Oxygen, now 21% of the air, is a relatively newcomer to the atmosphere that started accumulating with the development of photosynthesis a few billions of years ago. Respiration, which uses oxygen as the final electron acceptor, is a process that oxidizes organic matter through a series of complex electron transport, extracting most of the energy stored in sugars, amino acids, etc. Increased oxygen concentration in the atmosphere made possible the huge increase in energy extraction provided by respiration, and is a great advantage to life forms that can use oxygen, but it also brings disadvantages.
Reactive oxygen species (ROS) are free radicals that contain the oxygen atom and are highly reactive and can be very destructive. ROS are formed as a byproduct of respiration and other life processes and by external agents, like ultraviolet radiation. Living beings that survived the rise in oxygen concentration (from nothing to 21%) have evolved numerous anti-oxidant mechanisms to disarm ROS. Some antioxidants are obtained from the diet, like vitamin C, vitamin E, carotenoids, and polyphenols; and others are produced by our bodies like glutathione and thioredoxin. Antioxidant enzymes, like superoxide dismutases and glutathione peroxidases, are also required.
Insufficient or unsuitable antioxidants may lead to oxidative stress and the consequent oxidation of membrane lipids, damage to DNA, proteins, etc. Oxidative stress is partly responsible from a great number of age-related diseases as cancer, cardiovascular disorders, and neurodegenerative diseases as Alzheimer’s disease.
Damage by free radicals formed in response to ultraviolet (UV) light is now believed to be a major cause of skin aging, with the term "photo-aging" being used to describe the multitude of effects of sunlight on the skin, including wrinkles, changes in the matrix proteins elastin and collagen, “age” spots (also called sun spots) and an increase in the incidence of skin cancer.
When ROS reach our scalp there are enzymes ready to disarm them. When ROS bypass the defenses, they reach proteins and nucleic acids and damage; some enzymes are capable of repairing such damage.
Gray hair is what happens when endogenous antioxidant systems fail
Let’s talk about two antioxidant enzymes present in our scalp. One enzyme, catalase, protects us from ROS by disarming them. Another, methionine sulfoxide reductase (MSR), fixes damage to proteins after it occurs. Inadequacy of these two enzymes seems to be the key to why our hair turns gray.
Catalase is the enzyme that breaks down hydrogen peroxide into less reactive oxygen and water molecules, preventing damage to the cell's DNA, proteins and membrane lipids.
2 H2O2 → 2 H2O + O2
Methionine sulfoxide reductase repairs protein damage caused by ROS that escaped the fisr line of defense. In the scalp, MSR can fix a damaged amino acid in tyrosinase so that it can keep catalizing the first key step in the synthesis of melanin.
Gray hair is produced by hair follicles lacking in these two crucial antioxidant enzymes, and SAS is now offering these two enzymes in a hair serum that will help protect your scalp and prevent the loss of hair color (see above). Make sure you use it after swimming in chlorinated water, which is good at killing bacteria but also producing free radicals, or after a day walking in the city.
MSR is available for purchase separately for professional use. Contact Jonatan (jonatan@skinactives.com) for wholesale information and pricing.