China
Africa
Explore chapters and articles related to this topic
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.
On the Sophistication of Herbal Medicines
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
Such complexities are hardly limited to the berberine plants. The anticonvulsant actions of the kava lactones in Piper methysticum (i.e., yangonin and desmethoxyyangonin) are much stronger when used in combination with other kava constituents that are generally considered irrelevant in any standardization missives. As well, concentrations of yangonin and another lactone, kavain, are much higher in the brain when the whole plant extract is used instead of the purified lactones themselves. In other words, some of the other constituents in kava help move the bioactive lactones across the blood/brain barrier and into the brain where they will do the most good. Blood plasma concentrations of kavain are reduced by 50% if the purified compound is used rather than an extract of the plant itself.
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).
Recent progress and challenges in drug development to fight hand, foot and mouth disease
Published in Expert Opinion on Drug Discovery, 2020
Ze Qin Lim, Qing Yong Ng, Justin Wei Qing Ng, Vikneswari Mahendran, Sylvie Alonso
In 2016, Li and colleagues screened a natural products library containing 502 compounds, and three hits against EV-A71, namely Auraptene, Formononetin, and Yangonin, were identified [83]. All three compounds were found to inhibit EV-A71 infection not only at the attachment stage, but also at a post-attachment stage. Through the selection of escape mutant viruses, it was shown that Auraptene targets the main viral capsid VP1, while Formononetin and Yangonin target VP4 at two different sites [83]. Site-directed mutagenesis in VP1 or VP4 resulted in drug resistance against these compounds, further supporting that they are the targets of these drugs [83]. While Auraptene provided protection against CV-A16 and two EV-A71 clinical strains, Formononetin and Yangonin displayed antiviral activity only against the two EV-A71 isolates [83]. None of them showed any antiviral activity against other members of the Picornaviridae family including CV-B3, PV1, and EV-D68, suggesting that these compounds selectively target HFMD-causing enteroviruses [83].
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).