Sulforaphane

Sulforaphane is a molecule within the isothiocyanate group of organosulfur compounds. It exhibits anticancer and antimicrobial properties in experimental models. It is obtained from cruciferous vegetables such as broccoli, Brussels sprouts or cabbages. It is produced when the enzyme myrosinase transforms glucoraphanin, a glucosinolate, into sulforaphane upon damage to the plant (such as from chewing), which allows the two compounds to mix and react. Young sprouts of broccoli and cauliflower are particularly rich in glucoraphanin.

Occurrence and isolation
Sulforaphane was identified in broccoli sprouts, which, of the cruciferous vegetables, have the highest concentration of sulforaphane. It is also found in Brussels sprouts, cabbage, cauliflower, bok choy, kale, collards, Chinese broccoli, broccoli raab, kohlrabi, mustard, turnip, radish, arugula, and watercress.

Possible medicinal properties
Consumption of broccoli sprouts has shown to be potentially effective at inhibiting Helicobacter pylori growth, with sulforaphane being at least one of the active agents.

Consumption of raw broccoli has been shown to "result in faster absorption, higher bioavailability, and higher peak plasma amounts of sulforaphane, compared to cooked broccoli".

Sulforaphane and dietary consumption of cruciferous vegetables are known to affect the action of drug-metabolizing enzymes in vitro and in preliminary human studies. Although no side-effects or direct drug interactions have been reported as of 2008, people taking prescription drugs are advised to consult a doctor before taking sulforaphane or broccoli-sprout extracts.

The possible anticancer activity of sulforaphane may be related to the induction of phase-II enzymes of xenobiotic transformation (such as quinone reductase and glutathione S-transferase), and enhancing the transcription of tumor suppressor proteins, possibly via inhibitory effects on histone deacetylase.

Sulforaphane and diindolylmethane (another compound from Brassica vegetables) inhibit cancer growth in vitro and in experimental animals. Sulforaphane downregulated the Wnt/beta-catenin self-renewal pathway in breast cancer stem cells.

When applied topically, sulforaphane may protect skin against UV radiation damage, and thus potentially against cancer. Sulforaphane may inhibit histone deacetylase (HDAC) activity. Preliminary experiments indicate that sulforaphane may protect the heart from vascular inflammation and atherosclerosis.

In vitro studies
In vitro studies have shown that sulforaphane can inactivate histone deacetylase 6 (HDAC6), and so interfere with the expression of androgen receptor genes in prostate cancer cells.

Clinical trials
Sulforaphane (as broccoli sprout extracts) is in numerous clinical trials including a phase II trial for prostate cancer.