Indena Quercefit (Quercetin Phytosome)

Quercefit is a patented phytosome formulation of quercetin developed by Indena, in which quercetin is complexed with sunflower-derived phospholipids to dramatically enhance oral absorption. It works primarily by modulating NF-kB signaling and inhibiting COX and LOX enzymes, reducing pro-inflammatory mediator synthesis in joint and immune tissues.

Origin & History

Indena Quercefit (Quercetin Phytosome) is a branded phytosome formulation of quercetin, a flavonol derived from the flower buds of Sophora japonica L. (Japanese pagoda tree). It is produced using Indena's proprietary Phytosome technology, which complexes quercetin with sunflower lecithin in a 1:1 weight ratio, standardized to 34-42% total quercetin content by HPLC.

Historical & Cultural Context

Quercetin occurs naturally in vegetables, fruits, nuts, and oaks (named from Latin 'quercetum' for oak forest). No specific historical or traditional medicine uses for Quercefit or Sophora japonica-derived quercetin are documented in the available research.

Health Benefits

• Enhanced bioavailability: 20-fold higher plasma exposure compared to unformulated quercetin (pharmacokinetic study, n=14 healthy volunteers, PMID: 30813433)
• Inflammatory pathway modulation: May inhibit NF-kB and control COX/LOX enzymes (mechanism-based evidence only)
• Immunomodulation support: Potential histamine/IgE reduction and IFN-γ promotion (preclinical data)
• Cellular health: May influence autophagy, mitophagy, and senescent cell management (mechanism-based evidence)
• Respiratory health support: Claimed benefits rely on general quercetin data, not Quercefit-specific clinical trials

How It Works

Quercefit delivers quercetin complexed with phosphatidylcholine, allowing passive diffusion across intestinal epithelial membranes and bypassing the poor solubility that limits standard quercetin absorption. Once absorbed, quercetin inhibits IκB kinase (IKK), preventing NF-kB nuclear translocation and downstream transcription of pro-inflammatory cytokines such as TNF-α and IL-6. Quercetin also competitively inhibits cyclooxygenase (COX-1/COX-2) and 5-lipoxygenase (5-LOX), reducing prostaglandin E2 and leukotriene B4 synthesis in synovial and immune cells.

Scientific Research

The primary clinical evidence comes from an open-label, crossover pharmacokinetic study (PMID: 30813433) comparing Quercetin Phytosome to unformulated quercetin in 14 healthy volunteers, demonstrating 20-fold higher plasma exposure and dose linearity up to 500 mg. No large-scale RCTs, meta-analyses, or efficacy trials specifically on Quercefit for clinical outcomes are available; therapeutic claims rely on preclinical or general quercetin data.

Clinical Summary

A pharmacokinetic crossover study in 14 healthy volunteers (PMID: 30813433) demonstrated that Quercefit achieves approximately 20-fold greater plasma exposure (AUC) compared to unformulated quercetin at an equivalent dose, establishing its superior bioavailability. This enhanced absorption is the foundational clinical evidence for the formulation's advantage over standard quercetin supplements. Evidence for downstream anti-inflammatory and joint health outcomes is currently based on mechanistic and preclinical data, with limited controlled human trials specifically using Quercefit in joint disease populations. More robust randomized controlled trials with clinical endpoints such as joint pain scores, CRP, and IL-6 are needed to confirm therapeutic efficacy in target populations.

Nutritional Profile

{"bioactive_compounds": {"quercetin": {"concentration": "500 mg per serving", "bioavailability": "Enhanced, 20-fold higher plasma exposure compared to unformulated quercetin"}}, "macronutrients": {"protein": "Not applicable", "fiber": "Not applicable"}, "micronutrients": {"vitamins": "Not applicable", "minerals": "Not applicable"}}

Preparation & Dosage

Clinically studied doses: 250 mg Quercefit tablets (delivering ~100 mg quercetin) up to 500 mg (delivering ~200 mg quercetin), showing linear absorption. Standardization: ~40% total quercetin (HPLC) in phytosome powder form. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitamin C, Bromelain, Resveratrol, Curcumin, Green Tea Extract

Safety & Interactions

Quercefit and quercetin broadly are well-tolerated in studies up to 1,000 mg/day, with mild gastrointestinal discomfort being the most commonly reported side effect. Quercetin may inhibit CYP3A4 and CYP2C8 enzymes, potentially increasing plasma concentrations of drugs such as cyclosporine, statins, and certain anticoagulants like warfarin, warranting caution in patients on these medications. Quercetin has demonstrated estrogen-receptor binding activity in preclinical models, so individuals with hormone-sensitive conditions should consult a physician before use. Safety data in pregnant or breastfeeding women is insufficient to establish a recommendation, and use during pregnancy should be avoided without medical supervision.