ISOLATION AND THE EFFECT OF PEPTIDE FRACTIONS FROM Justicia gendarussa Burm f. LEAVES ON THE RELEASE OF PRO-INFLAMMATORY CYTOKINES IN VITRO

Abstract

Thanh tao plant (Justicia gendarussa Burm f.) is a medicinal plant belonging to the Acanthaceae family that it grows in many places in Vietnam and is used in folk medicine to treat a number of diseases such as: bone pain, arthritis, cough relief, fever reduction, acne... In recent years, the use of bioactive natural peptides from herbs to treat chronic diseases and improve human health has been increasing. In this study, natural peptides and hydrolyzed peptides from proteins of thanh tao plant (TT) were isolated and evaluated for their effects on the release of inflammatory cytokines in vitro. Natural peptide fractions and hydrolyzed peptides from protein of TT leaves were isolated using Amicon Ultra Centrifugal Filters (Millipore) with different molecular weight cut-offs (≤ 30kDa, ≤ 10kDa and ≤ 5kDa). The purity and molecular weight of peptides were determined by Tricine-SDS-PAGE gel electrophoresis. The results showed that the leaves of the TT were extracted with cold distilled water to obtain the natural peptide with molecular weight (14 kDa). Protein from the TT leaves was hydrolyzed by pepsin and pancreatin for 1 hour to obtain a peptide fraction ≤ 10 kDa. The effects of peptide fractions on inflammatory cytokines were evaluated on LPS-induced macrophages. The release of inflammatory cytokines was determined by ELISA method. The natural TT peptide fractions and hydrolyzed TT peptide fractions obtained at concentrations (10 - 40µg/mL) had no effect on macrophages. The hydrolyzed TT peptide fraction ≤ 10 kDa at a concentration of 10 - 40µg/mL higher inhibit the release of TNF-α, IL-6 and IL-8 than the natural TT peptide fraction in vitro. This is the initial basis to demonstrate the folk anti-inflammatory effect of this medicinal plant leaf.