Evaluation of Rhizobium tropici-Derived Extracellular Polymeric Substances on Selected Soil Properties, Seed Germination, and Growth of Black-Eyed Peas (Vigna unguiculata)

Rhizobium tropici-derived extracellular polymeric substances (EPS) have been used in soils to enhance soil structures and mitigate soil erosions. However, information on their use to improve soil health and fertility indicators, and plant growth is limited. In a greenhouse study, we investigated their effects on some soil health, soil fertility indices, and the growth of black-eyed peas (Vigna unguiculate). Results showed that soils incubated with EPS significantly increased basal soil respiration, soil microbial biomass, permanganate oxidizable carbon (POC), and potentially mineralizable nitrogen (PMN). The EPS shifted microbial populations from bacteria to fungi and Gram (−ve) to Gram ( ve) bacteria. However, it had little or no effects on soil pH, soil organic matter (SOM), and cation exchange capacity (CEC). The EPS decreased soil moisture loss, increased soil aggregate stability, but delayed blacked-eyed peas germinations in the soils. At 0.1% (w/w) concentrations in soils, there was increase in plant root nodulations and vegetative growth. This study was carried out within 40 days of incubating soils with EPS or growing the black-eyed peas in a greenhouse study. The plant growth parameters were taken before flowering and fruiting. Further studies of the effects of incubating soils with the extracellular polymeric substances on plant growth. Soil microbial biomass, microbial diversities, and other soil fertility indices are deemed necessary.

Anti-onchocerca Metabolites from Cyperus articulatus:Isolation,In Vitro Activity and In Silico‘Drug-Likeness’

The aims of this investigation were to isolate active ingredients from the roots/rhizomes of Cyperus articulatus used as herbal medicine in Cameroon for the treatment of human onchocerciasis and to assess the efficacy of the metabolites on the Onchocerca worm.The antifilarial activity was evaluated in vitro on microfilariae(Mfs)and adult worms of the bovine derived Onchocerca ochengi,a close relative of Onchocerca volvulus.Cytotoxicity was assessed in vitro on monkey kidney epithelial cells.The structures of the active compounds were determined using spectroscopic methods and their drug-likeness evaluated using Lipinski parameters.Two secondary metabolites,AMJ1[containing mustakone(1)as the major component]and linoleic acid or(9Z,12Z)-octadeca-9,12-dienoic acid(2)were isolated.Both compounds were found to kill both the microfilariae and adult worms of O.ochengi in a dose dependent manner.The IC50s for AMJ1 were 15.7 lg/mL for Mfs,17.4 lg/mL for adult males and 21.9 lg/mL for adult female worms while for linoleic acid the values were,15.7 lg/mL for Mfs,31.0 lg/mL for adult males and 44.2 lg/mL for adult females.The present report provides the first ever evidence of the anti-Onchocerca efficacy of AMJ1 and linoleic acid.Thus,these secondary metabolites may provide a lead for design and development of new antifilarial agents.