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Herbal Supplements and Health
Published in Anil K. Sharma, Raj K. Keservani, Surya Prakash Gautam, Herbal Product Development, 2020
Himangini Bansal, Sakshi Bajaj
Kava, a herbal sedative with antianxiety or calming effects, is prepared by extracting the rhizomes of Piper methysticum, a south pacific plant. There are at least 72 different cultivars of this species, which differ both in appearance and in chemical composition. The active chemicals of the plants, known as kavalactones, are concentrated in the rhizomes. Inhabitants of the south pacific islands prepare a kava-based drink by mixing fresh or dried rhizomes with cold water or coconut milk. Among more than 18 kavalactones characterized, 6 are considered the primary constituents of kava extracts: kawain, dihydrokawain, methysticine, dehydromethysticine, yangonin, and desmethoxyyangonin. Quite a considerable lot of these compounds, particularly those with a methylenedioxyphenyl derivatives (methysticine and dihydromethysticine), have been found to restrain various cytochrome P450s: CYP2C19, CYP1A2, CYP2C9, CYP3A4, CYP2D6, and CYPA4. It is therefore astonishing to discover that pharmacokinetic interactions among kava and Western medications are generally rare and are not very much reported in the literature. There is a case report that kava decreases the viability of levodopa (Dasgupta and Hammett-Stabler, 2010).
Herbs with Antidepressant Effects
Published in Scott Mendelson, Herbal Treatment of Major Depression, 2019
Among the many phytochemical constituents of kava, known collectively as kavalactones or kavapyrones, are dihydrokawain, kawain, methysticin, yangonin, dihydromethysticin, desmethoxyyangonin, flavokawin A, pinostrobinchalcone, dihydrotectochrysin, alpinetinchalcone, alpinetin, dihydrooroxylin A, and others in lesser degrees of concentration.2 Six of these kavalactones, including kavain, dihydrokavain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangonin, are responsible for nearly all of the plant's pharmacological activity.
Anxiety
Published in Ethan Russo, Handbook of Psychotropic Herbs, 2015
The active components of kava root are termed kavapyrones or kavalactones. Research in this area began in the 1860s with Gobley and Cuzent, followed by Lewin in the 1890s (who did the first pharmacological experiments on kava activity and demonstrated that active components were lipid soluble), and Borsche and colleagues from 1914 to 1933. Hänsel undertook an extensive review in 1968 (Hänsel, 1968). The older literature is replete with errors, accusations, and name changes for various chemicals and is not germane in this arena.
The sub-acute toxicity of kavalactone in rats: a study of the effect of oral doses and the mechanism of toxicity in combination with ethanol
Published in Drug and Chemical Toxicology, 2023
Mohammed Abdulabbas Hasan, Syam Mohan, Heshu Sulaiman Rahman, Hemn Hasan Othman, Shirwan Hamasalih Omer, Abdullah Farasani
The constituents of kava responsible for producing the desirable mood-altering effects, such as muscle relaxation and anxiety relief, are kavalactones or kava pyrones (Thomsen and Schmidt 2021). Kawain, dihydrokawain, methysticin, dihydromethysticin, yangonin, and desmethoxyyangoninare obtained from the lipid-soluble fraction, and they are the six main lactones being responsible for the potency of kavalactones. Dihydro kawain and dihydro methysticin are considered pain-relieving chemicals, which are believed to be as effective as aspirin (Ebadi 2006, Tauchen 2020). Research suggests that KL has a synergistic effect, as laboratory experiments have shown that lactones administered alone seem to have a more negligible impact compared to when they are administered in combination (Clough 2003, Fu et al. 2008). Animal experiments have demonstrated that the mechanism whereby kava components may cause sedative and hypnotic effects are similar to the mechanisms employed by the benzodiazepine group of drugs (Jussofie et al. 1994, White 2018). Folk medicine suggests that kava also may help treat sleeplessness, anxiety, headaches, colds, rheumatism, menopausal symptoms, venereal diseases, menstrual, and genitourinary tract problems (Amorim et al. 2007, Salehi et al. 2019). Kavalactones have also been mixed in certain commercially available beverages such as chocolate, tea, and drink mixes (Dennehy et al. 2005, Clayton et al. 2007, Aporosa 2020).
Indigenous Hawaiian Psychoactive Drug Use: Before European Contact, and after 1778
Published in Journal of Psychoactive Drugs, 2021
Izaak L. Williams, George K. Makini, William C. Rezentes
Traditional Hawaiian society had no notion of psychoactive addiction, because ‘awa lacked the necessary neurobiochemical agency to create such effect. The psychoactive component in ‘awa is caused by kavalactones, a class of lactone compounds found in the ‘awa shrub (Johnston and Rogers 2006). The chemical pharmacological effect of kavalactones is “non-narcotic, non-opiate, non-fermented, non-alcoholic, non-hallucinogenic, and physiologically non-addicting” (Norton 1998, 383). Among the larger segment of Hawaiian society, comprised maka‘āinana, the religious code of conduct and cultural ethics regarding any indulgent consumption of ‘awa would have made misuse difficult, and subject to taboo. Since ali‘i and kāhuna pule (priests) controlled the regulation of ‘awa, only this small segment of the population was exposed to the risk of ‘awa misuse; thereby preventing “abuse” from becoming widespread (Keaulana and Whitney 1988).1 Here, we employ the term “abuse” to denote chronic ‘awa use with the symptoms of persistent redness in the eyes, scaliness of the skin, and liver toxicity. Any ‘awa use outside the prescribed rituals was considered a violation of traditional (Kānaka Maoli) cultural conventions.
Bioactivation of herbal constituents: mechanisms and toxicological relevance
Published in Drug Metabolism Reviews, 2019
Kava (Piper methysticum) is an effective herbal medicine for anxiety and insomnia and has been consumed in Polynesia as a ceremonial and cultural drink for centuries. However, upon introduction as a dietary supplement in Western countries, there have been multiple case reports of kava-induced hepatotoxicity requiring liver transplantation (Becker et al. 2019). The major constituents of kava extracts are bioactive kavalactones including kawain, 7,8-dihydrokawain, methysticin, 7,8-dihydromethysticin, yangonin, and desmethoxyyangonin (Olsen et al. 2011). The two MDP-bearing lactones, methysticin and 7,8-dihydromethysticin, were shown to produce reactive o-quinones via initial CYP-mediated O-demethylenation of the MDP moiety to a catechol followed by two-electron oxidation (Johnson et al. 2003) (Figure 9(a)). GSH or mercapturic acid conjugates were not identified in human urine presumably due to extensive conjugation of the catechols via glucuronidation and sulfation in vivo. Detection of mercapturic acid adducts of 6-phenyl-3-hexen-2-one in human urine suggested an alternative bioactivation pathway of kavalactones (Zou et al. 2005). Scission of the pyrone ring followed by decarboxylation and o-demethylation led to formation of 6-phenyl-3-hexen-2-one, an α, β-unsaturated ketone metabolite which reacts with GSH or mercapturic acid via Michael-type addition (Zou et al. 2005).