L-Deoxyalliin , also known as S-allyl-L-cysteine, is a water soluble organosulfur compound derived from garlic that has neuroprotective and antioxidative activities. N-Acetyl-S-allyl-L-cysteine is a principal metabolite of L-deoxyalliin in humans, mice, rats, and dogs. It is readily detected in plasma and urine. The conversion of L-deoxyalliin to N-acetyl-S-allyl-L-cysteine appears to be mediated by a family of flavin-containing monooxygenases.