皂角苷

用茶粕清塘的原理是（）。

A、茶粕含皂角苷，它是-种溶血毒素，可使鱼的红细胞分解

B、茶粕中的皂角苷不能使鱼的红细胞分解

C、茶粕中的皂角苷能使虾、蟹类的红细胞分解

D、茶粕中的皂角苷对细菌有杀灭作用

下面属于多酚类植物化学物的是（）

A、槲皮素

B、皂角苷

C、大蒜素

D、儿茶素

E、二硫醇硫酮

With remarkable consistency, recent research has found that a diet high in plant -based foods—fruits, vegetables, dried peas and beans, grains, and starchy staples such as potatoes — is the body's best weapon in thwarting many health - related problems. These foods work against so many diseases that the same healthy ingredients you might use to protect your heart or ward off cancer will also benefit your intestinal tract and bones.

Here's what is currently known about these different disease -fighting foods. Cancer Fighters

Preventing cancer is a compelling reason to load up your cart in the produce department. Scientists have recently estimated that approximately 30 to 40 percent of all cancers could be averted if people ate more fruits, vegetables, and plant - based foods and minimized high -fat, high -calorie edibles that have scant nutritional value. Up to 70 percent of cancers might be eliminated if people also stopped smoking, exercised regularly, and controlled their weight.

In the past, researchers had linked fat consumption with the development of cancers, but they currently believe that eating fruits, vegetables, and grains may be more important in preventing the disease than not eating fat. "The evidence about a high- fat diet and cancer seemed a lot stronger several years ago than it does now," says Melanie Polk, a registered dietitian and director of nutrition education at the American Institute for Cancer Research.

Although scientists are still not certain about the specifics, they're beginning to close in on the healthful constituents of plant- based foods. In particular, they're looking closely at two components antioxidants and phytochemicals.

Antioxidants. The antioxidants (carotenoids, such as beta carotene and lycopene, and vitamins C and E) found in fruits, vegetables, and other plant -based foods fight free radicals, which are compounds in the body that attack and destroy cell membranes. The uncontrolled activity of free radicals is believed to cause many cancers.

The carotenoids, in particular, which give fruits and vegetables their bright yellow, orange, and red colors, are now gaining recognition for their nutritional worth. Numerous studies have extolled the virtues of lycopene (the carotenoid that makes tomatoes red) in preventing prostate cancer. One such study at Harvard University found that men who include tomato products in their meals twice a week could reduce their risk of developing prostate cancer by one third compared with men who never touch tomatoes.

Other lycopene - rich foods, such as watermelon, red grapefruit, and guava, are now piquing the interest of researchers. Watermelon not only yields more lycopene per serving (15 mg in 11/2 cups) than raw tomatoes (11 mg per 11/2 cups), but it's also a rich source of vitamins A and C.

Can watermelon help reduce the incidence of cancer? No one knows for sure because there haven' t been sufficient studies. "We assume that we'll see benefits," says Penelope Perkins Veazie, Ph. D., a research scientist with the USDA's Agricultural Research Service. Researchers there plan to compare people who eat watermelon with those who eat processed tomatoes because cooking enhances lycopene absorption—o see which group absorbs more lycopene. (A 11/2 cup serving of tomato sauce packs 53 mg of lycopene. )

Phytochemicals. The phytochemicals present in fruits and vegetables protect the body by stunting the growth of malignant cells. Phytochemicals, naturally occurring substances, include indoles ( [生化]吲哚) in cabbage or cauliflower, saponins ( [生化]皂角苷 ) in peas and beans, and isoflavones (异黄酮) in soy milk and tofu. Investigators have only an inkling of how many phytochemicals exist and how they work. They are confident, however, that you can get a basketful of anti- cancer nutrients by mi

A．Y

B．N

C．NG