Evaluation of flavonoids from Dorstenia barteri for their antimycobacterial, antigonorrheal and anti-reverse transcriptase activities.

The aim of this study was to evaluate the antimycobacterial, antigonorrheal and reverse transcriptase activities of five flavonoids: isobachalcone (IBC); kanzanol C (KAN); 4-hydroxylonchocarpin (4-LCP); stipulin (SPL) and amentoflavone (AMF) from Dortenia barteri, together with the crude extract from this plant. The Agar disc diffusion, broth microdilution, microplate alamar blue assay (MABA), radiometric respiratory technique using BACTEC 460 system and the reverse transcriptase (RT) assay were used for the investigations. The results of the antimycobacterial assay showed that the crude extract and compounds were able to prevent the growth of Mycobacteria with MIC<10 microg/ml being recorded with IBC on M. tuberculosis. Results of the killing rate experiment revealed that total inhibition effect on M. tuberculosis H37Rv strain was noted with IBC and SPL at day 9 when tested at 4x MIC. The results of the antigonorrheal assay indicated that MIC values below 10 microg/ml were also recorded with IBC on all the tested N. gonorrhoeae strains, meanwhile good activities (MIC<10 microg/ml) were also noted with the extract, KAN, 4-LCP and SPL on some of these strains. The anti-reverse transcriptase activities of extract and compounds also demonstrated that all samples were able to inhibit at various extents the reverse transcriptase activity, with IBC and 4-LCP showing the best effects. The overall results of this work provided evidence that the crude extract as well as some flavonoids from D. barteri could be potential sources of new antimicrobial drug against tuberculosis (TB), gonorrhea and probably the acquired immunodeficiency syndrome.

Antimicrobial activity of the methanolic extract and compounds from Morus mesozygia stem bark.

AIM OF THE STUDY: This study was aimed at investigating the antimicrobial activity of the methanolic extract (MMB) and compounds isolated from the stem bark of Morus mesozygia, namely 3beta-acetoxyurs-12-en-11-one (1), moracin Q (2), moracin T (3), artocarpesin (4), cycloartocarpesin (5), moracin R (6), moracin U (8), moracin C (9), and moracin M (10). MATERIALS AND METHODS: The liquid microdilution assay was used in the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC), against nine bacterial and two fungal species. RESULTS: The results of the MIC determination showed that the compounds 3, 4, 8 and 9 were able to prevent the growth of all tested microbial species. All other samples showed selective activities. Their inhibitory effects were noted on 90.9% studied organisms for the crude extract, 81.8% for compound 6, 72.7% for compound 10, 63.6% for compound 1, 54.5% for compound 5, and 45.5% for compound 2. The lowest MIC value of 39 microg/ml was obtained with the crude extract against Escherichia coli. The corresponding value for compounds (5 microg/ml) was registered with compound 9 on Shigella dysenteriae and compound 3 on E. coli, S. dysenteriae, Pseudomonas aeruginosa, Salmonella typhi and Bacillus cereus. The lowest MIC value (39 microg/ml) observed with the crude extract (on E. coli) was only eightfold greater than that of gentamycin used as reference antibiotic (RA) while the corresponding value (5 microg/ml) recorded with compounds 3 and 9 was equal to that of RA on the corresponding microorganisms. CONCLUSIONS: The obtained results highlighted the interesting antimicrobial potency of M. mesozygia as well as that of the studied compounds, and provided scientific basis for the traditional use of this species.