Inhibition of conidial germination and mycelial growth of Corynespora cassiicola (Berk and Curt) of rubber (Hevea brasiliensis muell. Arg.) using extracts of some plants

Twenty-one plants were screened for fungicidal effects on conidial germination and mycelial growth of Corynespora cassiicola. Out of this, 5 plants (Ageratum conyzoides, Centrosema pubescene, Emilia coccinea, Ocimum basilicum and Solanum torvum) were selected for evaluation of concentration effects. Treatment in O. basilicum resulted in the lowest mycelial growth at 100% extract concentration. An in vivo evaluation showed that treatment with 100% O. basilicum resulted in disease index (D.I) of 43% which was significantly lower than the control 65% D.I at 5% level of probability

Inhibition of Colletotrichum gloeosporioides (Penz) Sac. causal organism of rubber (Hevea brasiliensis Muell. Arg.) leaf spot using plant extracts

In vitro and in vivo antifungal evaluations were carried out on twenty-one plants selected from fourteen families on a folial pathogen of para rubber, Colletotrichum gloeosporioides (Penz). Sac. Extracts ofOcimum basilicum L. and Allium sativum L. exhibited total inhibitory effects on the mycelial growth of C. Gloeosporioides. An evaluation of concentration effects was carried out using four concentrations offive selected plants: A. sativum, Jatropha curcas, O. Basilicum, Vernonia amygdalina and Ageratum conyzoides. A. sativum and O. basilicum totally inhibited conidial germination 24 h after inoculation, and conidial germination in liquid amended media was recorded only in the A. conyzoides amended liquid media. An in vivo evaluation showed that treatment with 100% O. basilicum resulted in disease index (D.I) of 31.7% which was significantly lower than the control 65% D.I at 5% level of probability

Field evaluation of selected formulations of Trichoderma species as seed treatment to control damping-off of cowpea caused by Macrophomina phaseolina

The experiment was carried out between 1997 and 1998 at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria to test the efficacy of biological seed treatment of cowpea against Macrophomina phaseolina infection in the field. Trichoderma sp., T. koningii Oudem (IMI 361600) and T. harzianum Rifai (IMI 361601) were selected from soil dilutions and tested in vitro for their antagonistic behaviour against cowpea pathogen M. phaseolina before use in the field. The in vitro tests in dixenic cultures, showed all three Trichoderma species growing fast and stopping the growth of the pathogen by the third day of pairing. Two varieties IT86D-2120, and Ife Brown were tested and two formulations of each Trichoderma species (mycelial suspension and suspension + starch) were also tested. The analysis of variance showed that there were significant differences between stands from the two trials and varieties. Treatment effect was also significant. The variety IT86D-2120 had significantly better stands in both trials. The highest plant stand of 53.8% at 7 days after planting (DAP), from the first trial, was from IT86D-2120 seeds treated with T. koningii + starch, which decreased to 49.3% by 21 DAP due to post emergence damping off. In the second trial, IT86D-2120 seeds treated in T. harzianum suspension had percentage stand of 55% at 7 DAP, which reduced to 45.8% at 21 DAP.Keywords: Trichoderma harzianum, T. koningii; biological control, field trial, Macrophomina phaseolin

Oleanolic acid purified from the stem bark of Olax subscorpioidea Oliv. inhibits the function and catalysis of human 17β-hydroxysteroid dehydrogenase 1

Cancer is a leading cause of global death. Medicinal plants have gained increasing attention in cancer drug discovery. In this study, the stem bark extract of Olax subscorpioidea, which is used in ethnomedicine to treat cancer, was subjected to phytochemical investigation leading to the isolation of oleanolic acid (OA). The structure was elucidated by 1-dimensional and 2-dimensional nuclear magnetic resonance spectroscopic (NMR) data, and by comparing its data with previously reported data. Molecular docking was used to investigate the interactions of OA with nine selected cancer-related protein targets. OA docked well with human 17β-hydroxysteroid dehydrogenase type-1 (17βHSD1), caspase-3, and epidermal growth factor receptor tyrosine kinase (binding affinities: –9.8, –9.3, and –9.1 kcal/mol, respectively). OA is a triterpenoid compound with structural similarity to steroids. This similarity with the substrates of 17βHSD1 gives the inhibitor candidate an excellent opportunity to bind to 17βHSD1. The structural and functional dynamics of OA-17βHSD1 were investigated by molecular dynamics simulations at 240 ns. Molecular mechanics/Poisson-Boltzmann surface area (MMPBSA) studies showed that OA had a binding free energy that is comparable with that of vincristine (–52.76, and –63.56 kcal/mol, respectively). The average C-α root mean square of deviation (RMSD) value of OA (1.69 Å) compared with the unbound protein (2.01 Å) indicated its high stability at the protein’s active site. The binding energy and stability at the active site of 17βHSD1 recorded in this study indicate that OA exhibited profound inhibitory potential. OA could be a good scaffold for developing new anti-breast cancer drugs