Tubocurarine, a naturally occurring alkaloid, is used to treat smoking withdrawl syndrom. Tubocurarine, the chief alkaloid in tobacco products, binds stereo-selectively to nicotinic-cholinergic receptors at the autonomic ganglia, in the adrenal medulla, at neuromuscular junctions, and in the brain. Two types of central nervous system effects are believed to be the basis of Tubocurarine's positively reinforcing properties. A stimulating effect is exerted mainly in the cortex via the locus ceruleus and a reward effect is exerted in the limbic system. At low doses the stimulant effects predominate while at high doses the reward effects predominate. Intermittent intravenous administration of Tubocurarine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH. Tubocurarine competes with acetylcholine for post-synaptic nicotinic NM receptors and blocks them.

Hydrastinine is a synthetic alkaloid prepared by various processes from either hydrastine, berberine, or narcotine. It exerts a strong stimulating action on the uterus of all species studied, including human. Hydrastinine and the closely related alkaloid cotarnine have been employed as hemostatics, particularly in abnormal uterine conditions. In the non-pregnant animal, hydrastinine in doses of 10 mg. depressed both tonus and activity, even after the section of the hypogastric. In the pregnant cat, it caused the uterus to contract. A stimulant action was also noted in the non-pregnant animal if nicotine were administered prior to hydrastinine. The rabbit uterus in situ was strongly contracted. Laidlaw believed that hydrastinine acted on the uterus both directly on the smooth muscle and also through its sympathetic innervation. Repeated administration of large doses for a period of time resulted in greatly increased amplitude of contractions which persisted after removal of the drug. The drug was patented by Bayer as a haemostatic drug during the 1910s.

QUININE HYPOPHOSPHITE, a salt of quinine, was formerly used, along with the hypophosphites of sodium, potassium, calcium, and iron, in the treatment of phthisis and neurasthenic conditions.

Melatonin (5-methoxy N-acetyltryptamine) is a hormone synthesized and released from the pineal gland at night, which acts on specific high affinity G-protein coupled receptors to regulate various aspects of physiology and behaviour, including circadian and seasonal responses, and some retinal, cardiovascular and immunological functions. Melatonin is also made synthetically and available without a prescription as an over-the-counter (OTC) dietary supplement in the U.S. Melatonin supplementation has many uses, however, it has been widely studied for treatment of jet lag and sleep disorders. Parents may consider using melatonin to help their child who has a trouble falling asleep. A medical professional should always evaluate insomnia or other sleeping disorders in children. Additionally, melatonin has been shown to protect against oxidative stress in various, highly divergent experimental systems. There are many reasons for its remarkable protective potential. In mammals, melatonin binds to a number of receptor subtypes including high-affinity (MT1 and MT2) and low-affinity (MT3, nuclear orphan receptors) binding sites, which are distributed throughout the central nervous system and periphery.

Antipyrine is an analgesic and antipyretic that has been given by mouth and as ear drops. It is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. It inhibits cyclooxygenases and shows little anti-inflammatory activity. Like many old and approved substances after almost 100 years of use, antipyrine has been associated with some serious side effects, namely agranulocytosis and shock reactions.

Quinine ascorbate is a salt of antimalarial drug quinine and ascorbic acid (vitamin C). Ascorbate reduces the potency of quinolone-containing anti-malarial drugs. Quinine ascorbate was marketed as a component of over-the-counter smoking deterrent products but was not recognized as safe by the FDA regulation in 1993.

Ligustrazine (tetramethylpyrazine) is a bioactive ingredient extracted from the widely-used Chinese herb, Chuanxiong. It inhibits of platelet aggregation, enhances of vessel dilation, increases cerebral blood flow and possesses neuroprotective properties. The injection solution of ligustrazine has been used especially in China to treat ischemic stroke, coronary heart disease, diabetic nephropathy, and knee osteoarthritis. Ligustrazine was also evaluated in clinical as a remedy for pressure sores, as a salvage agent for patients with non-Hodgkin's lymphoma, as a treatment for bronchial asthma and vertebrobasilar insufficiency.

Sesamin is the most prominent lignan compound found in sesame seeds, one of the two highest sources of lignans in the human diet (the other being flax). Sesamin is catered to be a nutritional supplement that confers antioxidant and antiinflammatory effects (if touting its health properties) or possibly being an estrogen receptor modulator and fat burner (if targeting atheltes or persons wishing to lose weight). Sesamin has a few mechanisms, and when looking at it holistically it can be summed up as a fatty acid metabolism modifier. It appears to inhibit an enzyme known as delta-5-desaturase (Δ5-desaturase) which is a rate-limiting enzyme in fatty acid metabolism; inhibiting this enzyme results in lower levels of both eicosapentaenoic acid (EPA, one of the two fish oil fatty acids) as well as arachidonic acid, and this mechanism appears to be relevant following oral ingestion. The other main mechanism is inhibiting a process known as Tocopherol-ω-hydroxylation, which is the rate limiting step in the metabolism of Vitamin E; by inhibiting this enzyme, sesamin causes a relative increase of vitamin E in the body but particularly those of the gamma subset (γ-tocopherol and γ-tocotrienol) and this mechanism has also been confirmed to be active following oral ingestion. Sesamin is a potent and specific inhibitor of delta 5 desaturase in polyunsaturated fatty acid biosynthesis. Sesamin inhibits a particular CYP3A enzymes that is involved in vitamin E metabolism, where the enzyme initially ω-hydroxylates vitamin E (required step) and then the rest of vitamin E is subject to fat oxidation. By inhibiting this step, sesamin causes an increase in circulating and organ concentrations of vitamin E. Sesamin is thought to have PPARα activating potential in the liver, but it is uncertain how much practical relevance this has in humans due to this being a mechanism that differs between species.

Domperidone is a peripherally selective D2 receptor antagonist. It acts as an antiemetic and a prokinetic agent through its effects on the chemoreceptor trigger zone and motor function of the stomach and small intestine. Domperidone was not approved in USA due to risks of cardiac arrhythmias, cardiac arrest, and sudden death, but is available in other countries. However, FDA allows access to Domperidone through an expanded access investigational new drug application (IND) to patients with gastroesophageal reflux disease with upper GI symptoms, gastroparesis, and chronic constipation. As an “off-label” use, domperidone is prescribed to breastfeeding women to enhance their milk production.

An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. Papaverine is a vasodilating agent. Papaverine is used for the treating certain conditions that are accompanied by smooth muscle spasms (eg, blood vessel, urinary, gallbladder, or intestinal spasm). Papaverine is a nonxanthine phosphodiesterase inhibitor for the relief of cerebral and peripheral ischemia associated with arterial spasm and myocardial ischemia complicated by arrhythmias. The main actions of Papaverine are exerted on cardiac and smooth muscle. Like qathidine, Papaverine acts directly on the heart muscle to depress conduction and prolong the refractory period. Papaverine relaxes various smooth muscles. This relaxation may be prominent if spasm exists. The muscle cell is not paralyzed by Papaverine and still responds to drugs and other stimuli causing contraction. The antispasmodic effect is a direct one, and unrelated to muscle innervation. Papaverine is practically devoid of effects on the central nervous system. Papaverine relaxes the smooth musculature of the larger blood vessels, especially coronary, systemic peripheral, and pulmonary arteries. Papaverine is a potent, specific inhibitor of PDE10A. Papaverine for treatment of erectile dysfunction (ED) is excluded from coverage.