ETHNOPHARMACOLOGICAL RELEVANCE: Argyreia capitiformis (Poir.) Ooststr. (Convolvulaceae) is traditionally used by the Chakma community in the hilly region of Bangladesh to treat minor disorders such as pain.
AIM OF THE STUDY: This study intended to determine the secondary metabolites to identify bioactive compounds and evaluate antioxidant potential, in vitro anti-inflammatory and in vivo analgesic, anti-inflammatory, and antihyperglycemic activities of A. capitiformis along with in silico investigations.
MATERIALS AND METHODS: Chemical profiling was carried out using HPLC and GC-MS analysis. The analgesic effect was measured employing tail immersion and acetic acid-induced writhing methods. Following protein denaturation and formalin-induced paw edema, anti-inflammatory activity was studied. The antihyperglycemic potential was assessed using an oral glucose tolerance test (OGTT), while further mechanistic investigation was conducted using an alpha-glucosidase enzyme inhibitory assay. Simulations and molecular docking analyses were performed to ascertain the stability and binding affinities of the drug-protein complex.
RESULTS: A. capitiformis ethanolic extract confirmed the presence of phenolics, alkaloids, flavonoids, terpenoids, tannins, gums, steroids, and reducing sugars. HPLC analysis revealed the presence of eight polyphenolic compounds, the most abundant of which was myricetin (64.10 ± 0.14 mg per 100 g dry extract). Moreover, the GC-MS analysis revealed twenty-four molecules, the most important of which was 2,4-bis (dimethylbenzyl)-6-t-butylphenol (9.19%). The concentrations of total flavonoids, total terpenoids, total phenolics, and total tannins were ascertained to be 142.48 mg QE/g, 173.1 mg UAE/g, 19.35 mg GAE/g, and 13.05 mg GAE/g, respectively. Furthermore, the plant extract had a total antioxidant capacity of 388 mg AAE/g. In the writhing assay, the plant extract suppressed writhing by 59.73% and 76.99% at the doses of 250 and 500 mg/kg, respectively, compared to the standard diclofenac Na 87.17%, and in the tail immersion assay, the plant extract displayed a maximum average reaction time of 1.94 and 2.40 s at the doses of 250 and 500 mg/kg, respectively as compared to the control tramadol 2.84 s at 60 min. In an in vitro anti-inflammatory assay, the plant extract possessed an IC50 of 95.51 μg/ml while diclofenac Na (standard drug) was found to be 69.50 μg/ml. Afterward, in vivo anti-inflammatory activity was observed in mice over a period, particularly after 3 h, the plant extract exerted maximum percent inflammation inhibitions of 36.36% and 45.45% at the doses of 250 and 500 mg/kg, respectively whereas ibuprofen the standard drug (100 mg/kg) exhibited 61.82%. The plant extract demonstrated antihyperglycemic activity, lowering blood sugar levels to 5.7 and 4.62 mM at doses of 250 and 500 mg/kg, respectively, as opposed to 8.58 mM in the control group. Meanwhile, the standard drug glibenclamide (5 mg/kg) dropped blood glucose levels to 2.38 mM in 60 min after glucose administration. Molecular docking (MD) and molecular dynamics simulation (MDS) studies support the stability of the protein complex responsible for exerting pharmacological activities.
CONCLUSION: A. capitiformis extract exhibited strong medicinal values supporting its traditional uses.