Morphine is a powerful alkaloid and usually used in medicine.

吗啡是一种强力的生物碱，常用于医药。

Alkaloids are mainly found in plants.

生物碱主要存在于植物中。

Nicotine is a colorless and toxic alkaloid commonly found in tobacco.

尼古丁是一种无色有毒的生物碱，常见于烟草中。

So alkaloid is a type of poisonous chemical found in plants.

所以生物碱是植物中发现的有毒化学物质

The Saussurea involucrata chemical composition was: alkaloid, flavanone, sterol, volatile oil, 16 kind of amino acids, Saussurea involucrata lactone and so on.

雪莲化学成分为：生物碱、黄酮、甾醇、挥发油、16种氨基酸、雪莲内酯等。

Conclusion: III is a new alkaloid.

结论：III是新生物碱。

Nicotine is a colorless, poisonous alkaloid.

尼古丁是无色有毒生物碱。

The rhizomes are rich in the alkaloid colchicine.

根状茎富有生物碱秋水仙素。

Tryptanthrin is a kind of indole quinazoline alkaloid.

色胺酮属吲哚喹唑啉类生物碱。