Lipase and amylase inhibitory activities of black tea were examined. After solvent partitioning of a black tea extract with the ethyl acetate and n-butanol, the two soluble fractions showed comparable inhibitory activities. Activity in the ethyl acetate fraction was mainly attributable to polyphenols with low-molecular weights, such as theaflavin gallates. On the other hand, the active substanc...

1. Flavonoid synthesis was able to proceed in darkness in young shoots and seedlings of the tea plant, but was increased by light. 2. The initial effect of darkness was to inhibit synthesis of the A ring or its linkage to the phenylpropane moiety of the flavonoid, but later the hydroxylation state of the flavanols was affected, leading to smaller proportions of gallocatechins and of complex leu...

In this study, a new naphtol derivative was synthesized. The first stage, involved preparation of 1-[(2-Amino-ethylamino)-phenylmethyl]-naphthalen-2-ol (4) using a three-component system (β-naphtol [1], benzaldehyde [2], and ethylenediamine [3]), followed by the reaction of 4 with 3,5dinitrobenzoic acid (5) to form N-(2-{[(2-Hydroxy-naphtalen-1-yl)-phenyl-methyl]-amino}-ethyl)3,5-dinitro-benzam...

Reaction of N3,N8-diacyl 6-thia-3,8-diazabicyclo/3.2. l./octan-2-one (I) with PC15 or S02Cl2 gave 6-chloro substituted N2,N5-diacyl 7-thia-2,5-diazabicyclo/2.2.2./octan-3-one (II). Treatment of II with water yielded the 6-hydroxy derivative (III) while reaction with methanol gave the 6-methoxy derivative (IV). Under the same reaction conditions the mono N8-acyl derivative (V) gave a mixture of ...

A new alkyne functionalized pterin derivative was synthesized through a reaction of 7-chloropterin with propargyl alcohol in the presence sodium hydride. The purity and chemical structure compound validated by NMR (1H, 13C) spectroscopy, Mass (APCI source) spectrometry, elemental analysis, X-ray crystallography. title may be further exploiting yne moiety, for instance, using click chemistry. no...

This is the first Mizar article in a series aiming at a complete formalization of the textbook “General Topology” by Engelking [7]. We cover the first part of Section 1.3, by defining such notions as a derivative of a subset A of a topological space (usually denoted by A, but Der A in our notation), the derivative and the boundary of families of subsets, points of accumulation and isolated poin...