L-2-thiohistidine a natural amino-acid for active photo-protection
While ozone depletion and sun exposure make us prone to UV overexposure, the benefits of sunlight, such as vitamin D production and mood boosting, are overwhelmed by its deleterious effects on skin. Solar erythema, photo-dermatosis, photo-aging and skin cancers are well-documented examples of such effects. Thus in despite the use of sunscreens, photo-protection remains currently a major issue and complementary strategies need to be implemented.
UV radiation is a well-recognized generator of reactive oxygen species (ROS) and reactive nitrogen species (RNS) which play a key role in mediating its biological effects. Under the control of endogenous antioxidant system, ROS and RNS participate in redox-dependent regulation of cell metabolism in response to UV stress. However when the endogenous antioxidant system is exceeded ROS and/or RNS induce oxidative damage whose accumulation leads to photo-aging, photo-immunosuppression and photo-carcinogenesis.
Antioxidant supply is a strategy that deserves further attention for active photo-protection. Suitable intervention requires to define relevant targets and the oxidative pathways that may result in skin damage following UVA exposure. Two main interconnected pathways prove to underlie UVA-induced oxidative stress (see schema below). These pathways result in the production of strong oxidizing species: singlet oxygen (O21), the main contributor, peroxynitrite anion (ONOO-) and hydroxyl radical (OH°), whose formation is catalyzed by transition metals (such as copper and iron). Antioxidant supply, orally or topically, is therefore a strategy that deserves further attention.
The WHO estimates that between 2 and 3 million non-melanoma skin cancers and approximately 130,000 malignant melanomas occur each year. Despite of the use of sunscreens photoprotection remains currently a major issue and complementary strategies need to be implemented.
L-2-Thiohistidine is a natural sulfur-containing analog of L-histidine. It has been found as a post-translational modification of copper proteins, such as molluskan hemocyanin and fungal tyrosinase, in the vicinity of the copper ion that is coordinated at the active site of these proteins.
Stable towards oxygen, L-2-thiohistidine is an efficient antioxidant through its ability to prevent singlet oxygen (O21) formation. This supports the protective effect of L-2-thiohistidine that has been reported in studying the photochemical inactivation of various enzymes. L-2-thiohistidine can also trap ONOO– and OH., and it has been shown to chelate divalent cations of metals such as copper.
Thiodine® (pure L-2-thiohistidine) as protective agent against photo-aging
Therefore, the unique antioxidant properties of Thiodine® (as pure L-2-thiohistidine) provides a relevant strategy to counterbalance the production of key mediators of UVA-induced skin damage, thereby contributing to photo-protection (in complement or synergy to UV filters).
These antioxidant properties support the development of Thiodine® (pure L-2-thiohistidine) as a new candidate for active photo-protection, in synergy with or in complement of UV filters.
Thiodine® (pure L-2-thiohistidine) as depigmenting agent
Based on its chelation properties Thiodine® as pure L-2-thiohistidine has similar depigmenting activity compare to kojic acid but is much less toxic than kojic acid.
Thiodine® is high quality level :
- Good water solubility and heat stability, regardless of formulation
- Odorless white powder
- Highly pure L-2-thiohistidine (> 99.0%)
- Manufactured via a proprietary process using a sustainable technology (WO 2011042480-A1). Reagents are all non GMO; none are of neither human nor animal origin
Thiodine® is supplied :
- as pure powder: 1-g dose for easy formulation (resulting in 0.1% w/w or 5.35 mM of L-ergothioneine when dissolved in 1 liter of water)
- as ready-to-use aqueous solution: 1L at 0.1% (5.35 mM) or 1% w/w (53.5 mM)
- other concentrated aqueous solutions : on request
