Anti-inflammatory and Antinociceptive Potential of Hydroethanolic Extract of Bauhinia guianensis Aubl. In Zebrafish (Danio rerio)
Authors: Koga Rosemary de Carvalho Rocha , De Souza Agerdanio Andrade , Sales Priscila Faimann , Ferreira Adriana Maciel , Souza Gisele Custódio de , Carvalho José Carlos Tavares 
Published: October 2023

The leaves and stems of Bauhinia guianensis Aubl. are used in traditional Amazonian phytotherapy for the treatment of pain and inflammation. This study investigates the anti-inflammatory and antinociceptive effects of hydroethanolic extracts from B. guianensis Aubl. leaves and stems (HELBg and HESBg, respectively) in in vivo models of inflammation and hyperalgesia. Danio rerio experimental animals were submitted to the acute inflammation test, induced by intraperitoneal (ip.) administration of carrageenan 20 μg / animal (abdominal edema), the groups were previously treated orally with saline solution 2 μl / animal (SS), Dimethyl sulfoxide 2 μl / animal (DMSO), Indomethacin 10 mg/kg, HELBg 100 mg/kg and HESBg 100 mg/kg, n = 12 per experimental group, to evaluate inhibition of edema and alterations histopathology of the liver, intestine and kidney of these animals. The antinociceptive effect was observed from the body curvature index and the behavioral responses of Danio rerio, after an experimental protocol for the induction of hyperalgesia, by ip. administration of 10 μl / animal of 2.5% acetic acid, the animals were previously orally treated with saline solution 2 μl/animal (SS), dimethyl sulfoxide 2 μl/animal (DMSO), morphine 2.5 mg/kg, HELBg 100 mg/kg and HESBg 100 mg/kg, n = 5 per experimental group. In carrageenan-induced edema, the group treated with HESBg inhibited edema formation over the 3 hours of the experiment. Maximum edema was inhibited by 54% (p &amp;lt; 0.05) when compared to the control group. Both HELBg and HESBg prevented body curvature index changes (t (df = 3 8) =, 6.96 and t (df = 3, 8) = 6.61, respectively, both p &amp;lt; 0.0001). In the behavioral parameters sensitive to antinociceptive pharmacological modulation, due to the abdominal constriction induced by acetic acid, the administration of HELBg and HESBg resulted in an improvement in swimming activity, by increasing the distance covered (F (df = 3, 16) = 6.50 and F (df = 3, 16)  = 7.72, respectively, both p &amp;lt; 0.0001), decrease in freezing time (F (df = 3, 16)  = 2.04 and F (df = 3, 16)  = 1.28, respectively, both p &amp;lt; 0.0059), increase in the number of ascents to the upper area of the tank (F (df = 3, 16)  = 33.02 and F (df = 3, 16)  = 35.62, respectively, both p &amp;lt; 0.0009 ) and decreased time spent in that area (F (df = 3, 16)  = 101.19 and F (df = 3, 16)  = 103.59, respectively, both p &amp;lt; 0.0038). It is reasonable to suppose that both extracts modulated the variations induced by carrageenan and acetic acid through the inhibition of prostaglandin biosynthesis, decreasing the release of inflammatory mediators and the sensitization of peripheral nociceptors and, consequently, the perception of pain. These results suggest that HELBg and HESBg have anti-inflammatory and antinociceptive activities, probably of peripheral origin and linked to the inhibition of prostaglandin biosynthesis.