However, it had no antibacterial activity at the concentrations used (2, 20, 100, 200 μg/mL) and it did not affect adherence of enteropathogenic E. coli. Quercetin was confirmed as a major biomarker for the observed antidiarrheal potential of P. guajava against S. flexneri-induced infectious diarrhea in a model of diarrheal rat, as it significantly reduced the density of S. flexneri in stools, water content of stools and restored the alterations observed in blood parameters, and pro-inflammatory cytokines (IL-6 and TNF-α) expression at a dose of 50 mg/kg (Hirudkar et al., 2020a). The gene discussed is TNF; the disease is dysentery.