Nicotine - nicotine

It is a pyrimidine alkaloid that was first isolated from tobacco smoke in 1809 and was named after Jean Nicot (1530?-1600), the Portuguese ambassador who introduced the custom of smoking to France and made it popular. Pure nicotine is a colorless, odorless, volatile oily liquid that dissolves well in water, alcohol, ether, etc. Its boiling point is 247°C. It quickly turns brown in air. The tobacco odor in this case is due to the decomposition products.

Nicotine is contained in the leaves of tobacco plants of the Solanaceae family as malate or citrate at 2-8%, which is synthesized in the roots, transported with xylem sap, and accumulated in the leaves. It is also contained in plants such as Eucalyptus edulis of the Asteraceae family and Equisetum arvense of the Horsetail family. Nicotine is extracted from powdered tobacco leaves with water, added with alkali to liberate the base, and then steam distilled. It is a powerful neurotoxin that stimulates the ganglia of the sympathetic and parasympathetic nerves, and subsequently paralyzes the body. Its action is as fast as that of cyanide, and the oral lethal dose for adults is 0.06 grams, which is roughly equivalent to the amount contained in one cigar, but the amount ingested by smoking is much less. The habit of smoking is mostly due to a psychological need, and there is no sign of addiction. However, with chronic poisoning, symptoms such as catarrh in the pharynx and larynx, heart problems, impaired eyesight, dizziness, and arteriosclerosis can appear. Nicotine, on the other hand, is used as a raw material for synthesizing vitamin _B1 , and its sulfate is used as an agricultural insecticide to smoke greenhouses and kill insects.

[Ryota Uehara and Issei Mabuchi]

"The Smoking Cessation Situation in America: American-Style Smoking Cessation Laws and Their Evaluation," edited by the U.S. Department of Health and translated and written by Oda Seiichi (1990, Social Insurance Publishing)" ▽ "Will You Quit Smoking? Will You Quit, Humans?: A Hundred Harms of Tobacco," written by Hiroshima Prefectural Medical Association (1992, Goma Shobo)" ▽ "Illustrated Addiction Manual: From Narcotics to Sarin and Nicotine," edited by the Group to Consider the Dangers of Deadly Drugs and Poisons (1995, Dobun Shoin)" ▽ "The World History of Tobacco," written by Jordan Goodman and translated by Wada Mitsuhiro et al. (1996, Heibonsha)" ▽ "The Poisons That Sneak Into Our Entire World: From O157, Sarin, to Dioxins, and Environmental Hormones," written by Sawada Yasufumi (1998, Yodosha)" ▽ "Nicotine Poisoning Everywhere," edited by the Japan Association of Smoking Cessation-Promoting Doctors and Dentists (2000, Yobunkan Publishing)" ▽ "Why Can't People Quit Smoking?" written by Miyazato Katsumasa (Iwanami Shinsho)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

ピリミジンアルカロイドの一つで、1809年にタバコの煙より初めて単離され、ポルトガル大使で、喫煙の風習をフランスに導入し流行させたニコJean Nicot（1530？―1600）にちなんで命名された。純粋なニコチンは無色・無臭・揮発性の油状液体で、水、アルコール、エーテルなどによく溶ける。沸点247℃。空気中では速やかに褐変する。この場合のタバコ臭は分解生成物による。

　ニコチンはナス科のタバコの葉にリンゴ酸塩もしくはクエン酸塩として2～8％程度含まれているが、これは根で合成されたものが道管液とともに運ばれてきて葉に蓄積したものである。また、キク科のタカサブロウやトクサ科のスギナなどの植物にも含まれている。ニコチンは、タバコの葉の粉末から水で抽出し、アルカリを加えて塩基を遊離させ、水蒸気蒸留して得られる。猛烈な神経毒で、交感神経および副交感神経の神経節を刺激し、のちに麻痺(まひ)させる。その作用はシアン化物と同じくらい速く、成人の経口致死量は0.06グラムで、これは1本の葉巻タバコに含まれる量にほぼ相当するが、喫煙による摂取量ははるかに少ない。喫煙の習慣はほとんど精神的な欲求によるもので嗜癖(しへき)はみられない。ただし慢性中毒になると、咽頭(いんとう)や喉頭(こうとう)などのカタルをはじめ、心臓障害、視力減弱、めまい、動脈硬化などの症状がみられる。一方ニコチンは、ビタミンB₁の合成原料として使われるほか、その硫酸塩は農業用殺虫剤として温室をいぶして駆虫するのに用いられる。

［上原亮太・馬渕一誠］

『米国保健省編、小田清一訳・著『アメリカ禁煙事情――米国式禁煙法とその評価』（1990・社会保険出版社）』▽『広島県医師会著『タバコやめますか　人間やめますか――これだけあるタバコの百害』（1992・ごま書房）』▽『死に至る薬と毒の怖さを考える会編『図解中毒マニュアル――麻薬からサリン、ニコチンまで』（1995・同文書院）』▽『ジョーダン・グッドマン著、和田光弘ほか訳『タバコの世界史』（1996・平凡社）』▽『沢田康文著『しのびよる身近な毒――O157、サリンからダイオキシン‥‥環境ホルモンまで』（1998・羊土社）』▽『日本禁煙推進医師歯科医師連盟編『ニコチン中毒ところかまわず』（2000・葉文館出版）』▽『宮里勝政著『タバコはなぜやめられないか』（岩波新書）』

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