Phytochemical Investigation and Antimicrobial Evaluation of Root Extract of Law soniaInermis

Abstract

Medicinal plants are now more focused than ever because they have the capability of producing many benefits to society indeed to mankind, especially in the line of medicine and pharmaceutical. Lawsonia inermis is one of the most commonly known medicinal plants used. However, its phytochemical and biological information is very limited in Ethiopia. The aim of this study is to investigate phytochemical constituents and evaluate antimicrobial activity of the plant. The air dried plant was extracted using chloroform: methanol (1: 1) ratio by maceration at room temperature and gave 31 g. The crude extract 31 g (6.2% yield) was subjected to silica gel Column Chromatography (CC) for fractionation and purification of the compounds. The column was eluted using petroleum ether with increasing polarity of ethyl acetate and methanol. Fractions were merged depending on Rf values. βـsitosterol (C1) was obtained by recrystallization of fractions (F24 to F28) using ethyl acetate and n-hexane. Fractions (F10 to F23) and fraction left without recrystallized from C1 were merged and subjected to silica gel Column Chromatography (CC) for fractionation and purification of the compounds. Finally, fractions (F1 to F5) obtained from merged fractions of F10 to F28 were merged and subjected to a column packed by sephadex for separation of compound βـsitosterol oleate (C2) using chloroform: methanol. The structures of the isolated compounds (C1 & C2) were established using 1H, 13C-NMR, DEPT-135 and IR spectroscopic methods comparison with literature reports. The resulting crude extracts were in vitro assayed against four bacterial strains (B. cereus, S. aureus, E. coli, & S. typhi) and one fungal strain (C. albicans) using disc diffusion method. The crude extracts showed promising antibacterial activities with zone of inhibition 19.5 ± 0.5 (S. aureus), 18.5 ± 0.5 (C. albicans), 17.5 ± 0.5 (E. coli) and 18 ± 0 (B. cereus and S. aureus) at 300 mg/mL by comparison with standard antibiotics zone of inhibition 21.5±0.5 (S. aureus), 20±0 (C. albicans), 23.5±0.5 (E. coli), 23.5 ±0.5 (B. cereus) and 22.5±0.5 (S. typhi) at 300 mg/mL (Gent.) for bacteria and 200 mg/mL(Clotr.) for fungus. The antimicrobial activity of the extract indicates that the crude extract has good antibacterial and antifungal activities.