Spatial and Temporal Distribution of Phenolic and Flavonoid Compounds in Sour Jujube (Ziziphus. Acidojujuba Cheng et Liu) and Their Antioxidant Activities.

In order to comprehensively analyze the antioxidant substances in sour jujube, total phenolic content (TPC) and total flavonoids contents (TFC) in different organs, including stem, leaf, flower, fruit pulp, and seed were analyzed for their contents and antioxidant activities. The results showed that leaves possessed significantly higher TPC and TFC (20.4 and 20.5 mg/g, respectively) than the other organs and have the highest antioxidant activity, which were also higher than the wild blueberry (A well-known for its high TPC). Subsequently, the variations in the antioxidant content and antioxidant activity of leaves were analyzed during leaf development. TPC in leaves sampled in may and august were significantly higher than that in other months, while the highest one was found in may. The n-hexane, ethyl acetate, n-butanol, and water fractions obtained from the main methanol extract of sour jujube leaves were evaluated for TPC and TFC and their antioxidant activity and it was found that ethyl acetate fraction displayed the highest TPC and TFC (184.5 and 193.3 mg/g, respectively), as well as the best antioxidant activity. In addition, using LC-MS and HPLC, ethyl acetate fraction was analyzed from qualitative and quantitative aspects; 31-one phenolic compounds, including catechin (33.0 mg/g), epigallocatechin (15.3 mg/g), quercetin 3-O-glucoside (11.4 mg/g), naringenin (6.7 mg/g), esculetin (4.8 mg/g), and chlorogenic acid (4.6 mg/g) were identified. Catechin, esculetin, epigallocatechin, chlorogenic acid, quercetin 3-O-glucoside, and naringenin exhibited high antioxidant activity. These results provide a theoretical basis for further study and utilization of flavonoid and polyphenols in sour jujube.

Isolation and identification of antioxidant and hyaluronidase inhibitory compounds from Ficus microcarpa L. fil. bark.

The aerial roots and bark of Ficus microcarpa L. fil. have been used as folk herbs for perspiration, alleviating fever, and relieving pain in Okinawa. The methanol extract of its bark showed high antioxidant and potential inhibitory activity against hyaluronidase. It was fractionated into hexane, ethyl acetate, butanol, and water fractions. As the ethyl acetate fraction exhibited the strongest activity, it was selected for further purification by repeated Sephadex LH-20 column chromatography and preparative HPLC. Seven compounds were isolated and identified as protocatechuic acid, chlorogenic acid, methyl chlorogenate, catechin, epicatechin, procyanidin B1, and procyanidin B3 by analysis of ESI-MS, UV, and (1)H- and (13)C-NMR spectra. All isolated compounds showed strong antioxidant activity when tested by all applied methods. Catechin, epicatechin, procyanidin B1, and procyanidin B3 exhibited excellent inhibitory activity against hyaluronidase. The results indicate that the extract of F. microcarpa bark may be utilized as a potential antioxidant and hyaluronidase inhibitor.