Melatonin

Melatonin is a naturally occurring indoleamine produced primarily by the pineal gland in response to darkness. It functions as the principal hormonal regulator of circadian rhythms, signaling the body that it is time to initiate sleep‑related processes.

• Chemical Name: Melatonin (N‑acetyl‑5‑methoxy‑tryptamine)
• Molecular Formula: C₁₃H₂₁N₃O₂
• Molecular Weight: 232.28 g·mol⁻¹
• IUPAC Name: N‑acetyl‑5‑methoxy‑1H‑indole‑3‑ethanamine
• Molecular Structure: The molecule consists of an indole ring (a fused benzene‑pyrrole system) substituted at the 5‑position with a methoxy (–OCH₃) group and an N‑acetyl side‑chain attached at the 3‑position, forming an amide linkage.
• Lipophilicity: The compound is moderately lipophilic (log P ≈ 0.8), allowing it to cross the blood–brain barrier.
• Amphiphilic Properties: Melatonin is amphiphilic, displaying modest aqueous solubility (~1 mg mL⁻¹) and stability in acidic environments but rapid degradation under light and alkaline conditions.
• Metabolism: Its metabolic fate involves hepatic cytochrome P450 enzymes (primarily CYP1A2) converting it to 6‑hydroxymelatonin and subsequently to 6‑sulfate and 6‑glucuronide conjugates for renal excretion.

• Natural Synthesis: Naturally, melatonin is synthesized endogenously from the amino acid tryptophan via serotonin.
• Commercial Production: Commercially, it is obtained predominantly through chemical synthesis (e.g., condensation of 5‑methoxy‑tryptamine with acetic anhydride) which yields a high‑purity product at scale.
• Plant-Based Extracts: Plant‑based extracts (e.g., from Citrus sinensis or Moringa species) contain trace melatonin but are not used for pharmaceutical‑grade supplements due to low concentrations and variability.
• Manufacturing Practices: Quality‑focused manufacturers employ Good Manufacturing Practices (GMP) and provide third‑party testing for potency, purity, and absence of contaminants (heavy metals, microbial load).
• Packaging: The presence of a stable, light‑protected packaging is crucial to prevent degradation.
• Consumer Guidance: Consumers should look for products labeled “pharmaceutical‑grade,” with certificates of analysis and adherence to USP or NF standards to ensure consistent dosing and safety.