# Bitterwood (Picrasma excelsa) **Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/bitterwood **Data Source:** Hermetica Superfoods Ingredient Encyclopedia **Updated:** 2026-03-28 **Evidence Score:** 4 / 10 **Category:** Other **Also Known As:** Picrasma excelsa, Jamaican bitterwood, Jamaica bitterwood, Bitterwood tree, Picrasma, Caribbean bitterwood, Jamaican quassia ## Overview Bitterwood (Picrasma excelsa) is a Caribbean tree containing quassinoids, bitter compounds traditionally used in Jamaican folk medicine for blood sugar management. These quassinoids may influence [glucose metabolism](/ingredients/condition/weight-management) and enzyme activity, though clinical evidence remains limited. ## Health Benefits • Blood sugar management - traditionally used in Jamaican folk medicine for diabetes (traditional evidence only) • Digestive tonic - historically used for digestive support due to bitter principles (traditional evidence only) • Potential drug [metabolism](/ingredients/condition/weight-management) effects - inhibits CYP1A1 enzyme in vitro (IC50 9.2-11.9 μM) (preliminary in vitro evidence) • No clinical trial evidence available for any health benefits • Limited to traditional use reports without human studies ## Mechanism of Action Bitterwood's quassinoid compounds, particularly quassin and neoquassin, exert biological effects through bitter taste receptor activation and enzyme inhibition. The extract demonstrates CYP1A1 enzyme inhibition in vitro, potentially affecting drug metabolism pathways. These quassinoids may also influence [glucose metabolism](/ingredients/condition/weight-management) through unknown mechanisms in traditional diabetes management. ## Clinical Summary Current evidence for bitterwood is limited to traditional use documentation and in vitro studies. Laboratory research shows CYP1A1 enzyme inhibition with an IC50 value, but specific concentrations and clinical relevance remain unclear. No randomized controlled trials have evaluated bitterwood's effects on blood sugar management or [digestive health](/ingredients/condition/gut-health) in humans. Traditional evidence from Jamaican folk medicine provides historical context but lacks quantified clinical outcomes. ## Nutritional Profile Bitterwood (Picrasma excelsa) is a medicinal bark/wood preparation with negligible macronutrient content in typical therapeutic doses. Primary bioactive compounds are quassinoids (bitter principles), which are the defining phytochemical class: nigakilactone derivatives, picrasin A-F (particularly picrasin B as a dominant quassinoid), and beta-carboline alkaloids including 4-methoxy-1-vinyl-beta-carboline and canthin-6-one alkaloids. Quassinoid concentration in dried bark is estimated at 0.1-0.5% dry weight based on related Picrasma/Quassia species data. Canthin-6-one alkaloids present at trace levels (<0.1% dry weight). Also contains beta-sitosterol and campesterol (phytosterols), tannins (condensed and hydrolysable, estimated 2-5% dry weight), and flavonoid glycosides at low concentrations. No clinically meaningful vitamins or minerals are contributed in standard decoction doses. Fiber content is structurally present in bark preparations but not bioavailable in typical aqueous extracts. Bioavailability of quassinoids from decoctions is not formally characterized; lipophilic quassinoids likely have moderate oral bioavailability based on structural analogs. The CYP1A1 inhibitory activity (IC50 9.2-11.9 μM in vitro) is attributed to the alkaloid and quassinoid fractions collectively, though specific responsible compounds are not yet isolated with certainty. ## Dosage & Preparation No clinically studied dosage ranges have been established for Picrasma excelsa in any form (extracts, powder, or standardized preparations). Traditional use involves wood infusions prepared as tea, but specific amounts are not documented in available research. Consult a healthcare provider before starting any new supplement. ## Safety & Drug Interactions Bitterwood safety profile in humans has not been established through clinical trials. The documented CYP1A1 enzyme inhibition suggests potential drug interactions, particularly with medications metabolized by this pathway. Quassinoids can cause gastrointestinal irritation in sensitive individuals due to their intense bitter properties. Pregnancy and breastfeeding safety data is unavailable, warranting avoidance during these periods. ## Scientific Research No human clinical trials, RCTs, or meta-analyses were identified for Picrasma excelsa. The only scientific study found was an in vitro investigation (PMID: 19016402) examining CYP1A1 enzyme inhibition by quassin and neoquassin, reporting IC50 values of 9.2 μM and 11.9 μM respectively, which focused on drug [metabolism](/ingredients/condition/weight-management) interactions rather than therapeutic outcomes. ## Historical & Cultural Context In Jamaican folk medicine, Picrasma excelsa wood infusions, known as Jamaican bitterwood tea, are traditionally consumed to lower blood sugar in diabetics, often alongside prescription medications. The wood's intense bitterness has been historically valued as a tonic and digestif, similar to related Quassia species. ## Synergistic Combinations Gymnema sylvestre, Cinnamon bark, Bitter melon, Chromium picolinate ## Frequently Asked Questions ### What are the active compounds in bitterwood? Bitterwood contains quassinoids, primarily quassin and neoquassin, which are intensely bitter compounds responsible for the plant's traditional medicinal properties. These quassinoids give bitterwood its characteristic taste and potential biological activities. ### Can bitterwood lower blood sugar levels? Bitterwood has traditional use in Jamaican folk medicine for diabetes management, but no clinical studies have confirmed its blood sugar lowering effects. The mechanism by which it might influence glucose metabolism remains unknown and requires scientific validation. ### Does bitterwood interact with medications? Bitterwood demonstrates CYP1A1 enzyme inhibition in laboratory studies, suggesting potential interactions with drugs metabolized by this pathway. Individuals taking prescription medications should consult healthcare providers before using bitterwood supplements due to unknown interaction risks. ### What is the recommended dosage for bitterwood? No standardized dosage exists for bitterwood supplements due to lack of clinical research. Traditional preparations varied widely in concentration and preparation methods. Any dosing should be guided by qualified healthcare practitioners familiar with herbal medicine. ### Is bitterwood safe for long-term use? Long-term safety data for bitterwood is not available from human studies. The intense bitter compounds may cause digestive irritation with prolonged use. Safety evaluation requires clinical research to establish appropriate use duration and potential adverse effects. ### Is bitterwood safe during pregnancy and breastfeeding? There is no clinical safety data available for bitterwood use during pregnancy or breastfeeding, and traditional use alone does not establish safety for these populations. Due to its potent bitter principles and potential effects on digestion and metabolism, bitterwood should be avoided during pregnancy and lactation unless specifically directed by a qualified healthcare provider. Pregnant and nursing women should consult their doctor before considering any bitterwood supplement. ### What is the evidence quality for bitterwood's health benefits? Bitterwood lacks clinical trial evidence for any health claim, with its traditional use documented primarily in Jamaican folk medicine rather than scientific research. Current evidence is limited to traditional historical use for blood sugar and digestive support, plus preliminary in vitro studies showing CYP1A1 enzyme inhibition. More rigorous clinical research is needed to establish efficacy or safety in humans. ### How does bitterwood compare to other bitter digestive herbs like gentian or andrographis? Bitterwood, gentian, and andrographis are all traditionally used as bitter tonics, but they differ in origin and research status—bitterwood is specific to Jamaican traditional medicine while gentian and andrographis have more extensive ethnobotanical documentation. Unlike andrographis, which has some clinical research on immune function, bitterwood currently lacks human clinical trials for any indication. The choice between them should be based on traditional use patterns, individual tolerance, and availability rather than proven clinical superiority, as none have strong clinical evidence for digestive benefits. --- *Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com* *License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*