Evaluation of antibacterial activity of fractions from stem extract of tinospora crispa (L.) Hook. f. & Thomson

Abstract

The aim of this study is to evaluate the antibacterial activity of fractions from Tinospora crispa (L.) Hook. f. & Thomson stem extract. The extraction was fractionated by solvents with increasing polarity, then partioned with acidic water and base to concentrate alkaloids. There are totally 7 fractions named PD-hex, PD-K, PD-Cf2, PD-Cf1, PD-EtOAc, PD-BuOH and PD-N. With the help of disc diffusion method, 7 fractions were separately evaluated for their ability to inhibit the growth of some common bacterial species, including 3 Gram-positive and 3 Gram-negative bacteria. The result showed that Tinospora crispa was able to restrain the growth of the 3 Gram-positive species but not the 3 Gram-negative species. Antibacterial substances distributed in 6 over 7 fractions tested, excluding PD-K fraction. PD-K sample mainly contained strong basic alkaloid and soluble water. Especially, weak basic alkaloids in PD-Cf2 were able to restrict the bacterial growth stronger than stronger basic alkaloids in PD-K. On the other hand, ethyl acetate fraction (PD-EtOAc), which contained medium polar compounds, were able to restrict the growth of bacteria slightly better than the others. It was subjected to traditional column chromatography to isolate some components. The purified substance was structurally identified by thin-layer chromatography, high performance liquid chromatography and spectroscopic data analyses.