Tsutomu Kanazawa

Simultaneous determination of hydrolysable tannins in the petals of Rosa rugosa and allied plants

The petals of Rosa rugosa and allied plants for medicinal use contain abundant hydrolysable tannins, and they show remarkable biological activities. The activities are dependent on the structures of the hydrolysable tannins, so their contents and compositions are essential for evaluation of medicinal potency. Therefore, we optimized the simultaneous quantitative determination of the hydrolysable tannins using ultra-performance liquid chromatography. A column of ethylene bridged hybrid (BEH) phenyl (C6 alkyl phenyl group as solid-phase modification) was shown to be most effective for the separation of hydrolysable tannins isolated from R. rugosa and related compounds when the column temperature was kept under 25°C. The efficacy of the BEH phenyl column might be due to the interaction between solid phase and phenolic ester groups of hydrolysable tannins such as galloyl, hexahydroxydiphenoyl and valoneoyl groups. The relation between the retention times on the BEH phenyl column and the column temperature was demonstrated to depend on the structural characteristics of hydrolysable tannins.

Inhibitory effects of Rosa gallica on the digestive enzymes

The 50% aqueous ethanol extracts of petals of Rosa gallica collected in Xinjiang province, China, exhibited potent inhibitory effects against α-amylase and α-glucosidase. As the active principles, seven hydrolysable tannins were isolated from this species for the first time and elucidated by NMR and ESI-TOF-MS analysis. Quantitative analysis by ultra-performance liquid chromatography demonstrated that the contents of these hydrolysable tannins were 3–5% of the dry weight of the petals, and the hydrolysable tannins must be related to the medicinal utilization of this species.

Effects of Rosa rugosa Petals on Intestinal Bacteria

The effects of pulverized petal of Rosa rugosa on the growth of 10 species of intestinal and pathogenic bacteria were investigated. Growth of bifidobacteria and lactobacilli was not affected by the addition of the petal in plate cultivation. However, the growth of Bacteroides vulgatus, Escherichia coli, Staphylococcus aureus, and Bacillus cereus was completely inhibited by the addition of 0.1, 0.5, 0.1, and 0.05% (w/v) of the petal respectively. In liquid cultivation, the addition of the petal (0.5%) stimulated the growth of Bifidobacterium breve and slightly inhibited the growth of Lactobacillus salivarius. But the growth of E. coli, S. aureus, B. cereus, and Salmonella sp. was inhibited by nearly 50%. Hydrolyzable tannins isolated from R. rugosa, rugosin D, and tellimagradin II showed antibacterial activities against E. coli, S. aureus, B. cereus, and Salmonella sp., but little or no effect against Bif. breve and L. salivarius. R. rugosa petal showed selective antibacterial activities against intestinal and pathogenic bacteria, and the selectivity resembled that of prebiotics such as oligosaccharides and dietary fiber. Hydrolyzable tannins in R. rugosa, such as rugosin D and tellimagradin II, must be active constituents.

Phenolic compounds from the leaves of Psidium guajava II. Quercetin and its glycosides

0009-3130/12/4803-0477 2012 Springer Science+Business Media, Inc. 1) Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, 890-0065, Kagoshima, Japan, e-mail: parkbj71@mail.goo.ne.jp; 2) Meikai University School of Dentistry, 1-1 Keyakidai, Sakado, 350-0283, Saitama, Japan; 3) Harunire Bio Laboratory Co., Ltd., 603-2 Hakuyo-cho, 090-0013, Kitami, Japan; 4) Dept. of Bio-Health Technology, Kangwon National University, 200-701, Chuncheon, Korea; 5) Korea National University of Agricultural & Fisheries, 445-893, Hwasung, Korea. Published in Khimiya Prirodnykh Soedinenii, No. 3, May–June, 2012, pp. 429–431. Original article submitted February 1, 2011. Chemistry of Natural Compounds, Vol. 48, No. 3, July, 2012 [Russian original No. 3, May–June, 2012]

Botanical origin of Mei-gui Hua (petal of a Rosa species)

Mei-gui Hua has been used as a crude drug in traditional medicine and as herbal tea in China. The scientific name of Mei-gui is Rosa rugosa thunb. However, the morphological characteristics and botanical ecology of Mei-gui were different from those of R. rugosa. Since the botanical origins of Mei-gui cultivated in China have not yet been clarified, we compared Mei-gui and R. rugosa in terms of their morphological characteristics, phylogenetic analysis, and phytochemical studies. Our research suggested that Mei-gui cultivated around Tarim Basin in Xinjiang Province showed homology to Rosa gallica, while those cultivated in the northeastern parts of China are considered to be hybrids of R. rugosa.

Two Galloylated Flavonoids as Antioxidants in Rosa gallica Petals

MCl gel eluted with the solvent system H 2 O–MeOH–acetone, and five fractions were obtained. The fractions obtained by stepwise gradient with H 2 O–MeOH contained flavones with different degrees of galloylation. Fractions 1 and 2 eluted with 90 and 80% H 2 O, respectively, contain two galloylated flavonoids (compounds 1 and 2, respectively) and were isolated by repeated chromatography on Sephadex LH-20 and on a reversed phase column using Wakosil 40C 18 . In the 1 H NMR spectrum of compound 1, two meta-coupled signals were observed at 6.15 and 6.32, and three signals due to 1,3,4-trisubstituted benzene ring protons at 7.56, 7.51, and 6.82. Moreover, an anomeric proton of a sugar moiety was observed at 5.73 (d, J = 7.9) together with six signals of sugar protons at 5.11–3.33, and the coupling constants of these signals indicated the presence of glucose. The specific optical rotation of 1 also indicated the presence of the -D-glucosyl moiety. In the 1 H– 1 H COSY spectrum, the cross peaks of sugar protons were confirmed, but the signal of the H-2 proton of the glucosyl moiety was observed down field at 5.11. This indicated that the hydroxyl group at the C-2 position of glucose was acylated. The molecular weight of compound 1 and the signal of two proton singlets at 7.12 implied the presence of the galloyl group at C-2 of glucose. The signals at 167.8, 146.3, 139.2, 121.0, and 110.6 in the 13 C NMR spectrum also supported the presence of a galloyl group. These data indicated the presence of quercetin [3], the glycosyl unit [4], and the galloyl group. In the HMBC spectrum, H-1 ( 5.73) of the glycosyl moiety showed a correlation with the signal of C-3 ( 134.9) of quercetin. The carbonyl carbon ( 167.8) of the galloyl moiety also showed correlations with H-2 ( 5.11) and H-2 (7.12). Comparing these data with the literature [5, 6], we characterize compound 1 as quercetin 3-O-(2-O-galloyl)-D-glucoside. Compound 2 showed 1 H MNR spectral data similar to those of compound 1, except for the ortho-coupled two proton signals at 7.95 and 6.89 instead of the signals of 1,3,4-trisubstituted benzene. These data indicated the presence of kaempferol as aglycone. Comparing the 1 H and 13 C NMR data and the specific optical rotation with those in the literature [6], we characterize compound 2 as kaempferol 3-O-(2-O-galloyl)--D-glucoside. The two galloylated flavonoids have been isolated from Diospyros kaki Thunb., Geranium tuberosum subsp. tuberosum and Polygonum lapathifolium L. [7–9], but this is the first report on the isolation of these compounds from the plant belonging to the genus Rosa.

Phenolic compounds from the leaves of Psidium guajava. I. Hydrolysable tannins and benzophenone glycosides

0009-3130/11/4704-0632 2011 Springer Science+Business Media, Inc. 1) Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan, e-mail: parkbj71@mail.goo.ne.jp; 2) Harunire Bio Laboratory Co., Ltd., 603-2 Hakuyo-cho, Kitami, 090-0013, Japan; 3) Korea National University of Agricultural & Fisheries, Hwasung, 445-893, Korea; 4) Department of Bio-Health Technology, Kangwon National University, Chuncheon, 200-701, Korea. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 557–559, July– August, 2011. Original article submitted March 24, 2010. Chemistry of Natural Compounds, Vol. 47, No. 4, September, 2011 [Russian original No. 4, July–August, 2011]