Investigation of the Antioxidant Activity and Phenolic Compounds of Andricus quercustozae Gall and Host Plant (Quercus infectoria)

Abstract

Andricus quercustozae (Bosc, 1792) is a cynipid gall wasp, which induces gall on oaks (Quercus spp.). It is known that both cynipid galls and oaks are used in traditional medicine. In this study, some biological characteristics of various extracts (acetone and ethanol) of A. quercustozae asexual gall and its host plant, Quercus infectoria Olivier, were investigated. The antioxidant capacities of the extracts were evaluated using radical scavenging activity (ABTS and DPPH assays), the β-carotene-linoleic acid method, the phosphomolybdenum method, and the reducing power (CUPRAC method). Total phenolics, flavonoid and tannin contents were measured in the gall and the oak leaf extracts. Moreover, ethanol extracts of the gall and the host plant were evaluated using HPLC for the composition of phenolics. Generally, the gall extracts (acetone and ethanol, respectively) exhibited the strongest radical scavenging (DPPH, IC50 value of acetone extract: 11.00 μg/mL and IC50 value of ethanol extract: 8.67 μg/mL; ABTS, 52.27 μg/mL and 44.97 μg/mL) and antioxidant activities with the highest level of phenolics. The antioxidant activity of the gall extracts was in the range of 80.74 to 87.49 % for β-carotene-linoleic acid method, while and it was ranged from 75.68 to 78.20 mgAEs/g for phosphomolybdenum method. In the results of some antioxidant methods (ABTS and β-carotene-linoleic acid), it is observed that the host plant extract has values close or high to the gall extract. In this context, our results suggested that the cynipid gall extracts could be used as a natural agent in food, medicinal and pharmaceutical applications.