Diallyl disulfide

The natural product diallyl disulfide is the major constituent of oil of garlic (Allium sativum) and other members of the Allium genus, including onion (A. cepa). It is responsible for garlic’s characteristic odor.

Efforts to identify the active compound in garlic began in the mid-1800s; but it was not until a century later (1945) that Chester J. Cavallito, John Hays Bailey, and Johannes S. Buck at Winthrop Chemical Co. (Rensselaer, NY) described the “antibacterial principle of A. sativum”, which they derived from the “essential oil of garlic”. The researchers found that diallyl disulfide is biosynthesized via the enzymatic reduction of its S-oxide, allicin¹, the Molecule of the week for October 7, 2024.

Diallyl disulfide is not only responsible for the enjoyment of garlic, but it also has beneficial health effects. In 1988, Chung S. Yang and co-workers at the University of Medicine and Dentistry of New Jersey (Newark) and Rutgers University (Piscataway, NJ), following up on reports that diallyl disulfide inhibits 1,2-dimethylhydrazine²-induced colon and liver cancer in rodents, suggested a possible mechanism for this effect. They proposed that the disulfide could inhibit hepatic activation of the procarcinogen by suppressing the action of P450IIE1, an isozyme of cytochrome P-450 that promotes the oxidative metabolism of dimethylhydrazine. Tests on rats showed that diallyl disulfide decreased the activity of a key enzyme, and thus the level of P450IIE1, by 80% compared with controls.

Diallyl disulfide has also been shown to prevent colon cancer. In chapter 12 of Food Phytochemicals for Cancer Prevention I (1993), Bandaru S. Reddy and Chinthalapally V. Rao at the American Health Foundation (Valhalla, NY) examined the results of previous epidemiological studies that suggested that consuming garlic and cruciferous vegetables rich in organosulfur compounds is associated with a reduced risk for cancers, particularly colon cancer. They dosed rats that had azoxymethane³-induced colon cancer with diallyl disulfide and two other dietary organosulfur compounds, oltipraz⁴ and anethole trithione⁵, and found that all three “significantly inhibited colon carcinogenesis in a dose-dependent manner”.

1. CAS Reg. No. 539-86-6.
2. CAS Reg. No. 540-73-8.
3. CAS Reg. No. 25843-45-2.
4. CAS Reg. No. 64224-21-1.
5. CAS Reg. No. 532-11-6.