Psychoactive Plants Stimulants - III: Other Stimulants

Stimulants  Cocaine  Ephedrine  Nicotine  Khat - cathonine  Betel nuts - arecoline  Caffeine

Khat

Khat: stimulant from Catha Edulis

Alkaloids  Khat contain cathinone and cathine, two phenylisopropylamine alkaloids which resemble amphetamine –  Cathinone is the main alkaloid Produces amphetamine-like action - effects not distinguishable from amphetamine - a naturally occurring amphetamine - carbonyl group replaces methylene side chain Drug conditioned animals cannot distinguish cathinone from amphetamines  Khat consumption induces mild euphoria and excitement, reduces appetite, increases heart rate and blood pressure  Withdrawal symptoms can follow prolonged khat use include lethargy, depression, nightmares and tremor

Cathinone  Functions by releasing catecholamines (esp. dopamine) from presynaptic storage sites  Cathinone only present in fresh leaves – it degrades within 48 hrs  After this time only cathine left Cathine also a stimulant but has a lower potential for abuse

AmphetamineMeth-amphetamine CathinoneCathine EphedrinePseudoephedrine

Betel Nuts

Betel nuts from the betel palm Areca catechu

Traditional Use  Long history of use in Asia - recorded in 4th century in China  Traditionally chewed  Crushed betel nuts (from the betel palm) wrapped in pieces of betel leaf from the betel vine, Piper betel (in the pepper family - Piperaceae) along with lime and sometimes other flavorings  Lime (CaCO 3 ) needed to release alkaloid

Arecoline  Many active ingredient in betel nuts is the alkaloid arecoline - although betel nuts have several other alkaloids  Arecoline has also been shown to improve learning and memory  Also traditional use for intestinal worms Used as an antihelminthic in veternary medicine today

Mode of Action  Not completely understood  Believed to affect the central and autonomic nervous systems - increases plasma concentrations of norepinephrine and epinephrine  Evidence suggests also an inhibitor of GABA (gamma aminobutryc acid) uptake  Also Piper betel leaf contains aromatic phenolic compounds which have been found to stimulate the release of catecholamines in vitro

Effects of Betel Chewing  Stains mouth  Possible carcinogen Betel chewing associated with throat, mouth, and esophagal cancers  Betel chewing spreading Lime (CaCO 3 ) needed to release arecoline However some chew it only for flavor not stimulating effect Also mixed with tobacco and it strongly interacts with tobacco

Caffeine

Coffee and Caffeine  Made from seeds of Coffea arabica in the Rubiaceae  Seeds occur in coffee berries (cherries of commerce)

Flowers and berries of Coffea arabica

Coffee berries are picked by hand by worker in Columbia

Coffea arabica native to Ethiopia

Ethnobotany and history  Long history of use in Arab world  Introduced to Europe in 1615  By 1700 coffee houses popular throughout Europe  Dutch established plantations in East Indies late in 17th century  East Indies  Paris and Amsterdam  Caribbean Islans  South America

Caffeine  Caffeine occurs naturally in the leaves, seeds or fruit of more than 60 plant species, of which coffee, cocoa-beans, tea, cola and guarana are the best known  Like other stimulates, caffeine acts on CNS - noradrenergic receptors (norepinephrine)  Promotes alertness and endurance  Constricts blood vessels  Increase heart beat

H = theophyllineH = theobromine

Caffeine Content of Common Products  Drip coffee mg  Tea mg  Cocoa mg  Coca Cola mg  Diet Coke mg  Dr. Pepper mg  Mr. Pibb mg  Mt. Dew mg  Pepsi mg  Surge mg  Jolt Cola mg  Excedrin mg  Anacin mg  NoDoz mg  Vivarin mg  Midol mg