Simulated Gastrointestinal System Study of Centella asiatica Extract-loaded Gelatin Nanoparticles on Antioxidant and Antimicrobial Activities

Abstract

The aim of this study is to improve antibacterial activity and antioxidant activity of Centella asiatica in simulated gastrointestinal system. Gelatin one-step and two-step desolvation nanoparticle methods were used to prepare C. asiatica-loaded gelatin nanoparticles (CGNP) on three different ratio of 95% ethanolic C. asiatica crude extracts:Gelatin (1:2, 1:3, and 1:4). One-step CGNP (OSCGNP) was tested on antibacterial activity by using well agar diffusion method with different concentrations (100, 200, and 300 µg/ml) against seven foodborne pathogens and antioxidant activity by using DPPH method. The inhibition zones of OSCGNP showed highly significant effective at concentration of 300 µg/ml in oesophagus-stomach section against E. coli ATCC25822 and B. subtilis respectively. In addition, S. aureus, S. enterica Enteritidis (human), and S. enterica 4,5,12:i:- (human) US clone were strongly inhibited by OSCGNP at concentration of 100 µg/ml. The highest inhibition zone of OSCGNP was 1.00±0.17 cm at pH 2.0 using gelatin one-step desolvation method. The highest antioxidant activity was 22.70±4.69 µg GAE/ml per 10 mg of OSCGNP with ratio of 1:2 occurred in stomach at pH 2.0. Moreover, antioxidant activity of CGNPs (One-step and two-step gelatin nanoparticles) were dropped when they reached duodenum section. The results indicated that CGNPs gave lower antioxidant activity than crude extract.