Isolation of the active ingredients of antimalarial activity of the stem bark of <i>Pseudocedrela kotschyi</i> (Dry zone cedar)

Abstract

Natural products, either as pure compounds or as standardized extracts provide unlimited opportunities for new drug discoveries because of the  unmatched availability of chemical diversity. This study was carried out to isolate the active ingredients and determine the antimalarial activity of  fractions of Pseudocedrela kotschyi stem bark following a scientific report of the antimalarial activity of crude extract of the plant material. Atotal of seven  different fractions were obtained from 12g of the ethyl acetate crude extract using the flash chromatography method. GC-MS analysis of each of  the seven ethyl acetate fractions was done and the identification of components present was based on a direct a comparison of the similarity index,  retention times and mass spectral data with those for standard compounds. The compound prediction is based on NIST 05 Spectral library search  programme. LD₅₀ of 5 out of 7 fractions obtained was carried out using 45 mice of both sexes  weighing 17-34g. The antimalarial (suppressive and  curative) properties were evaluated in 40 mice in 3 different groups using NK 65 Plasmodium berghei berghei for each fraction. The plant treatments  were compared against chloroquine and dimethyl sulfoxide. Results of GC-MS analysis of the seven ethyl acetate fractions of the plant extract showed the  presence of forty-four different compounds, of which 3, 5-di-tert-butylphenol have been previously reported to have antimalarial properties. Acute  toxicity (LD₅₀ ) of fractions F1-4, F8, F9, F10-11, and F12-19 were 450mg/kg, 200mg/kg, 450mg/kg,  200mg/kg, and 450mg/kg respectively. All 7 fractions  exhibited antimalarial activity. Remarkably, fractions F8 and F6-7 showed significant antimalarial activities for both suppressive and curative tests. These  findings may benefit the antimalarial drug search in the current public health concerns of malaria disease.