The Magic of Melanin

 by Bianka Anszczak

I’m sure that by now, we have all heard of the word ‘Melanin’, but what is it? And is it responsible for more than just a suntan?

 ‘Beauty is only skin deep’, yet, for the biological compound melanin, it is quite literally the case.

Melanin is formed in melanosomes which are located melanocytes, found in the skin’s epidermis. This starshaped cell’s main purpose is to act as a natural sunscreen and protect you from harmful UV rays. The more melanin you have, the more protected you are from the sun’s rays. This explains why, at the equator, where the suns rays are strongest, natives have adapted to produce more melanin, resulting in a darker skin tone. Whereas people who live furtherer from the equator, where sunlight is less concentrated, produce less melanocytes, resulting in a lighter skin tone.

Now we know too much UV radiation is damaging, but too little is also damaging. UV light, is in fact an important source of vitamin D. By having a lighter skin tone, people who don’t have enough sunlight are still able to absorb vitamin D, without damaging their skin. Likewise, people who have access to more sunlight and have darker skin tones, can protect their skin, whilst still having lots of access to vitamin D.

 So how does melanin protect us?

For melanocytes to work, melanosomes must first turn tyrosine (an aromatic amino acid) into melanin. The melanosomes containing melanin, must then be transported into keratinocytes – which form the surface of the skin and are at the front line when taking insults from the environment. Melanosomes then surround the nucleus, preventing harmful UV rays from reaching the DNA inside. This is important, as too much UV radiation can cause mutations to the cell’s DNA, forming growths, known as cancer.

For many years, it was thought that melanin is an inbuilt sunscreen, but now researchers think that this may be an overly simplistic explanation. This is due to the structure of melanin, which is rich in carbon rings. So not only does its structure provide very good UV protection, but it’s also ideal for clearing up free radicals and other toxic molecules. Therefore, scientists now believe that perhaps, it plays a more general role, in maintaining the general health of the skin.

A different type of melanin called neuromelanin, is also found in the brain, in a region called, ‘substantia nigra’ which translates to ‘dark matter’. It is believed that the neurodegenerative condition, Parkinson’s disease is caused because of the ongoing death of brain cells in this area. This loss of cells, results in a loss of neuromelanin and its protective effects, and so, possibly linking it to the condition. The pigment is also found in the inner ear, but unfortunately it is still a mystery to why it is located there.

Now what’s even more amazing, is that melanin is found everywhere on the planet, and we are not the only species to have adapted to its production. Melanin gives colour to animal fur, bird feathers, fish scales and butterfly wings. Even the shimmering sheen on the shells of insets such as beetles, is due to this magical, biological compound. What’s more, is that melanin can determine the infectiousness of certain moulds, and therefore contributes to the ability of fungi surviving in harsh environments.

However, by far the most ‘ink-redible’, is cephalopod ink. When threatened by predators, cephalopods produce a dark, blue-black liquid to help act as a smokescreen and irritant - interfering with a predator’s sensory organs - allowing enough time for them to escape.

Melanin is ‘mother nature’s paint’ and something we should all be proud of.

Yet although it has UV protective properties, slowing down signs of aging, it is no excuse to stop wearing sunscreen!