Reciprocal interaction between gut microbiota and aloe-emodin results in altered microbiome composition and metabolism of aloe-emodin

Aloe vera is utilized as a functional food due to its health-beneficial effects, including facilitating digestion, enhancing the immune response, and providing antioxidant benefits. This work examines the bidirectional interaction between the gut microbiota and aloe-emodin, a key anthraquinone in A. vera, to understand its microbial metabolism and its impact on the gut microbiota using an anaerobic fecal slurry model. The findings indicated that gut microbiota metabolized aloe-emodin more effectively than individual probiotic species; however, its breakdown was delayed within the whole-leaf matrix. Aloe-emodin enhanced the proliferation of probiotic spp., lowered the Firmicutes-to-Bacteroidetes ratio, and augmented the abundance of Ruminococcus and Oscillospira. Functional investigation revealed a reduction of microbial lipopolysaccharide biosynthesis and energy-harvesting pathways under the influence of aloe-emodin. The whole-leaf matrix exhibited enhanced prebiotic benefits compared to aloe-emodin alone. These findings underscore the dual function of aloe-emodin as a microbiota-modulated phytochemical and a regulator of gut microbial ecology, with the potential for enhancing aloe-based therapeutics for metabolic health.