A tremendous 2021 study involving the group who published Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts:

“The aim was to evaluate the influence of red cabbage extracts on bioaccessibility of their isothiocyanates, and their effect on intestinal microbiota using a dynamic model of human digestion treated with the gut microbiome of obese adults.

Plant plasma membrane vesicles as delivery systems for bioactive compounds has been studied. Diverse types of plant membrane vesicles could be good candidates for this purpose, such as extracellular vesicles, which are spheroids of cytosolic material surrounded by a lipid bilayer, or extracted plasma membrane from fresh plant tissue.

As an example of the latter, we used cauliflower plasma membrane vesicles, which are proteoliposomes with a high proportion of unsaturated fatty acids. There could be an interaction between plant aquaporins found in our vesicles and isothiocyanates present in red cabbage aqueous extract, which could have increased stability.

Plasma membrane vesicles may act as stabilizing carriers and feeding agents for enzymes and bile salts rather than an encapsulating agent per se. However, this aspect should be further studied.

In the transversal colon reactor, butyric acid production by gut microbiota had a 3-fold increase after 14-day treatment for free red cabbage aqueous extract when compared to stabilization period. A 3.5-fold increase was observed when using nanonencapsulated extract.

Regarding the descending colon, a 2-fold increase in butyric acid was produced after 14 days of treatment with free red cabbage aqueous extract. A 4-fold increase was observed in production after treatment with nanoencapsulated extract.

Propionic and acetic acids were studied, but no changes were observed. The fact that encapsulated red cabbage extract provided a higher production of butyric acid pointed to future developments for design of a functional ingredient or food product for management of overweightness and obesity.”

https://www.mdpi.com/2304-8158/10/5/1038/htm “The Influence of Red Cabbage Extract Nanoencapsulated with Brassica Plasma Membrane Vesicles on the Gut Microbiome of Obese Volunteers”

This study demonstrated that iberin was initially the third highest isothiocyanate of red cabbage after glucosinolate hydrolysis. Iberin surpassed sulforaphane to become the predominant isothiocyanate – in both free and nanoencapsulated forms – when it reached the lower colon, where most of our gut microbiota reside.

These in vitro findings were after 14 days, though, which doesn’t happen in healthy humans in vivo. Also, if sulforaphane metabolites such as dithiocarbamates and I3C breakdown products such as DIM were measured, these findings may have changed.

As noted in Tailoring measurements for broccoli sprouts, study findings of mature plants don’t necessarily apply to their sprouts. Lab analyses of broccoli sprout compounds used 9-day-old red cabbage sprouts to measure iberin (3MSOP-ITC in Figure 5). Haven’t found recent studies on iberin’s effects on gut microbiota and intestinal epithelial cells.

This study showed “a 3 to 4-fold increase in production of butyric acid with encapsulated extract treatment.” Keep leading the way. 🙂