Phytochemical Profiling, Anti-Inflammatory Action, and Human Gut Microbiota-Assisted Digestion of Rheum officinale Petiole and Root Extracts-An In Vitro Study.

Background/Objectives:Rheum officinale, an ethnomedicinal plant, has roots widely employed in modern pharmacological formulations. However, many of its biological activities remain only partly recognized. Furthermore, the metabolome and biological activity of its edible petioles, often considered a waste product, have received limited scientific attention. Methods and Results: The examination of anti-inflammatory properties of both root and petiole extracts (1-50 µg/mL) revealed the inhibition of the pro-inflammatory cytokine release from human peripheral blood mononuclear cells, a reduction in ALOX5 gene expression in human umbilical vein endothelial cells, and the significant inhibition (>60%) of cyclooxygenase-2 and 5-lipoxygenase activities. Importantly, no cytotoxic effects were detected at the tested concentrations. Conclusions: The petiole extract demonstrated anti-inflammatory efficiency comparable to, or exceeding that of the root extract, suggesting that R. officinale petioles could be valuable source of bioactive compounds for future investigations.