Anti-inflammatory activity of 2-((3-(chloromethyl)benzoyl)oxy)benzoic acid in LPS-induced rat model

Salicylic acid derivate is very popular for its activity to suppress pain, fever, and inflammation. One of its derivatives is acetylsalicylic acid (ASA) which has been reported repeatedly that, as a non-steroidal anti-inflammatory drug (NSAID), it has a cardioprotective effect. Although ASA has various advantages, several studies have reported that it may induce severe peptic ulcer disease. We recently synthesized a new compound derived from salicylic acid, namely 2-((3-(chloromethyl)benzoyl)oxy)benzoic acid (3-CH₂Cl) which still has the benefit of acetylsalicylic acid as an analgesic and antiplatelet, but lacks its harmful side effects (Caroline et al., 2019). In addition, in silico studies of 3-CH₂Cl showed a higher affinity towards protein receptor cyclooxygenase-2 (COX-2; PDB: 5F1A) than ASA. We hypothesized that 3-CH₂Cl inhibits the COX-2 activity which could presumably decrease the inflammatory responses. However, no knowledge is available on the anti-inflammatory response and molecular signaling of this new compound. Hence, in this study, we investigated the potential functional relevance of 3-CH₂Cl in regulating the inflammatory response in lipopolysaccharide (LPS)-induced rats. The results of this study show that this compound could significantly reduce the inflammatory parameter in LPS-induced rats.

Rats were induced with LPS of 0.5 mg/kg bw intravenously, prior oral administration with vehicle (3% Pulvis Gummi Arabicum / PGA), 500 mg/60 kg body weight (bw; rat dosage converted to human) of 3-CH₂Cl and ASA. The inflammatory parameters such as changes in the temperature of septic shock, cardiac blood plasma concentrations of IL-1β and TNF-α (ELISA), blood inflammation parameters, white blood cell concentrations, and lung histopathology were observed. Meanwhile, the stability of 3-CH₂Cl powder was evaluated.

After the administration of 500 mg/60 kg bw of 3-CH₂Cl (rat dosage converted to human) to LPS-induced rats, we observed a significant reduction of both TNF-α (5.70+/-1.04 × 10³ pg/mL, p=<0.001) and IL-1β (2.32+/-0.28 × 10³ pg/mL, p=<0.001) cardiac blood plasma concentrations. Besides, we found a reduction of white blood cell concentration and the severity of lung injury in the 3-CH₂Cl group compared to the LPS-induced rat group. Additionally, this compound maintained the rat body temperature within normal limits during inflammation, preventing the rats to undergo septic shock, characterized by hypothermic (t = 120 min.) or hyperthermic (t = 360 min) conditions. Furthermore, 3-CH₂Cl was found to be stable until 3 years at 25°C with a relative humidity of 75 ± 5%.

3-CH₂Cl compound inhibited inflammation in the LPS-induced inflammation response model in rats, hypothetically through binding to COX-2, and presumably inhibited LPS-induced NF-κβ signaling pathways. This study could be used as a preliminary hint to investigate the target molecular pathways of 3-CH₂Cl as a novel and less toxic therapeutical agent in alleviating the COX-related inflammatory diseases, and most importantly to support the planning and development of clinical trial.