Nootkatone
Linda M. Castell, Samantha J. Stear (Nottingham), Louise M. Burke in Nutritional Supplements in Sport, Exercise and Health, 2015
A recent animal study demonstrated that 0.2% (wt/wt) nootkatone feeding for ten weeks improved swimming endurance (i.e. swimming time to fatigue) and that long-term intake of diets supplemented with 0.1% to 0.3% nootkatone significantly reduces high-fat and high-sucrose diet-induced body weight gain, abdominal fat accumulation, and the development of hyperglycaemia, hyperinsulinaemia and hyperleptineamia (Murase et al., 2010). These beneficial effects of nootkatone might be due in part to enhanced energy metabolism through the activation of AMP-activated protein kinase in the muscle and liver (Murase et al., 2010). These findings indicate that nootkatone is a potential candidate for ergogenic and anti-obesity compounds. A previous study indicated that consumption of a whole grapefruit or grapefruit juice before meals, three times a day for 12 weeks reduces body weight and improves insulin resistance in metabolic syndrome patients, compared to placebo (Fujioka et al., 2006). On the other hand, there are no reports on the effects of grapefruit, including nootkatone, on physical performance in humans. Therefore, further studies are required to clarify the efficacy of nootkatone as an ergogenic compound, especially for athletes.
Introduction to Toxicology
David Woolley, Adam Woolley in Practical Toxicology, 2017
There are many instances of interactions between herbal remedies and prescribed drugs, either through increased or decreased effect. Even simple dietary components can have unexpected effects; grapefruit juice consumption is known to be associated with inhibition of cytochrome P450 (CYP3A4), which is responsible for the metabolism of a wide range of drugs. This has been associated with increased plasma concentrations of cisapride, a drug given for irritable bowel syndrome. Inhibition of cisapride metabolism, which probably takes place in the small intestine, can increase the likelihood of life-threatening cardiac arrhythmias in some patients. A similar effect has been reported with carbamazepine, a drug given in epilepsy. Equally, administration of metabolism inhibitors can have useful effects, for instance, in reducing the doses of some drugs needed to achieve therapeutic effect.
Ciclosporin
Sarah H. Wakelin, Howard I. Maibach, Clive B. Archer in Handbook of Systemic Drug Treatment in Dermatology, 2015
Several branded formulations are available in the UK in the following forms: Capsules: 25 mg and 100 mg ciclosporin (Neoral, Gengraf, modified), 25 mg, 50 mg and 100 mg ciclosporin (Sandimmune, non-modified).Oral solution: sugar-free solution containing ciclosporin 100 mg/mL. This may be mixed with orange or apple juice to improve the taste but not with grapefruit juice. Avoid milk due to the unpleasant tasteSandimmune is also available in a concentrate for i/v infusion containing ciclosporin 50 mg/mL.
Influence of grapefruit juice on pharmacokinetics of triptolide in rats grapefruit juice on the effects of triptolide
Published in Xenobiotica, 2018
Grapefruit juice (GFJ) is widely consumed not only for its taste and nutritive value but also for its various pharmacological properties, and many compounds have been proposed to be the active ingredients in GFJ. These include both flavonoids (e.g. naringenin, naringin, quercetin and kaempferol) and nonflavanoids (e.g. 6′,7′-dihydroxybergamottin) (Bailey et al., 2007; Dahan & Amidon, 2009). GFJ has been reported to enhance the oral bioavailability of a variety of drugs that either undergo metabolism mediated by CYP3A and/or effluxed by the P-glycoprotein (P-gp) system including nifedipine, verapamil and felodipine (Bailey & Dresser, 2004; Nakagawa & Goto, 2010). However, GFJ has conflicting effects on the activity of P-gp, ranging from inhibition to activation (Honda et al., 2004; Ravi et al., 2012; Soldner et al., 1999).
Naringenin: a potential natural remedy against methotrexate-induced hepatotoxicity in rats
Published in Drug and Chemical Toxicology, 2022
Alireza Malayeri, Reza Badparva, Mohammad Amin Mombeini, Layasadat Khorsandi, Mehdi Goudarzi
Naringenin, abbreviated as NAR (5, 7-dihydroxy-2-(4-hydroxyphenyl) chroman-4-one), is a citrus flavanone and the predominant flavanone in Citrus paradisi or grapefruit (up to 10% of dry weight) (Figure 1). It is responsible for the bitterness of grapefruit juice and is recognized as one of the most consumed flavonoids (Ortuno et al.1995, Lee et al.2004, Moon et al.2011, Khajevand-Khazaei et al.2018). NAR exhibits anti-carcinogenic (Frydoonfar et al.2003), anti-inflammatory (Bodet et al.2008), anti-estrogenic (Bovee et al.2008), and anti-tumor effects (Kanno et al.2005). Furthermore, it seems to possess free radical scavenging properties, which effectively quench oxygen-derived free radicals, given the presence of hydroxyl groups (−OH) in its structure (Zbarsky et al.2005).
CYP2C19 and CYP3A4 activity and ADP-induced platelet reactivity in prasugrel- or ticagrelor-treated STEMI patients: monocentric study in PRAGUE-18 trial participants
Published in Xenobiotica, 2020
J. Máchal, O. Hlinomaz, K. Kostolanská, O. Peš, A. Máchalová, Z. Šplíchal, Z. Mot'ovská, J. Juřica
No correlation of lansoprazole metabolism with the ADP test was observable in the case of ticagrelor in our study. In the study of Holmberg et al, grapefruit juice markedly increased the plasma concentration and the antiplatelet effect of ticagrelor (Holmberg et al., 2013). The effect on the platelet function was quite low in the first hours, but higher 24 h after the loading dose, and might be possibly explained by reducing the formation of its inactive metabolite AR-C133913XX that is formed together with the active and equipotent AR-C124910XX (Teng et al., 2010; Zhou et al., 2011b), the former being not measured in the study. In our study, the administration of ticagrelor was continued after the loading dose, and two more doses of ticagrelor were given before the blood sampling after 24 h, suggesting that CYP3A4 activity may only be relevant in the single dose of ticagrelor and not when it is administered repeatedly. The possibility that the effect of CYP3A4 on the antiplatelet effect of repeatedly ticagrelor may manifest after more than 24 h cannot be excluded, either. Nevertheless, as both parent compound and CYP3A4 mediated active metabolite AR-C124910XX exert antiplatelet activity, the substantial role of CYP3A4 in the ticagrelor effect seems rather unlikely.
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