Cytotoxicity of the methanol extracts and compounds of Brucea antidysenterica (Simaroubaceae) towards multifactorial drug-resistant human cancer cell lines.

BACKGROUND: Cancer remains a global health concern and constitutes an important barrier to increasing life expectancy. Malignant cells rapidly develop drug resistance leading to many clinical therapeutic failures. The importance of medicinal plants as an alternative to classical drug discovery to fight cancer is well known. Brucea antidysenterica is an African medicinal plant traditionally used to treat cancer, dysentery, malaria, diarrhea, stomach aches, helminthic infections, fever, and asthma. The present work was designed to identify the cytotoxic constituents of Brucea antidysenterica on a broad range of cancer cell lines and to demonstrate the mode of induction of apoptosis of the most active samples. METHODS: Seven phytochemicals were isolated from the leaves (BAL) and stem (BAS) extract of Brucea antidysenterica by column chromatography and structurally elucidated using spectroscopic techniques. The antiproliferative effects of the crude extracts and compounds against 9 human cancer cell lines were evaluated by the resazurin reduction assay (RRA). The activity in cell lines was assessed by the Caspase-Glo assay. The cell cycle distribution, apoptosis via propidium iodide (PI) staining, mitochondrial membrane potential (MMP) through 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) staining, and the reactive oxygen species (ROS) via 2´,7´-dichlorodihydrofluoresceine diacetate (H2DCFH-DA) staining, were investigated by flow cytometry. RESULTS: Phytochemical studies of the botanicals (BAL and BAS) led to the isolation of seven compounds. BAL and its constituents 3, (3-(3-Methyl-1-oxo-2-butenyl))1H indole (1) and hydnocarpin (2), as well as the reference compound, doxorubicin, had antiproliferative activity against 9 cancer cell lines. The IC50 values varied from 17.42 µg/mL (against CCRF-CEM leukemia cells) to 38.70 µg/mL (against HCT116 p53-/- colon adenocarcinoma cells) for BAL, from 19.11 µM (against CCRF-CEM cells) to 47.50 µM (against MDA-MB-231-BCRP adenocarcinoma cells) for compound 1, and from 4.07 µM (against MDA-MB-231-pcDNA cells) to 11.44 µM (against HCT116 p53+/+ cells) for compound 2. Interestingly, hypersensitivity of resistant cancer cells to compound 2 was also observed. BAL and hydnocarpin induced apoptosis in CCRF-CEM cells mediated by caspase activation, the alteration of MMP, and increased ROS levels. CONCLUSION: BAL and its constituents, mostly compound 2, are potential antiproliferative products from Brucea antidysenterica. Other studies will be necessary in the perspective of the discovery of new antiproliferative agents to fight against resistance to anticancer drugs.

Origin and Global Expansion of Mycobacterium tuberculosis Complex Lineage 3.

Mycobacterium tuberculosis complex (MTBC) Lineage 3 (L3) strains are abundant in world regions with the highest tuberculosis burden. To investigate the population structure and the global diversity of this major lineage, we analyzed a dataset comprising 2682 L3 strains from 38 countries over 5 continents, by employing 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats genotyping (MIRU-VNTR) and drug susceptibility testing. We further combined whole-genome sequencing (WGS) and phylogeographic analysis for 373 strains representing the global L3 genetic diversity. Ancestral state reconstruction confirmed that the origin of L3 strains is located in Southern Asia and further revealed multiple independent introduction events into North-East and East Africa. This study provides a systematic understanding of the global diversity of L3 strains and reports phylogenetic variations that could inform clinical trials which evaluate the effectivity of new drugs/regimens or vaccine candidates.

Roeperone A, a new tetraoxygenated xanthone and other compounds from the leaves of Hypericum roeperianum Schimp. (Hypericaceae).

Chemical investigation of the methanol extract from the leaves of H. roeperianum led to the isolation of a new tetraoxygenated xanthone along with eleven known compounds including six xanthones, one polyketide, one flavonoid, one ferulic acid derivative and two pentacyclic triterpenoids. Their structures were established on the basis of 1D- and 2D-NMR, UV, IR, and MS experiments, and by comparison of their spectroscopic data with those of similar compounds reported in the literature. The new xanthone was tested against a panel of eight bacterial strains including six Gram-negative and two Gram-positive bacteria. As results, it exhibited weak antibacterial activity with MIC values ranging from 64 to 128 µg/mL.

An Efflux Pumps Inhibitor Significantly Improved the Antibacterial Activity of Botanicals from Plectranthus glandulosus towards MDR Phenotypes.

Bacterial multidrug resistance causes many therapeutic failures, making it more difficult to fight against bacterial diseases. This study aimed to investigate the antibacterial activity of extract, fractions, and phytochemicals from Plectranthus glandulosus (Lamiaceae) against multidrug-resistant (MDR) Gram-negative phenotypes expressing efflux pumps. The crude extract after extraction was subjected to column chromatography, and the structures of the isolated compounds were determined using spectrometric and spectroscopic techniques. Antibacterial assays of samples alone and in the presence of an efflux pump inhibitor (phenylalanine-arginine ß-naphthylamide, PAßN) were carried out using the broth microdilution method. The phytochemical study of P. glandulosus plant extract afforded seven major fractions (A-G) which lead to the isolation of seventeen known compounds. The ethanol extract of P. glandulosus was not active at up to 1024 µg/mL, whereas its fractions showed MICs varying from 32 to 512 µg/mL on the studied bacteria. Fraction C of P. glandulosus showed the lowest MIC (32 µg/mL) on E. coli ATCC8739 strain. Fraction D presented the highest activity spectrum by inhibiting the growth of 90% (9/10) of the studied bacteria. The presence of PAßN has improved the activity of extract and all fractions. Overall, the tested phytochemicals showed low activity against the studied bacteria. The overall results obtained in this study show that some fractions from P. glandulosus, mainly fractions C and D, should be investigated more for their possible use to fight against MDR bacteria.

The alkaloid, soyauxinium chloride, displays remarkable cytotoxic effects towards a panel of cancer cells, inducing apoptosis, ferroptosis and necroptosis.

The cytotoxic potential of a naturally occurring indoloquinazoline alkaloid, soyauxinium chloride (SCHL), was determined on a broad panel of animal and human cancer cell lines, including various sensitive and drug-resistant phenotypes. The cytotoxicity, SCHL-induced autophagic, ferroptotic, and necroptotic cell death were evaluated by the resazurin reduction assay (RRA). Caspase-Glo assay was used to detect the activity of caspases using spectrophotometric analysis. Flow cytometry was applied for cell cycle analysis (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP) (JC-1) and reactive oxygen species (ROS) (H2DCFH-DA). SCHL and doxorubicin (reference molecule) exhibited cytotoxic effects towards the 18 cancer cell lines tested. The IC50 values obtained ranged from 3.64 µM (towards CCRF-CEM leukemia cells) to 16.86 µM (against the BRAF-wildtype SKMel-505 melanoma cells for SCHL). Collateral sensitivity of the resistant HCT116 p53-/- colon adenocarcinoma cells to SCHL was observed as well as the normal sensitivity of CEM/ADR5000 leukemia cells, MDA-MB-231-BCRP breast adenocarcinoma cells and U87. MGΔEGFR glioblastoma cells. SCHL induced apoptosis in CCRF-CEM cells via caspases 3/7-, 8- and 9-activation, MMP alteration and increased ROS production, and otherwise ferroptosis and necroptosis. SCHL is a prominent cytotoxic alkaloid that should be further studied to develop a novel drug to combat cancers including refractory phenotypes.

Cytotoxicity of botanicals and isolated phytochemicals from Araliopsis soyauxii Engl. (Rutaceae) towards a panel of human cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Araliopsis soyauxii Engl. (Rutaceae) is a Cameroonian medicinal plant traditionally used to treat lung diseases, malaria, and gonorrhea. It has been demonstrated that infectious disease contribute to about 20% of all human tumours. AIMS OF THE STUDY: (1) To perform a phytochemical investigation of the dichloromethane-methanol 1:1 extracts of the bark (ASB), roots (ASR), and leaves (ASL) from Araliopsis soyauxii; (2) to evaluate the cytotoxicity of extracts and isolated compounds; (3) to determine the mode of induction of apoptosis of ASB and kihadanin B (12). MATERIALS AND METHODS: Fourteen constituents of the crude extracts were isolated by column chromatography, while spectroscopic techniques were used for structural elucidation. The resazurin reduction assay (RRA) was applied to determine the cytotoxicity of samples towards a panel of 9 cancer cell lines. For caspases activity, the Caspase-Glo assay was used; flow cytometry was applied to investigate the cell cycle distribution (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP; JC-1 staining), and the reactive oxygen species (ROS; H2DCFH-DA staining). RESULTS: Phytochemical investigations of botanicals (ASB, ASR, and ASL) led to the isolation of 14 compounds. Extract ASB, obacunone (11), kihadanin B (12) as well as doxorubicin (control drug) revealed cytotoxicity towards the 9 cancer cell lines tested. The IC50 values ranged from 11.11 µg/mL (against CCRF-CEM leukemia cells) to 28.18 µg/mL (against HCT116 p53+/+ colon adenocarcinoma cells) for ASB; from 28.25 µM (against MDA-MB-231-pcDNA breast adenocarcinoma cells) to 65.13 µM (against HepG2 hepatocarcinoma cells) for compound 11, and from 5.77 µM (against CCRF-CEM cells) to 43.56 µM (against U87.MGΔEGFR glioblastoma cells) for compound 12. ASB and compound 12 induced apoptosis in CCRF-CEM cells. ASB induced the apoptotic process mediated by MMP alteration and enhanced ROS production, while compound 12 induced apoptosis by caspases activation, MMP alteration, and enhanced ROS production. CONCLUSION: This study demonstrated that Araliopsis soyauxii is a potential source of cytotoxic phytochemicals such as kihadanin B and that ASB and compound 12. Extract and compounds will be explored further to develop anticancer drugs.

Haematological Features and Urologic Pathologies of Diabetic Subjects at Bafoussam Regional Hospital: A Cross-Sectional Study.

BACKGROUND: Diabetes mellitus is at the origin of long-term complications. OBJECTIVE: This study is aimed at assessing the haematological features and urologic pathologies of diabetic individuals at Bafoussam Regional Hospital. METHODS: This was a cross-sectional study conducted from August 2018 to May 2019 in Bafoussam Regional Hospital, West Cameroon. A structured questionnaire was used to gather sociodemographic data. A trained nurse measured the physical and clinical features. Fasting plasma glucose was determined using the glucose meter Accu-Chek Active system. The full blood count (FBC) was carried out using Automatic full Blood Counter, and the CD4, CD3, and CD8 T-cell counts were determined using the flow cytometry method. RESULTS: There were 455 diabetic patients, and 50 nondiabetic patients were included. The mean age of diabetic patients (56.94 ± 14.33 years) was higher compared to that of nondiabetic individuals (34.76 ± 14.35 years) (p < 0.001). There was a significant relationship between married individuals (χ 2 = 79.19, p < 0.001, and df = 4), housewife and retired (χ 2 = 1117.38, p < 0.001, and df = 37), old age (40 years and above) (χ 2 = 79.11, p < 0.001, and df = 3), and diabetes status. Diabetic patients had an odds of 5.52 to experience a urinary urge as compared to the controls (p < 0.001, 95% CI = 2.15-14.22). The majority of haematological parameters were negatively but not significantly correlated with diabetes. Binary logistic regression shows that MCV (r = -0.251, OR = 0.778, and 95% CI = 0.617-0.983; p = 0.035) and RDW-CV (r = -0.477, OR = 0.620, and 95% CI = 0.454-0.848; p = 0.003) negatively influence the probability of having diabetes. RDW-SD (r = 0.135, OR = 1.144, and 95% CI = 1.014-1.291; p = 0.029) positively influences the probability of having diabetes. CONCLUSION: This study revealed a significant haematological and urological profile difference according to diabetes status. Research and interventions targeted at diabetic population could help close gaps in diabetes complications.

Antistaphylococcal Activity of Extracts, Fractions, and Compounds of Acacia polyacantha Wild (Fabaceae).

Acacia polyacantha is a medicinal plant traditionally used to treat livestock diseases and gastrointestinal infections; our study was undertaken to evaluate the antistaphylococcal activities of the methanolic leaf, bark, and root extracts, fractions, and compounds from Acacia polyacantha against a panel of 14 multidrug-resistant Staphylococcus bacterial strains overexpressing efflux pumps. The study was also extended to investigate two possible modes of action, that is, influence on bacterial growth kinetics and influence on proton-ATPase pumps, of the most active compound against a reference strain. Materials and Methods. The crude extracts after extraction were subjected to column chromatography. Antibacterial assays of extracts, fractions, and compounds alone and in the presence of efflux pump inhibitors were carried out using the broth microdilution method and the study of two mechanisms of action achieved by standard methods with the most active compound. Results. The phytochemical study of Acacia polyacantha leaves leads to the isolation of stigmasterol (1), ß-amyrin (2), 3-O-methyl-D-chiro-inositol (3), epicatechin (4), quercetin-3-O-galactoside (5), 3-O-[ß-D-xylopyranosyl-(1 ⟶ 4)-ß-D-galactopyranosyl]-oleanolic acid (6), 3-O-[ß-galactopyranosyl-(1⟶ 4)-ß-D-galactopyranosyl]-oleanolic acid (7) and that of leaves lead to the isolation of lupeol (8) 2,3-dihydroxypropyltetracosanoate (9), and methyl-gallate (10). Leaf, root, and bark extracts inhibited 92.85% (13/14), 92.85% (13/14), and 71.43 % (10/14) of the tested bacteria strains, respectively, with minimum inhibitory concentration (MIC) varying between 16 and 1024 µg/mL. Fractions exhibited better activities compared to those of their extracts of origin, as their MICs ranged from 16 to 512 µg/mL, with fractions from leaves being more active than those obtained from barks. Compounds had varying activities; MICs varied from 16 to 512 µg/mL with compound 4 presenting the best activity as MICs ≤100 µg/mL were obtained against 11 of the tested bacteria. The activities of extracts, fractions, and compounds were improved in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) as an efflux pump inhibitor to as much as >128 folds. Meanwhile, in the presence of chlorpromazine as an efflux pump inhibitor, only the activity of compound 10 was improved on 10 of the tested bacteria strains. Compound 4 prolonged the lag phase of the growth kinetic in a concentration-dependent manner and equally inhibited the proton-ATPase pumps of the tested bacteria strains. Conclusion. The present study demonstrates the antistaphylococcal potential of Acacia polyacantha and its constituents to combat bacterial infections alone or in combination with efflux pump inhibitors.

Antibacterial and antibiotic-modifying activities of fractions and compounds from Albizia adianthifolia against MDR Gram-negative enteric bacteria.

BACKGROUND: Albizia adianthifolia (Schum.) is medicinally used in Cameroon to manage bronchitis and skin diseases. Our previous study documented the antibacterial potential of its roots' methanol extract. In this study, methanol roots extract was subjected to chromatography techniques and fractions (AARa and AARb), sub-fractions (AARa1-4, AARb1-2 and AARb11-14) together with isolated phytochemicals were assessed for their antimicrobial as well as their antibiotic-potentiating effects towards Gram-negative multidrug resistant (MDR) bacteria. METHODS: The antibacterial activities of the samples (determination of Minimal Inhibitory « MIC ¼ and Minimal Bactericidal Concentration « MBC ¼) were determined by the modified rapid p-iodonitrotetrazolium chloride (INT) colorimetric assay, as well as those of antibiotics in association with the compounds. Column chromatography was applied to isolate phytochemicals from roots extract and their chemical structures were determined using spectroscopic techniques. RESULTS: The phytochemicals isolated were stearic acid (1), a mixture (1:1) of stigmasterol and ß-sitosterol (2 +  3), ß-sitosterol 3-O-ß-D-glucopyranoside (4), palmatin (5), homomangiferin (6) and mangiferin (7). Fraction AARa exhibited selective inhibitory effects whilst all tested bacteria were inhibited by AARb in MIC ranges of 8 to 1024 µg/mL. Sub-fractions AARb1-2 had MIC values between 8 µg/mL and 1024 µg/mL on all tested bacteria. Phytochemicals 4, 2 +  3 and 7 inhibited the growth of 54.54% (6/11), 45.45% (5/11) and 27.27% (3/11) tested bacterial strains, respectively. When tested with an efflux pumps inhibitor (Phenylalanine-Arginine-ß-Naphthylamide or PAßN), the inhibitory effects of compounds 2 + 3 and 4 increased towards all the tested bacteria. In association with erythromycin (ERY), streptomycin (STR) and tetracycline (TET), compounds 2 + 3 and 4 had the most significant synergistic activity on the seven selected bacteria. CONCLUSION: The present study provides information on the possible use of Albizia adianthifolia and its constituents in the control of Gram-negative infections including MDR phenotypes.

Antibacterial and Antibiotic Modifying Potential of Crude Extracts, Fractions, and Compounds from Acacia polyacantha Willd. against MDR Gram-Negative Bacteria.

The present study aimed to assess the in vitro antibacterial and antibiotic modifying activities of methanol extracts prepared from the leaf (APL) and bark (APB) of Acacia polyacantha, fractions (APLa-d) and compounds isolated from APL against a panel of multidrug resistant (MDR) Gram-negative bacteria. Leaf extract was subjected to column chromatography for compounds isolation; antibacterial assays were performed on samples alone and with an efflux pump inhibitor (EPI), respectively, and several antibiotics on the tested bacteria. The phytochemical investigation of APL led to the isolation of stigmasterol (1), ß-amyrin (2), 3-O-ß-D-glucopyranosylstigmasterol (3), 3-O-methyl-D-chiro-inositol (4), epicatechin (5), quercetin-3-O-glucoside (6), 3-O-[ß-D-xylopyranosyl-(1→4)-ß-D-galactopyranosyl]-oleanolic acid (7), and 3-O-[ß-galactopyranosyl-(1→4)-ß-D-galactopyranosyl]-oleanolic acid (8). APL and APB had minimal inhibitory concentration (MIC) values ≤ 1024 µg/mL on 73.3% and 46.7% of the tested bacteria, respectively. APLb and APLd were effective against 88.9% of tested bacterial species with compound 8 showing the highest activity inhibiting 88.9% of tested bacteria. The EPI, phenylalanine-arginine-ß-naphthylamide (PAßN), strongly improved the activity of APL, APLb, APLd, and compound 8 on all tested bacteria. Synergistic effects were obtained when APL and compounds 7 and 8 were combined with erythromycin (ERY), gentamycin (GEN), ciprofloxacin (CIP), and norfloxacin (NOR). The present study demonstrates the antibacterial potential of Acacia polyacantha and its constituents to combat bacterial infections alone or in combination with EPI.

Multidrug resistant bacteria are sensitive to Euphorbia prostrata and six others Cameroonian medicinal plants extracts.

BACKGROUND: Multidrug resistant (MDR) bacteria are responsible for therapeutic failure and there is an urgent need for novels compounds efficient on them. METHODS: Eleven methanol extracts from seven Cameroonian medicinal plants were tested for their antibacterial activity using broth micro-dilution method against 36 MDR bacterial strains including Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus. RESULTS: Euphorbia prostrata extract was found active against all the 36 tested bacteria including Gram-negative phenotypes over-expressing efflux pumps such as P. aeruginosa PA124, E. aerogenes CM64 and E. coli AG102. E. prostrata had minimal inhibitory concentrations values between 128 and 256 µg/mL on 55.55% of the studied microorganisms. Other plants extract displayed selective antibacterial activity. CONCLUSIONS: Results obtained in this study highlight the antibacterial potential of the tested plants and the possible use of E. prostrata to combat bacterial infections including MDR phenotypes.

Antibacterial activities of the methanol extracts of Albizia adianthifolia, Alchornea laxiflora, Laportea ovalifolia and three other Cameroonian plants against multi-drug resistant Gram-negative bacteria.

In the last 10 years, resistance in Gram-negative bacteria has been increasing. The present study was designed to evaluate the in vitro antibacterial activities of the methanol extracts of six Cameroonian medicinal plants Albizia adianthifolia, Alchornea laxiflora, Boerhavia diffusa, Combretum hispidum, Laportea ovalifolia and Scoparia dulcis against a panel of 15 multidrug resistant Gram-negative bacterial strains. The broth microdilution was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts. The preliminary phytochemical screening of the extracts was conducted according to the reference qualitative phytochemical methods. Results showed that all extracts contained compounds belonging to the classes of polyphenols and triterpenes, other classes of chemicals being selectively distributed. The best antibacterial activities were recorded with bark and root extracts of A. adianthifolia as well as with L. ovalifolia extract, with MIC values ranging from 64 to 1024 µg/mL on 93.3% of the fifteen tested bacteria. The lowest MIC value of 64 µg/mL was recorded with A. laxiflora bark extract against Enterobacter aerogenes EA289. Finally, the results of this study provide evidence of the antibacterial activity of the tested plants and suggest their possible use in the control of multidrug resistant phenotypes.

Cytotoxicity of the methanol extracts of Elephantopus mollis, Kalanchoe crenata and 4 other Cameroonian medicinal plants towards human carcinoma cells.

BACKGROUND: Cancer still constitutes one of the major health concerns globally, causing serious threats on patients, their families, and the healthcare system. METHODS: In this study, the cytotoxicity of the methanol extract of Elephantopus mollis whole plant (EMW), Enantia chlorantha bark (ECB), Kalanchoe crenata leaves (KCL), Lophira alata bark (LAB), Millettia macrophylla leaves (MML) and Phragmanthera capitata leaves (PCL) towards five human solid cancer cell lines and normal CRL2120 fibroblasts, was evaluated. Extracts were subjected to qualitative chemical screening of their secondary metabolite contents using standard methods. The cytotoxicity of samples was evaluated using neutral red uptake (NR) assay meanwhile caspase activation was detected by caspase-Glo assay. Flow cytometry was used to analyze the cell cycle distribution and the mitochondrial membrane potential (MMP) whilst spectrophotometry was used to measure the levels of reactive oxygen species (ROS). RESULTS: Phytochemical analysis revealed the presence of polyphenols, triterpenes and sterols in all extracts. The IC50 values of the best samples ranged from 3.29 µg/mL (towards DLD-1 colorectal adenocarcinoma cells) to 24.38 µg/mL (against small lung cancer A549 cells) for EMW, from 2.33 µg/mL (mesothelioma SPC212 cells) to 28.96 µg/mL (HepG2 hepatocarcinoma) for KCL, and from 0.04 µg/mL (towards SPC212 cells) to 0.55 µg/mL (towards A549 cells) for doxorubicin. EMW induced apoptosis in MCF-7 cells mediated by MMP loss and increased ROS production whilst KCL induced apoptosis via ROS production. CONCLUSION: This study provides evidences of the cytotoxicity of the tested plant extract and highlights the good activity of Elephantopus mollis and Kalanchoe crenata. They deserve more exploration to develop novel cytotoxic drugs.

Antibacterial activities of the methanol extract, fractions and compounds from Elaeophorbia drupifera (Thonn.) Stapf. (Euphorbiaceae).

BACKGROUND: Elaeophorbia drupifera (Thonn.) Stapf. (Euphorbiaceae) is used in Cameroonian folk medicine to treat several ailments including bacterial-related diseases such as skin infections. In this study, the methanol extract from the leaves (EDL), fractions (EDLa-d), sub-fractions EDLc1-7 and EDLc31-35 as well as isolated compounds were tested for their antimicrobial activities against a panel of Gram-negative and Gram-positive bacteria including multidrug resistant (MDR) phenotypes. METHODS: The broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples; column chromatography was used for the fractionation and purification of the leaves extract whilst the chemical structures of compounds were determined using spectroscopic techniques. RESULTS: Phytochemical investigation lead to the isolation of a mixture (1:3) of stigmasterol and ß-sitosterol (1 + 2), euphol (3), sitosterol-O-ß- D -xylopyranoside (4), 3,3',4'-tri-O-methylellagic acid (5), a mixture (1:1) of afzelin and quercetin-3-O-ß-D-xylopyranoside (6 + 7), 3,3',4'-tri-O-methylellagic acid 4-O-ß-D-glucopyranoside (8), ellagic acid-4-O-ß-xylopyranoside-3,3',4'-trimethyl ether (9) from EDLc. Crude extract and fractions displayed selective activities with MIC values ranged from 32 to 1024 µg/mL for EDL against 84.9% of the 33 tested bacteria, 93.9% for EDLc, 69.7% for EDLb, 33.4% for EDLa and 0.03% for EDLd. MIC values ranged from 16 to 1024 µg/mL were obtained with EDLc3 and EDLc4 on all tested bacteria meanwhile other sub-fractions displayed selective activities. MIC value of 32 µg/mL was obtained with fractions EDLa against Escherichia coli AG100, EDLc against Enterobacer aerogenes ATCC13048 and EA298. For sub-fractions obtained from EDLc, the lowest MIC value of 16 µg/mL was recorded with EDLc3 against Staphylococcus aureus MRSA11. A corresponding value of 8 µg/mL against Providencia stuartii NAE16 was recorded with EDLc33 obtained from further fractionation of EDLc3. EDLc3 had MIC values below 100 µg/mL against all tested bacteria. Compound 5 as well as the mixture (1:1) of 6 and 7 inhibited the growth of all the tested bacteria with MICs ranged from 64 to 256 µg/mL. CONCLUSION: Elaeophorbia drupifera is a potential source of phytomedicine to tackle MDR bacteria. Sub-fraction EDLc3 was more active than all isolated compounds and deserves further investigations to develop natural drug to combat Gram-negative, Gram-positive bacteria and otherwise MDR phenotypes.

Antibacterial activity of six medicinal Cameroonian plants against Gram-positive and Gram-negative multidrug resistant phenotypes.

BACKGROUND: Infectious diseases due to multidrug-resistant bacteria are one of the causes of treatment failures contributing to an increase in mortality and/or morbidity. In this study, we evaluated the antibacterial potential of different parts of six medicinal plants namely Alstonia boonei, Ageratum conyzoides, Croton macrostachys, Cassia obtusifolia, Catharanthus roseus and Paullinia pinnata against a panel of 36 multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria. METHODS: Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of the methanol extracts from different parts of the plants were determined using broth microdilution method; standard phytochemical methods were used for phytochemical screening. RESULTS: Several phytochemical classes such as polyphenols, sterols, triterpenes, alkaloids, flavonoids and saponins were identified in the plant extracts. MIC values obtained ranged from 64 to 1024 µg/mL. Leaves extract of Catharanthus roseus (86.11 %), Croton macrostachys (83.33 %) and Paullinia pinnata (80.55 %) displayed the best antibacterial spectra. The lowest MIC value of 64 µg/mL was obtained with the Paullinia pinnata stems extract and Cassia obtusifolia extract against the strain of Staphylococcus aureus MRSA8. Results also showed that the tested samples generally displayed bacteriostatic effects with MBC values obtained in only 3.35 % of the cases where plant extracts were active. CONCLUSION: The results obtained at the end of this study demonstrate for the first time the antibacterial activity of the studied medicinal plants against MDR bacteria. The tested plants could be a reservoir of molecules to fight against MDR bacterial infections.

Cytotoxicity of methanol extracts of 10 Cameroonian medicinal plants towards multi-factorial drug-resistant cancer cell lines.

BACKGROUND: Cancer chemotherapy is still hampered by clinical failures due to multi-drug resistance (MDR) of tumor cells. In the present study, we have investigated the cytotoxicity of 20 methanol extracts from 10 medicinal plants against the sensitive leukemia CCRF-CEM cells. The most cytotoxic extracts were then further tested on a panel of 8 human cancer cell lines, including various MDR phenotypes. METHODS: The cytotoxicity of the 20 methanol extracts from 10 Cameroonian medicinal plants was determined using a resazurin reduction assay. Meanwhile, flow cytometry was used to measure cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS). RESULTS: In the preliminary assay using CCRF-CEM cells, 12 extracts from five plants displayed IC50 values below 80 µg/mL, namely Albizia adianthifolia, Alchornea cordifolia, Alchornea laxiflora, Pennisetum purpureum, and Spathodea campanulata. the four best extracts were from two plants: Albizia adianthifolia roots (AAR) and bark (AAB) as well as Alchornea cordifolia leaves (ACL) and bark (ACB) had respective IC50 values of 0.98 µg/mL, 1.45 µg/mL, 8.02 µg/mL and 12.57 µg/mL in CCRF-CEM cells. They were further tested in 8 other cell lines as well as in normal AML12 hepatocytes. IC50 values ranging from 2.71 µg/mL (towards glioblastoma U87MG.ΔEGFR cells) to 10.30 µg/mL (towards breast adenocarcinoma MDA-MB-231-BCRP cells) for AAB, from 3.43 µg/mL (towards U87MG cells) to 10.77 µg/mL (towards colon carcinoma HCT116 (p53 (-/-) ) cells) for AAR and from 0.11 µg/mL (towards CCRF-CEM cells) to 108 µg/mL (towards leukemia CEM/ADR5000 cells) for doxorubicin (as control drug) were obtained. ACL and ACB extracts displayed selective activities. AAR and ACL extracts induced apoptosis in CCRF-CEM cells, through caspases activation and loss of MMP, while apoptotic cell death was mediated by MMP diruption and increase ROS production for ACL. CONCLUSION: Some of the tested plants namely Albizia adianthifolia, Alchornea cordifolia, Alchornea laxiflora, Pennisetum purpureum, Spathodea campanulata represent a potential source of novel anticancer drugs. Especially, Albizia adianthifolia and Alchornea cordifolia revealed considerable cytotoxic activities that could be exploited to develop phytomedicines to fight cancers including MDR phenotypes.

Cytotoxicity of Elaoephorbia drupifera and other Cameroonian medicinal plants against drug sensitive and multidrug resistant cancer cells.

BACKGROUND: Multidrug resistance (MDR) is a major hurdle for cancer treatment worldwide and accounts for chemotherapy failure in over 90% of patients with metastatic cancer. Evidence of the cytotoxicity of Cameroonian plants against cancer cell lines including MDR phenotypes is been intensively and progressively provided. The present work was therefore designed to evaluate the cytotoxicity of the methanol extracts of twenty-two Cameroonian medicinal plants against sensitive and MDR cancer cell lines. METHODS: The methanol maceration was used to obtain the crude plant extracts whilst the cytotoxicity of the studied extracts was determined using a resazurin reduction assay. RESULTS: A preliminary assay on leukemia CCRF-CEM cells at 40 µg/mL shows that six of the twenty plant extract were able to enhance less than 50% of the growth proliferation of CCRF-CEM cells. These include Crinum zeylanicum (32.22%), Entada abyssinica (34.67%), Elaoephorbia drupifera (35.05%), Dioscorea bulbifera (45.88%), Eremomastax speciosa (46.07%) and Polistigma thonningii (45.11%). Among these six plants, E. drupifera showed the best activity with IC50 values below or around 30 µg/mL against the nine tested cancer cell lines. The lowest IC50 value of 8.40 µg/mL was recorded with the extract of E. drupifera against MDA-MB231 breast cancer cell line. The IC50 values below 10 µg/mL were recorded with the extracts of E. drupifera against MDA-MB231 breast cancer cells, C. zeylanicum against HCT116 p53⁺/⁺ and HCT116p53⁻/⁻ colon cancer cells and E. abyssinica against HCT116 p53⁺/⁺ cells. CONCLUSION: The results of the present study provide evidence of the cytotoxic potential of some Cameroonian medicinal plants and a baseline information for the potential use of Elaoephorbia drupifera in the treatment of sensitive and drug-resistant cancer cell lines.

Antimicrobial activities of the methanol extract and compounds from the twigs of Dorstenia mannii (Moraceae).

BACKGROUND: Dorstenia mannii (Moraceae) is a medicinal herb used traditionally for the treatment of many diseases. In the present study, the methanol extract of D. mannii and nine of its isolated compounds, namely dorsmanin A (1), B (2), C (3), D (4), E (6), F (7), G (8) dorsmanin I (9) and 6,8-diprenyleriodictyol (5), were tested for their antimicrobial activities against yeast, Mycobacteria and Gram-negative bacteria. METHODS: The microplate alamar blue assay (MABA) and the broth microdilution method were used to determine the minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of the above extract and compounds on a panel of bacterial species. RESULTS: The results of the MIC determinations demonstrated that the methanol extract as well as compounds 3 and 8 were able to prevent the growth of all the fourteen studied microorganisms within the concentration range of 4 to 1024 µg/ml. The lowest MIC value for the methanol extract (64 µg/ml) was obtained on Candida albicans. The lowest value for individual compounds (4 µg/ml) was recorded with compounds 3 on Pseudomonas aeruginosa PA01 and 7 on Eschericia coli ATCC strain. The MIC values recorded with compounds 3 on P. aeruginosa PA01, 6 on C. albicans,7 on P. aeruginosa PA01 and K. pneumoniae ATCC strain and C. albicans,and 8 on P. aeruginosa PA01, PA124, P. stuartii, M. tuberculosis MTCS1 were lower than or equal to those of the reference drugs. MMC values not greater than 1024 µg/ml were recorded on all studied microorganisms with compounds 3 and 8. CONCLUSION: The overall results of the present investigation provided evidence that the crude extract of D. mannii as well as some of its compounds such compounds 3 and 8 could be a potential source of natural antimicrobial products.

Evaluation of four Cameroonian medicinal plants for anticancer, antigonorrheal and antireverse transcriptase activities.

Methanol extracts from the leaves, bark and roots of four Cameroonian medicinal plants, Bersama engleriana, Cupressus lusitanica, Vitellaria paradoxa and Guibourtia tessmannii were tested for their in vitro cytotoxicity, antigonorrheal and antireverse transcriptase activities. The XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt) assay, the dilution method and reverse transcriptase (RT) assay were used for the investigations. Preliminary phytochemical analysis of the extracts was also conducted using standard methods. Results showed that all extracts contained compounds belonging to the classes of phenols and terpenoids. They were also able to reduce in dose dependent manner, the proliferation of the cancer THP-1, DU145, HeLa, MCF-7, HepG2 and the normal Vero cells. IC(50) values below 30µg/ml were noted with extract from the three parts of B. engleriana on at least two of the five studied cancer cell lines, the lowest value of 5.9µg/ml being obtained with sample from the bark. IC(50) values below 30µg/ml were also recorded with extracts from the leaves (on HeLa cells) and bark (on MCF-7) of G. tessmanii, and that from the bark of C. lusitanica on MCF-7. Extracts from B. engleriana and those from the bark of V. paradoxa gave the minimal inhibitory concentrations (MIC) values below 100µg/ml on most of the 10 tested Nesseria gonorrhoeae strains. Extracts from B. engleriana also inhibited more than 80% the activity of the Human Immuno-deficiency Virus (HIV) enzyme. Finally, the results of the present study provide baseline information for the use of B. engleriana, C. lusitanica, G. tessmanii, V. paradoxa.

Toxicological evaluation of the hydroethanol extract of Tabernaemontana crassa (Apocynaceae) stem bark.

AIM: Tabernaemontana crassa Benth. is a medicinal plant widely used in Cameroon folk medicine to treat a variety of affections. This study was aimed at evaluating its toxicological profile. MATERIALS AND METHODS: The 70% (v/v) hydroethanol (HE) extract from the stem bark of this plant was given to albino Wistar rats by oral gavage to study the acute and sub-acute toxicities. RESULTS: The results of histopathological studies revealed that there was a dose-related effect in liver, lungs and kidneys and that there was no difference in tissue profile of control group and those receiving 6 weeks daily treatment of 0.5 g/kg b.w. The result of the acute toxicity indicated the medium lethal dose (LD50) of 6.75 g/kg body weight (b.w.) after 48 h of treatment and the significant variation (P<0.05) of the relative body weight, serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), total bilirubin (TBil), direct bilirubin (DBil) and creatinine (SCr) at the dose of 6g/kg b.w. These results also indicated significant variation of the liver alkaline phosphatase, aspartate aminotransferase (AST), ALT, total proteins (TP), glutathione (GSH) and malondialdehyde (MDA) and renal creatinine (RCr) and urea (RU) at 6g/kg b.w. The result of the sub-acute toxicity showed significant changes in the body weight but no modification (P>0.05) of blood and liver indices for the animal taking 6 weeks daily doses of the HE compared to the control group. CONCLUSIONS: The results showed that this extract was fairly non-toxic but that consumption of higher doses up to 6 g/kg b.w. could cause organ injuries. Moderated consumption of small doses up to 0.5 g/kg b.w. daily for 6 weeks appeared to be safe.