Anti-inflammatory effect of the total flavonoid content of the hydroalcoholic extract of the leaves of Senna alata (L.) Roxb. in an experimental model of acute inflammation

Context: Acute inflammation due to persistent stimulation of noxes evolves into chronic inflammation that contributes to the pathogenesis of asthma, arthritis, atherosclerosis, diabetes, aging, and cancer; therefore, it is justified to study plants with anti-inflammatory activity and fewer adverse effects. Aims: To evaluate the potential anti-inflammatory effect of the total flavonoid content of the hydroalcoholic extract of the leaves of Senna alata (L.) Roxb (HELSA) in an experimental model of acute inflammation induced by carrageenan in rats. Methods: The total flavonoid content (TFC) was determined by spectrophotometry at 510 nm, total polyphenolic content (TPC) by the Folin-Ciocalteu method, and antioxidant activity by two in vitro methods. The oral median lethal dose (LD50) was determined by the logarithmic method, and acute inflammation was induced by 1% carrageenan in rats. Results: The TFC was 1.63 ± 0.02 mg QE/100 mg and TPC was 22.90 ± 0.05 mg GAE/100 mg. Antioxidant capacity: DPPH IC50 2.89 ± 0.04 µg/µL; ABTS 11.67 ± 0.03 mM TEAC/100 mg dry extract. Correlation relationship TFC/DPPH (r = -0.9941; R2 = 0.9884), TFC/ABTS (r = 0.9971; R2 = 0.9944), TPC/DPPH (r = 0.5694; R2 = 0.3243) and TPC/ABTS (r = -0.5960; R2 = 0.3553). The LD50 was 9602 mg/kg. A significant decrease in rat paw edema (p<0.05) was evident from the first hour, in contrast to the negative control. The highest percentage of anti-inflammatory inhibition (75.75%) was at 7 hours with a dose of 500 mg/kg of HELSA, being higher than the effect of ibuprofen (39.40%) and lower than dexamethasone (87.87%). Conclusions: The total flavonoid content and polyphenols of the hydroalcoholic extract of the leaves of S. alata exhibit potential anti-inflammatory activity in a model of acute inflammation that should be examined with other experimental models to initiate clinical trials in humans.