perr. (Fabaceae).

The chemical investigation of the ethanol/water (7:3) extract of the roots of Detarium microcarpum (Fabaceae) led to the isolation of one new labdane diterpenoid, microcarpin (1) and one new ceramide derivative, microcarpamide (2), along with eight known secondary metabolites (3-10) including, 5-(carboxymethyl)-5,6,8a-trimethyl-3,4,4a,5,6,7,8,8a-octahydronaphthalene-1-carboxylic acid (3), microcarposide (4), rhinocerotinoic acid (5), 1,7-dihydroxy-6-methylxanthone (6), ursolic acid (7), 3ß,23-dihydroxylup-20(29)-en-28-oic acid (8), alphitolic acid (9), and stigmasterol glucoside (10). The structures of these compounds were elucidated based on their spectroscopic data. Although compounds 3 and 4 are known, their crystalline structures are reported here for the first time. These compounds were evaluated in vitro for their antisalmonella activity. The results obtained showed that, microcarpamide (2), microcarposide (4), and rhinocerotinoic acid (5) were moderately active against three salmonella strains: Salmonella typhi, Salmonella enteritidis and Salmonella typhimirium, with minimum inhibition concentration values of 76.7 and 153.5 µM.

Antiproliferative activity of a new xanthone derivative from leaves of Garcinia nobilis Engl.

A new xanthone, mboudiexanthone (1), together with five known compounds, euxanthone (2), isogarcinol (3), garcinol (4), betulinic acid (5) and zeorin (6) were isolated from the leaves of Garcinia nobilis Engl. The structures were determined by 1D and 2D NMR techniques and X-ray diffraction for 6. The in vitro antiproliferative properties of isolated compounds were evaluated against the human breast cancer cell line MCF-7. All compounds showed an antiproliferative activity with an IC50 value down to ∼11 µM for isogarcinol.

In vitro and in vivo anti-salmonella properties of hydroethanolic extract of Detarium microcarpum Guill. & Perr. (Leguminosae) root bark and LC-MS-based phytochemical analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Typhoid fever treatment remains a challenge in endemic countries. Detarium microcarpum is traditionally used to manage typhoid. AIM OF THE STUDY: The study aims to explore the efficacy of hydroethanolic extract of Detarium microcarpum root bark in rats infected with salmonella. MATERIAL AND METHODS: The phytochemical profile of the extract was obtained by UHPLC-MS analysis in an attempt of standardization. The in vitro antimicrobial activity was determined using broth dilution method. Salmonella infection was induced by oral administration of S. thyphimurium to immunosuppressed rats. Infected rats were then treated 2 h later with the extract (75, 150 and 300 mg/kg), distilled water (normal and salmonella control) and ciprofloxacin (8 mg/kg) for control. Body weight was monitored and stools were cultured to determine the number of colony-forming units. At the end of treatment, animals were sacrificed, blood and organs were collected for hematological, biochemical and histopathological analyses. RESULTS: Detarium microcarpum extract as well as the isolated compound (rhinocerotinoic acid) exhibited good antimicrobial activity in vitro with bacteriostatic effects. The plant extract significantly (p < 0.05) inhibited the bacterial development in infected animals with an effective dose (ED50) of 75 mg/kg. In addition, the extract prevented body weight loss, hematological, biochemical and histopathological damages in treated rats. CONCLUSION: Detarium microcarpum extract possesses antisalmonella properties justifying its traditional use for the typhoid fever management.

Chemical constituents from leaves and trunk bark of Rinorea oblongifolia (Violaceae).

Two new coruleoellagic acid derivatives, 3,4',5,5',-tetramethylcoruleoellagic acid (1); 3',4,4',5,5'-pentamethylcoruleoellagic acid (2) and a new friedelane-type triterpene derivative rinol (5), were isolated from leaves and trunk bark of Rinorea oblongifolia (Violaceae) along with seven known compounds including 3,3',4,4',5'-pentamethylcoruleoellagic acid (3), hexamethylcoruleoellagic acid (4), 28-hydroxyfriedelin (6), friedelin (7), friedelan-3-ol (8), scopoletin (9) and ß-sitosterol-3-O-ß-D-glucopyranoside (10). Their structures were elucidated by means of spectroscopic methods including IR, 1D and 2D NMR in conjunction with mass spectrometry. Crude extracts of leaves and trunk bark as well as compounds 1-4 were evaluated for their antibacterial activities against 7 pathogenic bacterial strains (Streptococcus pneumoniae ATCC49619, Staphylococcus aureus ATCC 43300, Klepsiella pneumoniae ATCC 700603, Haemophilus influenza ATCC 49247, Escherichia coli ATCC 25922, Pseudomonas aeruginosa HM601, Staphylococcus aureus BAA 977). Compound (3) displayed noteworthy activity against Haemophilus influenza with MIC value of 9.38 µg/mL.

Rubescins I and J, further limonoid derivatives from the stem bark of Trichilia rubescens (Meliaceae).

Two new tetranorterpenoid derivatives named rubescins I (1) and J (2), were isolated along with six known compounds including rubescin D (3), lichexanthone (4), scopoletin (5), scopoletin O-glycoside (6), ß-sitosterol (7) and stigmasterol (8) from the stem bark of Trichilia rubescens (Meliaceae). The structures of the compounds were determined by means of MS, different NMR and by comparison with related data reported in the literature.

Phytochemical analysis with free radical scavenging, nitric oxide inhibition and antiproliferative activity of Sarcocephalus pobeguinii extracts.

BACKGROUND: Free radicals have been implicated in the pathogenesis of diverse metabolic disorders including cancer. Therefore, fighting against free radicals has become an important strategy in the prevention or treatment of such diseases, in addition to direct or indirect anticancer chemotherapy. Sarcocephalus pobeguinii has been used traditionally to treat various diseases in which excess production of free radicals is implicated, warranting investigation of its free radical scavenging, anticancer and anti-inflammatory activity. METHODS: In the present study, extracts from leaves, fruits, roots and bark of Sarcocephalus pobeguinii were evaluated on four human cancer cell lines (MCF-7, HeLa, Caco-2 and A549 cells) and a non-cancerous cell line for their antiproliferative potential. The cells were incubated with the plant extracts for 48 h at 37 °C in a 5% CO2 humidified environment and their cytotoxic effect was determined using the tetrazolium-based colorimetric (MTT) assay. The radical inhibition was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging techniques. The nitric oxide inhibitory activity was determined using LPS-activated RAW 264.7 macrophages. The correlation between radical scavenging capacity and antiproliferative activity was also analysed. RESULTS: The extract from leaves of Sarcocephalus pobeguinii (LSP) exhibited the highest cytotoxic effect on all four of the human cancer cell lines but with some cytotoxicity to the normal Vero cells. However, the LSP extract had the best selectivity index, ranging from 3.15 to 18.28. Also, antioxidant and anti-inflammatory assays indicated that the LSP extract had the highest radical scavenging capacity of all the extracts. A positive linear correlation was found between free radical scavenging ability and antiproliferative activity against the four cancer cell lines, with the highest correlation factor (R2 = 0.9914) obtained between DPPH inhibition and antiproliferative activity against A549 cells. CONCLUSIONS: The high selectivity index of the Sarcocephalus pobeguinii leaf extract indicates the potential of using this extract in cancer therapy. Furthermore, the positive correlation between free radical scavenging and antiproliferative activity suggests that the radical scavenging capacity of extracts may contribute to a prediction of their anticancer property.

Antimicrobial structure activity relationship of five anthraquinones of emodine type isolated from Vismia laurentii.

BACKGROUND: Antimicrobial activity of anthraquinone compounds of emodine type has been reported by many authors. These compounds are found in Vismia laurentii (Clusiaceae), a plant used in traditional pharmacopoeia for treatment of microbial infections among others affections. The continuous identification of new compounds has raised the problem of the relation between the structure and antimicrobial properties. RESULTS: The yeast growth kinetics parameters were not influenced by the pH variation as it was the case for the other tested bacteria. Fungicidal activities were noted for all molecules while only few of them had bactericidal activities, mostly on Gram positive bacteria. Mathematical model establishing a quantitative relationship between physicochemical properties of molecules and their fungicidal activities were obtained for Candida albicans and showed that physicochemical properties impacting on antifungal activity were polarizability, partition coefficient, molecular weight and hydrogen bond acceptor. CONCLUSIONS: This work demonstrated that the presence of a long aliphatic chain methoxy group substituted in position two of the emodine structure increased the antibacterial properties of the studied compounds. Moreover this antimicrobial property depends on the pH of the environment, and specifically on the polarizability and number of hydrogen bond acceptors of the compound.

The Limonoids TS3 and Rubescin E Induce Apoptosis in Human Hepatoma Cell Lines and Interfere with NF-κB Signaling.

Hepatocellular carcinoma (HCC) is extremely resistant towards pharmacological therapy. To date, the multi-kinase inhibitor Sorafenib is the only available therapeutic agent with the potential to prolong patient survival. Using the human hepatoma cell lines HepG2 and Huh7, we analyzed anti-cancer activities of 6 purified havanensin type limonoids isolated from the traditional African medicinal plant Trichilia rubescens Oliv. Our results show that two of the compounds, TR4 (TS3) and TR9 (Rubescin E) reduced hepatoma cell viability, but not primary hepatocyte viability, at TC50s of 5 to 10 µM. These were significantly lower than the TC50s for Sorafenib, the histone deacetylase inhibitor SAHA or 5-Fluoruracil. In comparison, TR3 (Rubescin D), a limonoid isolated in parallel and structurally highly similar to TR4 and TR9, did not interfere with hepatoma cell viability. Both, TR4 and TR9, but not TR3, induced apoptosis in hepatoma cells and interfered with NF-κB activation. TR4 as well as TR9 significantly supported anti-cancer activities of Sorafenib. In summary, the limonoids TR4 and TR9 exhibit anti-cancer activities and support Sorafenib effects in vitro, having the potential to support future HCC therapy.

Antibacterial and antioxidant xanthones and benzophenone from garcinia smeathmannii.

A new prenylated xanthone, 1,3,5,8-tetrahydroxy-2-(3-methybut-2-enyl)-4-(3,7-dimethylocta-2,6-dienyl) xanthone (1), and a new benzophenone (2), together with four known xanthone derivatives, cheffouxanthone (3), smeathxanthone A (4), smeathxanthone B (5), ananixanthone (6), and two pentacyclic triterpenes, epi-friedelinol (7) and friedelin (8), were isolated from the stem bark of Garcinia smeathmannii. The structures of the compounds were elucidated on the basis of 1D and 2D NMR experiments, and compound 2 was further characterized and confirmed by single X-ray analysis. Compounds 1, 2, and 3 exhibited the most prominent antibacterial activity against gram-positive Enterococcus faecalis with minimal inhibitory concentration values of 8, 8, and 2 µg/mL, respectively, while compounds 1, 3, 4, and 6 showed the capacity to scavenge free radicals.

Isolation and biological activity of compounds from Garcinia preussii.

CONTEXT: Plants of the genus Garcinia (Clusiaceae) are traditionally used to relieve stomachaches, toothaches, and as a chew stick. OBJECTIVE: In order to determine which compounds were responsible for these activities, a phytochemical investigation of the fruits and leaves of Garcinia preussii Engl. was pursued. MATERIALS AND METHODS: Plants were extracted by solvents of various polarities. Compounds isolation was then carried out using chromatography methods (medium- and high-pressure liquid chromatography, open column and thin-layer chromatography). The isolated compounds were identified and characterized by using 1D and 2D NMR spectroscopies. The antioxidant activity was evaluated using DPPH(•), ABTS(•-), ALP, and ORAC assays. The antimicrobial activity was assayed against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis by determining the minimum inhibitory concentration (MIC) value. The cytotoxic activity of most of the isolated compounds was evaluated on a small panel of human cancer cell lines (DU145, HeLa, HT-29, and A431) using the XTT method. RESULTS: The phytochemical investigation of G. preussii led to the isolation of eight known compounds, six benzophenones and two flavonoids. These compounds were tested for their biological activities. 1, 2, 3, 4, 7 and 8 demonstrated a high free radical scavenging activity with ER50 ranging from 0.1 to 0.7. The antimicrobial activity was shown only against Gram-positive bacteria for 1, 4, and 5. A moderate cytotoxic activity with IC50 ranging from 7 to 50 µM was observed, except for 6 which was not active. CONCLUSION: These results appear to support some of the properties reported for Garcinia species.

Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by Flow Injection Analysis-Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry.

The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography-Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

Norbergenin derivatives from Diospyros crassiflora (Ebenaceae).

From the ethyl acetate extract of the stems of Diospyros crassiflora Hiern, three new norbergenin derivatives, 4,11-di-O-galloylnorbergenin (1), 3-O-galloylnorbergenin (2), and 4-O-(4'-hydroxy-3'-methoxybenzoyl)-norbergenin (3), were isolated along with ten known compounds (4-13). Their structures were established by mean of spectroscopic techniques namely 1- and 2-D NMR experiments, mass spectrometry and comparison with reported data. Isolates 1-9 were evaluated for their ability to protect PC12 cells against hydrogen peroxide induced injury. Compounds with a galloyl group in their structure were found to prevent toxicity induced by H2O2 in PC12 cells.

Terpenoids from Turraeanthus species.

Chemical investigation of the root bark of Turraeanthus mannii and the stem of T. longipes resulted in the isolation of two new diterpenes, 13-methyl-labda-8(17)-en-15-oic acid (1) and 13-(hydroxymethyl)-14-hydroxy-ent-labda-8(17)-en-15-oic acid (2), along with two known diterpenes, 19-hydroxy-ent-labda-8(17),13-dien-15,16-olide (3) and 19-acetoxy-ent-labda-8(17),13-dien-15,16-olide (4), and the phytosterol, stigmasterol. The structure elucidation of the new compounds has been achieved using spectroscopic techniques.

New coumarin glycosides from the leaves of Diospyros crassiflora (Hiern).

Two new 5-methylcoumarin glycosides named diosfeboside A (1) and B (2) and five known compounds namely kaempferol 3-O-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranoside (3), ursolic acid (4), betulinic acid (5), stigmasterol (6) and stigmasterol 3-O-ß-D-glucopyranoside (7) were isolated from the leaves of Diospyros crassiflora (Hiern). Their structures were established through interpretation of 1 and 2D NMR, mass spectra analysis and comparison with reported data. In vitro cytotoxic activity of the new compounds against human carcinoma cell lines (HL-60, Bel-7402, BGC-823, and KB) was evaluated and no cytotoxicity was observed for each of them.

Xanthones from the seeds of Allanblackia monticola and their apoptotic and antiproliferative activities.

Phytochemical investigations of the seeds of ALLANBLACKIA MONTICOLA have led to the isolation and characterization of one new xanthone derivative, named allanxanthone E ( 1), together with seven known compounds, including five xanthones, 1,7-dihydroxy-3-methoxy-2-(3-methylbut-2-enyl)xanthone ( 2), alpha-mangostin ( 3) , garciniafuran ( 4) , allanxanthone C ( 5), and 1,6-dihydroxy-2,4-diprenylxanthone ( 6), and two pentacyclic triterpenes, friedelin and lupeol. The structures of these compounds were established on the basis of one- and two-dimensional NMR homo- and heteronuclear correlation evidence. Some of these compounds were evaluated for their apoptotic and antiproliferative activities against human leukemic B lymphocytes, such as the hairy cell leukemia-derived ESKOL cell line and cells from B-CLL (B-cell chronic lymphocytic leukemia) patients.

Diterpenoids from Turraeanthus mannii.

Three new compounds, 15-acetoxy-12-hydroxy-16-methyl-labda-8(17),13E-diene (1), ent-labda-8(17),13-dien-15,16-olid-19-oic acid methyl ester (2), and 12-hydroxy-labda-8(17),13-dien-15,16-olide (3), together with two known compounds, 19-acetoxy-ent-labda-8(17),13-dien-15,16-olide (4), and 16-acetoxy-12,15-epoxy-15beta-hydroxy-labda-8(17),13(16)-diene (5) were isolated from the stem bark of Turraeanthus mannii (Meliaceae). The structures of compounds 1 - 3 were elucidated by analysis of the spectroscopic data. The crude methanol extract and compound 5 exhibited weak antibacterial and antifungal activity.

Antimicrobial activity of the methanolic extracts and compounds from Vismia laurentii De Wild (Guttiferae).

Methanolic extracts prepared from the leaves, twigs and the roots of Vismia laurentii De Wild as well as nine compounds isolated from these crude extracts, were tested for their antimicrobial activity against Gram-positive bacteria (six species), Gram-negative bacteria (12 species) and two Candida species using disc diffusion and well micro-dilution methods. The disc diffusion assay indicated that the crude extract was active against all the pathogens tested, whereas isolated compounds showed selective activities. The degree of sensitivity of the test organisms to purified compounds varied from 25 to 90%. Fridelin (8) was found to be the most active compound, while Bivismiaquinone (3) was the least active. The lowest minimum inhibition concentration (MIC) values as obtained by the micro-dilution assays were 19.53 and 1.22 microg/ml for the crude extracts and purified compounds, respectively. The lowest value for the purified compounds (1.22 microg/ml) was obtained with O(1)-demethyl-3',4'-deoxypsorospermin-3',4'-diol (6) on Candida gabrata and Bacillus subtilis; 1,8-dihydroxy-6-methoxy-3-methylanthraquinone (5) on Bacillus subtilis and 6-deoxyisojacareubin (7) on Bacillus stearothermophilus. These results provide promising baseline information for the potential use of these crude extracts as well as some of the isolated compounds in the treatment of bacterial and fungal infections.