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Hiroki Hamada

Publications and source records attributed to Hiroki Hamada.

8 recordsLinked to original sources
PubMed2007

Biotransformation of raspberry ketone and zingerone by cultured cells of Phytolacca americana.

The biotransformation of raspberry ketone and zingerone were individually investigated using cultured cells of Phytolacca americana. In addition to (2S)-4-(4-hydroxyphenyl)-2-butanol (2%), (2S)-4-(3,4-dihydroxyphenyl)-2-butanol (5%), 4-[4-(beta-d-glucopyranosyloxy)phenyl]-2-butanone (19%), 4-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (23%), and (2S)-4-(4-hydroxyphenyl)but-2-yl-beta-d-glucopyranoside (20%), two biotransformation products, i.e., 2-hydroxy-4-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (12%) and 2-hydroxy-5-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (11%), were isolated from suspension cells after incubation with raspberry ketone for three days. On the other hand, two compounds, i.e., (2S)-4-(4-hydroxy-3-methoxyphenyl)but-2-yl-beta-d-glucopyranoside (17%) and (2S)-2-(beta-d-glucopyranosyloxy)-4-[4-(beta-d-glucopyranosyloxy)-3-methoxyphenyl]butane (16%), together with (2S)-4-(4-hydroxy-3-methoxyphenyl)-2-butanol (15%), 4-[4-(beta-d-glucopyranosyloxy)-3-methoxyphenyl]-2-butanone (21%), and 4-[(3S)-3-hydroxybutyl]-2-methoxyphenyl-beta-d-glucopyranoside (24%) were obtained upon addition of zingerone. Cultured cells of P. americana can reduce, and regioselectively hydroxylate and glucosylate, these food ingredients to their beta-glycosides.

Biotransformation↗
PubMed2006

The liverwort Marchantia polymorpha expresses orthologs of the fungal Agaricus bisporus agglutinin family.

A lectin different from the previously described mannose-binding agglutinins has been isolated from the liverwort Marchantia polymorpha. Biochemical characterization of the purified lectin combined with the data from earlier transcriptome analyses demonstrated that the novel M. polymorpha agglutinin is not related to any of the known plant lectin families, but closely resembles the Agaricus bisporus-type lectins, which hitherto have been found exclusively in fungi. Immunolocalization studies confirmed that lectin is exclusively associated with plant cells, ruling out the possibility of a fungal origin. Extensive screening of publicly accessible databases confirmed that, apart from fungi, the occurrence of A. bisporus-type lectins is confined to M. polymorpha and the moss Tortula ruralis. Expression of a typical fungal protein in a liverwort and a moss raises the question of the origin of the corresponding genes. Regardless of the evolutionary origin, the presence of a functional A. bisporus lectin ortholog in M. polymorpha provides evidence for the expression of an additional carbohydrate-binding domain in Viridiplantae.

Agaricus↗
PubMed2006

Biotransformation of thymol, carvacrol, and eugenol by cultured cells of Eucalyptus perriniana.

The biotransformations of aroma compounds of spices, such as thymol (1), carvacrol (2), and eugenol (3), were investigated using cultured plant cells of Eucalyptus perriniana. Besides a beta-glucoside product (4, 3%), a biotransformation product, i.e., 5-methyl-2-(1-methylethyl)phenyl 6-O-(beta-d-glucopyranosyl)-beta-d-glucopyranoside (5, beta-gentiobioside, 87%), was isolated from the suspension cells after the five-day incubation of 1. On administration of 2, a beta-glucoside (6, 5%) and a beta-gentiobioside, i.e., 2-methyl-5-(1-methylethyl)phenyl 6-O-(beta-d-glucopyranosyl)-beta-d-glucopyranoside (7, 56%), were produced. Furthermore, E. perriniana cells also converted 3 into the corresponding beta-glucoside (8, 7%) and beta-gentiobioside (9, 58%). The cultured cells of E. perriniana are able to convert these aroma compounds of spices into glycosides which are accumulated in the cells.

Biotransformation↗
PubMed2006

Enhancement of water-solubility and bioactivity of paclitaxel using modified cyclodextrins.

We investigated the aqueous solubility of paclitaxel using 11 kinds of cyclodextrins (CDs) and the bioactivity of the paclitaxel-CD inclusion complex. 2,6-Dimethyl beta-cyclodextrin was the most effective and its solubility was 2.3 mM in a 0.1 M 2,6-dimethyl beta-cyclodextrin aqueous solution. The inclusion complex of paclitaxel and 2,6-dimethyl beta-cyclodextrin had a 1.23-fold polymerization activity as paclitaxel in a tubulin assay.

Antineoplastic Agents, Phytogenic↗
PubMed2004

Chemoprevention of colorectal cancer by grape seed proanthocyanidin is accompanied by a decrease in proliferation and increase in apoptosis.

Effects of proanthocyanidin (PA), procyanidin B-2 (B-2), and epigallocatechin gallate (EGCG) on azoxymethane (AOM)-induced colonic preneoplastic aberrant crypt foci (ACF) formation were investigated using F344 rats. The numbers of total ACF in rats treated with 0.002% PA and 0.05% B-2 were significantly decreased compared with the AOM alone group (control). Cell proliferation in the colon, as shown by proliferating cells nuclear antigen (PCNA), was also reduced in those treatments. The single-stranded DNA (ssDNA) labeling index, a marker for apoptosis, was significantly increased in 0.002% PA and 0.05% B-2 groups compared with control. Moreover, the numbers of CD11b/c+ cells (macrophages) and NKR-P1A+ cells (NK cells) in the all groups were significantly increased compared with control. In an in vitro study using rat colon cancer cell line RCN-9, PA, especially 5-10mer of PA (PA5/10), strong growth inhibition was shown. PA5/10 caused the most remarkable apoptosis as cleared by FACS analysis. These cells showed significantly increased caspase-3 activity. The results would suggest that the PA, especially PA5/10, might strongly enhance caspase-3 activity and cause apoptosis in cancer cells. PA at fairly low doses in the long term might serve as an effective means for preventing colon carcinogenesis.

Animals↗
PubMed2004

Effects of capsinoid on serum and liver lipids in hyperlipidemic rats.

We compared the effects of capsinoid, a non-pungent component, on serum and liver lipids, with that of synthetic capsaicin in hyperlipidemic rats. Male Wistar rats of 9 wk old were divided into 4 groups: a control group receiving a high-fat diet containing 1% cholesterol, and capsaicin, capsinoid-I and capsinoid-II groups supplemented with 0.1 mmol of N-pelargonylvanillylamide (synthetic capsaicin), and 0.1 mmol and 1.0 mmol of capsinoid (capsiate: dihydrocapsiate=63 : 37) per kg of control diet, respectively. All groups were pair-fed for 4 wk. Compared with the control group, serum lipid levels in both capsinoid groups and liver lipid contents in the capsinoid-II group showed the same reduction as that of the capsaicin group. In the capsaicin and capsinoid-I groups, fatty acid synthase (FAS) activities were lower and hepatic triacylglycerol lipase (HTGL) [EC 3.1.1.3] activities tended to be higher than those of control group. Lipoprotein lipase (LPL) [EC 3.1.1.34] activity in adipose tissue was higher in the capsaicin and capsinoid-II groups than in the control group. These results showed that capsinoid can improve serum and liver lipid metabolism comparable to synthetic capsaicin.

Adipose Tissue↗
PubMed2003

Stereoselective biotransformation of limonene and limonene oxide by cyanobacterium, Synechococcus sp. PCC 7942.

The biotransformation of limonene and limonene oxide by the cyanobacterium, Synechococcus sp. PCC 7942, was investigated. (S)-(+)-Limonene was hydroxylated stereo- and regioselectively at its allylic position of the endocyclic C=C double bond by the cyanobacterial cells to its corresponding alcohol. The cells also showed the ability for the enantio- and stereoselective cleavage of the epoxide group of (1S,2R,4R)-limonene oxide to give (1S,2S,4R)-limonene-1,2-diol. The repetitive production of carveol from limonene was achieved using Ca2+-alginate-immobilized cyanobacterial cells.

Journal Article↗