In vitro antioxidant activity and in vivo antinociceptive and anti-inflammatory effects of the hydroethanolic extract from leaves of Myrciaria floribunda (H. West ex Willd.) O. Berg in Swiss mice

Myrciaria floribunda (H. West ex Willd.) O. Berg, a native species of the Myrtaceae family, is traditionally used in folk medicine and is known for its anticholinesterase, antioxidant, and antitumor properties. Despite this, its analgesic and anti-inflammatory effects remain underexplored. This study aimed to investigate the in vitro antioxidant and in vivo antinociceptive and anti-inflammatory activities of the hydroethanolic extract from M. floribunda leaves (MfHE). MfHE was prepared and analyzed by HPLC–DAD-MS, revealing 25 compounds, mainly tannins and flavonoids. Quantification showed 403.09 mg GAE/g of total phenolics and 2.94 mg QE/g of flavonoids. Antioxidant potential was evaluated using the DPPH assay (IC₅₀ = 63.24 μg/mL) and total antioxidant capacity (TAC 37.84%). Antinociceptive activity was assessed through acetic acid-induced writhing, formalin, and tail flick tests. MfHE (25, 50, and 100 mg/kg, p.o.) significantly reduced writhes by 35.30%, 47.06%, and 66.47%, respectively, inhibited both phases of the formalin test, and increased latency in the tail flick test by 100% at 100 mg/kg. Anti-inflammatory effects were evaluated in carrageenan-induced paw edema and peritonitis models. MfHE reduced paw edema at all doses and lowered total leukocytes (34.57%, 49.39%, 67.91%), neutrophils (28.31%, 52.84%, 60.33%), and pro-inflammatory cytokines IL-1β (52.46%, 66.84%, 75.85%) and TNF-α (44.75%, 69.05%, 87.26%) in peritonitis test. These findings suggest that MfHE, rich in polyphenols, has promising antioxidant, antinociceptive, and anti-inflammatory properties.