前立腺癌に有効なトマトの成分

 トマトが脱水されると生じるケトサミンの一種である FruHis という炭水化物が、前立腺癌に効果があるかもしれない。
 2005年時点で、FDAは lycopene にがん予防効果があるという証拠はないと言う。トマトの成分とリコペンとの相互作用が有効なのかもしれない。
 マウスの実験では、トマトペースト+FruHis が腫瘍の生存率が高かった。
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カロテノイド
出典: フリー百科事典『ウィキペディア(Wikipedia)』
 カロテノイド (carotenoid) は天然に存在する色素で、化学式 C40H56 の基本構造を持つ化合物の誘導体をいい、カロチノイドともいう。テルペノイドの一種で、テトラテルペンに分類される。炭素と水素のみでできているものはカロテン (carotene) 類、それ以外のものを含むものはキサントフィル (xanthophyll) 類という。カロテンやキサントフィルは二重結合を多く含むので抗酸化作用が大きく、植物では酸素が多く発生する場所に多く存在する。極性溶媒に溶けにくく、非極性溶媒に溶ける。したがって、脂肪とともに摂取すると効率的である。なお、カロテンは動物に吸収されるとビタミンAとなる。
リコペン
 リコペン(lycopene、ドイツ語読みでリコピン)は化学式 C40H56、分子量 536.87 のカロテノイド。水にはほとんど溶けない脂溶性の赤色色素。多くの植物ではβカロテンやαカロテンの前駆体としてわずかに存在するのみであるが、トマトや柿、グミなどに多量に存在する。抗酸化作用が大きいと考えられている。
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アミノ糖
出典: フリー百科事典『ウィキペディア(Wikipedia)』
アミノ糖(アミノとう、Amino sugar)は、アミンを含む糖である。誘導体にはN-アセチルグルコサミン、シアル酸などがある。
アミノグリコシド
アミノグリコシドは、細菌のタンパク質合成の化学反応を抑制する抗細菌化合物に分類される。これらの化合物にはしばしばアミノ糖が含まれる(アミノシクリトールが含まれることもある)。
おもな誘導体
* グルコサミン
* N-アセチルグルコサミン
* N-アセチルムラミン酸
* ガラクトサミン
* N-アセチルガラクトサミン
* マンノサミン
* N-アセチルマンノサミン
* ノイラミン酸
* N-アセチルノイラミン酸
* ダウノサミン
* フルクトサミン
* ヘキソサミン
* ケトサミン
* ムラミルジペプチド
* ペロサミン
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Type of Tomato Product Determines Power Against Prostate Cancer
Compound produced during drying works with lycopene to protect against malignancies, study suggests
By Amanda Gardner, HealthDay Reporter
Compound produced during drying works with lycopene to protect against malignancies, study suggests.
http://health.msn.com/nutrition/articlepage.aspx?cp-documentid=100204478
THURSDAY, May 29 (HealthDay News) -- Dried tomatoes, anyone?

A study in the June 1 issue of Cancer Research finds that the type of tomato product you eat may play a role in whether it can fight prostate cancer.

Specifically, an organic carbohydrate known as FruHis, which is produced when tomatoes are dehydrated, could be the secret ingredient.

But the study only looked at animals and, the authors warned, FruHis is not ready for the doctor's office or medicine cabinet just yet.

"This study was conducted in a rat model, and you cannot possibly draw any conclusions for people," said study author Valeri Mossine, a research assistant professor of biochemistry at the University of Missouri. "That's something we need to do next. But before you enter a study with humans, you have to prove that something works with animals. If it works, then you go on."

Several studies have pointed to a prostate cancer-fighting quality in tomatoes, but the exact mechanisms have been elusive.

In fact, the U.S. Food and Drug Administration laid out evidence or rather, a lack of it, behind a previous statement the agency had issued that tomato consumption is not linked to any reduction in risk of prostate tumors (or ovarian, stomach or pancreatic malignancies).

The November 2005 statement issued by the FDA contended that, "there is no credible evidence to support qualified health claims for lycopene, as a food ingredient, component or food, or as a dietary supplement, and reduced risk of any of the cancers in the petition."

But other experts, including the authors of the current study, are speculating that some other compound in tomatoes might interact with lycopene to produce the protective effect.

As the study points out, processing of edible plants (heating, grinding, mixing, drying, etc.) may have an effect on the nutritional value of the product, largely due to changes that occur in organic carbohydrates.

And a dietary component to prostate cancer risk and protection could help explain well-known geographical differences in the incidence of the disease.

"We were trying to show that a combination of two different entities in tomato products which appear out of the preparation of tomato powder might interact together," Mossine said.

For this study, rats were divided into four groups of 20: one group received a control diet, another group received a diet that included tomato paste, a third group received a diet including tomato paste plus additional FruHis, and the final group received tomato powder alone.

All rats were injected with chemicals to induce prostate cancer.

Rats fed the tomato paste-plus-FruHis survived the longest, 51 weeks without developing tumors, compared with 50 weeks in the tomato powder group, 45 weeks in the tomato paste group, and 40 weeks in the control group. The study only lasted 51 weeks, so the tomato paste plus FruHis group could have even longer survival times, Mossine noted.

Prostate tumors were found in 10 percent of the animals that had consumed tomato paste plus FruHis, compared with 30 percent of animals receiving tomato powder alone, 25 percent receiving tomato paste alone and 60 percent in the control group.

"Our study shows that one of these carbohydrates that we were suspecting interacts with lycopene, at least in that model that we were using," Mossine said.

"This is a very reasonable basic laboratory assessment of this issue with regard to prostate cancer risk," said Dr. K. Scott Coffield, a professor of surgery at Texas A & M Health Science Center College of Medicine and a urologist-oncologist with Scott & White. "What will be necessary at this point will be some translational research to take this into a clinical setting."

More information

Visit the National Cancer Institute for more on prostate cancer.
content by:
Healthday
SOURCES: Valeri V. Mossine, Ph.D., research assistant professor, biochemistry, University of Missouri, Columbia; K. Scott Coffield, M.D., professor, surgery, Texas A&M Health Science Center College of Medicine, and urologist-oncologist, Scott & White, Temple, Texas; June 1, 2008, Cancer Research
Copyright (c) 2008 ScoutNews, LLC. All rights reserved.

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Cancer Research 68, 4384-4391, June 1, 2008. doi: 10.1158/0008-5472.CAN-08-0108
(c) 2008 American Association for Cancer Research

Interaction of Tomato Lycopene and Ketosamine against Rat Prostate Tumorigenesis

Valeri V. Mossine1, Pankaj Chopra1 and Thomas P. Mawhinney1,2

Departments of 1 Biochemistry and 2 Child Health, University of Missouri-Columbia, Columbia, Missouri

Requests for reprints: Valeri V. Mossine, Department of Biochemistry, University of Missouri-Columbia, Agriculture Building, Room 4, Columbia, MO 65211. Phone: 573-882-2608; Fax: 573-884-4631; E-mail: MossineV@missouri.edu.

Key Words: Prostate Cancer . Prevention . Tomato . Ketosamine . Antioxidant

Prior investigations on the beneficial effect of dietary processed tomato products and lycopene on prostate cancer risk suggested that lycopene may require the presence of other constituents to exert its chemopreventive potential. We investigated whether ketosamines, a group of carbohydrate derivatives present in dehydrated tomato products, may interact with lycopene against prostate tumorigenesis. One ketosamine, FruHis, strongly synergized with lycopene against proliferation of the highly metastatic rat prostate adenocarcinoma MAT-LyLu cell line in vitro. The FruHis/lycopene combination significantly inhibited in vivo tumor formation by MAT-LyLu cells in syngeneic Copenhagen rats. Energy-balanced diets, supplemented with tomato paste, tomato powder, or tomato paste plus FruHis, were fed to Wistar-Unilever rats (n = 20 per group) treated with N-nitroso-N-methylurea and testosterone to induce prostate carcinogenesis. Survival from carcinogenesis was lowest in the control group (median survival time, 40 weeks) and highest in the group fed the tomato paste/FruHis diet (51 weeks; P = 0.004, versus control). The proportions of dying rats with macroscopic prostate tumors in the control, tomato paste, tomato powder, and tomato paste/FruHis groups were 63% (12 of 19), 39% (5 of 13), 43% (6 of 14), and 18% (2 of 11), respectively. FruHis completely blocked DNA oxidative degradation at >250 ?mol/L in vitro, whereas neither ascorbate nor phenolic antioxidants from tomato were effective protectors in this assay. FruHis, therefore, may exert tumor-preventive effect through its antioxidant activity and interaction with lycopene. [Cancer Res 2008;68(11):4384--91]

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