1. [Study on hydrolysable tannin constituents of seed of Juglans regia II]
Zhe-xiong Jin, Zhong-yuan Qu Zhongguo Zhong Yao Za Zhi. 2008 Jul;33(14):1705-7.
Objective: To study hydrolysable tannin constituents of the seed of Juglans regia. Method: The chemical constituents were isolated by Diaion HP-20, Toyopaerl HW-40 and MCI gel CHP-20P column chromatogramphy and identified by physicochemical identification and spectral data. Result: Six compounds obtained from the 70% ethanol extract were identified as 1, 2, 3, 4, 6-penta-O-galloyl-3-D-glucose (1), rugosin C (2), 1, 2, 3, 6-tetra-O-galloyl-3-D-glugose (3), tellimagrandin II (4), casuarictin (5), 1-degalloylrugosin F (6). Conclusion: All compouds were isolated from the seeds of J. regia for the first time.
2. Isolation and characterization of novel antimicrobial peptides, rugosins A, B and C, from the skin of the frog, Rana rugosa
S Suzuki, Y Ohe, T Okubo, T Kakegawa, K Tatemoto Biochem Biophys Res Commun. 1995 Jul 6;212(1):249-54. doi: 10.1006/bbrc.1995.1963.
Three antimicrobial peptides were isolated from the skin of Rana rugosa. The major component, designated rugosin A, consisted of 33 amino acid residues and had structural homology (45%) with brevinin-2 of Rana porosa brevipoda. This peptide strongly inhibited the growth of gram-positive bacteria (e.g. Staphylococcus aureus 209P). The second peptide (rugosin B), a minor component, also had 33 amino acid residues, but was less homologous (33%) with brevinin-2. This peptide exhibited a striking antimicrobial activity against both gram-negative (e.g., Escherichia coli NIHJ) and gram-positive bacterial species. The third one, named rugosin C, composed of 37 amino acid residues, exhibited an antimicrobial activity against gram-positive bacteria. All three peptides had an intramolecular disulfide bond at the C-terminus.
3. Walnut polyphenols prevent liver damage induced by carbon tetrachloride and d-galactosamine: hepatoprotective hydrolyzable tannins in the kernel pellicles of walnut
Hiroshi Shimoda, Junji Tanaka, Mitsunori Kikuchi, Toshiyuji Fukuda, Hideyuki Ito, Tsutomu Hatano, Takashi Yoshida J Agric Food Chem. 2008 Jun 25;56(12):4444-9. doi: 10.1021/jf8002174. Epub 2008 May 22.
The polyphenol-rich fraction (WP, 45% polyphenol) prepared from the kernel pellicles of walnuts was assessed for its hepatoprotective effect in mice. A single oral administration of WP (200 mg/kg) significantly suppressed serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) elevation in liver injury induced by carbon tetrachloride (CCl 4), while it did not suppress d-galactosamine (GalN)-induced liver injury. In order to identify the active principles in WP, we examined individual constituents for the protective effect on cell damage induced by CCl 4 and d-GalN in primary cultured rat hepatocytes. WP was effective against both CCl 4- and d-GalN-induced hepatocyte damages. Among the constituents, only ellagitannins with a galloylated glucopyranose core, such as tellimagrandins I, II, and rugosin C, suppressed CCl 4-induced hepatocyte damage significantly. Most of the ellagitannins including tellimagrandin I and 2,3- O-hexahydroxydiphenoylglucose exhibited remarkable inhibitory effect against d-GalN-induced damage. Telliamgrandin I especially completely suppressed both CCl 4- and d-GalN-induced cell damage, and thus is likely the principal constituent for the hepatoprotective effect of WP.
