Background: The fronds of Drynaria quercifolia have traditionally been used in rheumatic pain management. The goal of the present study was to validate the potent anti-inflammatory and anti-rheumatoid properties of the methanolic-extract of its rhizome using in vitro, in vivo and in silico strategies.
Methods: The plant was collected and the methanolic extract was prepared from its rhizome. Protein denaturation test, hypotonicity and heat-induced haemolysis assays were performed in vitro. The in vivo anti-rheumatoid potential was assessed in Freund's complete adjuvant (FCA)-induced Wistar rat model through inflammatory paw-edema, haematological, biochemical, radiological and histopathological measurements. Moreover, metabolites of methanolic extract were screened by gas chromatography-mass spectrometry (GC-MS) and 3D molecular structures of active components were utilized for in silico docking study using AutoDock.
Results: In vitro results evinced a significant (p < 0.05) anti-inflammatory activity of the rhizome methanolic extract in a dose-linear response. Further, Drynaria quercifolia rhizome methanolic extract (DME) significantly ameliorated rheumatoid arthritis as indicated by the inhibition of arthritic paw-edema (in millimeter) in the rat rheumatoid arthritis models in both the low (57.71 ± 0.99, p < 0.01) and high dose groups (54.45 ± 1.30, p < 0.001) when compared to arthritic control. Treatment with DME also normalized the haematological (RBC, WBC, platelet counts and hemoglobin contents) and biochemical parameters (total protein, albumin, creatinine and ceruloplasmin) significantly (p < 0.05), which were further supported by histopathological and radiological analyses. Furthermore, GC-MS analysis of DME demonstrated the presence of 47 phytochemical compounds. Compounds like Squalene, Gamma Tocopherol, n-Hexadecanoic acid showed potent inhibition of cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukin (IL-6) in the docking analysis.
Conclusion: Results from in vivo and in vitro studies indicated that DME possesses a potent anti-inflammatory and anti-arthritic activity. In silico studies delineated the emergent potent inhibitory effects of several bio-active components on the target inflammatory markers (COX-2, TNF-α and IL-6).
Keywords: Drynaria quercifolia; GC-MS; Inflammation; Molecular docking; Paw edema; Rheumatoid arthritis.