What is the iron chelation capacity of black raisin seed?

Laboratory studies show black raisin seed has an iron chelation capacity of up to 261.12 mg EDTAE/100 mL. This measurement indicates the seed's ability to bind iron ions, potentially reducing oxidative stress caused by free iron in biological systems.

What polyphenolic compounds are found in black raisin seed?

Black raisin seed contains various polyphenolic compounds, with oleanolic acid being a key bioactive component. These polyphenolic compounds are responsible for the seed's antioxidant and antimicrobial properties demonstrated in laboratory studies.

Are there any human studies on black raisin seed benefits?

No human clinical trials have been conducted on black raisin seed supplements. All current evidence comes from in vitro laboratory studies examining antioxidant activity and antimicrobial effects in controlled laboratory conditions.

How does black raisin seed compare to grape seed extract?

Both black raisin seed and grape seed come from Vitis vinifera and contain similar polyphenolic compounds. However, grape seed extract has extensive human research while black raisin seed evidence remains limited to preliminary laboratory studies.

What antimicrobial effects does black raisin seed have?

Laboratory extract studies demonstrate antimicrobial effects against various bacterial strains, likely through polyphenolic compounds disrupting bacterial cell membranes. However, these effects have only been observed in controlled laboratory conditions, not in human infections or clinical settings.

What is the bioavailability of polyphenols in black raisin seed, and does processing affect extraction?

Black raisin seed polyphenols, including oleanolic acid, show variable bioavailability depending on extraction method, with solvent-based extracts demonstrating higher in vitro antioxidant activity than whole seed preparations. Processing techniques such as fermentation or enzymatic treatment may enhance polyphenol release, though human absorption studies are currently lacking. The lipid matrix of the seed (containing 5-8% linoleic acid and 3-6% oleic acid) may influence bioavailability of fat-soluble phenolic compounds.

Can black raisin seed be safely used alongside blood thinners or iron supplements?

Black raisin seed's iron chelation capacity (up to 261.12 mg EDTAE/100 mL in laboratory studies) suggests potential interactions with iron supplementation or iron-dependent medications, though no human interaction studies have been conducted. The polyphenolic content may theoretically enhance anticoagulant effects in individuals taking blood thinners, warranting caution and medical consultation. Individuals on these medications should consult healthcare providers before supplementation.

Who would benefit most from black raisin seed supplementation based on current evidence?

Current evidence is limited to in vitro and animal studies, making it difficult to identify specific populations that would benefit; however, individuals seeking antioxidant support from natural seed sources may consider it as a dietary component. Those interested in polyphenol intake from food sources rather than isolated extracts represent a logical target population. Until human clinical trials are conducted, supplementation recommendations remain speculative and should be individualized by healthcare practitioners.

Black Raisin Seed (Vitis vinifera)

Black raisin seed (Vitis vinifera) contains polyphenolic compounds including oleanolic acid that demonstrate antioxidant and antimicrobial properties. The seeds exhibit DPPH radical scavenging activity and iron chelation capacity of up to 261.12 mg EDTAE/100 mL in laboratory studies.

Category: Seed Evidence: 2/10 Tier: Emerging

Black Raisin Seed (Vitis vinifera) — Hermetica Encyclopedia

Origin & History

Black raisin seed derives from dried black grapes of Vitis vinifera, a woody vine native to the Mediterranean region and cultivated globally. The seeds are extracted using methanol reflux followed by solvent fractionation to isolate compounds like oleanolic acid, with standardized extracts containing 92-95% oligomeric proanthocyanidins.

Historical & Cultural Context

The research provides no specific historical context or traditional medicine use for black raisin seeds. General Vitis vinifera polyphenols are noted for health-promoting benefits, but without detailing traditional applications or duration of use.

Health Benefits

• Antioxidant activity through DPPH radical scavenging (in vitro evidence only)
• Fe²⁺ chelation capacity up to 261.12 mg EDTAE/100 mL (laboratory studies)
• Antimicrobial effects demonstrated in extract studies (no human trials)
• Rich in polyphenolic compounds including oleanolic acid (preliminary evidence)
• Contains beneficial fatty acids including linoleic (5-8%) and oleic (3-6%) acids (compositional analysis only)

How It Works

Black raisin seed polyphenolic compounds, particularly oleanolic acid, neutralize free radicals through DPPH radical scavenging mechanisms. The seeds demonstrate iron chelation capacity by binding Fe²⁺ ions, potentially reducing oxidative stress. Antimicrobial effects appear to involve disruption of bacterial cell membranes through phenolic compound interactions.

Scientific Research

No human clinical trials, RCTs, or meta-analyses were found specifically for black raisin seed. Available research consists solely of in vitro antioxidant activity studies, antimicrobial assays, and compositional analyses without clinical outcomes or PubMed PMIDs.

Clinical Summary

Current evidence for black raisin seed is limited to in vitro laboratory studies with no human clinical trials available. Laboratory studies demonstrate antioxidant activity through DPPH assays and quantified iron chelation capacity of 261.12 mg EDTAE/100 mL. Antimicrobial effects have been observed in extract studies against various bacterial strains. The preliminary nature of existing research means therapeutic benefits in humans remain unestablished.

Nutritional Profile

Black raisin seeds (Vitis vinifera) are predominantly composed of bioactive lipid and polyphenolic fractions. Fixed oil content ranges from 6–20% of seed dry weight, with fatty acid composition dominated by linoleic acid (omega-6, 58–78%), oleic acid (omega-9, 3–6%), palmitic acid (7–11%), stearic acid (3–6%), and minor linolenic acid (<1%). Protein content is approximately 10–13% dry weight, containing essential amino acids including arginine, leucine, and glutamic acid. Crude fiber constitutes 35–55% of seed dry weight, primarily as insoluble fiber (cellulose, hemicellulose, lignin), contributing to low digestibility of the seed matrix. Total polyphenolic content is substantial at 3,000–6,000 mg GAE/100 g dry seed, with procyanidins (oligomeric proanthocyanidins, OPCs) as the dominant class (800–2,500 mg/100 g). Identified polyphenols include catechin (~300–600 mg/100 g), epicatechin (~200–500 mg/100 g), gallic acid (~100–300 mg/100 g), epicatechin gallate, and oleanolic acid (a pentacyclic triterpenoid). Tocopherols are present primarily as alpha- and beta-tocopherol (approximately 40–120 mg/100 g oil). Mineral content includes potassium (~800–1,200 mg/100 g), calcium (~200–400 mg/100 g), magnesium (~100–200 mg/100 g), iron (~3–8 mg/100 g), phosphorus (~200–400 mg/100 g), and trace zinc and copper. Bioavailability note: polyphenol bioavailability from intact seeds is significantly limited by the tough seed coat and tannin-protein binding; ground seed or standardized extracts yield markedly higher absorption. Fe²⁺ chelation capacity measured at up to 261.12 mg EDTAE/100 mL in extract studies may reduce iron bioavailability when co-consumed with iron-rich foods.

Preparation & Dosage

No clinically studied dosage ranges have been established for black raisin seed extracts, powders, or standardized forms due to the absence of human trials. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Grape seed extract, resveratrol, quercetin, vitamin C, green tea extract

Safety & Interactions

Safety data for black raisin seed supplements is extremely limited due to lack of human studies. Potential allergic reactions may occur in individuals sensitive to grape products or related Vitaceae family plants. Drug interactions are unknown but theoretically possible with anticoagulant medications due to polyphenolic content. Pregnancy and breastfeeding safety has not been established, so avoidance is recommended during these periods.