Enhancing the biological activities and altering the chemical structure of clove aqueous extract prepared with plasma-activated water as a novel technique

Abstract

This investigation assesses the effect of plasma-activated water (PAW) as a solvent during the preparation of clove aqueous extract. PAW was generated by surface dielectric barrier discharge (SDBD) plasma device for 5, 10, and 15 min, respectively. The conventional method of maceration was used as a control group. We evaluated the biological activity and physicochemical characteristics of clove extracts. In the color assay, the clove extract produced by PAW showed a slightly higher color parameter than the control extract. The Fourier transform infrared (FTIR) results demonstrated several higher absorption intensities at specific regions in the PAW-clove extract structure. Liquid chromatography-mass spectrometry (LC-MS) analysis of the PAW extracts showed more bioactive components than the maceration extract. The clove extract prepared by the PAW -5 min group had the highest total phenolic content (TPC) at 821.6 mg GAE/g, the highest free radical scavenging activity (DPPH) and ferric-reducing antioxidant power (FRAP) compared to other groups. These alterations could be due to reactive oxygen-nitrogen species (RONS) generated in PAW, which can modify the physicochemical properties of clove. The findings indicated that PAW is a unique extraction solvent that improves the extraction of phenolic compounds from clove.