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Polyphenols of Melaleuca quinquenervia leaves – pharmacological studies of grandinin
Author(s) -
Moharram F. A.,
Marzouk M. S.,
ElToumy S. A. A.,
Ahmed A. A. E.,
Aboutabl E. A.
Publication year - 2003
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.1214
Subject(s) - ellagic acid , gallic acid , chemistry , polyphenol , dpph , methyl gallate , antioxidant , stereochemistry , food science , biochemistry , traditional medicine , medicine
Four polyphenolic acid derivatives and three ellagitannins were isolated from the leaves of Melaleuca quinquenervia (Clav.) S. T. Blake for the rst time. Their structures were elucidated as gallic acid (1), ellagic acid (2), 3‐ O ‐methylellagic acid (3), 3,4,3′‐tri‐ O ‐methylellagic acid (4), 2,3‐ O ‐hexahydroxydiphenoyl‐( α / β )‐D‐ 4 C 1 ‐glucopyranose (5), castalin (6) and grandinin (7) on the basis of chemical, mass spectrometric (‐ve ESI‐MS) and spectroscopic (UV, 1 H‐, 13 C NMR, 1 H, 1 H‐, 1 H, 13 C‐COSY, 1 H, 1 H‐TOCSY and HMBC) analyses. Grandinin (the major compound) showed radical scavenging properties by its reaction with 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical [EC 50 = 4.3 ± 0.3 µg mL −1 ]. It was found to be relatively nontoxic in mice [LD 50 = 316 mg Kg −1 b.wt.]. It exhibited a signicant dose‐dependent (35–70 mg Kg −1 ) hypoglycemic effect by signic‐antly reducing blood glucose level in basal condition and after heavy glucose load in normal mice. Moreover, it reduced the elevated blood glucose level in STZ‐induced diabetic mice. In addition, grandinin reduced the elevated blood urea nitrogen and serum lipid peroxides in STZ‐induced diabetic mice. Copyright © 2003 John Wiley & Sons, Ltd.