The selection of medicinal plants based on long-term usage by human beings with significant biological activities that correlate with ethnomedicinal usages are quite successful (Rout et al., 2009).
Many potential natural products have been derived from medicinal plants which were traditionally used in ethnomedicine and agriculture, while few other natural products were discovered via random screening of plant extracts by evaluating their biological activity against various pathogens (Harvey and Cree, 2010; Hupfeld and Efferth, 2009). The selection of medicinal plants based on long-term usage by human beings with significant biological activities that correlate with ethnomedicinal usages are quite successful (Rout et al., 2009). The first commercial natural product introduced as therapeutics was morphine, which was marketed from Merck in 1826 (Veeresham, 2012). Aspirin is the first semisynthetic drug, based on salicin derived from Salix alba (Jones, 2011).