Quercetin is a unique bioflavonoid that has been extensively studied by researchers over the past 30 years. Quercetin, the most abundant of the flavonoids (the name comes from the Latin –quercetum, meaning oak forest, quercus oak) consists of 3 rings and 5 hydroxyl groups. Quercetin is a member of the class of flavonoids called flavonoles and forms the backbone for many other flavonoids including the citrus flavonoids like rutin, hesperidins, Naringenin and tangeritin. It is widely distributed in the plant kingdom in rinds and barks. The best described property of Quercetin is its ability to act as antioxidant. Quercetin seems to be the most powerful flavonoids for protecting the body against reactive oxygen species, produced during the normal oxygen metabolism or are induced by exogenous damage [9, 10]. One of the most important mechanisms and the sequence of events by which free radicals interfere with the cellular functions seem to be the lipid peroxidation leading eventually the cell death. To protect this cellular death to happen from reactive oxygen species, living organisms have developed antioxidant line of defense systems [11]. These include enzymatic and non-enzymatic antioxidants that keep in check ROS/RNS level and repair oxidative cellular damage. The major enzymes, constituting the first line of defence, directly involved in the neutralization of ROS/RNS are: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) The second line of defence is represented by radical scavenging antioxidants such as vitamin C, vitamin A and plant phytochemicals including quercetin that inhibit the oxidation chain initiation and prevent chain propagation. This may also include the termination of a chain by the reaction of two radicals. The repair and de novo enzymes act as the third line of defence by repairing damage and reconstituting membranes. These include lipases, proteases, DNA repair enzymes and transferases. Quercetin is a specific quinone reductase 2 (QR2) inhibitor, an enzyme (along with the human QR1 homolog) which catalyzes metabolism of toxic quinolines. Inhibition of QR2 in plasmodium may potentially cause lethal oxidative stress. The inhibition of antioxidant activity in plasmodium may contribute to killing the malaria causing parasites.

Phenylbutazone is an anti-inflammatory drug, which binds to and inactivates cyclooxygenases and prostacyclin synthase through peroxide (H2O2) mediated deactivation. The reduced production of prostaglandin leads to reduced inflammation of the surrounding tissues. Phenylbutazone was marked under the brand name butazolidin for the treatment rheumatoid arthritis and gout, but then this usage was discontinued. In addition, phenylbutazone is used in UK for the treatment of ankylosing spondylitis, but only in those cases, when other therapies are unsuitable.

Dihydro-alpha-ergocryptine is an ergot alkaloid that has an agonist activity on D2 dopaminergic receptors and a partial agonist activity on D1 receptors. It also demonstrated antagonistic activity towards alpha-adrenergic receptors. The drug was approved by FDA in combination with other alkaloids (dihydroergocornine, dihydroergocristine and dihydro-beta-ergocryptine mesylate salts) under the name Hydergine for the treatment of dimentia and cerebrovascular insufficiency.

Lindane is an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical. As a shampoo, lindane is used for treamtment lice infestation. Lindane lotion is used for treatment of scabies. Due to toxicities, associated with lindane, it is used only in patients who cannot tolerate or have failed first-line treatment with safer medication. Lindane exerts its parasiticidal action by being directly absorbed into the parasites and their ova, where it interferes with GABA neurotransmitter function by interacting with the GABAA channel complex at the picrotoxin binding site.

Sulfisoxazole is a sulfonamide antibacterial antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfisoxazole acetyl in combination with erythromycin ethylsuccinate is used for treatment of ACUTE OTITIS MEDIA in children that is caused by susceptible strains of Haemophilus influenzae. Sulfisoxazole acetyl is a prodrug of sulfisoxazole. Acetyl group is added to make the drug poorly water soluble, and is hydrolyzed in vivo to the active drug. Sulfisoxazole and its acetylated metabolites are excreted primarily by the kidneys through glomerular filtration. Sulfisoxazole is a competitive inhibitor of the enzyme dihydropteroate synthetase. It inhibits bacterial synthesis of dihydrofolic acid by preventing the condensation of the pteridine with para-aminobenzoic acid (PABA), a substrate of the enzyme dihydropteroate synthetase. The inhibited reaction is necessary in these organisms for the synthesis of folic acid

Sulfamethazine is a sulfonamide used to treat a variety of bacterial diseases in animals. It inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA) for binding to dihydropteroate synthetase (dihydrofolate synthetase).

Barbiturates are non-selective depressants of the central nervous system. Butabarbital is one of them, which is used under brand name butisol sodium as a sedative or hypnotic. Like other barbiturates, butabarbital is capable of producing all levels of CNS mood alteration from excitation to mild sedation, to hypnosis, and deep coma. The mechanism of action by which barbiturates exert their effect is not yet completely understood, but is assumed, that butabarbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.

Santonin, a natural compound, is a sesquiterpene lactone. It is known as an anthelmintic drug which was used in the past (19th - early 20th centuries) mainly to treat different kinds of intestinal worms such as roundworm or ascaris lumbricoides except the tapeworm. It was also indicated for use in retention of urine and nocturnal enuresis from atony, urethral irritation with pain at uterine disorders, retention of urine in fevers, deficient spinal innervation, as evidenced by impaired respiration and tympanitis, vesical tenesmus and strangury, retention of urine from the use of opiates. Santonin was formerly listed in U.S. and British pharmacopoeia but due to the severe side effects and the development of many safer deworming drugsa it is no longer registered as a drug in most countries. Originally isolated from the poisons plant Artemisia maritima, santonin is itself a toxic compound. It is the anhydride of santonic acid, which is a derivative of dimethyl-naphtalene. It dissolves in alkalies with formation of salts of this acid. In acetic acid solution, when exposed to sunlight for about a month, santonin is converted into photosantonic acid. Santonin was found to have significant anti-inflammatory activity on acute inflammatory processes and as shown in vitro can activate pregnane X receptors and constitutive androstane receptors and subsequently increases the expression of drug-metabolizing enzymes.

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.

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.