Methysticin is a kavalactone originally found in Piper methysticum (kava plant). Methysticin exhibits neuroprotective, neuromodulatory, and antifungal activities. Methysticin may also display anti-inflammatory benefit, inhibiting activation of NF-κB in lung adenocarcinoma tissue. Methysticin activates Nrf2 in neurons and astroglia, protecting against amyloid-β (Aβ)-induced neurotoxicity. This compound displays antimicrobial efficacy against species of Fusarium, Trichoderma, and Colletotrichum. Additionally, methysticin inhibits peak amplitude of voltage-gated Na+ channels in hippocampal neurons. Methysticin administration activates the Nrf2 pathway and reduces neuroinflammation, hippocampal oxidative damage and memory loss in a mouse model of AD. Therefore, kavalactones might be suitable candidates to serve as lead compounds for the development of a new class of neuroprotective drugs.

Sesamolin from Sesamun indicum seeds plays important role in plant defense, such as antifeedant as well as potent antioxidants and insecticides. Sesaminol has potent inhibition of cytochrome P450 (CYPs). The neuroprotective effect of sesamolin was also observed in vivo using gerbils subjected to a focal cerebral ischemia induced by occlusion of the right common carotid artery and the right middle cerebral artery. Lipid peroxidation activity, measured as 2-thiobarbituric acid reactive substances, was significantly lower in the kidneys and liver of the sesamolin-fed rats than in the controls.

Alantolactone and isoalantolactone, main bioactive compounds that are present in many medicinal plants such as Inula helenium, L. Inula japonica, Aucklandia lappa, Inula racemosa, and Radix inulae, have been found to have various pharmacological actions including anti-inflammatory, antimicrobial, and anticancer properties, with no significant toxicity. Alantolactone and isoalantolactone have been reported for their wide spectrum of biological effects, including antifungal, anthelmintic activities, antimicrobial activities, anti-inflammatory activities, antitrypanosomal activities, and antiproliferative effects on several cancer cell lines, such as colon, melanoma, ovary, prostate, lung, and leukemia. Alantolactone isolated from Inula helenium (Compositae), a traditional Chinese medicinal herb, provides an effective inhibitory activity for cell growth against MK-1, HeLa, B16F10, and K562 cell lines. Many other human cancer cell lines, including U87 glioma cells, Bel-742, SMMC-7721 and HepG2 liver cancer cells, PANC-1 pancreatic carcinoma cells, A59 lung cancer cells, colon adenocarcinoma HCT-8 cells, CNS cancer cell line SF-295, leukemia HL-60, Hepa1c1c7 cells, BPRc1 Hepatic cancer cells, and HCT-8 colon cancer cells, have also been reported for apoptosis caused by alantolactone.

6',7'-Dihydroxybergamottin is a natural furanocoumarin found principally in grapefruit juice. Along with the chemically related compound bergamottin, it is believed to be responsible for a number of grapefruit–drug interactions, in which the consumption of the juice affects the metabolism of a variety of pharmaceutical drugs.

Paritaprevir is a potent inhibitor of the NS3/4A protease that rapidly and consistently suppresses HCV. Paritaprevir is metabolized by the Cytochrome P450 isoform 3A (CYP3A); therefore, ritonavir was used concurrently to increase plasma concentrations and to prolong the half-life of this agent allowing for once-daily dosing. Several antiviral regimens combining paritaprevir with other agents have shown impressive results, tolerable side effects, and importantly, provided support of ‘all-oral’ interferon-free regimens against HCV. Paritaprevir monotherapy is discontinued now but paritaprevir is used as a component of Viekira Pak and Technivie for the treatment of patients with genotype 1 chronic hepatitis C virus (HCV) infection.

Cisapride is chemically related to metoclopramide, but unlike metoclopramide, it does not cross the blood-brain barrier or have antidopaminergic effects. Cisapride is a serotonin-4 (5-HT4) receptor agonist. Cisapride was indicated for the symptomatic treatment of adult patients with nocturnal heartburn due to gastroesophageal reflux disease. The Food and Drug Administration (FDA) in America stopped the marketing of cisapride as of 14th July 2000. They had received at least 341 reports of heart rhythm abnormalities and these led to 80 deaths. Other reported adverse effects are: headache, diarrhea, abdominal pain, nausea, constipation. Cisapride for animals has been found helpful in some cases of megaesophagus and is a common treatment for feline megacolon. Clarithromycin, erythromycin, and troleandomycin markedly inhibit the metabolism of cisapride. Concurrent administration of certain anticholinergic compounds, such as belladonna alkaloids and dicyclomine, would be expected to compromise the beneficial effects of cisapride.

Phenprocoumon is the dominant anticoagulant in clinical use in several continental European countries. It used for the prevention and treatment of thromboembolic disease including venous thrombosis, thromboembolism, and pulmonary embolism as well as for the prevention of ischemic stroke in patients with atrial fibrillation. Phenprocoumon inhibits vitamin K reductase, resulting in depletion of the reduced form of vitamin K (vitamin KH2). Bleedings are the most important side -effects of oral anticoagulants. The gastrointestinal and the urinary tract are often affected; the most dangerous are intracerebral hemorrhages. A great number of drugs increase the risk of bleeding of oral anticoagulants. Enzyme inhibitors (e.g. allopurinol, androgens, cimetidine, ciprofloxacin, co-trimoxazole, certain anti-inflammatory agents, fibrates, imidazoles, macrolide antibiotics, etc.) reinforce, and enzyme inducers (e.g. barbiturates, rifampicin) and oral contraceptives reduce, the anticoagulant action.

Madecassoside is a triterpenoid compound found in Centella asiatica (Gotu kola), a medicinal herb used in traditional Chinese medicine (TCM), Ayurvedic medicine, and traditional African medicine. Madecassoside has a wide range of reported biological activities including, anti-inflammatory, wound healing, and anti-oxidant activities. It has been reported to suppress LPS-induced TNF-alpha production via inhibition of ERK, p38, and NF-kappaB activity. Madecassoside, a triterpenoid derivative isolated from Centella asiatica, exhibits anti-inflammatory and antioxidant activities. Madecassoside significantly reduced brain infarct area, resolved neurological deficit, and ameliorated neuronal apoptosis. It also significantly reduced the levels of malondialdehyde and nitric oxide, and augmented the antioxidant activity in rats subjected to cerebral I/R. Moreover, the levels of pro-inflammatory cytokines and NF-κB p65 significantly reduced after madecassoside treatment. Madecassoside is neuroprotective and may be useful in reducing the damage caused by stroke. Madecassoside has being shown to inhibits melanin synthesis by blocking ultraviolet-induced inflammation.

Piperine is a simple and pungent alkaloid found in the seeds of black pepper (Piper nigrum). Following its isolation and full characterization, the biological properties of piperine have been extensively studied, and piperine-like derivatives have shown an interesting range of pharmacological activities. Piperine is currently paving its way to become a privileged scaffold for the development of bioactive compounds with therapeutic application in multiple human diseases. In particular, piperine derivatives were shown to modulate the activity of several targets related to neurological disorders, including epilepsy, Parkinson's disease, depression and pain related disorders. Moreover, the efflux pump inhibitory ability of piperine and its analogues tackles important drug resistance mechanisms and may improve the clinical efficacy of antibiotic and anticancer drugs. Piperine has been found to have immunomodulatory, anti-oxidant, anti-asthmatic, anti-carcinogenic, anti-inflammatory, anti-ulcer, and anti-amoebic properties.

Laquinimod is a new orally available carboxamide derivative, which is currently developed for relapsing remitting (RR) and chronic progressive (CP) forms of multiple sclerosis (MS; RRMS or CPMS) as well as neurodegenerative diseases. The mechanism of action of laquinimod is not fully elucidated because the molecular target is not known. Treatment with laquinimod led to a significant and persistent increase in brain-derived neuroprotective factor (BDNF) serum levels compared to placebo treatment. In human studies, a decrease of pro-inflammatory and an increase of anti-inflammatory cytokines have been measured. After commercial launch the unexpected severe cardiac adverse events (AEs) such as serositis, pericarditis, and myocardial infarction were detected.