Rhapontigenin

Rhapontigenin is a stilbene compound found in rhubarb that exhibits anti-cancer and anti-angiogenic properties through inhibition of HIF-1α accumulation. This bioactive polyphenol demonstrates selective estrogen receptor modulation and tyrosinase inhibition in preclinical studies.

Origin & History

Rhapontigenin is a naturally occurring stilbenoid polyphenol found in plants such as rhubarb, Vitis coignetiae, and Gnetum cleistostachyum. It is typically isolated as a powder or crystalline solid with ≥98% purity, soluble in organic solvents but poorly in water.

Historical & Cultural Context

No traditional or historical medicinal uses of rhapontigenin are documented. It is primarily noted as a plant metabolite without reference to specific traditional systems.

Health Benefits

• Inhibits HIF-1α accumulation and angiogenesis in prostate cancer cells (preclinical evidence). • Suppresses breast cancer cell migration by inhibiting the PI3K/Rac1 pathway (in vitro studies). • Shows dose-dependent tyrosinase inhibition in melanoma cells (cell-based study). • Acts as a selective inactivator of cytochrome P450 1A1 (IC50: 400 nM, experimental evidence). • Inhibits colorectal adenocarcinoma cell growth (preclinical models).

How It Works

Rhapontigenin inhibits hypoxia-inducible factor-1α (HIF-1α) accumulation, which suppresses angiogenesis and tumor growth in cancer cells. It blocks the PI3K/Rac1 signaling pathway to prevent cancer cell migration and metastasis. The compound also acts as a competitive tyrosinase inhibitor and demonstrates selective estrogen receptor β (ERβ) agonist activity.

Scientific Research

No human clinical trials, RCTs, or meta-analyses have been conducted on rhapontigenin. The evidence is limited to preclinical in vitro and cell-based studies, without specific PubMed PMIDs.

Clinical Summary

Current research on rhapontigenin is limited to preclinical in vitro and cell culture studies. Studies show dose-dependent inhibition of prostate cancer angiogenesis and breast cancer cell migration at concentrations of 10-50 μM. Tyrosinase inhibition studies demonstrate IC50 values around 15-25 μM in melanoma cell lines. No human clinical trials have been conducted to establish safety, efficacy, or optimal dosing in humans.

Nutritional Profile

Rhapontigenin (3,3',5-trihydroxy-4'-methoxystilbene) is a naturally occurring stilbenoid compound, not a conventional food ingredient with macronutrient or micronutrient content. It is a low-molecular-weight polyphenol (MW: 258.27 g/mol) classified as a hydroxystilbene. Key bioactive profile: It is structurally analogous to resveratrol with an additional methoxy group at the 4' position, which confers distinct pharmacological selectivity. Found naturally in rhubarb (Rheum rhaponticum, Rheum undulatum) at trace concentrations, typically in the range of 0.01–0.5 mg/g dry weight in root extracts, depending on species and extraction method. No meaningful macronutrient (carbohydrate, fat, protein) or micronutrient (vitamin, mineral) content is attributable to rhapontigenin itself as an isolated compound. Bioavailability notes: As a stilbenoid, rhapontigenin is subject to phase I and phase II hepatic metabolism; it is notably a mechanism-based inactivator of CYP1A1 (IC50: ~400 nM), suggesting potential for metabolic interactions that could affect its own clearance and that of co-administered substrates. Oral bioavailability is expected to be moderate, consistent with other stilbenes, with significant first-pass metabolism; precise human pharmacokinetic data are limited. Gut microbiota may further metabolize stilbenoids, though rhapontigenin-specific microbial transformation data are sparse.

Preparation & Dosage

There are no clinically studied dosage ranges due to the absence of human trials. Preclinical studies use nanomolar to micromolar concentrations in cell models. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Resveratrol, Quercetin, Curcumin, Green Tea Extract, Pterostilbene

Safety & Interactions

Safety data for rhapontigenin supplementation in humans is lacking due to the absence of clinical trials. Potential estrogenic activity through ERβ modulation may contraindicate use in hormone-sensitive conditions or during pregnancy and breastfeeding. Drug interactions are unknown but may theoretically affect medications metabolized through pathways involving PI3K or HIF-1α. Consultation with healthcare providers is recommended before supplementation, especially for individuals with cancer or taking chemotherapy medications.