In Vitro and In Vivo Studies on Quercus acuta Thunb. (Fagaceae) Extract: Active Constituents, Serum Uric Acid Suppression, and Xanthine Oxidase Inhibitory Activity

Abstract

Quercus acuta Thunb. (Fagaceae) (QA) is cultivated as a dietary and ornamental plant in China, Japan, South Korea, and Taiwan. It has been widely used as the main ingredient of acorn tofu, a traditional food in China and South Korea. The aim of this study was to determine in vitro and in vivo xanthine oxidase (XO) inhibitory and antihyperuricemic activities of an ethyl acetate extract of QA leaf (QALE) and identify its active phytochemicals using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC) systems. The QALE was found to possess potent in vitro antioxidant and XO inhibitory activities. In vivo study using hyperuricemic mice induced with potassium oxonate demonstrated that the QALE could inhibit hepatic XO activity at a relatively low oral dose (50 mg/kg) and significantly alleviate hyperuricemia to a similar extent as allopurinol. Several active compounds including vitamin E known to possess XO inhibitory activity were identified from the QALE. To the best of our knowledge, this is the first study that reports the active constituents and antihyperuricemic effect of QA, suggesting that it is feasible to use QALE as a food therapy or alternative medicine for alleviating hyperuricemia and gout.

Development and Validation of a HPLC-UV Method for Extraction Optimization and Biological Evaluation of Hot-Water and Ethanolic Extracts of Dendropanax morbifera Leaves

“…The XO inhibitory activity of the 80% ethanolic extract tended to increase in a concentration-dependent manner with increasing the extract concentration tested by up to 2 mg/mL (data not shown). Previously, we reported four different botanical extracts as potential XO inhibitors [ 18 ]. Yoon et al [ 19 , 20 ] reported that the optimized extracts of Corylopsis coreana and Camellia japonica inhibited XO activity by approximately 50% at a concentration of 2 mg/mL.…”

“…Yoon et al [ 19 , 20 ] reported that the optimized extracts of Corylopsis coreana and Camellia japonica inhibited XO activity by approximately 50% at a concentration of 2 mg/mL. Additionally, Yoon et al [ 18 ] demonstrated that Quercus acuta extract showed approximately 50% XO inhibitory activity at a concentration of 1 mg/mL. Cudrania tricuspidata extract inhibited XO by approximately 75% at a concentration of 2 mg/mL [ 21 ].…”

Quantitative Analysis, Extraction Optimization, and Biological Evaluation of Cudrania tricuspidata Leaf and Fruit Extracts

“…Previously, we had screened various medicinal sources for XO inhibitory activity. Among 229 medicinal plant extracts, 3 extracts were selected as potential XO inhibitors [ 26 ]. Extracts from Corylopsis coreana and Camellia japonica inhibited the XO at a concentration of 2 mg/mL, and relative inhibiton levels were 50% to 60% [ 20 , 27 ].…”

“…Extracts from Corylopsis coreana and Camellia japonica inhibited the XO at a concentration of 2 mg/mL, and relative inhibiton levels were 50% to 60% [ 20 , 27 ]. The extract from Quercus acuta inhibited the XO at a concentration of 1 mg/mL, and the inhibition level was ~50% [ 26 ]. The plant extracts with XO inhibitory activity in the range of 1–2 mg/mL demonstrated consistent effects in the in vivo animal disease model.…”

Analysis of the Active Constituents and Evaluation of the Biological Effects of Quercus acuta Thunb. (Fagaceae) Extracts

“…Quercus acuta (QA) is widely distributed in the southern part of Korea, China, Japan, and Taiwan [ 1 ]. It is mainly cultivated as an ornamental plant in Japan, and its fruit (acorn) is the main ingredient in acorn jelly, which is a popular traditional food in Korea [ 2 ].…”