Xanthone and Flavonoid Derivatives from the Leaves of Maclura tricuspidata with Antioxidant and Anti-tyrosinase Activity

Masclura tricuspidata, also called as Cudrania tricuspidata, is one of the most common Moraceae family plants in East Asia. Its trivial name follows mulberry due to the similar morphology. Investigation of the bioactive constituents of M. tricuspidata leaves yielded a new xanthone derivative along with twenty known compounds through various chromatographic techniques. A new compound was defined as mascluraxanthone (3), a prenylated xanthone glucoside on the basis of 1D and 2D NMR and MS data. Twenty known compounds were identified as four xanthone derivatives (1-2 and 4-5), two flavans (6-7), six flavanol derivatives (8-13), a flavonone (14) and seven flavonol derivatives (15-21). Among the isolated compounds, flavanol and flavonoid derivatives with 3′,4′-OH groups showed antioxidant and anti-tyrosinase activities. Conclusively, the leaves of M.tricuspidata are rich in aromatic compounds including xanthones and flavonoids. In addition, these constituents showed antioxidant and anti-tyrosinase potentials, which might be useful for oxidative stress related diseases.

Antioxidant Activity and Phenolic Content of Different Parts of Lotus and Optimization of Extraction Condition using Response Surface Methodology

Nelumbo nucifera Gaertn. (Nymphaeaceae) is commonly called lotus and its leaves are widely been used as functional ingredients due to its antioxidant activity. For maximum efficacy, optimized extraction condition was established using response surface methodology. The high F-values, low p-values and insignificant p-value for lack-of-fit supported the fitness of the model and yielded the second-order polynomial regression for the antioxidant activity. The optimized extract was obtained by the extraction of 1 g of lotus leaves with 40 mL of 50% MeOH at 10.0℃, which exerted 70.1% antioxidant activity. Close correlation between phenolic content and antioxidant activity suggested phenolic compounds as active constituents of lotus leaves. In addition, comparison of different parts of lotus demonstrated the most potent antioxidant activity of flowers, followed by leaves and roots. Taken together, these results provide useful information about lotus leaves for the development as antioxidant ingredients. In addition, flowers and roots as well as leaves are suggested as good sources for antioxidant activity.

Two New Caffeoyl Threonate Esters from the Leaves of Toxicodendron vernicifluum

Toxicodendron vernicifluum, also called as Rhus verniciflua is a deciduous tree belonging to Anacardiaceae family. Two new caffeoyl threonate esters, rhuseols A (1) and B (2), together with 5-O-(E)-caffeoylquinic acid methyl ester (3) were isolated from the leaves of T. vernicifluum. The structures of isolated compounds were established by using 1D and 2D NMR in combination with HR-ESI-MS. Compounds 1 – 3 showed DPPH radical scavenging effects with IC₅₀ values of 47.9, 107.8 and 15.4 µM, respectively. Taken together, these compounds might contribute to the antioxidant properties of the leaves of T. vernicifluum, which will be useful for various oxidative stress mediated diseases.

Optimization of Extraction Condition of Methyl Jasmonate-treated Wild Ginseng Adventitious Root Cultures using Response Surface Methodology

The usage of wild ginseng (Panax ginseng C.A. Meyer) has been limited due to short supply and high price. Therefore, sufficient production as well as efficient extraction of mountain ginseng are required for the development as products. In this study, wild ginseng adventitious root cultures were prepared for efficient production with advantages of fast growth and stable production. Treatment of methyl jasmonate (MJ) to wild ginseng adventitious root cultures increased the extraction yield and antioxidative activity. Further investigation on effect of extraction conditions suggested the importance of ethanol concentration on antioxidative activity and extraction yield of MJ-treated wild ginseng adventitious root cultures. Optimized extraction condition of MJ-treated wild ginseng adventitious root cultures for maximum extraction yield and antioxidative activity was determined using response surface methodology with three-level-three-factor Box-Behnken design (BBD). Extraction of 1 g MJ-treated wild ginseng adventitious root culture with 30 ml of 9% ethanol at 30 ℃ produced 310.2 mg extract with 71.0% antioxidative activity at 100 µg/ml. Taken together, MJ-treated wild ginseng adventitious root culture is valuable source for wild ginseng usage and optimized extraction condition can be used for the development of functional products or folk remedies.

Effect of Extraction Conditions of Green Tea on Antioxidant Activity and EGCG Content: Optimization using Response Surface Methodology

Green tea, the leaves of Camellia sinsneis (Theaceae), is generally acknowledged as the most consumed beverage with multiple pharmacological functions including antioxidant activity. This study was performed to analyze the effect of extraction conditions of green tea on its antioxidant effects using DPPH assay. Three extraction factors such as extraction solvent (EtOH, 0 – 100%), extraction time (3 – 15 min) and extraction temperature (10 – 70℃) were analyzed and optimized extraction condition for antioxidant activity of green tea extract (GTE) was determined using response surface methodology with three-level-three-factor Box-Behnken design (BBD). Regression analysis showed a good fit of data and the optimal conditions of extraction were found to be 57.7% EtOH, 15 min and 70℃. Under this condition, antioxidant activity of experimental data was 88.4% which was almost fit to the ideal value of 88.6%. As epigallocatechin gallate (EGCG) is known for the major ingredient for antioxidant activity of green tea, we investigated the effect of EGCG on antioxidant activity of GTE. EGCG showed antioxidant activity with the IC50 value of 4.2 µg/ml and a positive correlation was observed between EGCG content and the antioxidant activity of GTE with R2 = 0.7134. Interestingly, however, GTE with 50 – 70% antioxidant activity contain less than 1.0 µg/ml of EGCG, which is much lower than IC50 value of EGCG. Therefore, we suppose that EGCG together with other constituents contribute to antioxidant activity of GTE. Taken together, these results suggest that green tea is more beneficial than EGCG alone for antioxidant ability and optimal extraction condition of green tea will be useful for the development of food and pharmaceutical applications.

Optimization of Extraction Condition of Hesperidin in Citrus unshiu Peels using Response Surface Methodology

Hesperidin, which is the most abundant flavonoid of Citrus unshiu (Rutaceae), has been reported to possess diverse activities and widely used as functional foods and cosmetics. For the development of functional products, extraction procedure is indispensable. Extraction conditions affect the composition of extract as well as its biological activity. Therefore, we tried to optimize extraction conditions such as extraction solvent, extraction time and extraction temperature for maximum yield of hesperidin using response surface methodology with threelevel-three-factor Box-Behnken design (BBD). Regression analysis showed a good fit of the experimental data and the optimal condition was obtained as ethanol concentration, 59.0%; temperature 71.5degrees C and extraction time, 12.4 h. The hesperidin yield under the optimal condition was found to be 287.8 microg per 5 mg extract, which was well matched with the predicted value of 290.5 microg. These results provides optimized extraction condition for hesperidin and might be useful for the development of hesperidin as functional products like health supplements, cosmetics and medicinal products.