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Synthesis, spectroscopic and anti‐tumor studies of polyphenol‐linoleates derived from natural polyphenols
Author(s) -
Mustafa Jamal,
Khan Shabana I.,
Ferreira Daneel,
Khan Ikhlas A.
Publication year - 2007
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.200600235
Subject(s) - chemistry , carbodiimide , polyphenol , ginkgo biloba , diene , epigallocatechin gallate , reagent , hexa , stereochemistry , organic chemistry , medicinal chemistry , antioxidant , biology , botany , natural rubber
An efficient first synthesis of di‐, hexa‐ and octa‐esters (octadeca‐ Z ‐9,12‐dienoates, linoleates) from natural 1,5‐bis‐(4'‐hydroxyphenyl)penta‐ Z ‐1,4‐diene ( Ginkgo biloba L.), (–)‐epigallocatechin and (–)‐epigallocatechin‐3‐ O ‐gallate (jasmine tea/green tea), respectively, was developed. Using dicyclohexyl carbodiimide as an activating reagent in the presence of a catalytic amount of 4‐dimethylaminopyridine in polyesterification reactions gave di‐, hexa‐ and octa‐products ( 4 ), ( 7 ), and ( 8 ), respectively, in quantitative yields. A three‐step efficient procedure for the synthesis of 1,5‐bis‐[4'‐ O ‐(octadec‐ Z ‐9”,12”‐dienoate)phenyl]penta‐ Z ‐1,4‐diene ( 4 ) was also developed. The key step in the synthesis involved a stereo selective Wittig diolefination reaction that produced the penta‐ Z ‐1,4‐diene system of ( 4 ). 1 H and 13 C NMR and MS techniques confirmed the structures of the esters. The esterified compounds were tested for in vitro anti‐tumor activities against four and three human cancer cell lines at NCNPR and at NCI, respectively. They were found inactive as they failed to inhibit 50% growth of these cancer cells.