Metabolomics Analysis of Aged Garlic Extract for the Identification of Novel Compounds

Aged garlic extract (AGE), produced by aging raw garlic in an aqueous ethanol solution for over 10 months, exhibits multiple pharmacological activities, including antioxidant and anti-inflammatory effects. However, because AGE has a complex composition and many constituents remain insufficiently characterized, the chemical basis underlying its broad activities is not fully understood. This study aimed to investigate these previously overlooked compounds in AGE to better understand its chemical complexity.

AGE was fractionated using bioactivity assays to select target fractions for detailed chemical analysis. Metabolomics profiling was performed using liquid chromatography-mass spectrometry (LC-MS). Compounds were tentatively identified through database matching, fragmentation pattern analysis, and comparison with authentic standards.

Thirteen compounds not previously reported in AGE were tentatively identified. Citric acid was present at high levels. Citrulline and galacturonic acid were detected in AGE but not in raw garlic, suggesting that they are formed during the aging process. Trigonelline was detected and tentatively identified in the AGE sample used in this study. The remaining compounds included choline, 5-oxoproline, malic acid, gluconic acid, adenine, succinic acid, mucic acid, pipecolinic acid, and caffeic acid. These compounds may contribute to the diverse biological activities of AGE.

These findings expand the chemical characterization of AGE and provide a foundation for understanding its broad pharmacological activities. They may also support future studies on functional food development and the health benefits of AGE.