Modulatory Effects of Triphala and Manjistha Dietary Supplementation on Human Gut Microbiota: A Double-Blind,...

Triphala (which contains Emblica officinalis, Terminalia bellerica, and Terminalia chebula) and manjistha (Rubia cordifolia), have received increased clinical attention. The aim of the study was to evaluate the effects of triphala, manjistha, or placebo dietary supplementation on gut microbiota as such studies in humans are lacking. This was a 4-week randomized, double-blind, placebo-controlled pilot trial. This trial was conducted at the University of California Davis, Department of Dermatology. A total of 31 healthy human subjects were randomized to 3 groups. The 3 groups were instructed to take 2,000 mg of either triphala, manjistha or placebo daily for 4 weeks. The impact of treatment on gut microbiota composition was evaluated following a 4-week dietary intervention by profiling fecal communities with 16S rRNA profiling in triphala (n = 9), manjistha (n = 9), or placebo (n = 11) treated subjects that completed the intervention. An average of 336 phylotypes were detected in each sample (range: 161 to 648). The analysis of gut microbiota in placebo control and herb-supplemented participants indicated that responses were highly personalized, and no taxa were uniformly altered by the medicinal herb supplementation protocol. Subjects in both treatment groups displayed a trend toward decreased Firmicutes to Bacteroidetes ratio and increased relative abundance of Akkermansia muciniphila. Both medicinal herb treatments reduced the relative abundance of Rikenellaceae, primarily reflecting changes in Alistipes spp. Dietary supplementation with medicinal herbs altered fecal microbial communities. Despite the lack of a clear response signature, a group of bacterial taxa were identified that were more commonly altered in herb-supplemented participants compared to placebo controls. Clinicaltrials.gov identifier NCT03477825.