Overall, AqME showed maximum amounts of polyphenols followed by ME, AqE and AE, respectively. Likewise, AqME showed significantly higher amount of ascorbic acid. Antioxidant potential of plants is generally attributed to phytochemicals present and the synergies between them and therefore, should not to be evaluated by a single method. Hence, in order to explore and understand possible mechanisms, array of antioxidant assays including TAA, FRAP, DPPH and OH radical scavenging assays were performed for evaluating antioxidant activities of H. isora. These results validated the traditional
usage of this plant against aging and diabetes and shown a broad-range of antioxidant properties. The results of TAA and FRAP scavenging activity are summarized in Table 2. Extracts Adriamycin in vitro showed concentration-dependent TAA. AqME showed highest TAA whereas AE showed lowest TAA among all the extracts. The results presented in Table 2 showed notable antioxidant potential of extracts of H. isora in terms of FRAP in a dose-dependent manner. AqME showed highest ferric reducing power with
Saracatinib cost 360 ± 5.9 GAE followed by ME (270 ± 3.9 GAE), AqE (239 ± 4.9 GAE) and AE (200 ± 3.1 GAE) at 1000 μg/ml extract concentration. Since antioxidant capacity is directly correlated with the reducing capacity of plants and their products, the FRAP assay is considered as a reliable method for evaluation of antioxidant potentials of plant extracts and compounds 21 and our results are in conformity of these hypotheses.
The reduction capacity of stable DPPH radicals was determined next by decrease in its absorbance at 517 nm induced by the antioxidants present in extracts and the results are illustrated in Fig. 1. All extracts showed tendency to quench the DPPH radicals in a concentration-dependent fashion. AqME proved a potent free radical scavenger and showed DPPH inhibition followed by AqE, ME and AE, respectively, at 1 mg/ml concentration. Many authors have attributed higher free radical scavenging ability of plants to their phenol contents and their ability to donate hydrogen atom.2, 6 and 16 Likewise, OH radical scavenging activity was also observed maximum in AqME (Fig. 2). One of the major consequences of free radical formation is the oxidative damage to cellular components including lipid membranes, and is believed to be associated with pathology of many diseases and conditions.16 Therefore, inhibition of lipid peroxidation is considered as most important index of antioxidant potential. Fig. 3 illustrates that this plant has tremendous potential in terms of lipid peroxidation inhibition. AqME offered a good degree of protection against the biological end-point of oxidative damage and showed 97% lipid peroxidation inhibition at 1 mg/ml concentration. Extracts were evaluated for their oxidative damage protective activity against a model DNA pBR322 and the results are illustrated in Fig. 4.