Petunidin

Petunidin at a Glance

Petunidin is a purple-blue anthocyanidin — one of the six common dietary anthocyanidin pigments, and structurally the 3’-O-methyl ether of delphinidin. It colors grapes, bilberries, blueberries and many other dark fruits, where, like all anthocyanidins, it occurs almost entirely as glycosides (sugar-bearing anthocyanins, chiefly petunidin-3-glucoside) rather than as the free aglycone.

The single most important thing to know is that petunidin as a free molecule is largely a paper entity in the body. Like its parent delphinidin and its relative cyanidin, the aglycone is chemically unstable at physiological pH and poorly bioavailable, so nearly every “petunidin” finding is really about its glycoside, an anthocyanin mixture (berry or grape extract), or the wider anthocyanin class — not the isolated pigment. Isolate-specific data are minimal.

Its documented properties are the ones shared across the anthocyanin family: antioxidant radical scavenging in the test tube, with a scattering of preclinical signals (antiglycation, bone-cell effects). None of this rests on human outcome trials of petunidin itself.

Petunidin in the Anthocyanidin Series

The six common anthocyanidins differ only in the substitution pattern of their B-ring, and petunidin sits at a specific rung of that ladder. Starting from delphinidin, which carries three hydroxyl groups on the B-ring (3’, 4’, 5’), progressive O-methylation of those meta hydroxyls generates the methylated pigments:

• Delphinidin — 3’,4’,5’-trihydroxy (no methylation); blue-purple.
• Petunidin — one hydroxyl methylated (3’-O-methyl, 4’-OH, 5’-OH); purple-blue. This is petunidin.
• Malvidin — two hydroxyls methylated (3’,5’-di-O-methyl, 4’-OH); the dominant blue-red pigment of red grapes and wine.

So petunidin is the single-methyl intermediate between delphinidin and malvidin. The parallel branch runs from cyanidin (3’,4’-dihydroxy) to peonidin (3’-O-methyl cyanidin), and pelargonidin (4’-hydroxy only) completes the six. Because methylation removes a free hydroxyl, it tends to modestly lower direct antioxidant capacity but improve pigment stability and color — the anthocyanin B-ring antioxidant activity rises with the number of free hydroxyls, so petunidin scavenges somewhat less avidly than delphinidin but more than the doubly-methylated malvidin ^{1Reference 1Kähkönen MP · 2003Antioxidant activity of anthocyanins and their aglyconsView study →}.

That last sentence needs a qualification the hydroxyl count alone does not give. When 15 purified bilberry anthocyanins were ranked side by side against two separate oxidants, petunidin placed second only to delphinidin against superoxide — ahead of both malvidin and the unmethylated cyanidin — and level with cyanidin against peroxynitrite ^{8Reference 8Rahman MM et al. · 2006In vitroSuperoxide radical- and peroxynitrite-scavenging activity of anthocyanins; structure-activity relationship and their synergism — in vitroView study →}:

Radical	Potency order (most → least)
Superoxide (O₂⁻)	delphinidin > petunidin > malvidin ≈ cyanidin > (+)-catechin > peonidin > pelargonidin
Peroxynitrite (ONOO⁻)	delphinidin > cyanidin ≈ petunidin > malvidin ≈ (+)-catechin > peonidin > pelargonidin

The reason petunidin ranks higher than “one methyl group down from delphinidin” implies is which hydroxyl it lost. Methylation of the 4’-hydroxyl is what markedly reduces activity in this series, and petunidin’s methyl sits at 3’; its 4’-OH is intact ^{8Reference 8Rahman MM et al. · 2006In vitroSuperoxide radical- and peroxynitrite-scavenging activity of anthocyanins; structure-activity relationship and their synergism — in vitroView study →}. So the cost of that first methylation is modest, and petunidin keeps most of the parent’s scavenging power. The same study found that the aglycone structure mattered more than the attached sugar, and that the pigments assayed as a mixture scavenged synergistically — more than their individual activities predicted ^{8Reference 8Rahman MM et al. · 2006In vitroSuperoxide radical- and peroxynitrite-scavenging activity of anthocyanins; structure-activity relationship and their synergism — in vitroView study →}. A berry supplies the assortment, not the leader.

In nature petunidin is a characteristic, if usually minor pigment of dark berries and red grapes — bilberry, blueberry, bog bilberry, chokeberry and Vitis vinifera — where it and its glycosides co-occur with the delphinidin- and malvidin-type pigments ^{4,5Reference 4Fraisse D et al. · 2020Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assaysView study →Reference 5Ichiyanagi T et al. · 2000Comparison of anthocyanin distribution in different blueberry sources by capillary zone electrophoresisView study →}. It takes its name from the ornamental petunia, whose flowers carry petunidin-based pigments.

What It's Used For

Petunidin’s pharmacology is best read as anthocyanin-class pharmacology, because the isolated aglycone is rarely the thing tested. The evidence splits by whether the study used petunidin itself, its glycoside, or a whole berry/grape mixture — and almost none of it is human.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Petunidin has essentially no isolated human data, so scores stay low by design; read each row’s basis.

01Antioxidant (property)Shaky42%Cell-free / computational; second in the series against superoxide ^{1,2,8Reference 1Kähkönen MP · 2003Antioxidant activity of anthocyanins and their aglyconsView study →Reference 2Rajan VK et al. · 2019A computational exploration into the structure, antioxidant capacity, toxicity and drug-like activity of the anthocyanidin “Petunidin”View study →Reference 8Rahman MM et al. · 2006In vitroSuperoxide radical- and peroxynitrite-scavenging activity of anthocyanins; structure-activity relationship and their synergism — in vitroView study →}

02Antiglycation (glycoside)Shaky24%Petunidin-3-glucoside, bilberry HPLC assay ^{4Reference 4Fraisse D et al. · 2020Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assaysView study →}

03Bone / osteoblast (isolate)Shaky22%One cell + ovariectomised-mouse study of the aglycone ^{3Reference 3Nagaoka M et al. · 2019Petunidin, a B-ring 5’-O-methylated derivative of delphinidin, stimulates osteoblastogenesis and reduces sRANKL-induced bone lossView study →}

04Anticancer (class)Shaky18%Anthocyanin mixtures/extracts, not the isolate ^{7Reference 7Wang LS · 2008Anthocyanins and their role in cancer preventionView study →}

Mechanisms

Every row except the bone study reflects the anthocyanin class rather than petunidin tested as an isolate; the methylation of one B-ring hydroxyl is what distinguishes petunidin’s chemistry from delphinidin’s.

Pharmacokinetics

Petunidin shares the anthocyanin family’s defining liability: poor bioavailability and chemical instability. Intact anthocyanins circulate at nanomolar levels in humans, with most of an ingested dose recovered as downstream phenolic-acid and conjugated metabolites rather than the parent pigment ^{6Reference 6de Ferrars RM et al. · 2014The pharmacokinetics of anthocyanins and their metabolites in humansView study →}. The free aglycone is unstable at neutral pH — the colored flavylium cation opens to colorless carbinol and chalcone forms — so petunidin barely exists as such in plasma; it is a transient deglycosylation/breakdown species. Its 3’-O-methyl, 4’,5’-dihydroxy B-ring degrades to methylated phenolic acids, paralleling how cyanidin yields protocatechuic acid and delphinidin yields gallic-acid-type fragments. As with the class, much of any bioactivity attributed to “petunidin” may in practice belong to these metabolites ^{6Reference 6de Ferrars RM et al. · 2014The pharmacokinetics of anthocyanins and their metabolites in humansView study →}. Where those losses occur has been mapped in bilberry specifically: in healthy volunteers and ileostomists, about 30% of ingested anthocyanins survived the 8-hour passage through the upper intestine, mostly intact anthocyanins were absorbed from the small intestine, circulation was dominated by glucuronides, and subjects with an intact colon carried substantially more anthocyanins and degradants than those without — so the colon is a significant absorption site, not only a site of destruction ^{9Reference 9Mueller D et al. · 2017Clinical trialHuman intervention study to investigate the intestinal accessibility and bioavailability of anthocyanins from bilberries — human volunteersView study →}. Formulation moves those numbers: whey-protein encapsulation modulated short-term bioavailability, and citrus-pectin encapsulation raised small-intestinal accessibility and altered plasma formation of the degradant phloroglucinol aldehyde ^{10Reference 10Mueller D et al. · 2018Clinical trialEncapsulation of anthocyanins from bilberries — effects on bioavailability and intestinal accessibility in humans — clinical trialView study →}.

Clinical Trials

There are no clinical trials of isolated petunidin — its instability makes that impractical. Human data touching petunidin are anthocyanin pharmacokinetic studies ^{6,9,10Reference 6de Ferrars RM et al. · 2014The pharmacokinetics of anthocyanins and their metabolites in humansView study →Reference 9Mueller D et al. · 2017Clinical trialHuman intervention study to investigate the intestinal accessibility and bioavailability of anthocyanins from bilberries — human volunteersView study →Reference 10Mueller D et al. · 2018Clinical trialEncapsulation of anthocyanins from bilberries — effects on bioavailability and intestinal accessibility in humans — clinical trialView study →} or berry/grape mixture trials in which it is one pigment among many. All human evidence should be attributed to anthocyanin mixtures or glycosides, never to the isolated aglycone.

Last checked: July 2026.

Prevalence in Nature

Petunidin occurs across dark berries and red grapes, almost always as its glycosides rather than the free aglycone. It is a characteristic pigment of bilberry (Vaccinium myrtillus), blueberry (Vaccinium spp.), bog bilberry (Vaccinium uliginosum) and chokeberry, and of red grapes (Vitis vinifera) and red wine, where petunidin-3-glucoside co-occurs with the delphinidin- and malvidin-type pigments ^{4,5Reference 4Fraisse D et al. · 2020Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assaysView study →Reference 5Ichiyanagi T et al. · 2000Comparison of anthocyanin distribution in different blueberry sources by capillary zone electrophoresisView study →}. Different berry sources carry their own anthocyanin fingerprints — the relative amount of petunidin versus the other five anthocyanidins varies by species, cultivar, ripeness and growing conditions, which is why anthocyanin profiling is used for berry quality control ^{5Reference 5Ichiyanagi T et al. · 2000Comparison of anthocyanin distribution in different blueberry sources by capillary zone electrophoresisView study →}. It also gives its name to, and colors, the ornamental petunia.

Major Natural Sources

Source (botanical)	Part	Form present	Notes
Grape (Vitis vinifera)	Skin / fruit	Petunidin-3-glucoside	Co-pigment with malvidin/delphinidin in red grapes & wine
Bilberry (Vaccinium myrtillus)	Fruit	Petunidin-3-glucoside/-galactoside/-arabinoside	One of the effective antiglycoxidant anthocyanins 4Reference 4Fraisse D et al. · 2020Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assaysView study →
Blueberry (Vaccinium spp.)	Fruit	Petunidin glycosides	Profile varies by source/cultivar 5Reference 5Ichiyanagi T et al. · 2000Comparison of anthocyanin distribution in different blueberry sources by capillary zone electrophoresisView study →
Bog bilberry (Vaccinium uliginosum)	Fruit	Petunidin-3-glucoside	A predominant pigment in bog-bilberry products
Petunia (Petunia spp.)	Flower	Petunidin-based anthocyanins	Namesake ornamental source

Quantitative, same-unit petunidin figures across these sources are not well documented — the holes are tracked in this compound’s gaps note rather than guessed at here.

Discovery & Synthesis

Petunidin is one of the six long-recognised common anthocyanidins of the classical plant-pigment chemistry established across the early twentieth century; it takes its name from the petunia (Petunia), in whose flowers its pigments occur. A precise first-isolation date and worker for the aglycone are not cleanly documented in the accessible literature (logged as a gap). It is isolated and handled as the stable petunidin chloride salt.

Manufacture today is not by dedicated synthesis of the aglycone. Petunidin reaches people almost entirely as its glycosides within whole foods and berry/grape extracts; for research, petunidin-3-O-glucoside has been prepared by optimized semi-synthesis from delphinidin-type precursors, but the free aglycone is not a commercial standalone ingredient because of its instability. There is no established total-synthesis or fermentation route in routine commercial use for the isolated pigment.

Patents: not yet researched.

Toxicity & Safety

Petunidin and its glycosides are ubiquitous dietary pigments, eaten routinely in blueberries, bilberries, grapes, red wine and other dark-colored fruits, and are regarded as low in toxicity at ordinary dietary levels. A computational toxicity profile of the isolated aglycone predicted low toxicity and drug-like properties ^{2Reference 2Rajan VK et al. · 2019A computational exploration into the structure, antioxidant capacity, toxicity and drug-like activity of the anthocyanidin “Petunidin”View study →}, consistent with the anthocyanin class’s food-safe track record.

Safety at a Glance

✅ Low / no toxicity

• Ordinary dietary pigment. Consumed in berries, grapes and red wine with no significant toxicity at food levels; anthocyanin/berry supplements are well tolerated in trials above dietary intake.
• Not a characterised standalone supplement. The isolated aglycone is unstable and not sold or dosed on its own; safety data are class-level, not petunidin-specific.
• No isolate human safety dataset. Drug interactions, and reproductive/developmental effects of the pure molecule, have not been formally assessed; the poor systemic bioavailability limits, but does not itself establish, systemic safety.

There are no established drug interactions for isolated petunidin. Theoretical additive antioxidant or mild antiplatelet effects from anthocyanin-rich intake are unconfirmed, and the pigment’s poor systemic bioavailability further limits any systemic-toxicity concern. As with the other plant anthocyanidins, any reproductive or developmental caution is a per-food / per-supplement decision made where intake is decided, not a property established for this molecule — no dedicated isolate reproductive-toxicity dataset exists for petunidin.

Dosage

There is no established dose for isolated petunidin — it is not used as a standalone supplement and is chemically unstable. For research context only (mixture/glycoside figures, not aglycone dosing, and not a recommendation): human exposure is dietary, as petunidin glycosides within anthocyanin-rich foods; bilberry fruit carries roughly 300–700 mg total anthocyanins per 100 g fresh weight (of which petunidin is one of several pigments) ^{4Reference 4Fraisse D et al. · 2020Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assaysView study →}, and typical Western dietary anthocyanin intake is on the order of ~200 mg/day across all pigments ^{6Reference 6de Ferrars RM et al. · 2014The pharmacokinetics of anthocyanins and their metabolites in humansView study →}. These are research and dietary figures, not a personal recommendation.

References

1. Kähkönen MP, Heinonen M (2003). Antioxidant activity of anthocyanins and their aglycons. Journal of Agricultural and Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/12537433/
2. Rajan VK, Ragi C, Muraleedharan K (2019). A computational exploration into the structure, antioxidant capacity, toxicity and drug-like activity of the anthocyanidin “Petunidin”. Heliyon. https://pubmed.ncbi.nlm.nih.gov/32346622/
3. Nagaoka M, et al. (2019). Petunidin, a B-ring 5’-O-methylated derivative of delphinidin, stimulates osteoblastogenesis and reduces sRANKL-induced bone loss. International Journal of Molecular Sciences. https://pubmed.ncbi.nlm.nih.gov/31181661/
4. Fraisse D, et al. (2020). Screening and characterization of antiglycoxidant anthocyanins from Vaccinium myrtillus fruit using DPPH and methylglyoxal pre-column HPLC assays. Antioxidants (Basel). https://pubmed.ncbi.nlm.nih.gov/32532151/
5. Ichiyanagi T, et al. (2000). Comparison of anthocyanin distribution in different blueberry sources by capillary zone electrophoresis. Biological & Pharmaceutical Bulletin. https://pubmed.ncbi.nlm.nih.gov/10784434/
6. de Ferrars RM, et al. (2014). The pharmacokinetics of anthocyanins and their metabolites in humans. British Journal of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/24602005/
7. Wang LS, Stoner GD (2008). Anthocyanins and their role in cancer prevention. Cancer Letters. https://pubmed.ncbi.nlm.nih.gov/18571839/
8. Rahman MM, Ichiyanagi T, Komiyama T, et al. (2006). Superoxide radical- and peroxynitrite-scavenging activity of anthocyanins; structure-activity relationship and their synergism — in vitro. Free Radical Research. https://pubmed.ncbi.nlm.nih.gov/17015281/
9. Mueller D, Jung K, Winter M, et al. (2017). Human intervention study to investigate the intestinal accessibility and bioavailability of anthocyanins from bilberries — human volunteers. Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/28450007/
10. Mueller D, Jung K, Winter M, et al. (2018). Encapsulation of anthocyanins from bilberries — effects on bioavailability and intestinal accessibility in humans — clinical trial. Food Chemistry. https://pubmed.ncbi.nlm.nih.gov/29329847/

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