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1) Background: Green tea (GT) contains well-known phytochemical compounds; namely, it is rich in flavan-3-ols (catechins) and flavonols comprising all glycoside forms. These compounds in GT might show better biological activities after a feasible enzymatic process, and the process on an industrial scale should consider enzyme specificity and cost-effectiveness. (2) Methods: In this study, we evaluated the most effective method for the enzymatic conversion of flavonoids from GT extract. One enzyme derived from Aspergillus niger (molecular weight 80-90 kDa) was ultimately selected, showing two distinct but simultaneous activities: intense glycoside hydrolase activity via deglycosylation and weak tannin acyl hydrolase activity via degalloylation. (3) Results: The optimum conditions for producing flavonol aglycones were pH 4.0 and 50 • C. Myricetin glycosides were cleaved 3.7-7.0 times faster than kaempferol glycosides. Flavonol aglycones were produced effectively by both enzymatic and hydrochloride treatment in a time-course reaction. Enzymatic treatment retained 80% (w/w) catechins, whereas 70% (w/w) of catechins disappeared by hydrochloride treatment. (4) Conclusions: This enzymatic process offers an effective method of conditionally producing flavonol aglycones and de-galloylated catechins from conversion of food-grade enzyme.

Ring-closing metathesis has become a very powerful, versatile, and widely used method for the construction of cyclic ring systems in organic synthesis. 1 The superior reactivity of Grubbs second generation catalyst 1, which has air-stability and thermal stability, is very important for the formation of tri-and tetra-substituted olefins having electron withdrawing groups. Recently, Weinreb, 2a Salim, 2b and Rutjes 2c reported on the formation of carbocyclic and heterocyclic olefin by ring-closing metathesis of halogen (F, Cl, CF3) substituted olefins. Literature survey reveals that most of bisterminal olefins with electron withdrawing groups such as CO2Et, Br, and CN resulted in little to no yield of the RCM product under the condition of using the Grubbs first generation catalyst, 3 but the microwave irradiation on olefin with carboxymethyl substituent (CO2Me) provided the desired product. 4

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