Background: Our present study was carried out to explore the potential role of the methanol extract from the leavesof Phlogocanthus thyrsiflorus (PT) Nees. in central and peripheral analgesic activities using hot plate and acetic acid-induced writhing methods. We also tested the antiinflammatory effects and anti-oxidant activity using carrageenan-induced paw edema and the DPPH method, respectively.
Methods: Methanol extracts of PT leaves were prepared using 500 g powder in 1.8 L methanol by percolation method, followed by evaporation in a rotary evaporator under controlled temperature and pressure. The crude methanol extract was dried by freeze drier and preserved at 4 °C.
Results: Oral administration of PT significantly (p < 0.05)increased the reaction time at 55.73% (250 mg/kg) and 72.81% (500 mg/kg) inhibition (p < 0.05) in the hot plate test at 3 h. PT significantly (p < 0.05) inhibited 42.17% (250 mg/kg) and 56.63% (500 mg/kg) acetic acid-induced writhing. PT leaves (250 and 500 mg/kg) also significantly (p < 0.05) inhibited paw edema 6 h after carrageenan injection. Furthermore, this plant showed significant (p < 0.05) free radical-scavenging activity at a dose range of 25–800 μg/mL.
Conclusions: Based on the findings, we can conclude that PT leaf possesses analgesic, anti-inflammatory, and antioxidant activities. Preliminary phytochemical study of PT leaves revealed the presence of flavonoids, tannins and triterpens in methanol extract which could be correlated with its observed biological activities.