# Flavoxine (Aqueous Extract of Grape Seed)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/flavoxine
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Other
**Also Known As:** Vitis vinifera seed extract, GSE, Grape seed proanthocyanidin extract, GSPE, Oligomeric proanthocyanidins, OPC, Leucoanthocyanidins

## Overview

Flavoxine is an aqueous extract of grape seed standardized for procyanidins and flavonoids, which act as potent antioxidants primarily by scavenging superoxide radicals and inhibiting key enzymes linked to [oxidative stress](/ingredients/condition/antioxidant) and blood sugar regulation. Its α-glucosidase inhibitory activity, with a measured IC50 of approximately 2.53 µg/mL, suggests meaningful antidiabetic potential that distinguishes it from conventional grape seed oil extracts.

## Health Benefits

• [Antioxidant](/ingredients/condition/antioxidant) properties through superoxide radical scavenging (evidence from in vitro studies only)
• [Anti-inflammatory](/ingredients/condition/inflammation) effects attributed to high procyanidin and flavonoid content (preliminary evidence from laboratory studies)
• Antidiabetic potential via α-glucosidase inhibition with IC50 ~2.53 µg/mL (in vitro data only)
• Anticancer properties suggested from cell culture models (no human clinical evidence)
• Anti-obesity effects shown in enzyme inhibition assays (preliminary laboratory evidence only)

## Mechanism of Action

Flavoxine exerts antioxidant activity primarily through direct superoxide radical scavenging by its procyanidin oligomers and flavonoids such as catechin and epicatechin, which donate hydrogen atoms to neutralize [reactive oxygen species](/ingredients/condition/antioxidant) before they damage cellular membranes or DNA. It inhibits α-glucosidase, the intestinal enzyme responsible for converting dietary carbohydrates into absorbable glucose, thereby slowing postprandial glucose uptake in a mechanism comparable to the drug acarbose. Its [anti-inflammatory](/ingredients/condition/inflammation) effects are attributed to downregulation of pro-inflammatory mediator pathways, likely involving NF-κB signaling suppression secondary to reduced oxidative stress load.

## Clinical Summary

Current evidence for Flavoxine specifically is limited to in vitro and laboratory-based studies; no published randomized controlled trials in human subjects have evaluated this particular aqueous extract formulation directly. In vitro [antioxidant](/ingredients/condition/antioxidant) assays demonstrate superoxide scavenging activity, and enzyme inhibition studies document an α-glucosidase IC50 of approximately 2.53 µg/mL, which is a competitive benchmark against standard antidiabetic reference compounds. Broader human clinical research on grape seed procyanidin extracts generally supports antioxidant and modest [cardiovascular](/ingredients/condition/heart-health) benefits at doses of 150–300 mg daily, though these findings cannot be directly extrapolated to Flavoxine without formulation-specific trials. The overall evidence base must be characterized as preliminary, and clinical efficacy claims require validation through adequately powered human studies.

## Nutritional Profile

Flavoxine is a concentrated aqueous extract of grape seed (Vitis vinifera), not a whole food ingredient, so traditional macronutrient framing is largely inapplicable. Its nutritional and bioactive profile is dominated by polyphenolic compounds: Proanthocyanidins (oligomeric procyanidins, OPCs) are the primary bioactive class, typically comprising 60–80% of a standardized grape seed extract by dry weight, with dimers, trimers, and higher-order oligomers of catechin and epicatechin units. Monomeric flavan-3-ols include catechin and epicatechin, commonly present at 5–15% of extract weight in standard preparations. Flavonoids including quercetin glycosides and kaempferol derivatives are present in smaller quantities (estimated 1–5%). Phenolic acids such as gallic acid and its esters (e.g., epicatechin gallate) contribute to the total polyphenol pool. Total polyphenol content in standardized grape seed extracts typically ranges from 95–99% polyphenols by specification (per certificate of analysis standards), though aqueous extraction yields may be lower than solvent-based extracts, typically 40–75% total polyphenols by dry weight. Mineral content is negligible in a concentrated extract form. Protein and fiber content are minimal (<2% combined in purified extract). Vitamins are not a meaningful component. Bioavailability note: Monomeric catechins exhibit moderate oral bioavailability (~20–30%), while larger OPC oligomers have significantly lower and more variable absorption; gut microbiota [metabolism](/ingredients/condition/weight-management) to smaller phenolic acids (e.g., 3-hydroxyphenylpropionic acid, 4-hydroxyphenylacetic acid) likely contributes to systemic effects. The aqueous extraction method favors water-soluble lower-molecular-weight procyanidins over larger, less-soluble oligomers, which may enhance relative bioavailability compared to whole grape seed powder. Specific concentration data for Flavoxine as a proprietary extract are not publicly disclosed beyond the IC50 antidiabetic assay value of ~2.53 µg/mL (α-glucosidase inhibition, in vitro).

## Dosage & Preparation

No clinically studied dosage ranges are available for Flavoxine. Studies only mention standardization methods using total phenolic content, total flavonoids, and procyanidins measured via spectrophotometric methods. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Grape seed extracts are generally well tolerated in adults at commonly studied doses up to 300 mg per day, with reported adverse effects limited to mild gastrointestinal discomfort, headache, and dizziness in isolated cases. Flavoxine's procyanidin content may potentiate the effects of anticoagulant and antiplatelet medications such as warfarin and aspirin due to mild platelet aggregation inhibition, making concurrent use a clinical consideration requiring monitoring. Because aqueous extraction retains highly polar polyphenolic compounds, individuals with known grape or wine allergies should exercise caution. Safety data specific to pregnancy, lactation, and pediatric populations are absent for this formulation, and use in these groups cannot be recommended without further study.

## Scientific Research

No human clinical trials, randomized controlled trials, or meta-analyses were found for Flavoxine or grape seed aqueous extracts in the research dossier. All available evidence comes from in vitro and animal models, with no PubMed PMIDs provided for human studies.

## Historical & Cultural Context

No historical or traditional medicine context was documented in the research for Flavoxine or grape seed extracts. The research dossier provides no information on traditional uses or cultural significance.

## Synergistic Combinations

Vitamin C, Vitamin E, Alpha-lipoic acid, Green tea extract, Resveratrol

## Frequently Asked Questions

### What is Flavoxine and how does it differ from standard grape seed extract?

Flavoxine is specifically an aqueous-process extract of grape seed, meaning water is used as the solvent rather than ethanol or acetone, which selectively concentrates highly polar procyanidins and flavonoids while minimizing lipid-soluble compounds. This aqueous extraction method may yield a different polyphenolic profile and bioavailability compared to conventional solvent-based grape seed extracts standardized to OPC content. The distinction matters because bioactive compound ratios directly influence which mechanisms—antioxidant, anti-inflammatory, or antidiabetic—are most prominent.

### Can Flavoxine help lower blood sugar levels?

Flavoxine demonstrates α-glucosidase inhibitory activity with an IC50 of approximately 2.53 µg/mL in laboratory studies, meaning it can slow the enzyme that breaks down carbohydrates into glucose in the intestine, potentially blunting postprandial blood sugar spikes. This mechanism is pharmacologically similar to the prescription drug acarbose, though potency and clinical relevance in living humans have not yet been confirmed through clinical trials. Individuals with diabetes or prediabetes should not use Flavoxine as a replacement for prescribed therapies without physician guidance.

### What are the main antioxidant compounds in Flavoxine grape seed extract?

The primary antioxidant constituents in Flavoxine are oligomeric procyanidins (OPCs), including dimeric and trimeric forms of catechin and epicatechin, along with monomeric flavonoids such as catechin, epicatechin, and gallic acid. These compounds scavenge superoxide radicals (O₂⁻) by donating electrons or hydrogen atoms, neutralizing the radical before it propagates oxidative chain reactions in cellular lipids and proteins. The procyanidin content is generally considered the key marker compound for standardization and antioxidant potency benchmarking.

### Are there any drug interactions with Flavoxine grape seed extract?

Flavoxine's procyanidins may inhibit platelet aggregation, creating an additive bleeding risk when combined with anticoagulants such as warfarin, heparins, or antiplatelet drugs like clopidogrel and aspirin—patients on these medications should inform their physician before use. Some grape seed polyphenols are metabolized via cytochrome P450 enzymes (notably CYP3A4 and CYP2C9), and theoretical interactions with drugs using these pathways, including certain statins and immunosuppressants, warrant caution. No formal pharmacokinetic interaction studies have been published specifically for the Flavoxine formulation, so clinical guidance currently relies on class-level evidence from grape seed extract research broadly.

### What dosage of grape seed aqueous extract is typically used in research?

Human clinical studies on grape seed procyanidin extracts most commonly use doses ranging from 150 mg to 300 mg per day, often divided into two administrations, with antioxidant and cardiovascular endpoints assessed over 4–12 week periods. The specific Flavoxine formulation lacks published human dosing trials, so no evidence-based recommended dose can be assigned to it directly at this time. In vitro effective concentrations (such as the α-glucosidase IC50 of 2.53 µg/mL) are not directly translatable to human oral doses due to bioavailability and first-pass metabolism variables.

### How does the aqueous extraction method of Flavoxine grape seed compare to other extraction methods?

Aqueous extraction of Flavoxine uses water as the primary solvent, which selectively isolates water-soluble flavonoids and procyanidins while minimizing solvent residues compared to alcohol or acetone-based methods. This approach may enhance safety for supplement use and potentially improve bioavailability of specific polyphenol fractions, though direct comparative studies on extraction efficiency are limited. The aqueous method also avoids concerns associated with residual organic solvents in final products.

### Is Flavoxine grape seed extract safe for people taking blood thinners or antiplatelet medications?

While grape seed extracts are generally recognized as safe, Flavoxine contains high levels of procyanidins that may have mild antiplatelet properties based on preliminary research. Individuals taking warfarin, aspirin, clopidogrel, or similar blood-thinning medications should consult their healthcare provider before supplementing, as potential additive effects have not been thoroughly studied in human trials. Medical supervision is recommended to monitor for any increased bleeding risk.

### What does current research reveal about the limitations of Flavoxine's studied health benefits?

Most evidence for Flavoxine's antidiabetic, anti-inflammatory, and antioxidant effects comes exclusively from in vitro (test tube) and laboratory cell studies, with minimal human clinical trial data available. The antioxidant superoxide radical scavenging activity and anticancer potential shown in cell culture models have not been validated in human subjects, meaning real-world effectiveness remains unproven. Any health claims based on this ingredient should be viewed as preliminary until robust clinical trials are completed.

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