Table 1. List of microbiome-derived metabolites and their concentrations used in this study (the source of the metabolites is also indicated).

Molecule	Low concentration	High concentration	Reference	Catalogue	Company
l-Tryptophan	10 µM	30 µM	[23]	T0254	Sigma-Aldrich
Sodium butyrate	0.5 mM	2 mM	[26]	B5887	Sigma-Aldrich
Trimethylamine hydrochloride	10 µM	30 µM	[28]	T72761	Sigma-Aldrich
3,4-TMAB	20 µM	1 mM	[27]	Custom made	AstraZeneca
4-TMAP	20 µM	1 mM	[27]	Custom made	AstraZeneca
UDCA	10 µM	30 µM	[78]	U5127	Sigma-Aldrich
GCA	250 nM	500 nM	[26]*	G2878	Sigma-Aldrich
Sodium benzoate	10 µM	50 µM	[30]	B3420	Sigma-Aldrich

*Concentration based on that used in a similar in vitro study.