Antibacterial activities of the extracts, fractions and compounds from Dioscorea bulbifera.

BACKGROUND: Dioscorea bulbifera is an African medicinal plant used to treat microbial infections. In the present study, the methanol extract, fractions (DBB1 and DBB2) and six compounds isolated from the bulbils of D. bulbifera, namely bafoudiosbulbins A (1), B (2), C (3), F (4), G (5) and 2,7-dihydroxy-4-methoxyphenanthrene (6), were tested for their antimicrobial activities against Mycobacteria and Gram-negative bacteria involving multidrug resistant (MDR) phenotypes expressing active efflux pumps. METHODS: The microplate alamar blue assay (MABA) and the broth microdilution methods were used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples. RESULTS: The results of the MIC determinations indicated that when tested alone, the crude extract, fractions DBB1 and DBB2 as well as compounds 2 to 5 were able to prevent the growth of all the fifteen studied microorganisms, within the concentration range of 8 to 256 µg/mL. The lowest MIC value for the methanol extract and fractions (16 µg/mL) was obtained with DBB1 and DBB2 on E, coli AG100A and DBB2 on Mycobacterium tuberculosis MTCS2. The lowest value for individual compounds (8 µg/mL) was recorded with compound 3 on M. smegmatis and M. tuberculosis ATCC and MTCS2 strains respectively. The activity of the samples on many MDR bacteria such as Enterobacter aerogenes EA289, CM64, Klebsiella pneumoniae KP63 and Pseudomonas aeruginosa PA124 was better than that of chloramphenicol. When tested in the presence of the efflux pump inhibitor against MDR Gram-negative bacteria, the activity of most of the samples increased. MBC values not greater than 512 µg/mL were recorded on all studied microorganisms with fraction DBB2 and compounds 2 to 5. CONCLUSIONS: The overall results of the present investigation provided evidence that the crude extract D. bulbifera as well as some of the compounds and mostly compounds 3 could be considered as potential antimicrobial drugs to fight against MDR bacteria.

Immunological Profile and Bacterial Drug Resistance in Pregnant Women: A Cross Sectional Study.

OBJECTIVES: This study aimed to investigate the immunological and bacterial profiles in pregnant women of Bafang-Cameroon. METHODS: Stool and midstream urine were cultured using specific culture media. The disk diffusion method was used for the antimicrobial susceptibility test. T-cell lymphocyte counts (CD3, CD4 and CD8), white blood cell counts, sensitive C-reactive protein, and interleukin-6, were measured by flow cytometry, optical detection, and the enzyme-linked immunosorbent assay solid phase direct sandwich method. RESULTS: Out of 700 participants, 71.43% were pregnant, and 28.57% were non-pregnant women. The mean age was 29.40 ± 8.27 and 27.41 ± 6.55 years in non-pregnant and pregnant women, respectively. CD4 T-cells were not significantly lower in pregnant women compared with non-pregnant women. There were 43.65% and 56.35% bacteria isolates obtained from urine and stool samples, respectively. Bacteria were mostly isolated in patients with a CD4 T-cell count between 461 and 806 cells/µL. Isolates of Klebsiella pneumoniae and Enterobacter aerogenes showed 100% resistance in non-pregnant women, however all isolated bacteria were shown to be multidrug resistant in pregnant women. Salmonella sp. (24.3%) and Escherichia coli (21.51%) showed an increase in multidrug resistant phenotypes in pregnant women. CONCLUSION: This study demonstrated that routine bacteriological analysis during pregnancy is necessary for their follow-up care.

Resistance Profiles of Staphylococcus aureus and Immunological Status in Pregnant Women at Bafang, West Region of Cameroon: A Cross-Sectional Study.

Background Staphylococcus aureus, a facultative aero-anaerobic Gram-positive coccus typically considered normal flora in the human gastrointestinal tract, have increasingly become a major cause of healthcare-associated infections over the past decade. This study aimed to evaluate the changes in immune factors in pregnant women colonized by S. aureus in the town of Bafang, West Region of Cameroon. Methods A cross-sectional study was carried in antenatal care unit in various health center in Bafang. S. aureus were isolated in stools using specific bacterial culture media. Antimicrobial susceptibility test was carried out using disk diffusion method. Blood was used to measure CD3, CD4 and CD8 T-cell lymphocyte counts, white blood cell count, high sensitivity C-reactive protein (hs-CRP) and interleukin-6 measurement using flow cytometry, optical detection and the ELISA solid phase direct sandwich method, respectively. Results Out of the 169 patients studied, 76.30% patients were pregnant women and 23.70% were non-pregnant women. S. aureus were isolated in 70.41% participants that is, 78.15% in pregnant and 21.85% in non-pregnant women. The mean age was significantly higher in non-pregnant women (29.38 ± 7.685 years) compared to pregnant women (25.55 ± 5.521 years). CD4 T-cell (574.80 ± 165.94; 754.03 ± 162.28, p < 0.001), were significantly lower in pregnant than non-pregnant women respectively, contrary for CD8 T-cell (333.86 ± 233.04; 250.40 ± 227.75, p = 0.043). S. aureus were significantly more isolated in pregnant women with a CD4 T-cell count between 410 and 625 cells/µl (p < 0.001). S. aureus were more susceptible to imipenem (91.40%), (100%); ciprofloxacin (65.59%), (69.44%); amikacin (96.77%), (100%) and resistant to chloramphenicol (78.49%), doxycycline (64.52%) and cefotaxime (51.61%) in pregnant women. Staphylococcus aureus showed a significant increased multidrug resistant (MDR) and methicillin-resistant S. aureus (MRSA) phenotypes in pregnant compared to non-pregnant women (p < 0.05). Conclusion The present study revealed that, Staphylococcus aureus, including resistant phenotypes should be considered in pregnant women to improve their health care.

Antitumor, antioxidant and antimicrobial activities of Bersama engleriana (Melianthaceae).

The aim of this study was to evaluate the antitumor, antioxidant and antimicrobial activities as well as the phytochemical composition and the acute toxicity of the methanolic extracts from the roots (BER), stem bark (BEB), leaves (BEL) and wood (BEW) of Bersama engleriana. The crown gall tumor and DPPH radical scavenging assays were used to detect respectively the antitumoral and oxidant activities. Agar diffusion and liquid dilution were used for antimicrobial tests and the phytochemical assays were conducted according to Harbone methods. The single-dose oral toxicity test was performed in accordance with the OPPTS 870.1100 and OECD 401 guidelines. The phytochemical tests indicated the presence of flavonoids, phenols, triterpenes and anthraquinones in all extracts. Pronounced tumor reducing activity was observed with the extracts from the roots (69.32%) and leaves (65.42%). The DPPH scavenging activity showed that the extract from the leaves was the most active with 93.71% inhibition rate at the 1000 microg/ml. The results of antimicrobial activity showed that all tested extracts were active against all tested microbial species, including Gram-positive, and negative bacteria, the two Candida species and mycobacteria. The MIC values obtained ranged from 9.76 to 156.25 microg/ml. Under the conditions of the studied toxicity, all extracts were found to be non-toxic. The overall results of this study indicates that the extracts from the roots, stem bark, leaves and wood have interesting antioxidant properties and represent a potential source of medicine for the treatment of infectious diseases and cancer.

Antimicrobial activity of the crude extracts and five flavonoids from the twigs of Dorstenia barteri (Moraceae).

The aim of this study was to evaluate the antimicrobial activity of the crude extract of the twigs of Dorstenia barteri (DBT) as well as that of four of the five flavonoids isolated from this extract. Gram-positive bacteria (six species), Gram-negative bacteria (12 species) and fungi (four species) were used. The agar disc diffusion test was used to determine the sensitivity of the tested samples while the well micro-dilution was used to determine the minimal inhibition concentrations (MIC) and the minimal microbicidal concentration (MMC) of the active samples. The results of the disc diffusion assay showed that DBT, isobavachalcone (1), and kanzonol C (4) prevented the growth of all the 22 tested microbial species. Other compounds showed selective activity. The inhibitory activity of the most active compounds namely compounds 1 and 4 was noted on 86.4% of the tested microorganisms and that of 4-hydroxylonchocarpin (3) was observed on 72.7%. This lowest MIC value of 19.06microg/ml was observed with the crude extract on seven microorganisms namely Citrobacter freundii, Enterobacter aerogens, Proteus mirabilis, Proteus vulgaris, Bacillus megaterium, Bacillus stearothermophilus and Candida albicans. For the tested compounds, the lowest MIC value of 0.3microg/ml (on six of the 22 organisms tested) was obtained only with compound 1, which appeared as the most active compound. This lowest MIC value (0.3microg/ml) is about 4-fold lower than that of the RA, indicating the powerful and very interesting antimicrobial potential of isobavachalcone (1). The antimicrobial activities of DBT, as well as that of compounds 1, 3, 4, amentoflavone (5) are being reported for the first time. The overall results provide promising baseline information for the potential use of the crude extracts from DBT as well as some of the isolated compounds in the treatment of bacterial and fungal infections.

Antimicrobial activity of the methanolic extract, fractions and compounds from the stem bark of Irvingia gabonensis (Ixonanthaceae).

The antimicrobial activity of the methanolic extract from the stem bark of Irvingia gabonensis (IGM), fractions and compounds isolated from IGM [3-friedelanone (1), betulinic acid (2), oleanolic acid (3), 3,3',4'-tri-O-methylellagic acid (4), 3,4-di-O-methylellagic acid (5) and hardwickiic acid (6)] was evaluated against Gram-positive bacteria (6 species), Gram-negative bacteria (13 species) and three Candida species using dilution methods for the determination of the minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC). From the obtained results, IGM prevented the growth of all the species of microorganisms tested at a concentration limit of 312.50 microg/ml. Compounds 4-6 also inhibited the growth of all the tested microbial species while compounds 1-3 showed selective activities. The lowest MIC values (78.12 microg/ml) were obtained with IGM on 13 of the 22 microorganisms tested. The corresponding value of 1.22 microg/ml (4.26 microM) for compounds was recorded with compound 6 on Neisseria gonorrhoeae. The obtained results confirmed the use of Irvingia gabonensis in the treatment of bacterial and fungal infections.

Antimicrobial activity of the crude extract, fractions and compounds from stem bark of Ficus ovata (Moraceae).

AIM OF THE STUDY: This study was designed to investigate the antimicrobial activities of the methanol extracts from the stem bark of Ficus ovata (FOB), fractions (FOB1-6) and compounds isolated following bio-guided fractionation [3-friedelanone (1), taraxeryl acetate (2), betulinic acid (3), oleanoïc acid (4), 2-hydroxyisoprunetin (5), 6,7-(2-isopropenyl furo)-5,2,4-trihydroxyisoflavone (6), Cajanin (7) and protocatechuic acid (8)]. MATERIALS AND METHODS: The micro-dilution method was used for the determination of the minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC) against fungi (two species), gram-positive (three species) and gram-negative bacteria (five species). RESULTS: The results of the MIC determinations indicated that the crude extract (FOB), fractions FOB2 and FOB4 as well as compound 5 were active on the entire studied organisms. Other samples showed selective activity, fractions FOB1, FOB3 and FOB5 being active against 50% of the tested microbial species while FOB6 was active on 40%. Compounds 8, 6, 2 and 7 prevented the growth of 80%, 70%, 50% and 20% of the organisms respectively. The lowest MIC value (156 g/ml) observed with the crude extract was recorded on Streptococcus faecalis, Candida albicans and Microsporum audouinii. The corresponding value for fractions (39 microg/ml) was noted with FOB4 against Staphylococcus aureus, while that of the tested compounds (10 microg/ml) was observed with compound 8 on Microsporum audouinii. The results of the MMC determination suggested that the cidal effect of most of the tested samples on the studied microorganisms could be expected. CONCLUSIONS: The overall results provided evidence that the studied plant extract, as well as some of the isolated compounds might be potential sources of new antimicrobial drug.