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蒜素摧毁癌细胞
蒜素是决定大蒜独特气味的一种化学物质，由蒜氨酸酶和蒜碱两种酶组成。科学家很早以前就发现，蒜素具有一定毒性，能够杀死肿瘤细胞和致病微生物，但它也能杀死正常人体细胞。由于蒜素在人体内不稳定且很容易分解，因此日常生活中吃蒜不会对人体造成伤害。研究人员就是利用蒜素的这一特点，研制出了摧毁癌细胞的“两步”疗法。
由于大多数癌细胞表面都有特定的受体，科学家将一种附着在蒜氨酸酶上的可以识别特定受体的抗体注入血液中，该抗体能够发现并吸附在癌细胞上。研究人员将一种稳定性比较好的蒜碱注入到老鼠体内，蒜氨酸酶遇到蒜碱后会发生化学反应，重新合成蒜素，有毒的蒜素就会进入肿瘤细胞并将其杀死。这样，由于抗体只识别特定的癌细胞，正常健康组织并未受到有毒蒜素的“攻击”。 科学家说，只要能找到针对各种癌细胞的特定抗体，该疗法就能治疗多种癌症，蒜素会像激光制导炸弹一样精确地摧毁癌细胞。 有没有原文？ Weizmann Institute's Garlic 'Smart Bomb' Destroys Tumor Cells in Mice
Judy Siegel-Itzkovich Dec. 31, 2003
JERUSULUM POST: A chemical naturally found in garlic has been used by Weizmann Institute researchers to destroy malignant tumors in mice while leaving healthy tissue intact. The key to the scientists' success lies in the development of a two-step system for delivering the cancer-wrecking chemical straight to the tumor cells.
A team of the Rehovot institute's biological chemistry department comprised of Drs. Aharon Rabinkov, Talia Miron and Marina Mironchick, along with Profs. David Mirelman and Meir Wilchek, designed the innovative delivery method that works with the pinpoint accuracy of a smart bomb. Their findings were reported in the December issue of Molecular Cancer Therapeutics.
Allicin is the natural chemical that gives garlic its distinctive aroma and flavor. For many years, scientists studying allicin have known that it is as toxic as it is pungent. It has been shown to kill not only cancer cells but also cells of disease-causing microbes and even healthy human body cells. Fortunately for our body's cells, allicin is highly unstable, and breaks down quickly once ingested. However, the rapid breakdown and undiscriminating toxicity presented twin hurdles to creating an allicin-based therapy.
The method parallels the way allicin is synthesized in nature. Absent from whole, unbroken cloves of garlic, allicin is the product of a biochemical reaction between two substances stored apart in tiny, adjoining compartments within each clove. The two are an enzyme, alliinase, and a normally inert chemical called alliin. When the clove is damaged, whether by soil parasites intending to eat the tender tissues, or by cooks making sauce, the membranes separating compartments are ruptured and rapid allicin production follows. The scientists realized that if doses of allicin could be repeatedly generated in this way at the site of the tumor, the highest concentration of the toxic molecules would be available for killing cancer cells.
To zero in on the targeted tumor, scientists took advantage of the fact that most types of cancer cells exhibit distinctive receptors on their surfaces. An antibody that is "programmed" to recognize the tumor's characteristic receptor is chemically bound to the enzyme, which is called alliinase. Injected into the bloodstream, the antibody seeks out these cells and lodges itself and its passenger enzyme on the tumor cells. The scientists then inject the second component, alliin, at intervals.
When it encounters the alliinase, the resulting reaction turns the normally inert alliin molecules into lethal allicin molecules, which penetrate and kill the tumor cells.
Thanks to the precise delivery system, healthy cells nearby remain intact. Using this method, the team succeeded in blocking the growth of gastric tumors in mice. The tumor-inhibiting effects were seen up to the end of the experimental period, long after the internally produced allicin was gone.
The scientists note that the method could work for most types of cancer, as long as a specific antibody can be customized to recognize receptors unique to the cancer cells.
The technique could prove invaluable for preventing metastasis following surgery, the researchers claim. "Even though doctors cannot detect where metastatic cells have migrated and lodged themselves," says Mirelman, "the antibody-alliinase-alliin combination should chase them down and destroy them anywhere in the body."
http://www.youngagain.com/allicin1.html
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作者:admin@医学,生命科学 2011-01-07 15:46
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