Sinigrin Extract.

Sinigrin is the intact glucosinolate and allyl isothiocyanate is what myrosinase releases from it once plant tissue is disrupted. Formulating both covers the storage form and the released form.

Ascorbate is the recognised cofactor of plant myrosinase and raises the rate at which sinigrin is hydrolysed to its isothiocyanate. Conversion runs slowly without it.

Sprout material that retains active myrosinase supplies the enzyme sinigrin needs, since heat-processed mustard extracts often carry the glucosinolate with no enzyme left. The pairing restores the missing half of the reaction.

Both are isothiocyanates that act through the same Nrf2 and phase II conjugation response. They arise from different glucosinolate parents and reach that pathway by the same route.

Isothiocyanates are conjugated to glutathione by glutathione S-transferases before export. Glutathione supply sets how quickly that handling step proceeds.

The isothiocyanate released from sinigrin is cleared as an N-acetylcysteine conjugate through the mercapturic acid route. Cysteine from NAC feeds the same conjugation pool.

Glucosinolate breakdown also yields thiocyanate, which competes with iodide at the sodium-iodide symporter. Sustained high mustard glucosinolate intake alongside marginal iodine intake works against normal iodide uptake.

Watercress carries gluconasturtiin and its own myrosinase, so it adds a second glucosinolate and more converting enzyme. Both sources feed the same isothiocyanate pool.

Arugula seed carries glucoerucin with intact myrosinase activity. Adding it broadens the glucosinolate profile and supplies more of the hydrolysing enzyme.

When plant myrosinase has been destroyed by cooking or processing, intact sinigrin passes to the colon where bacterial thioglucosidases can release the isothiocyanate. Conversion by this route is slower and far more variable between people than plant-enzyme conversion. Supplying converting organisms is a mechanistically sound pairing, but yield per person is not predictable.

Lactic acid bacteria are the organisms responsible for glucosinolate conversion in fermented cabbage and mustard preparations, which is where this activity was first characterised. That gives a plausible route to isothiocyanate release from a myrosinase-inactive extract. Strain-level differences are large, so the pairing is a mechanism rather than a specified dose relationship.

Colonic conversion of glucosinolates is a community property and this species is among those studied for it. The evidence sits at the in vitro fermentation level rather than in human isothiocyanate recovery studies. Label it as an early mechanistic pairing.

If bacterial thioglucosidase activity is the conversion route for an enzyme-inactive extract, then the composition and activity of that community matters. A fermentable fructan shifts community composition and lowers colonic pH. Whether that translates into more isothiocyanate released has not been established, so this stays at the low end.

Allyl isothiocyanate is electrophilic and is disposed of almost entirely through glutathione S-transferase conjugation, ending as an allyl mercapturic acid in urine. Cysteine availability sets the ceiling on the glutathione that route consumes. This describes disposal capacity, not a boost in effect.

Glutathione is a tripeptide of glutamate, cysteine and glycine, and the conjugation of isothiocyanates draws on the glutathione pool. Glycine supply supports synthesis of that pool, although cysteine is usually the limiting piece. The pairing is about substrate supply for a disposal route rather than about a stronger effect.

Isothiocyanates modify Keap1 cysteines and raise transcription of antioxidant response element genes, some of which encode selenoproteins. Those enzymes need selenocysteine, so selenium adequacy determines whether the transcriptional response yields working enzyme. Selenium is narrow-window, so this is an adequacy argument and not a case for a high dose.

Alpha-lipoic acid is reduced in the cell to dihydrolipoate, which contributes to keeping glutathione in its reduced form. Since isothiocyanate disposal consumes reduced glutathione, that recycling capacity sits alongside the pathway. Both are also independent Nrf2 activators, so the overlap runs in two directions.

Quercetin and allyl isothiocyanate both push the Keap1 and Nrf2 axis, though through different chemistry, one as a flavonoid and one as an electrophile. Combining them in a formula covers the same signalling node from two directions. The evidence is cell and animal level, so keep the claim mechanistic.

EGCG and isothiocyanates are both handled by phase II conjugation and both raise antioxidant response element transcription in cell models. A formula carrying both is not duplicating one input. Because they compete for the same conjugating enzymes, exposure to each can shift when they are taken together.

Curcumin and allyl isothiocyanate act on the same set of reactive cysteines on Keap1, releasing Nrf2 to the nucleus. That makes them mechanistically parallel rather than complementary, which is worth stating plainly. Both also carry a heavy phase II conjugation load, so co-exposure changes clearance for each.