In vitro antimycobacterial activity of six Cameroonian medicinal plants using microplate alamarBlue assay

AbstractObjective/backgroundThe latest incidence of tuberculosis (TB) (per 100,000 people) in Cameroon was 243.00 as of 2011. Over the past 21years, the value for this indicator has fluctuated between 112.00 in 1990 and 320.00 in 2003. Worldwide, this incidence has also increased, bringing back TB as a reemerging disease. On the same note, resistance to anti-TB drugs has increased, urging the search for new molecules.MethodsThis study was carried out to evaluate the antimycobacterial activity of six medicinal plants on the virulent strain, H37Rv, using the microplate alamarBlue assay. Mycobacterium tuberculosis (H37Rv strain) was incubated with decreased concentrations of six plant extracts, ranging from 250μg/mL to 31.25μg/mL. After 7days of incubation at 37°C, the effects of these plant extracts on the viability of the mycobacteria were evaluated. For each plant extract, the minimal inhibitory concentration was determined.ResultsThe results showed that the compounds MBC1, MBC24, MBC68, MBC81, MBC117, and MBC118 were the best candidates with minimal inhibitory concentrations of 31.25, 62.5, 125, 62.5, and 125μg/mL, respectively.ConclusionThese results confirm and validate the traditional use of these plants to treat respiratory diseases, which could be good sources and alternatives of plant metabolites for anti-TB-drug development

Anticancer and antibacterial secondary metabolites from the endophytic fungus Penicillium sp. CAM64 against multi-drug resistant Gram-negative bacteria.

Background: The emergence of multiple-drug resistance bacteria has become a major threat and thus calls for an urgent need to search for new effective and safe anti-bacterial agents. Objectives: This study aims to evaluate the anticancer and antibacterial activities of secondary metabolites from Penicillium sp. , an endophytic fungus associated with leaves of Garcinia nobilis . Methods: The culture filtrate from the fermentation of Penicillium sp. was extracted and analyzed by liquid chromatography\u2013 mass spectrometry, and the major metabolites were isolated and identified by spectroscopic analyses and by comparison with published data. The antibacterial activity of the compounds was assessed by broth microdilution method while the anticancer activity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Results: The fractionation of the crude extract afforded penialidin A-C (1-3), citromycetin (4), p-hydroxyphenylglyoxalaldoxime (5) and brefelfin A (6). All of the compounds tested here showed antibacterial activity (MIC = 0.50 \u2013 128 \u3bcg/mL) against Gramnegative multi-drug resistance bacteria, Vibrio cholerae (causative agent of dreadful disease cholera) and Shigella flexneri (causative agent of shigellosis), as well as the significant anticancer activity (LC50 = 0.88 \u2013 9.21 \u3bcg/mL) against HeLa cells. Conclusion: The results obtained indicate that compounds 1-6 showed good antibacterial and anticancer activities with no toxicity to human red blood cells and normal Vero cells

Anti-mycobacterial activity of polyketides from Penicillium sp. endophyte isolated from Garcinia nobilis against Mycobacterium smegmatis

Objective/background: According to estimates by the World Health Organization, there were 9.6 million new tuberculosis (TB) cases in 2014: 5.4 million among men, 3.2 million among women, and 1.0 million among children. There were also 1.5 million TB deaths. Although there are potent anti-TB molecules, the misuse of these drugs in addition to inconsistent or partial treatment have led to the development of multidrug-resistant TB and extensively drug-resistant TB. It is established that plants harbor microorganisms, collectively known as endophytes, which also produce metabolites. Exploring the as-yet untapped natural products from the endophytes increases the chances of finding novel and active compounds. The present study was aimed to investigate the antimycobacterial activity of the crude extract and compounds isolated from Penicillium sp. endophyte associated with Garcinia nobilis against Mycobacterium smegmatis. Methods: Liquid culture obtained from the fermentation of Penicillium sp. was extracted using ethylacetate and the liquid chromatography–mass spectrometry monitored fractionation of crude extracts yielded six compounds. Their structures were elucidated with spectroscopic analyses including two-dimensional nuclear magnetic resonance, high resolution mass spectrometry by dereplication using Antibase, and by comparison to literature data. All compounds and the crude extract from the liquid medium were evaluated for their antimycobacterial activity against M. smegmatis. Results: In this study, the activity of penialidins A–C (1–3), citromycetin (4), p-hydroxy phenyl glyoxalaldoxime (5), and Brefeldin A (6) were tested against nonpathogenic M. smegmatis. Penialidin C was the most active compound with a minimum inhibitory concentration of 15.6μg/mL. Conclusion: Isolated compounds from Penicillium sp. harbored in G. nobilis exhibited promising antimycobacterial activity against M. smegmatis thus supporting the immensity of the potential of antimycobacterial drug discovery from endophytes from medicinal plants. Penialidin C could further be investigated for antimycobacterial drug development

A New Chromene Derivative and a New Polyalcohol Isolated From the Fungus Xylaria sp. 111A Associated With Garcinia polyantha Leaves

Tegha HF, Jouda J-B, Dzoyem JP, et al. A New Chromene Derivative and a New Polyalcohol Isolated From the Fungus Xylaria sp. 111A Associated With Garcinia polyantha Leaves. Natural Product Communications. 2021;16(1).From the crude extract of the plant-associated fungus Xylaria sp. collected in Cameroon, a new 2H-chromene derivative, hexacycloxylariolone (1), and a new polyalcohol, xylatriol (2), were isolated, in addition to 3 known compounds, 2,3-furandiol (3), 1,8-dimethoxynaphthalene (4), and 1-palmitoyl-rac-glycerol (5). Their chemical structures were established on the basis of the interpretation of spectroscopic data. Hexacycloxylariolone (1), 1,8-dimethoxynaphthalene (4), and 1-palmitoyl-rac-glycerol (5) showed antiproliferative activity by inhibiting the growth of Raw 264.7 and THP-1 cancer cell lines

Lambertellin from Pycnoporus sanguineus MUCL 51321 and its anti-inflammatory effect via modulation of MAPK and NF-kappa B signaling pathways

Lambertellin (1) and ergosta-5,7,22-trien-3-ol (2) were isolated from the solid rice fermentation of the plant pathogenic fungus Pycnoporus sanguineus MUCL 51321. Their structures were elucidated using comprehensive spectroscopic methods. The isolated compounds were tested on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Lambertellin (1) exhibited promising inhibitory activity against nitric oxide (NO) production with IC50 value of 3.19 mu M, and it significantly inhibited the expression of inducible NO synthase (iNOS) and cyclooxygenase 2 (COX-2). Lambertellin (1) also decreased the expression of pro-inflammatory cytokines IL-6 and IL-1 beta. The study of the mechanistic pathways revealed that lambertellin (1) exerts its anti-inflammatory effect in LPS-stimulated RAW 264.7 macrophage cells by modulating the activation of the mitogen activated protein kinase (MAPK) and nuclear factor kappa B (NF-kappa B) signaling pathways. Therefore, lambertellin (1) could be a promising lead compound for the development of new anti-inflammatory drugs

Pentacyclic triterpenoids and other constituents isolated from the leaves of Gambeya lacourtiana and their antibacterial activity

Talla RM, Jouda J-B, Mbazoa CD, et al. Pentacyclic triterpenoids and other constituents isolated from the leaves of Gambeya lacourtiana and their antibacterial activity. Biochemical Systematics and Ecology. 2021;98: 104322.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

Asperpyrone, a rare alpha-pyrone metabolite produced by an endophytic fungus Aspergillus sp. isolated from Garicinia smeathmannii (Planch. & Triana) Oliv.

Jouda J-B, Njoya EM, Nguengang RT, et al. Asperpyrone, a rare alpha-pyrone metabolite produced by an endophytic fungus Aspergillus sp. isolated from Garicinia smeathmannii (Planch. & Triana) Oliv. Natural product research. 2021.A new alpha-pyrone, asperpyrone (1) and two known compounds, stigmasterol (2) and 7-hydroxy-3-(2,3-dihydroxybutyl)-1(3H)-Isobenzofuranone (3) were isolated from the solid rice culture of the endophytic fungus Aspergillus sp., an endophytic fungus isolated from the fresh inner tissue of the barks of Garicinia smeathmannii. Their structures were determined by extensive spectral analysis including 1D and 2D NMR, HRESIMS and single-crystal X-ray crystallographic analysis. Asperpyrone (1) was tested against an axenic culture of Entamoeba moshkovskii, but did not exhibit any significant amoebicidal activity

One new constituent from the stem bark of Chrysophyllum lacourtianum De Wild. (sapotaceae)

Talla RM, Jouda J-B, Mawabo IK, et al. One new constituent from the stem bark of Chrysophyllum lacourtianum De Wild. (sapotaceae). Natural Product Research . 2021.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 1D and 2D 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 500g/mL. The n-hexane fraction showed moderate activity against Staphylococcus aureus (ATCC 43300 and ATCC 25923) with MIC values of 125g/mL and ursolic acid (5) exhibited strong activity against Enterobacter aerogenes CPC and Escherichia coli ATCC 25322 with MIC values of 7.8 and 3.9g/mL respectively

A new flavonol derivative and other compounds from the leaves of Bauhinia thonningii Schum with activity against multidrug-resistant bacteria

Nouemsi GRS, Jouda J-B, Leutcha PB, et al. A new flavonol derivative and other compounds from the leaves of Bauhinia thonningii Schum with activity against multidrug-resistant bacteria. Natural Product Research. 2022.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-beta-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 128g/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 4g/mL), KP55 and Staphylococcus aureus MRSA6 in the presence of the PaSSN