Cassia fistula leaves extract profiling and its emphasis on induced ulcerative colitis in male rats through inhibition of caspase 3 and cyclooxygenase-2

The objective of the study was to determine the total phenolic and total flavonoid contents (TPC and TFC, respectively), as well as the solvent-partitioned fractions, of the leaf extract of Cassia fistula. Using DPPH, TAC, and FRAP tests, the in vitro antioxidant properties of crude extract and its ethyl acetate fraction were investigated. Additionally, C. fistula chemical profiling was accomplished using LC-ESI-MS/MS. Along with that, the effectiveness of crude extract (200 and 400 mg/kg) in treating male rats with ulcerative colitis (UC) induced by acetic acid was assessed. According to the findings, the ethyl acetate fraction had the highest concentrations of TPC (12.36 1.46 mg GAE/100 mg) and TFC (5.12 0.64 mg QE/100 mg), as well as impressive in vitro antioxidant activity with IC50 values of DPPH (12.7 g/mL), FRAP (4.87 0.71 mM Fe+2/g), and TAC (55. Fifty-five chemicals, predominantly phenolics (catechins, flavonoids, anthraquinones, chalcones, and phenolic acids), were detected by the LC/MS/MS. The anti-UC effect of C. fistula was dose-dependent. The hematological parameters, liver biomarkers, oxidative stress, histopathology, and immunohistochemistry revealed that prophylactic administration of crude extract to colitis rats ameliorated all the previous biomarkers. However, when the crude extract was administered on established colitis, it facilitated the recovery of the inflamed mucosa and showed better results than the protection mode. The phytoconstituents of C. fistula that were discovered here by LC/MS/MS were examined by molecular docking studies for their binding affinities towards COX-2 and caspase-3 proteins to highlight the anti-inflammatory and antiapoptotic activities of the plant. The Emodin compound displayed the highest binding affinity for COX-2 proteins, while isorhamnetin was discovered to have the best binding associations with the essential amino acids of caspase-3. Procyanidin B2 interestingly shows potent interactions with important amino acids of two targets. This study has made it possible to utilize C. fistula in the treatment of UC and has clarified its mechanism of action.