Crystallization studies of epigallocatechin gallate

• Main Author: Kesani, Sheshanka
• Format: Others
• Published: Scholar Commons 2007
• Subjects: EGCG; Flavonoids; Green tea; Pharmaceutical crystal forms; Supramolecular chemistry; American Studies; Arts and Humanities
• Online Access: http://scholarcommons.usf.edu/etd/2242; http://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=3241&context=etd

Flavonoids are a long and well known class of natural products. Their potential health benefits can be attributed to their antioxidant activity, and modulation of cell signaling pathways. Green tea one of the most widely consumed beverages, consist of flavonoids such as catechins and tannins. Epigallocatechin gallate (EGCG) the major catechin of green tea exhibits multiple health benefits due to its antioxidant nature. The radical scavenging activity of EGCG is attributed to its structure. Therefore, a study on molecular features of EGCG would provide valuable information on structural modifications, which may change the physiochemical properties such as bioavailability and solubility. Although flavonoids are abundant and commercially available they are difficult to purify and crystallize. In this respect, crystallizing EGCG was challenging. By exploring different techniques EGCG was crystallized. Here in this study one new form of EGCG and two solvates, acetonitrile and nitrobenzene, have been synthesized and structurally characterized by differential scanning calorimetry (DSC), infrared (IR) and powder X-ray diffraction (PXRD). The crystal structures were solved by single-crystal X-ray diffraction and a detailed description of synthesis and about the supramolecular synthons that exist in these crystal forms are given.