Palythine

Palythine is a type of mycosporine-like amino acid (MAA), a natural compound commonly found in marine organisms such as algae, corals, and some fish. These compounds are produced in response to ultraviolet (UV) radiation and serve as a form of UV protection. MAAs, including palythine, absorb UV light and protect marine organisms from the harmful effects of solar radiation, acting as natural sunscreens.

Palythine specifically has a high capacity to absorb UV-A radiation (320–400 nm), which makes it a valuable antioxidant. This UV-absorbing property has attracted interest in skincare and cosmetic industries, where it is being explored as a potential natural ingredient for sunscreens. In addition to UV protection, palythine has antioxidant properties that help neutralize free radicals, further reducing oxidative stress on cells.

Synthesis in Algae

Palythine, like other mycosporine-like amino acids (MAAs), is synthesized in algae through a specific biosynthetic pathway that is primarily triggered by exposure to ultraviolet (UV) radiation. The basic outline of synthesis is described here and it is true to say that biochemical synthesis is much more complex.

1. UV Exposure as a Trigger

Algae produce palythine and other MAAs in response to environmental stress, particularly UV radiation. When algae are exposed to sunlight, the increase in UV levels stimulates the production of MAAs, which act as natural sunscreens, protecting the algae from UV-induced damage.

2. Biosynthetic Pathway

The production of palythine involves the shikimate pathway, a series of biochemical reactions that are crucial in synthesizing aromatic amino acids and other secondary metabolites in plants and microorganisms, including algae. In this pathway:

• Precursors: The biosynthesis of palythine begins with simple organic compounds such as sedoheptulose-7-phosphate (a carbohydrate metabolite) and other intermediates from the shikimate pathway.
• Enzymatic Reactions: Specific enzymes catalyze the conversion of these precursors into intermediates like 4-deoxygadusol. Further enzymatic modifications convert these intermediates into various mycosporine-like amino acids, including palythine.

3. UV Absorbing Structure

The final product, palythine, contains a unique molecular structure that absorbs UV-A radiation, protecting the algae’s cellular components like DNA, proteins, and lipids from UV damage.

4. Regulation

The production of palythine is regulated by environmental factors such as light intensity and UV exposure. In environments with higher levels of UV radiation, algae tend to produce more palythine to increase their protection.

5. Storage in Cells

Once synthesized, palythine is accumulated in the cytoplasm or other cellular structures of the algae, where it functions as a UV filter, absorbing harmful radiation and preventing oxidative damage to the cells.

This natural UV protection mechanism is why algae thrive even in environments with intense sunlight, such as shallow waters and tidal zones.

Use In Cosmetics

Palythine is considered a promising ingredient for UV protection in cosmetics due to several advantages over conventional synthetic ingredients. Here’s why it might be better:

1. Natural Origin and Biocompatibility

Palythine is a naturally occurring compound produced by marine organisms, making it more biocompatible and less likely to cause irritation or allergic reactions compared to synthetic UV filters. Many synthetic sunscreens can be harsh on sensitive skin, whereas palythine’s natural origin might offer a gentler alternative.

2. Broad-Spectrum UV Protection

Palythine has the ability to absorb UV-A radiation (320–400 nm), which penetrates deeper into the skin and is primarily responsible for skin aging, oxidative damage, and the risk of skin cancer. Conventional sunscreens often focus on UV-B protection (280–320 nm), but the broad-spectrum coverage of palythine offers comprehensive protection.

3. Photostability

One of the common issues with synthetic UV filters is photodegradation, where exposure to sunlight can reduce their effectiveness over time. Palythine is highly photostable, meaning it retains its UV-protective properties even after prolonged sun exposure, making it a more reliable long-term protector.

4. Antioxidant Properties

In addition to absorbing UV radiation, palythine has strong antioxidant properties. It neutralizes free radicals generated by UV exposure, which helps protect the skin from oxidative stress and inflammation. Many synthetic UV filters don’t have this dual function of both blocking UV light and scavenging harmful free radicals.

5. Eco-friendliness

Many conventional sunscreen ingredients, such as oxybenzone and octinoxate, have been linked to environmental concerns, particularly coral bleaching and marine ecosystem damage. Since palythine is derived from marine organisms and is biodegradable, it is a more environmentally friendly alternative. Using palythine in cosmetics could help reduce the ecological impact of sunscreens on marine life.

6. Gentleness for Daily Use

Palythine’s natural structure and antioxidant benefits make it well-suited for daily skincare products, not just as a sunscreen. Synthetic UV filters can be drying or irritating, while palythine’s protective and hydrating effects could offer daily UV protection without compromising skin health.

7. Non-toxic to Humans and Marine Life

Many synthetic sunscreen ingredients have been flagged for potential endocrine-disrupting effects and other health concerns. Palythine, being a naturally evolved UV protector in marine life, is unlikely to carry these risks and is seen as non-toxic to both humans and marine ecosystems.

For these reasons, palythine could offer a safer, more effective, and environmentally responsible option for UV protection in cosmetics.

Its discovery in marine life underscores the potential for natural substances to be used in biotechnology and health products.