In vitro antimycobacterial activity and toxicity of eight medicinal plants against pathogenic and nonpathogenic mycobacterial strains

Tuberculosis (TB) caused by Mycobacterium tuberculosis remains a serious public health challenge towards which new hits are urgently needed. Medicinal plants remains a major source of new ligands against global infectious illnesses. In our laboratories, we are currently investigating locally used ethnobotanicals for novel compounds against zoonotic tuberculosis. The microplate alamar blue assay (MABA) was used to study the anti-TB activity while the CellTiter 96® AQueous Assay, which is composed of solutions of a novel tetrazolium compound [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; MTS] and an electron coupling reagent (phenazine methosulfate) PMS, was used for cytotoxic studies. Correlation coefficients (R2) were used to compare the relationship between antimycobacterial activity of the eight crude extracts against nonpathogenic strains and the pathogenic Mycobacterium bovis. Minimum inhibitory concentration (MICs) values indicated that all the eight tested medicinal plant species had activity against all the three tested mycobacterial strains. Minimum inhibitory concentration value as low as 19.5 μg/mL was observed against non-pathogenic strains M. bovis. Activity of the crude extracts against M. aurum was the best predictor of natural product activity against the pathogenic Mycobacterium bovis strain, with a correlation coefficient value (R2) of 0.1371. Results obtained from the current study validate, in part, the traditional utilization of the tested medicinal plants against tuberculosis. The unripe fruits from Solanum torvum are a potential source of safe and efficacious anti-TB crude drugs as well as a source for natural compounds that act as new anti-infection agents, and thus deserve further investigation towards development of a new class of molecules with activity against sensitive and drug resistant strains of M. bovis

Are Competitive Microfinance Services Worth Regulating? Evidence from Sub-Saharan Africa

In recent years there is increasing appetite for regulation of financial institutions after the 2008 financial crisis. Policy questions such as whether competitive micro finance institution (MFI) requires strong regulation to reduce, for example credit risk or competition and regulation operate in the opposite direction, which each tends to dampen the effect of the other, is an empirical issue that this paper provide answers based on data on Sub-Saharan Africa (SSA) for the period 1995 to 2015, utilizing panel data approaches. Finding from the study indicates that competition increases credit risk among MFIs in SSA, which regulation helps reduce such behaviour. The effect of regulation on credit risk is conditional on the level of competition, at the first percentile of competition; regulation does not reduce credit risk behaviour of MFIs, but does at competition level above the 25th percentile. Regulation on the other hand does not affect operational risk at any level of competition