Nowadays, obesity is one of the most prevalent human health problems. Research from the last 30 years has clarified the role of the imbalance between energy intake and expenditure, unhealthy lifestyle, and genetic variability in the development of obesity. More recently, the composition and metabolic functions of gut microbiota have been proposed as being able to affect obesity development. Here, we will report the current knowledge on the definition, composition, and functions of intestinal microbiota. We have performed an extensive review of the literature, searching for the following keywords: metabolism, gut microbiota, dysbiosis, obesity. There is evidence for the association between gut bacteria and obesity both in infancy and in adults. There are several genetic, metabolic, and inflammatory pathophysiological mechanisms involved in the interplay between gut microbes and obesity. Microbial changes in the human gut can be considered a factor involved in obesity development in humans. The modulation of the bacterial strains in the digestive tract can help to reshape the metabolic profile in the human obese host as suggested by several data from animal and human studies. Thus, a deep revision of the evidence pertaining to the use probiotics, prebiotics, and antibiotics in obese patients is conceivable

Background and Purpose: The non‐psychotropic cannabinoid cannabichromene is known to activate the transient receptor potential ankyrin‐type1 (TRPA1) and to inhibit endocannabinoid inactivation, both of which are involved in inflammatory processes. We examined here the effects of this phytocannabinoid on peritoneal macrophages and its efficacy in an experimental model of colitis.Experimental Approach: Murine peritoneal macrophages were activated in vitro by LPS. Nitrite levels were measured using a fluorescent assay; inducible nitric oxide (iNOS), cyclooxygenase‐2 (COX‐2) and cannabinoid (CB₁ and CB₂) receptors were analysed by RT‐PCR (and/or Western blot analysis); colitis was induced by dinitrobenzene sulphonic acid (DNBS). Endocannabinoid (anandamide and 2‐arachidonoylglycerol), palmitoylethanolamide and oleoylethanolamide levels were measured by liquid chromatography‐mass spectrometry. Colonic inflammation was assessed by evaluating the myeloperoxidase activity as well as by histology and immunohistochemistry.Key Results: LPS caused a significant production of nitrites, associated to up‐regulation of anandamide, iNOS, COX‐2, CB₁ receptors and down‐regulation of CB₂ receptors mRNA expression. Cannabichromene significantly reduced LPS‐stimulated nitrite levels, and its effect was mimicked by cannabinoid receptor and TRPA1 agonists (carvacrol and cinnamaldehyde) and enhanced by CB₁ receptor antagonists. LPS‐induced anandamide, iNOS, COX‐2 and cannabinoid receptor changes were not significantly modified by cannabichromene, which, however, increased oleoylethanolamide levels. In vivo, cannabichromene ameliorated DNBS‐induced colonic inflammation, as revealed by histology, immunohistochemistry and myeloperoxidase activity.Conclusion and Implications: Cannabichromene exerts anti‐inflammatory actions in activated macrophages – with tonic CB₁ cannabinoid signalling being negatively coupled to this effect – and ameliorates experimental murine colitis.