Separation and Quantification of Sinensetin, Imperatorin and Total Tannin Content as Active Phytoconstituents of Methanol Extract of Imperata cylindrica Root from Kendari

Abstract

Introduction: Imperata cylindrica root methanol extract harvested from Kendari had anti-hypertensive activity stated in a study on hypertension rat models at the doses 60 and 90 mg/kg-bw. The extract also contained phenolic compound 1.53% (GAE) and flavonoid 1.17% (QE) and had antioxidant activity IC50 0.32 mg/mL. Aim of the study was to determine the active secondary metabolites in the extract. Materials and Method: Sinensetin and imperatorin in the extract were separated on silica gel 60 column, eluted with a gradient eluent system as follows (1) n-hexane- ethyl acetate (3:7); (2) n-hexane – ethyl acetate (2:8); (3) ethyl acetate -MeOH (8:2), and (4) methanol. Imperatorin and sinensetin in fractions were identified and quantified by HPLC method with column LiChroCART 250-4,6 RP 18E, isocratic mobile phases with the composition of mixture as follows, 0.1% formic acid, acetonitrile and methanol (40:50:10) respectively, and at temperature 400 C. The total tannin was determined by spectrophotometry method with Fe(III) chloride and 1.10-Phenanthroline at wave length 510 nm. Results: Imperatorin and sinensetin were identified in fractions 5 to 9. The concentrations of sinensetin and imperatorin in Imperata cylindrica root methanol extract were of 32.348 and 37.014 mg/kg extract, respectively. The total tannin content was 1.06 % (w/w) (TAE). Conclusion: Imperata cylindrica root methanol extract from Kendari had active phytoconstituents, namely sinensetin, imperatorin, and tannin. Key words: Imperata cylindrica, Imperatorin, Sinensetin, Tannin.