Bioavailability of Organosulfur Compounds after the Ingestion of Black Garlic by Healthy Humans

The consumption of black garlic has been related to a decreased risk of many human diseases due to the presence of phytochemicals such as organosulfur compounds (OSCs). However, information on the metabolization of these compounds in humans is limited. By means of ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS), this study aims to determine the OSCs and their metabolites excreted in urine 24 h after an acute intake of 20 g of black garlic by healthy humans. Thirty-three OSCs were identified and quantified, methiin (17,954 +/- 6040 nmol), isoalliin (15,001 +/- 9241 nmol), S-(2-carboxypropyl)-L-cysteine (8804 +/- 7220 nmol) and S-propyl-L-cysteine (deoxypropiin) (7035 +/- 1392 nmol) being the main ones. Also detected were the metabolites N-acetyl-S-allyl-L-cysteine (NASAC), N-acetyl-S-allyl-L-cysteine sulfoxide (NASACS) and N-acetyl-S-(2-carboxypropyl)-L-cysteine (NACPC), derived from S-allyl-L-cysteine (SAC), alliin and S-(2-carboxypropyl)-L-cysteine, respectively. These compounds are potentially N-acetylated in the liver and kidney. The total excretion of OSCs 24 h after the ingestion of black garlic was 64,312 +/- 26,584 nmol. A tentative metabolic pathway has been proposed for OSCs in humans.

Automated summary

By using UHPLC-HRMS, this study identified and quantified 33 OSCs excreted in urine 24 h after the consumption of 20 g of black garlic. The main OSCs were methiin, isoalliin, S-(2-carboxypropyl)-L-cysteine, and S-propyl-L-cysteine. Metabolites such as NASAC, NASACS, and NACPC derived from SAC, alliin, and S-(2-carboxypropyl)-L-cysteine were also detected. The total excretion of OSCs after the ingestion of black garlic was 64,312 +/- 26,584 nmol.