RESUMO
ABSTRACT Biologically active proteins isolated from plant species can be used in traditional medicine as prolific resources for new drugs Morinda pubescens Sm., Rubiaceae, is a promising medicinal plant which is widely used in folk medicine to treat fever due to primary complex, ulcer and glandular swellings. In this study, proteins were extracted from the leaves of M. pubescens, and precipitated with ammonium sulphate at various saturation concentrations ranging from 20 to 80%. The precipitated protein sample obtained with 80% saturation was further purified using ultrafiltration membrane (<10 kDa). SDS-PAGE analysis identified the presence of crude and ultrafiltered protein bands. FTIR spectrum of the ultrafiltered protein fractions depicted the presence of hydroxyl and carbonyl groups of proteins. The ultrafiltered proteins exhibited increased cytotoxic activity on A549 cells at the concentrations ranging from 15 to 100 µg/ml. About 98% cell viability was also observed in Vero cells treated with the maximum concentration of 100 µg/ml of ultrafiltered protein extract. DNA fragmentation was observed in A549 cells treated with 10 µg/ml of ultrafiltered proteins, indicating the onset of apoptosis.