Effects of Myrica esculenta Bark Extracts on Melanin Biosynthesis
In this study, we investigated the effect of crude extracts, derived from stem bark of Myrica esculenta on melanin production in mouse B16 melanoma cells. In response to a-melanocyte stimulating hormone (a-MSH), B16 melanoma cells underwent differentiation characterized by increased melanin biosynthesis. Treatment of Myrica esculenta bark extracts significantly blocked a-MSH-induced melanogenesis in a dose-dependent manner. a-MSH stimulated the activity of tyrosinase, a key melanogenic enzyme in melanin biosynthesis, which was significantly reduced by Myrica esculenta bark extracts. In addition, treatment of B16 melanoma cells with Myrica esculenta bark extracts decreased the protein expression level of tyrosinase. These results demonstrated that the inhibitory effects of Myrica esculenta bark extracts on melanogenesis may be due to the suppression of tyrosinase protein levels.
Orobanche Species distribution and severity of infested areas in south and north Wollo zones of Amhara region, Ethiopia
Broomrapes (Orobanche species) are obligate holoparasitic flowering plant. Orobanche species are root parasite which can damage the crops underground before the weed emerged. Complete faba bean yield loss by this weed forced farmers to replace faba bean by cereal crops. The distribution of the weed is increasing annually. To obtain relevant information on the introduction and distribution of the weed, survey was conducted on randomly selected 72 farmers’ fields in 12 woredas in two zones, south and north Wollo. Four woredas, Kutaber, Dessie-zuria, Tenta and Mekidela are out of legumes production in south Wollo. In this survey, information was also gathered regarding farmers attitude and local control practices. Farmers practice is hand weeding but Orobanche shoots were emerged again in doubling and tripling. We cannot stop the dissemination of the weed due to the nature of dispersed agents such as wind, flood, farm machinery, crop seeds, animals, humans etc and the undulating features of the areas are all favorable agents to disperse the minute seeds of the parasitic weed and are beyond our capacity to control them, but we may bring a solution by multi-sector approach through developing resistant varieties using molecular breeding and with chemical control measures.
