Three 2022 papers of interest cited Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease. Let’s start with a fairly straightforward analysis of blanching broccoli sprouts to produce sulforaphane:
“We investigated the effect of blanching conditions to determine the optimal treatment that maximizes sulforaphane (SFN) content in broccoli sprouts. Broccoli seeds grown under controlled conditions were harvested after 11 days from germination and subjected to different blanching conditions based on a central composite design with temperature and time as experimental factors.
Optimum conditions were blanching at 61 °C for 4.8 min, resulting in 54.3 ± 0.20 µmol SFN/g dry weight, representing a 3.3-fold increase with respect to untreated sprouts. This is the highest SFN content reported for sprouts subjected to any treatment so far.
Broccoli sprouts (20 g) were put in plastic bags, which were vacuum-sealed, and then subjected to time (3.4–11 min)–temperature (32–88 °C) combinations.
- Blanching at 60 °C for less than 8 min resulted in the highest SFN content.
- Above this temperature, SFN content decreases.
- The exceptionally high values obtained in this work may be related to treatment, but also to broccoli cultivar and culture conditions.
Different broccoli tissues and developmental stages express different myrosinase isoforms, and catalytic properties of the enzyme may vary among different tissues. Myrosinase found in broccoli florets has an optimal temperature of around 40 °C, and considering myrosinases from other sources, this temperature may vary between 30 and 70 °C.”
https://www.mdpi.com/2304-8158/11/13/1906/htm “Maximization of Sulforaphane Content in Broccoli Sprouts by Blanching”
This first study used heat-only techniques similar to the uncited Enhancing sulforaphane content. It similarly found a 60°C (140°F) myrosinase cliff as have many other uncited studies.
A second paper was a rodent study:
“We investigated the role of sulforaphane, a well-known NRF2 activator, on age-related mitochondrial and kidney dysfunction. Young (2–4 month) and aged (20–24 month) male Fischer 344 rats were treated with sulforaphane (15 mg/kg body wt/day) in drinking water for four weeks.
Sulforaphane significantly improved mitochondrial function and ameliorated kidney injury by increasing cortical NRF2 expression and activity and decreasing protein expression of KEAP1, a NRF2 repressor. Sulforaphane treatment did not affect renal NRF2 expression or activity and mitochondrial function in young rats.”
https://www.mdpi.com/2076-3921/11/1/156/htm “Age-Related Mitochondrial Impairment and Renal Injury Is Ameliorated by Sulforaphane via Activation of Transcription Factor NRF2”
A human equivalent to this second study’s daily dose was intolerable at (.162 x 15 mg) x 70 kg = 170 mg. I curated this study anyway just to show an example of negligible treatment effects in young animals even when a dose is too high for humans.
A third paper was a review that focused on sulforaphane and its analogs’ chemistry:
“Analysis of the Web of Science database shows that, since 1992, about 3,890 articles have been published on SFN, and over 5,600 on isothiocyanates. Its natural analogs include iberin, alyssin, iberverin, erucin, berteroin, cheirolin, and erysolin.
SFN is a biologically active, natural isothiocyanate found in cruciferous vegetables, and is non-toxic. It has been selected for phase I and II clinical trials, where it is administered in the form of an extract or broccoli sprouts. There are no differences in biological activity between SFN and its natural analogs, such as erucin or alyssin.
No synthetic analogs of SFN described in this review qualified for clinical trials. This is likely due to the toxicity of these compounds in higher doses.”
https://www.mdpi.com/1420-3049/27/5/1750/htm “Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity”