Abstract
The two herbal plants of Adhatoda vasica and Calotropis procera, commonly available in worldwide, were selected to explore their medicinal significance. The isolation and quantitative analysis of ten important bioactive compounds such as P-hydroxy-benzoic, Stictic acid, Usnic acid, Epigallocatechin gallate, Quercetin, Epigallocatechin, Catechin, Morin, Epicatechin and Naringenin, isolated from various parts was performed by using UF-HPLC-DAD and FTIR techniques. The antioxidant potentials of isolated bioactive compounds were evaluated through six methods including Electron spin resonance spectrometry, ABTS Assay, Diphenyl picrylhydrazyl (DPPH) radical scavenging assay, total radical-trapping, ORAC, and phycoerythrin assay on various plant parts. The advanced ESR method along with five other methods was applied for the first time on these species to evaluate the antioxidant potential of both species. The results showed that the flowers of Adhatoda vasica prove to be a rich source of important compounds in which Naringenin (15 ± 0.41) was higher in the flowers. The similar trend observed in twigs and seeds of Adhatoda vasica, the Epicatechin was higher in seeds of Calotropis procera. Results showed that the electron spin resonance spectrometry and ABTS radical scavenging assay methods showed higher antioxidant potential in Adhatoda vasica and Calotropis procera as compared to Diphenyl picrylhydrazyl (DPPH) radical scavenging assay.