Antioxidant and antifungal activities of Myrianthus arboreus P. Beauv. (Moraceae), Allanblackia gabonensis Pellegr. (Clusiaceae) and three other Cameroonian medicinal plants

Background: Biological activities of medicinal plants make them attractive alternative complementary medicines. Therefore, this study aimed to assess the antioxidant and antifungal activities of the methanol extract of Myrianthus arboreus, Allanblackia gabonensis, Gladiolus quartinianus, Peperomia fernandopoiana and Vepris soyauxii. Methods: Total phenolic contents (TPC) and flavonoid contents (FC) were evaluated using standard methods. The antioxidant activity of the extracts was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing power assays. Antifungal activity was evaluated by the broth micro-dilution method. Results: TPC of extracts ranging from 67.89 to 196.01 mgGAE/g TPC were very higher in P. fernandopoiana whole plant (PFW) extract (196.01±10.25 mgGAE/g) and MAL (165.71±10.68 mgGAE/g) whereas the A. gabonensis fruit extract (AGF) and M. arboreus bark extract (MAB) had the highest flavonoid content (66.54 ± 2.12 and 48.13 ± 1.65 mgEC/g of extract, respectively). Apart from M. arboreus leave extract (MAL), all extracts showed important DPPH radical scavenging activity (IC50 < 20 μg/mL). AGFl and PFW exhibited significant ferric reducing power compared to ascorbic acid and other extracts (P<0.05). Each of the tested extracts showed antifungal activity against atleast one of the five pathogenic fungi, with MICs ranging from 128 to 1024 µg/mL. MAL was active on all the tested fungi whereas MAB showed the highest antifungal activity (MIC=128 µg/mL). Conclusion: The findings of this study emphasize the evidence that the methanol extracts of the leave and bark of Myrianthus arboreus could be an alternative to fight against oxidative stresses and infections due to opportunistic yeast pathogens. Keywords: Oxidative stress; fungal infection; medicinal plant; antioxidant activity; antifungal activity.

Diversity, Distribution, and Abundance of Plants in Lewoh-Lebang in the Lebialem Highlands of Southwestern Cameroon

A survey was conducted between October 2010 and June 2011 to determine the diversity, distribution, and abundance of plants in 4 sites of the Lebialem highlands and to relate species diversity and abundance to altitude and soil types. Twelve (12) plots, each of 1 ha (250 × 40 m), were surveyed at the submontane and montane altitudes of the sites. One hundred (100) species belonging to 82 genera were identified with the genera Cola and Psychotria being the most represented. Vulnerable species included Guarea thompsonii, Schefflera hierniana, Allanblackia gabonensis, Cyclomorpha solmsii, Vepris trifoliolata, and Xylopia africana. Species such as Xymalos monospora, Tricalysia atherura, and Piptostigma oyemense present in the study area were endemic to Cameroon. Diversity and distribution of plants were affected by parameters such as the altitude and the soil type. Soil analysis revealed that diversity in the study area was affected by the organic carbon, nitrogen, calcium, and the cation exchange capacity of the soil.