Allicin, the Odor of Freshly Crushed Garlic: A Review of Recent Progress in Understanding Allicin’s Effects on Cells

Abstract

The volatile organic sulfur compound allicin (diallyl thiosulfinate) is produced as a defense substance when garlic (Allium sativum) tissues are damaged, for example by the activities of pathogens or pests. Allicin gives crushed garlic its characteristic odor, is membrane permeable and readily taken up by exposed cells. It is a reactive thiol-trapping sulfur compound that S-thioallylates accessible cysteine residues in proteins and low molecular weight thiols including the cellular redox buffer glutathione (GSH) in eukaryotes and Gram-negative bacteria, as well as bacillithiol (BSH) in Gram-positive firmicutes. Allicin shows dose-dependent antimicrobial activity. At higher doses in eukaryotes allicin can induce apoptosis or necrosis, whereas lower, biocompatible amounts can modulate the activity of redox-sensitive proteins and affect cellular signaling. This review summarizes our current knowledge of how bacterial and eukaryotic cells are specifically affected by, and respond to, allicin.

Allicin inhibits SARS-CoV-2 replication and abrogates the antiviral host response in the Calu-3 proteome

“…However, over-dosage of allicin can be also toxic to human cells, as confirmed in this work. Consequently, the question arises about the biocompatible doses of allicin in humans to prevent bacterial and viral infections (Borlinghaus et al 2021). Allicin is very instable and quickly decomposes to polysulfanes, ajoene and other sulfur compounds during cooking (Block 2010, Borlinghaus et al 2021).…”

“…Consequently, the question arises about the biocompatible doses of allicin in humans to prevent bacterial and viral infections (Borlinghaus et al 2021). Allicin is very instable and quickly decomposes to polysulfanes, ajoene and other sulfur compounds during cooking (Block 2010, Borlinghaus et al 2021). In the acidic stomach, the majority of allicin is degraded to 2-propenethiol and allyl methyl sulfide, which are excreted (Block 2010, Borlinghaus et al 2021).…”

“…Allicin is very instable and quickly decomposes to polysulfanes, ajoene and other sulfur compounds during cooking (Block 2010, Borlinghaus et al 2021). In the acidic stomach, the majority of allicin is degraded to 2-propenethiol and allyl methyl sulfide, which are excreted (Block 2010, Borlinghaus et al 2021). In the blood, the effective doses of allicin is further reduced by its reaction with GSH (Block 2010, Borlinghaus et al 2021).…”

“…In the acidic stomach, the majority of allicin is degraded to 2-propenethiol and allyl methyl sulfide, which are excreted (Block 2010, Borlinghaus et al 2021). In the blood, the effective doses of allicin is further reduced by its reaction with GSH (Block 2010, Borlinghaus et al 2021). Thus, biocompatible and therapeutically relevant concentrations of allicin for the treatment of respiratory tract infections might not be reached with the consumption of garlic-containing food (Borlinghaus et al 2021).…”

“…In the blood, the effective doses of allicin is further reduced by its reaction with GSH (Block 2010, Borlinghaus et al 2021). Thus, biocompatible and therapeutically relevant concentrations of allicin for the treatment of respiratory tract infections might not be reached with the consumption of garlic-containing food (Borlinghaus et al 2021). Therefore, future investigations should be directed to exploit the volatile nature of biocompatible doses of allicin for the treatment of COVID-19 patients via the pulmonary route to efficiently reach the virus, without damaging host cells.…”