Functionality of garlic sulfur compounds (Review)

Abstract

Garlic (Allium sativum L.), a perennial herbaceous edible plant, is classified in the Amaryllidaceae family and belongs to the Allium genus. It has a higher sulfur content than other plants. Garlic is extensively used worldwide as a spice and flavoring agent, and it generates a unique aroma during cooking. Garlic possesses various properties, including anti-thrombotic, antioxidant, blood cholesterol-lowering, anti-obesity and anti-dementia effects. These properties have been attributed to various garlic-derived sulfur-containing compounds, including S-allyl cysteine, allicin, allyl sulfides and ajoene. The present review provides an overview of the mechanisms that underlie the generation of odor compounds in garlic and discusses certain observed effects of garlic consumption.

Keywords: AGE; DATS; allicin; alliin; garlic; organosulfur compound.

Figure 1

Mechanism of odor compound generation in garlic. When garlic tissue is disrupted through cooking or other methods, alliin in the cytoplasm of mesophyll storage cells reacts with alliinase in the vacuoles of vascular sheath cells, resulting in allyl sulfenic acid production. Allyl sulfenic acid is promptly converted into allicin, which is inherently unstable and undergoes non-enzymatic reactions that lead to the formation of various sulfides.

Figure 2

Chemical structures of garlic-derived compounds. Sulfur is stored as (A) amino acids, and major sulfur-containing compounds are produced through (B) crushing, (C) steam distillation, (D) heating in oil, and (E) prolonged alcohol treatment of garlic.

Figure 3

Post-translational protein modification by allicin and DATS. Allicin and diallyl trisulfide oxidatively modify specific SH groups of cysteine residues in proteins that regulate the functions of other proteins.