Polymer characteristics of catechin and catechin-Ge4+ measured with a technology of mass spectrometry

Abstract

The catachin mainly consists of (-)-epigallocatechin (EGC), (-)-epicate-chin (EC),(-) epigallocatechin-3-gallate (EGCG), and (-)-epicatechin-3-gallate (ECG). Using a combined method of high performance liquid chromatography-electrospray ionization-Q-time of flight (HPLC-ESI-Q-TOF) mass spectrometry (MS), polymer compounds of EGCG in the catachin can be separated and analyed the same results were further approved by matrix assisted laser desorption ionization (MALDI)-TOF MS. The EGCG-Ge4+ compounds synthesized by normal organic synthesis were further purified by a rapid reversed phase-HPLC for studying inhibition growth rate of the lung cancer cells. During the analytical process of EGCG-Ge4+ molecular structures with infrared spectrometry and MALDI-TOF MS, it was found that EGCG not only had polymer characteristics, but also bound to the metal Ge4+ (or other heavy metal ions, M2+) for forming EGCG-Ge4+ (or EGCG-M2+) and its polymers. The experimental results showed that both EGCG and EGCG-Ge4+ could inhibit the growth rate of lung cancer cells, showing the similar rate within the 24 h for cell incubating. However, this inhibition rate with EGCG-Ge4+ was much higher than that of EGCG, approximately enhancing 30% similar to 40% rate for inhibiting growth of lung cancer cells was observed within the incubating time covering from 24 to 72 h. Even so, both compounds cannot inhibit the growth rate of melanoma cells. It suggest that the compound EGCG-Ge4+ has potentials for developing new drugs for curing lung cancer.