Anthocyanin

Some plants have bright colors.

These colors can be red, pink, blue, or purple.

These colors come from tiny parts inside the plant.

You can find these colors in many foods. Blueberries and raspberries are bright. Black rice and black beans have them too.

These colors help the plants. In flowers, they draw in animals. In fruit, they help animals find food.

Colors also change in the fall. Some leaves turn red or purple then. This happens as the summer ends.

These colors can even help plants stay safe. They can help some plants stay healthy in the cold. It is a colorful way to live!

Many plants have bright colors like red, purple, or blue.

These colors come from things called anthocyanins.

Anthocyanins are tiny parts that mix with water. They can change color if the acid levels in a plant change.

You can find these colors in many foods. Blueberries, raspberries, and black rice have them.

Some plants, like purple corn, have a lot of them. Even some tomatoes are bred to be purple.

These colors help plants in many ways. In flowers, colors help draw in animals. In fruit, colors help animals find food to eat. This helps the plant spread its seeds. Anthocyanins also help plants stay safe. They can protect leaves from the cold. They can even help leaves hide from animals that want to eat them. In the fall, some leaves turn red or purple. This happens because the plant makes more anthocyanins as summer ends.

Have you ever wondered why some fruits are so brightly colored?

Many plants use special pigments called anthocyanins to create beautiful shades. These pigments can appear as red, pink, purple, blue, or even black.

They are water-soluble, which means they can dissolve in the liquid inside plant cells. These pigments are found in many different parts of a plant. You might see them in leaves, stems, roots, flowers, or fruits.

They are very important for how plants look and function in nature.

Anthocyanins work in a very specific way within the plant. They are part of a larger group of molecules called flavonoids. To make an anthocyanin, the plant starts with a structure called an anthocyanidin. Then, the plant adds sugar molecules to that structure. This process creates the final anthocyanin that we see.

These pigments live inside a small space in the cell called a vacuole. The color you see depends on the pH, or acid level, of that space. If the environment changes from acidic to basic, the color can change too.

Humans have been studying these colorful molecules for a long time. In 1835, a German pharmacist named Ludwig Clamor Marquart wrote about them. He wrote a book called Die Farben der Blüthen, which means The Colors of Flowers.

In his writing, he named a chemical that makes flowers look blue as Anthokyan. Since then, scientists have discovered hundreds of different types of these molecules. They have even found more than 550 different versions in recent years.

There are many places to find high amounts of these pigments. For example, black chokeberry has a lot of anthocyanins in its skin and pulp.

Purple corn is another great source, especially in its husks. Some foods have very high amounts, like black crowberry with 4,180 mg per 100 g. Other foods, like blueberries or raspberries, are also very rich in them.

Even some tomatoes, like the "Indigo Rose," have been bred to have more color. These special tomatoes became available to gardeners in 2012.

These colors are not just for show; they help plants survive. In flowers, bright colors attract animals to help with pollination. In fruits, colors help animals find the food so they can spread seeds.

Anthocyanins can also protect plants from extreme weather. For example, tomato plants use them to help fight cold stress. They can even help protect leaves from being eaten by hungry animals.

In the autumn, many trees produce these pigments as summer ends. This is why many leaves turn beautiful shades of red and purple.

Anthocyanins are a group of water-soluble pigments found within the vacuoles of plant cells.

These pigments are responsible for a wide spectrum of colors, including red, pink, purple, blue, and black. The specific color displayed by an anthocyanin depends on the pH level, or acidity, of its environment. This property is known as halochromism, where a substance changes color in response to pH shifts. In acidic conditions, these pigments often appear red, while they shift toward blue in more basic environments.

Because of this sensitivity, they are often used as pH indicators.

Chemically, anthocyanins belong to a larger class of molecules called flavonoids. They are synthesized through a biological process known as the phenylpropanoid pathway. To create an anthocyanin, the plant first produces a basic structure called an anthocyanidin. The plant then attaches sugar groups to this structure, turning it into an anthocyanin glycoside.

There are many different types of these molecules in nature. The most common glycosides include those derived from cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin. Scientists have identified more than 550 different types of anthocyanins.

These pigments serve several vital roles in plant physiology. In flowers, the accumulation of anthocyanins helps attract various animal pollinators. In fruits, the bright colors aid in seed dispersal by attracting herbivorous animals to edible fruit.

Anthocyanins also provide protection against environmental stress. For example, tomato plants use them to counter reactive oxygen species during cold stress, which lowers the rate of cell death in leaves. In some leaves, the red color may also protect against herbivores that are attracted to green colors.

This color can be complementary to the green light absorbed by chlorophyll.

Anthocyanins are found in many plant tissues, including leaves, stems, roots, flowers, and fruits. They are most often located in the outer cell layers, such as the epidermis and peripheral mesophyll cells. While many land plants contain them, some groups like the Caryophyllales do not. In plants like cacti and beets, anthocyanins are replaced by a different pigment called betalains. Interestingly, betalains and anthocyanins are never found in the same plant.

Humans have studied these pigments for nearly two centuries. In 1835, a German pharmacist named Ludwig Clamor Marquart published a treatise titled *Die Farben der Blüthen*, or *The Colors of Flowers*.

In this work, he named a chemical that gives flowers a blue color as "Anthokyan." Since that time, research has expanded to understand the complex chemistry of these colorful molecules.

Many foods are exceptionally rich in anthocyanins. Black crowberry contains approximately 4,180 mg per 100 g, while purple corn husks contain ten times more than the kernels.

Other notable sources include black chokeberry, wild blueberries, and black rice. Even some vegetables, like red cabbage, are high in these pigments.

In the autumn, many tree species produce anthocyanins as the seasons change. This results in the red and purple foliage seen in temperate regions.

In some areas, like New England, up to 70% of tree species may produce them.

Modern agriculture has also utilized these pigments through selective breeding. For instance, the "Indigo Rose" tomato was made available to gardeners in 2012.

High anthocyanin content in tomatoes can double their shelf-life and inhibit the growth of the mold *Botrytis cinerea*. Some scientists have even used genetic transcription factors from snapdragons to produce high levels of anthocyanins in fruit. While the European Union approves anthocyanins as food colorants under the code E163, they are not currently approved as food additives in the United States.