Benzyl isothiocyanate

Benzyl isothiocyanate occurs in nasturtium absolute at very high concentration (72.3 percent). The compound is severely irritating, hepatotoxic and nephrotoxic, with potential to induce bladder cancer in animal models.

Skin. Severely irritating according to Lewis. Adequate clinical patch-test data are lacking.

Acute toxicity. Low lethal doses by intraperitoneal and subcutaneous routes are 100 mg/kg in rats and mice. Subcutaneous LD50 in mice is 150 mg/kg.

Reproductive. Oral 12.5–50 mg/kg in female rats pre- and post-implantation reduced fetal and placental weight at 25 and 50 mg/kg. Three maternal deaths occurred at the high dose with hypoactivity, perinasal staining and weight loss.

Liver. Benzyl isothiocyanate is considerably more toxic to rat RL-4 hepatocytes than its glutathione and N-acetylcysteine conjugates.

Carcinogenicity. Feeding 0.1 percent for 32 weeks to male rats increased bladder hyperplasia and cancer, especially in animals previously exposed to carcinogen promoters. The compound also has substantial anticancer activity in other tissues by inducing apoptosis.

Genotoxicity. At 5 mM and above, the compound itself causes DNA damage in vitro.

Benzyl isothiocyanate reacts rapidly with glutathione to form a conjugate that degrades to the cysteine conjugate and is acetylated to the mercapturic acid N-acetyl-S-(N-benzylthiocarbamoyl)-cysteine, the major urinary metabolite in both rat (40 percent) and human (54 percent).

The compound has antimicrobial and chemopreventive activity against gastrointestinal cancers when consumed at low doses through Brassica vegetables. In the essential oil context, exposure levels are very different and the risk tilts toward toxicity.