Matching chemical properties to molecular biological activities opens a new perspective on l-ergothioneine.

l-ergothioneine is a low-molecular weight natural product, the chemical structure of which comprises oxygen-, nitrogen- and sulfur-containing functional groups. This gives l-ergothioneine specific physicochemical properties and allows a better understanding of its chemical reactivity, which is primarily due to the 2-thio-imidazole group. Here, a review is provided of how different modes of chemical reactivity account for the reported molecular biological activities of l-ergothioneine. By matching the physicochemical properties to the biological properties of l-ergothioneine, a new perspective of the function and the mode of action of this enigmatic molecule emerges.

Short protecting-group-free synthesis of 5-acetylsulfanyl-histidines in water: novel precursors of 5-sulfanyl-histidine and its analogues.

The discovery of a non-enzymatic oxidative introduction of sulfur to the 5-position of histidine is reported, by activation with bromine or NBS followed by reaction with thioacetic acid forming novel 5-acetylsulfanyl-histidine. Complementing the previously developed regioselective oxidative S-introduction to the 2-position of histidine by reaction with cysteine, this surprising finding provides straightforward access in multi-gram quantities to naturally occurring 5-sulfanyl-histidine and its N-methylated analogues, including a hitherto unknown regioisomer of l-ergothioneine.

Reproductive safety evaluation of L-Ergothioneine.

L-Ergothioneine is a naturally occurring histidine-derived betaine (CAS No: 497-30-3) synthesized by bacteria and fungi, and found ubiquitously in plants and animals. It is present in many human foodstuffs. We evaluated the potential reproductive toxicity of L-Ergothioneine in Sprague-Dawley rats. L-Ergothioneine was administered at concentrations of 0.1, 0.3 or 0.9% in diet to F0 males (for 10 weeks before pairing and 3 weeks during pairing) and F0 females (for 13 weeks before pairing, during pairing and gestation, and until day 5 of lactation). Systemic exposure increased with dose-level, but not dose proportionally, suggesting saturation of uptake mechanisms. No clinical signs of toxicity were observed and there were no effects of L-Ergothioneine treatment on mating and reproductive performance or parameters of fertility. All animals mated within a similar number of days and pregnancy rates were uniformly high in control and treated groups. There were no effects of treatment with L-Ergothioneine on the duration of gestation, pre- and post-implantation losses, number of pups delivered and viability index, or on litter parameters (litter size, clinical signs, body weight or sex ratio) and the repartition of found dead/cannibalized pups. In conclusion, L-Ergothioneine was well tolerated and without adverse effects on the reproductive parameters evaluated.

Simultaneous speciation of selenomethionine and 2-hydroxy-4-methylselenobutanoic acid by HPLC-ICP MS in biological samples.

An analytical method was developed for the simultaneous speciation of selenomethionine (SeMet) and 2-hydroxy-4-methylselenobutanoic acid (NutraSelen), a new SeMet precursor. The compounds could be baseline resolved by ion-pairing reversed-phase HPLC using ICP MS detection. Detection limits of 1 ng mL(-1) (Se content) could be reached. SELM-1 reference material was used to validate the SeMet measurement. Additionally, the quantification of NutraSelen was validated by standard addition together with checking the Se mass balance. The procedure developed was then applied to the monitoring of the conversion of NutraSelen into SeMet by yeast.