Adenosine 5'-monophosphate monohydrate is an adenosine A₁ receptor agonist. Adenosine 5'-monophosphate monohydrate has significant antiviral activity against HSV-1 and HSV-2. IC50 & Target: Adenosine A₁ receptor^[1] In Vitro: Adenosine 5'-monophosphate monohydrate is an adenosine A1 receptor agonist^[1]. Adenosine 5'-monophosphate monohydrate (5′-AMP)-induced cell toxicity is negligible at concentrations of 25 to 400 μM in RAW264.7 cells. Adenosine 5'-monophosphate monohydrate significantly attenuates the mRNA expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in RAW264.7 cells. The dose-dependence of TNF-α and IL-6 mRNA show that at concentration of 400 μM, Adenosine 5'-monophosphate monohydrate exhibits the maximum inhibition. Exposure of cells to Adenosine 5'-monophosphate monohydrate significantly reduces recruitment of NF-κB p65 to TNF-α, IL-6, and IL-1β gene promoters^[2]. In Vivo: C57BL/6J mice treated with Adenosine 5'-monophosphate monohydrate (5′-AMP) markedly increases hepatic adenosine level. Survival rate in PBS-treated mice (n=15) is 60% (8 h) and 33.3% (24 h), whereas survival rate in Adenosine 5'-monophosphate monohydrate-treated mice (n=15) is 100% (8 h) and 93.3% (24 h). Serum aspartate transaminase (AST) and alanine transaminase (ALT) levels are significantly lowered in the Adenosine 5'-monophosphate monohydrate group than in the vehicle group. The area and extent of necrosis is attenuated and the infiltration of inflammatory cells is reduced in the Adenosine 5'-monophosphate monohydrate group^[2].