Screening of anticancer agents from natural products

Abstract

In order to obtain anticancer substances from natural products, screenings were made among extracts of 38 different plants and animals which have long been used as oriental medicine to treat cancer or cancer-like diseases. Water extracts of these natural products were prepared and added to the culture solutions of murine leukemic L1210 and P388 cells. After 48 hours of incubation, cells were counted and amounts of dry extracts to achieve 50% inhibition of the control growth ($ED_{50}$) were computed. Among the 38 natural products, water extracts of $\underline{Cinnamomum}$ $\underline{cassiae}$, $\underline{Phellodendron}$ $\underline{amurense}$, and $\underline{Coptis}$ $\underline{japonica}$ showed $ED_{50}$ values significantly low. These three natural products and four more species, i.e., $\underline{Panax}$ $\underline{ginseng}$, $\underline{Benzoin}$ $\underline{strychnifolium}$, $\underline{Scutellaria}$ $\underline{baikalensis}$, and $\underline{Citrus}$ $\underline{trifoliata}$, were further extracted with different solvents such as ethanol, petroleum ether and chloroform. The chloroform extracts of these plants showed higher inhibition and $ED_{50}$ values for both L1210 and P388 cells less than 10 μg/ml. Based on the low $ED_{50}$ values together with the availability and possible selectivity on their cytotoxicity, two species, i.e., $\underline{Cinnamomum}$ $\underline{cassiae}$ and $\underline{Citrus}$ $\underline{trifoliata}$, were selected for the future studies.