Bark
Quassia Bark
Moderate EvidenceCompound10 PubMed Studies
Hermetica Superfood Encyclopedia
Quassia bark contains potent quassinoid compounds—primarily quassin and neoquassin—that activate TAS2R bitter taste receptors to stimulate digestive secretions, bile flow, and gastric acid production, while demonstrating significant antiparasitic, hepatoprotective, and antiulcerogenic activity in preclinical models. A 2021 study (PMID 33544994) confirmed that Quassia amara stem bark extract exerts measurable hepatoprotective effects against cadmium-induced liver toxicity in Wistar rats, while earlier research (PMID 12230107) demonstrated its antiulcerogenic activity across four distinct bark extract preparations.
Quassia amara, a small tree, is native to tropical Central and South America, particularly Brazil, Suriname, and Colombia, as well as parts of the Caribbean. Its bark is a potent source of bitter quassinoids, valued in functional nutrition for its digestive, antiparasitic, and liver-supporting properties.
Obembe et al. (2021) demonstrated that Quassia amara stem bark extract significantly attenuated cadmium-induced hepatotoxicity in male Wistar rats, restoring liver enzyme levels and reducing oxidative stress biomarkers (PMID 33544994, J Basic Clin Physiol Pharmacol). Toma et al. (2002) evaluated four bark wood extracts of Q. amara and confirmed dose-dependent antiulcerogenic activity using ethanol- and indomethacin-induced gastric lesion models in rats (PMID 12230107, Biol Pharm Bull). The same research group (Toma et al., 2003) further established significant analgesic and antiedematogenic properties of the bark extract in rodent models (PMID 12576198, J Ethnopharmacol). In vitro antiplasmodial screening of 18 traditional Congolese medicinal plants confirmed activity of Quassia-related species against Plasmodium falciparum strains (PMID 16257160, J Ethnopharmacol), while simalikalactone D, a quassinoid from Quassia africana, showed notable antiviral activity (PMID 11842321, Planta Med).
- Phytochemicals: Quassinoids (quassin, neoquassin), beta-sitosterol, alkaloids, flavonoids, lignans, coumarins. - Minerals: Potassium, magnesium, iron.
Quassin and neoquassin activate TAS2R family bitter taste receptors on enteroendocrine and gustatory cells, triggering vagal afferent signaling that upregulates salivary, gastric acid, and pancreatic enzyme secretions alongside enhanced bile flow via cholecystokinin (CCK) release. Neoquassin and related quassinoids disrupt protozoal mitochondrial electron transport chain complexes and inhibit heme polymerization in Plasmodium parasites, accounting for the in vitro antiplasmodial effects documented across multiple studies (PMID 16257160; PMID 22394563). The canthin-6-one alkaloid 2-methoxycanthin-6-one contributes cytoprotective effects by scavenging reactive oxygen species and modulating NF-κB–mediated inflammatory cascades, which supports the antiulcerogenic and hepatoprotective outcomes observed in rodent models (PMID 12230107; PMID 33544994). Additionally, quassinoids appear to modulate prostaglandin synthesis pathways, contributing to the analgesic and antiedematogenic effects demonstrated by Toma et al. (PMID 12576198).
Human clinical trials for Quassia bark are currently absent from the literature, with evidence limited to animal and in vitro studies. In rat studies, Q. amara extract at 800 mg/kg orally and 2-methoxycanthin-6-one at 12.5 mg/kg provided 77-85% cytoprotection against indomethacin-induced gastric ulcers with statistically significant (P<0.01) reductions in gastric acidity. The antiulcer effects showed dose-dependent improvements and were enhanced when combined with cimetidine. While animal studies suggest efficacy for digestive and gastroprotective applications, human safety and efficacy data remain lacking.
Quassia bark may potentiate the effects of anticoagulant and antiplatelet drugs; Heck et al. (2000) identified quassia among herbal therapies with potential interactions with warfarin, advising close INR monitoring in patients on concurrent anticoagulant therapy (PMID 10902065, Am J Health Syst Pharm). A comprehensive reproductive toxicity evaluation by Parveen et al. (2003) in male rats reported adverse effects on sperm parameters and testicular histology at higher doses, indicating that quassia bark should be avoided by men actively seeking fertility and by pregnant or breastfeeding women (PMID 12507657, Reprod Toxicol). High doses may cause gastrointestinal irritation, nausea, and vomiting due to excessive stimulation of gastric acid secretion. While specific CYP450 inhibition data remain limited, the presence of canthin-6-one alkaloids suggests theoretical potential for interactions with CYP3A4-metabolized medications, warranting caution and clinical monitoring.
