Impacts of the independent and synergistic effects of curcuma and mangosteen extracts on the gut bacterial composition in lean and obese rats.

Dietary polyphenols in plant extracts are being widely investigated due to their great health-promoting activities and effect on modulating gut ecology. In turn, gut microbiota, plays a vital role in the biological activities of phenolic metabolites, particularly after the intake of food rich in polyphenols, such as plant extracts. However, this two-way relationship between polyphenols and microbiota is poorly understood. We prepared curcuma and mangosteen methanol extracts and fed them to healthy, lean, and obese rats over a period of 10 weeks. Subsequent alterations in the gut microbiota were determined. Overall, Firmicutes were more abundant than Bacteroidetes throughout the experiment. A particular increase of gram-positive cocci species and a significant decrease in both Clostridium and Bacteroides species were noted primarily in the first weeks of both plant extract intake in the control and lean rats. Compared to obese rats fed a regular diet, obese rats fed plant extracts showed an increase in Enterobacteriacea, Clostridium, and Bacteroides species and a decrease in gram-positive cocci in the first weeks of treatment with the last weeks of treatment the results at the species level were inverted.