Tobacco contains an alkaloid called nicotine.

烟草含有一种叫做尼古丁的生物碱。

It's hard to know exactly why we evolved to be better at digesting theobromine, but it might be because alkaloids mostly come from plants, and our ancestors ate a lot more plants than early cats or dogs did.

我们很难确切了解为什么我们的身体会进成能较容易消可可碱，有可能是因为生物碱大部分都来自植物，而我们的的植物比以前的猫和狗所的植物多很多。

The bitter alkaloid that has this formula is caffeine.

这种苦味生物碱的配方是咖啡因。

That's an alkaloid—so it's in the same class of molecules as caffeine and nicotine.

那是一种生物碱——与咖啡因和尼古丁属于同一类分子。

It was but for a moment, for the action of the alkaloid is rapid.

可是这一切是一会儿功夫，因为那种生物硷的作用发挥得很快。

But a series of experiments revealed that although these caterpillars only have four tastebuds, one is specifically tuned to pyrrolizidine alkaloids, and it is specifically activated to make the toxic chemicals taste better when the caterpillar is sick with parasites.

但一系列实验表明，虽然这些毛毛虫有四个味蕾，但其中一个味蕾专门针对吡咯里西啶生物碱，当毛毛虫感染寄生虫时，它会被专门激活，使有学物质的味道更好。

On top of this, alkaloids from the vine have been shown to induce apoptosis in mice melanoma cells and certain liver cancer cells in humans.

除此之外，卡皮木藤条的生物碱已被证实能促进小鼠黑素瘤细胞和人类的某些肝癌细胞凋亡。

While alkaloids as a whole are a broader group of naturally occurring organic compounds, defined by having at least one nitrogen atom.

而生物碱作为一个整体是一个更广泛的自然存在的有机合物组，定义为至少有一个氮原子。

And it's capable of producing a whole soup of compounds called alkaloids, which can have a variety of effects on the human body.

它能够产生一系列被称为生物碱的合物，这些合物对人体有多种不同的影响。

A group of drugs known as the vinca alkaloids, commonly included in chemotherapy regimens, are derived from Madagascar periwinkle.

常在疗方案中看到的一种被称为长春花生物碱的药物，是从马达加斯加的长春花中提取的。

Like caffeine, theobromine is a type of alkaloid, which is a huge class of molecules that generally contain rings with at least one nitrogen atom in them, and alkaloids often have physiological effects on humans and other animals.

和咖啡因一样，可可碱属于生物碱的一种，生物碱是相当大的一类分子，一般来说它的环中会包含至少一个氮原子，生物碱通常会使人类及其他动物产生生理作用。

It's native to India and Southeast Asia, and its bark contains a poison called brucine, but the real lethality comes from the trees round green-to-orange fruit which contains the alkaloid strychnine.

马钱子原产印度与东南亚，它的树皮富含称为 Brucine 的有生物碱。但真正会死人的部分是马钱子-圆圆的，绿色到橙色的果实含有有生物碱：马钱子碱。

Now, from a chemical perspective, caffeine can be described as both a methylxanthine and an alkaloid.

从学角度来看，咖啡因既可以被描述为甲基黄嘌呤，也可以被描述为生物碱。

Alkaloids have many functions and effects, but almost all a bitter in taste.

生物碱有许多功能和作用，但几乎所有的苦味。

" Tabloid" , a portmanteau of " tablet" and " alkaloid" , denoted drugs in tablet form but quickly assumed a broader meaning: " anything compressed or concentrated for easy assimilation" .

“Tabloid” 是“tablet”和“alkaloid”的混合词，原指片剂形式的药物，但很快就有了更广泛的含义：“任何压缩或浓缩以便于吸收的东西”。

In the late 19th century, a tabloid was a type of medicine, a mixture of tablet and alkaloid in a condensed tablet, meaning made up of two or more parts or ingredients.

在19世纪末， 小报是一种药物，由药片和生物碱混合而成的一种浓缩药片，意思是包含两种或更多部分或成分。

And it's quite possible that alkaloid levels of the current trees are lower than we could find 200 years ago in natural forests.

现在树木中的生物碱含量很可能低于 200 年前天然森林中的生物碱含量。

They also experimented with local anaesthetics applied to smaller areas of the body, and initially used the South American alkaloid cocaine.

他们还试验了应用于身体较小区域的局部麻醉剂，并最初使用了南美的生物碱可卡因。

The plants produce this alkaloid in order to protect them against insects and from other plants growing too close to them.

植物产生这种生物碱是为了保护它们免受昆虫和其他生长在它们附近的植物的侵害。

Think of the molecular target of a neurotoxic alkaloid as a lock, and the alkaloid itself as the key.

将神经性生物碱的分子靶标想象成一把锁，将生物碱本身想象成钥匙。