Effect of gamma irradiation on suruhan (Peperomia pellucida (L.) Kunth) herb powder

Introduction: Peperomia pellucida (L.) Kunth is known as a raw material for herbal medicine; Preservation of herbs powder by gamma irradiation is reported to be able to keep products free from contamination. Methods: This study aims to evaluate the effect of gamma irradiation (0; 2.5; 5; 7.5; and 10 kGy) on the ACE inhibitory activity (ACE Kit - WST test kit method), antioxidant activity (DPPH radical scavenging method), total phenolic content (colorimetric method using Folin-Ciocalteu reagent), total flavonoid content (colorimetric method using AlCl3 and sodium acetate), and TLC profiling (silica gel F254 as the stationary phase and dichlormethane:methanol [92:8] as the mobile phase) of suruhan herb powder. Results: Results showed that the 2.5 kGy irradiation dose gave the smallest alteration in ACE inhibitory activity compared to others irradiated doses. Furthermore, the 5 and 7.5 kGy dose didn't cause significant change (p>0.05) on antioxidant activity, total phenolic content, and total flavonoid content. Antioxidant activity was found to correlate with the total phenolic content but not with the total flavonoid content. Conclusion: Based on these finding, it is concluded that gamma irradiation can be used as a preservation method for P. pellucida herb powder.