Gallic Acid Attenuates Ifosfamide-Induced Gut Microbiota Dysbiosis: A Full-Length 16S rRNA Amplicon Sequencing Study

Chemotherapy-induced gastrointestinal toxicity represents a major clinical challenge, with accumulating evidence implicating gut microbiota dysbiosis in reduced treatment tolerance. Ifosfamide is a widely used alkylating agent; however, its effects on gut microbial community structure remain incompletely understood. This preclinical study investigated ifosfamide-associated microbiota alterations and evaluated the microbiota-modulating potential of gallic acid as a supportive intervention. Male rats were assigned to control, ifosfamide, gallic acid, and combined ifosfamide + gallic acid groups. Fecal samples were collected longitudinally and analyzed using full-length 16S rRNA gene sequencing for high-resolution taxonomic profiling. At the phylum level, ifosfamide exposure induced a marked decrease in Bacillota accompanied by a significant expansion of Bacteroidota, reflecting a dysbiotic shift associated with intestinal stress. Genus-level analysis revealed substantial reductions in beneficial taxa, including Lactobacillus, Ligilactobacillus, and Blautia, alongside enrichment of stress-adaptive and opportunistic genera such as Romboutsia and Segatella. Species-level profiling demonstrated significant depletion of mucosa-associated lactic acid bacteria, including Lactobacillus johnsonii, Lactobacillus intestinalis, and Ligilactobacillus murinus, following ifosfamide treatment. Conversely, opportunistic taxa such as Romboutsia ilealis and Segatella copri and transient increases in Escherichia coli were observed, consistent with chemotherapy-induced intestinal perturbation. Gallic acid administration partially preserved microbial diversity, attenuated the expansion of opportunistic taxa, and supported recovery of beneficial bacteria, resulting in an intermediate microbial profile under combination treatment. These findings provide preclinical evidence that gallic acid mitigates ifosfamide-associated gut dysbiosis and highlight gut microbiota modulation as a potential adjunctive strategy to improve chemotherapy tolerance. Further translational and clinical investigations are warranted.