Phytochemical Evaluation and Molecular Docking of Bioactive Compounds in Citrus sinensis Stem Bark with Anti-Inflammatory Activity

Sweet orange has been claimed to possess anti-carcinogenic properties, anti-inflammatory, antioxidant, and as a relief agent to many health conditions which can be attributed to its chemical composition. This study has been carried out to validate the claim of the anti-inflammatory activity of the plant stem bark. The Chloroform extract of Citrus sinensis stem bark was screened for its phytochemical composition and anti-inflammatory activity using gas chromatography-mass spectrometry (GCMS), and in silico molecular docking. Twenty-four (26) phytochemical compounds were identified in the extract. The major phytochemical with highest percentage area was 9-Octadecenoic acid. The molecular docking analysis showed that the compounds had good binding affinity against the target protein cyclooxygenase-2 (COX-2) active site. The best binding affinity was observed in 9-Octadecenoic acid (-8.3 kcal/mol), and Cyclododecanol, 1-aminomethyl- (-7.2 kcal/mol). The binding affinities were better than the non-steroidal anti-inflammatory drug (NSAIDs), Ibuprofen (-6.8 kcal/mol). These findings provide more evidence to support the traditional use of sweet orange stem bark for anti-inflammatory treatment. Structural models of the interactions of the compounds with high binding affinities at the (COX-2) active site are plausibly useful for the future design of anti-inflammatory agent.