also: Anthocyanidin (delphinidin)
A natural blue-purple pigment extracted from berries and dark-coloured plants, used to add or restore colour in food and drink.
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Delphinidin is an anthocyanidin, the aglycone (sugar-free) form of a family of natural plant pigments called anthocyanins.
Delphinidin is an anthocyanidin, the aglycone (sugar-free) form of a family of natural plant pigments called anthocyanins. It gives blueberries, bilberries, elderberries, blackcurrants, purple corn, and aubergine skin their deep blue-purple hue. When extracted for use as a food colourant it typically appears as the glycoside form, with a sugar molecule attached. Its colour shifts with pH, turning red-purple in acidic conditions and blue in alkaline ones.
Delphinidin absorbs light in the yellow-green part of the visible spectrum, reflecting blue and purple wavelengths. Manufacturers add it to restore colour lost during heating or processing, or to give a consistent appearance to naturally variable ingredients. It is water-soluble and blends readily into beverages, dairy, and wet confectionery.
Mainly found in fruit-flavoured soft drinks, blackcurrant cordials, yogurts, ice creams, jams, fruit-flavoured sweets, and some liqueurs. On a UK ingredient list it will appear as colour (anthocyanins), colour (E163), or simply E163. The sub-designation E163b does not appear on consumer labels as UK and EU regulations use the single E163 code for all anthocyanin variants.
When the European Food Safety Authority re-evaluated anthocyanins (the broader E163 group, of which delphinidin is one member) in 2013, the panel concluded that the toxicological database was too limited to set a firm daily intake figure. They found no specific cause for concern at the amounts present in food, but noted that long-term studies on chronic toxicity, carcinogenicity, and effects on reproduction were extremely scarce. This leaves regulatory oversight relying on the principle that additive exposure is broadly comparable to ordinary dietary intake from foods naturally rich in anthocyanins.
EFSA concluded that the available toxicological data were inadequate to set a numerical ADI for E163 anthocyanins, citing major gaps in long-term chronic toxicity, carcinogenicity, and reproductive studies.
For anthocyanins extracted from sources other than grape skin or blackcurrant, or using non-aqueous methods, EFSA stated the absence of adequate characterisation meant its safety conclusion could not be confirmed.
Laboratory and animal studies have found that delphinidin can slow the growth of cancer cells and trigger cell death across a wide range of tumour types. However, the concentrations used in these experiments are hundreds to thousands of times higher than the amounts that reach the bloodstream after eating or drinking foods containing it. No human clinical trials have tested delphinidin for cancer prevention or treatment, so the cell-culture findings cannot be translated into practical health claims.
In vitro studies across multiple cancer cell lines consistently show delphinidin inducing apoptosis and inhibiting cell proliferation through PI3K/AKT, NF-kB, and MAPK pathways, but the effective concentrations used are in the micromolar range, far above realistic human plasma levels.
After oral intake, plasma delphinidin concentrations remain in the low nanomolar range, creating a large gap between the doses active in the laboratory and what the body actually absorbs from food.
Delphinidin is among the more potent antioxidants in the anthocyanin family. Cell and animal studies show it can reduce LDL oxidation, support blood vessel function, and dampen inflammatory signalling. Small human studies have examined specific concentrated extracts rather than delphinidin in isolation, and the results, while positive, cover mostly metabolic markers rather than clinical outcomes such as heart events.
Delphinidin reduces intracellular oxygen radicals and increases nitric oxide synthase expression in human endothelial cells in culture, pointing to a potential cardiovascular protective mechanism.
Delphinidin-3-glucoside inhibits platelet activation and reduces thrombus formation in animal models, suggesting anticoagulant properties at concentrations tested in vivo.
One laboratory study found delphinidin inhibits CYP3A4, an enzyme responsible for metabolising around half of all prescription drugs, by over 90% at a concentration of 100 micromolar. The concentration needed to produce meaningful inhibition in the lab is many times higher than what reaches the bloodstream after eating, so scientists currently consider clinically significant drug interactions from normal food intake unlikely.
Delphinidin inhibits CYP3A4 by more than 90% at 100 micromolar (IC50 approximately 32 micromolar) in human liver microsome preparations, but dietary exposure concentrations are considerably lower than those required for significant inhibition in vivo.
Delphinidin is poorly absorbed from the gut. Oral bioavailability of some glycoside forms is below 0.5%. Gut bacteria help break down the glycoside into the active aglycone, but the process is variable between individuals. The compound is also unstable at neutral to alkaline pH, degrading into gallic acid and other breakdown products. This limits how much of what you eat or drink actually reaches target tissues.
Oral bioavailability of delphinidin-3-rutinoside is approximately 0.49% in pharmacokinetic studies; peak plasma concentration occurs around two hours after ingestion.
No specific at-risk group has been identified by UK or EU regulators. People who observe Jewish dietary laws (kashrut) should be aware that some anthocyanin extracts are derived from grape products and may not be kosher certified without specific verification. Look for colour (E163) or colour (anthocyanins) on the label.
Delphinidin is an ordinary natural pigment that has been part of the human diet through berries, grapes, and dark vegetables for millennia. Its long dietary history is the foundation of the regulatory view that it presents no particular concern at additive-level doses. The honest caveat is that the formal toxicology file is thin: EFSA in 2013 could not set a daily intake number because the long-term studies simply had not been done. The research attention delphinidin currently attracts is largely about its potential benefits rather than any harm, with laboratory results suggesting antioxidant and anticancer properties that, so far, have not been demonstrated in human trials at the concentrations achievable through normal eating. The science here is active and early.
No. Delphinidin (E163b) is an approved food colour in the UK under the assimilated EU Regulation 1333/2008, authorised at quantum satis within the E163 anthocyanins group.
When EFSA reviewed anthocyanins in 2013 it found the existing toxicological studies too limited to calculate a numerical acceptable daily intake. It identified data gaps in long-term chronic toxicity, carcinogenicity, and reproductive studies. This does not mean a concern was found; it means the formal evidence base was considered incomplete.
Delphinidin as E163 can appear in fruit-flavoured soft drinks, blackcurrant cordials, yogurts, ice creams, jams, fruit-flavoured sweets, and some liqueurs. On the label it will read as colour (E163) or colour (anthocyanins), not as E163b specifically.
Yes, anthocyanins including delphinidin are extracted entirely from plant sources such as berries, red cabbage, grapes, and black carrots. They are suitable for vegans and vegetarians. People who observe Jewish dietary laws should check whether the specific product uses grape-derived extract, as this may require kosher certification.
Last reviewed: 20 June 2026
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