A quiet analytical research laboratory at night, racks of glass vials along a dim bench.

Sulforaphane

Sulforaphane is unstable as a pure compound, so most products deliver its precursor glucoraphanin and rely on the enzyme myrosinase to convert it. Whether that conversion happens decides bioavailability: human studies show roughly 70% urinary recovery from sulforaphane-rich preparations versus about 5% from glucoraphanin without active enzyme.

Chemistry and conversion

Sulforaphane (C6H11NOS2, 177.3 Da) is an isothiocyanate formed when myrosinase hydrolyzes glucoraphanin, a glucosinolate concentrated in broccoli seeds and sprouts. Plant tissue damage brings enzyme and substrate together; cooking inactivates myrosinase, and conversion then depends on gut bacteria, which is slow and highly variable between people. Pure sulforaphane is an oily liquid that degrades with heat, alkaline pH and time. Conversion can also be diverted to sulforaphane nitrile, an inactive product favored by the epithiospecifier protein at low pH or in the presence of iron. Commercial forms therefore include glucoraphanin extracts, glucoraphanin plus active myrosinase, and stabilized sulforaphane complexes.

Regulatory status

Broccoli sprout and seed extracts standardized to glucoraphanin or sulforaphane are sold as dietary supplement ingredients in the United States and as natural health product ingredients in Canada, subject to the usual limits on disease claims. A stabilized sulforaphane and alpha-cyclodextrin complex (SFX-01) has been evaluated as an investigational drug in clinical trials, which illustrates that the same molecule sits in different regulatory categories depending on form and intended use. Sulforaphane is not on the WADA Prohibited List.

Mechanism and evidence tier

Sulforaphane is among the most potent natural inducers of the Nrf2 pathway, which regulates phase II detoxification and antioxidant enzymes. This mechanism is well characterized in cell and animal work. In humans, controlled trials have measured biomarker changes, including increased urinary excretion of airborne pollutant metabolites in a randomized trial in Qidong, China. Clinical outcome evidence for disease endpoints is limited and mixed. The most robust human finding is pharmacokinetic: the form delivered, and whether myrosinase is active, dominates how much sulforaphane reaches circulation.

Key facts

Urinary recovery was about 70% from a sulforaphane-rich beverage versus about 5% from a glucoraphanin-rich beverage (Egner et al. 2011, Cancer Prev Res)
Active endogenous myrosinase controls sulforaphane bioavailability from glucoraphanin-rich broccoli preparations (Fahey et al. 2015, PLoS One)
A broccoli sprout beverage increased urinary excretion of benzene and acrolein metabolites in a randomized trial (Egner et al. 2014, Cancer Prev Res)
Sulforaphane is a potent inducer of Nrf2-regulated phase II enzymes (Zhang et al. 1992, Proc Natl Acad Sci USA)

How our delivery technology applies

Two routes are open. The first protects preformed sulforaphane: a multi-layer shell isolates the isothiocyanate from heat, moisture and alkaline pH and releases it in the small intestine. The second co-encapsulates glucoraphanin and myrosinase in separate compartments so conversion occurs only on release, at a pH that favors sulforaphane over the nitrile. Either route is measured by urinary dithiocarbamate recovery against a reference product.

Send your broccoli extract specification to scope a stabilized sulforaphane format.