What are Anthocyanins?

Anthocyanins are organic pigments found in the vacuole (cell) of some plants and flowers. They are part of the flavonoid group of phytochemicals (active compounds found in plants) that play an important function for the plant’s reproduction and survival. They give plants, fruits and vegetables, their bright red pink, blue and purple colour. (Khoo et al, 2013) The name is derived from greek anthos, a flower, and kyanos, dark blue. (Delgado-Vargas et al, 2000)

Pollinators such as bees, butterflies, wasps and moths are attracted to their bright colours and help pollinate the plants. They also provide two further functions relating to their protection and reproduction; on the one hand their bright colours can repel some herbivores and on the other, attract them. Those that eat the fruits, will spread the seeds far and wide, aiding germination and new seedlings.

Anthocyanins are also thought to protect plants from oxidative stress, as well as protect the green leaves from light degradation caused by some types of sun rays. (Khoo et al, 2013)

Anthocyanins and Human Health

When ingested, anthocyanins are considered by some to be beneficial to humans; they are thought to be powerful antioxidant and free radical scavengers. Some research suggests they may be able to prevent heart disease, age related cognitive disease and some cancers.(Wang et al, 2008, Khoo et al 2013)

In addition to coloring property, anthocyanin extracts may act as quality control marker for foodstuffs; improve the nutritional quality of foods and beverages, possibly play an important role in reducing the risk of coronary heart disease, cancer, and stroke. (Mansour et al, 2018)

Anthocyanins and the Skin

Sun exposure is widely believed to be the main contributor to extrinsic skin ageing and finding natural ingredients that can help protect the skin from UVA and UVB radiation has been a hot topic. Anthocyanins are thought to be natural sun protectants as well as having antioxidant and anti-inflammatory properties.

There have been a variety of studies that suggest anthocyanins have the potential to protect the skin from UV damage. One in vitro study showed that a concentration of 0.61mg/100 g of sweet potato anthocyanins in a cream absorbed up to 46% of UV radiation. Though this was a purely chemical based study, it did suggest that topical use of anthocyanins at a low dose may prevent UV skin damage by lowering the amount of UVB radiation getting to the epidermis. Similarly, another study, this time on reconstituted human skin, showed that pomegranate derived extracts and juices rich in anthocyanins prevented UVB-induced damage to the dermis. It is important to note with this study, it is uncertain whether the protection came from the anthocyanins, other flavonoids or their combinations. From the literature, it seems that a lot more work needs to be done, but the consensus is that anthocyanins may be an effective alternative to current sun protection ingredients.

Fruits and Vegetables with the Highest Levels of Anthocyanins?

You can normally tell if a fruit is high in anthocyanins by its colour. If they are black, blue, bright red, pink and violet, you can be certain it contains high levels of anthocyanins. This is a short list of fruit containing the highest levels of anthocyanins: Black raspberries, Blackcurrants, Blueberries, Blackberries, Red cabbage, Black plums, Red radish, Red raspberries, Sweet potato, Beetroot.

Formulating with Anthocyanins

pH plays an important factor in determining the final colour of the anthocyanin and of the final colour of your natural skincare product. They tend to be pink at a lower pH and purple at a higher one (Khoo et al, 2013)

Anthocyanins can be used to give colour ranging from purple to red. Their colour and stability is largely related to the type of cosmetic formulation; whether it is water based or anhydrous.

In a water-based product the pH of the final formulation will be a factor in deciding how stable it is; depending on the type of anthocyanin, the formula should not be higher than 4-4.5 or the colour will likely morph or fade (Delgado-Vargas et al 2000) One piece of literature pertaining to the textile industry, suggested that, ‘Chelation between anthocyanin and metal cation can increase stability as well.’ (Mansour et al, 2018)

If you are using anthocyanins in an anhydrous product such as a balm it is it is important to use one that is processed as this will be pre-stabilised to the correct pH, normally with an acid. If using it in a more solid product like a balm, it will need to be suspended, so add it when the product starts to gel.

How your product is packaged will also govern how long the colour stays true. I have seen a big difference in colour fastness depending on the type of packaging used i.e. the colour of a balm in a clear glass jar faded whereas the same sample in violet miron and amber jars did not.

Anthocyanins have been studied in great detail in the food and textile industry and are accepted as not being particularly heat, light and pH stable, and are prone to oxygen degradation. However, not all anthocyanins are created equally; anthocyanins from some sources are more stable than others. I have read that, because of their chemical structure, anthocyanins from vegetables tend to be more colour stable than those from fruit (Delgado-Vargas, 2000). I am not sure how true this is as I haven’t tested them all to see but if you are working with anthocyanins and you run into problems this might be the reason why.

Using Anthocyanins in Skincare

What are Anthocyanins?

Anthocyanins and Human Health

Anthocyanins and the Skin

Fruits and Vegetables with the Highest Levels of Anthocyanins?

Formulating with Anthocyanins

Further Reading