Anti-inflammatory, Antinociceptive, and Toxicological Properties of Uvaria comperei Stem Crude Extract and Fractions

Abstract

The present study was carried out to investigate the anti-inflammatory activity of a methanolic extract and fractions of Uvaria comperei stems. The crude extract was obtained by maceration of the powder in methanol and fractions by vacuum chromatography from the methanolic extract. To study the anti-inflammatory activity in vitro, red blood cell lysis inhibition assay and albumin denaturation inhibition were performed, while in vivo measurements of carrageenan-induced paw oedema and formalin-induced pain in albino mice were performed. Acute toxicity and cytotoxicity studies of the fraction F2 were performed, as well as its HPLC, and some biochemical parameters were quantified. Uvaria comperei crude extract (UCCE) at 250 and 500 μg/mL completely inhibited albumin denaturation, while decreasing 75.5% of heat blood cell lysis at 500 μg/mL. The fractions 128-136 (F3), 10-11 (F1), and 56-62 (F2) at 500 μg/mL displayed a significant anti-inflammatory activity with percentages of inhibition of 60.5, 67.4, and 100%, respectively. Administration of fraction F2 (25, 50, and 100 mg/kg, p.o.) produced a dose-dependent inhibition of formalin-induced pain of 60.2% at 50 mg/kg in the neurogenic phase ( $p<0.05$ ) and 70.2% at 25 mg/kg in the inflammatory phase ( $p<0.05$ ). Similarly, the time-dependent increase in carrageenan-induced paw circumference induced by carrageenan was inhibited by pretreatment with F2: 50% of inhibition at 25 mg/kg after 30 min ( $p<0.05$ ) and 96.5% inhibition at 25 mg/kg after 6 h ( $p<0.05$ ). In this research, the fraction F2 presented its maximum analgesic property at 50 mg/kg, while it presented the highest anti-inflammatory property at 25 mg/kg. The oral lethal median dose (LD50) of F2 was determined to be greater than 2000 mg/kg; further low cytotoxicity in RAW cells was also observed. Overall, this work shows that the methanolic crude extract and fractions, mainly F2, of Uvaria comperei stem have interesting anti-inflammatory properties.