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

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