The aim of this study was to evaluate the effect of ylang-ylang (Cananga odorata) essential oil (YEO) on models of experimental arthritis, persistent inflammation, and nociception in mice. YEO treatment at doses of 100 and 200 mg/kg reduced the infiltration of leukocytes into the joint cavities of mice submitted to zymosan-induced arthritis 6 h and 7 days after arthritis induction. At these doses, YEO treatment reduced the formation of joint edema 4 and 6 h after arthritis induction, and at a dose of 200 mg/kg, YEO treatment reduced mechanical hyperalgesia 3 and 4 h after arthritis induction. At the dose of 200 mg/kg, YEO treatment reduced interleukin-6 (IL-6) levels and cartilage destruction in the zymosan-induced arthritis model, and reduced edema formation and mechanical hyperalgesia in the model of persistent inflammation (21 days) induced by complete Freund’s adjuvant (CFA) in mice. YEO treatment at a dose of 200 mg/kg reduced the nociceptive response in experimental models of nociception induced by acetic acid and formalin. The YEO treatment reduced inflammatory parameters in the experimental arthritis model, and presented antiarthritic, anti-hyperalgesic, antinociceptive, and anti-inflammatory properties.

Nonclinical trials are important to validate the efficacy and safety of medicinal plants. Scientific toxicological studies with Piper vicosanum Yuncker have showed its safety; however, no studies have indicated the analgesic or antiarthritic potential of the ethanolic extract of P. vicosanum leaves (EEPV). The objective of the present work was to evaluate the antiarthritic and antinociceptive effects of EEPV in experimental mouse models. The oral administration of EEPV (100, 300, and 700 mg/kg) and dexamethasone (1 mg/kg) were performed in carrageenan-induced pleurisy, in formalin and acetic-acid-induced nociception, and in zymosan-induced articular inflammation models in Swiss mice. The EEPV (300 mg/kg) was tested in zymosan-articular inflammation, the complete Freund’s adjuvant (CFA) inflammatory model, and in in situ intravitreal microscopy analysis of rolling and adhesion events of leukocytes in the mesenteric microcirculation in mice. EEPV significantly inhibited: (i) nociceptive response at phase 1 and 2, and also in the cold response in the formalin model; (ii) abdominal contortion induced by acetic acid; (iii) mechanical hyperalgesia after 4 and 6 h, knee edema after 6 h, and leukocyte migration in articular inflammation induced by zymosan. All doses of EEPV reduced the leukocyte migration to the inflamed pleural cavity and knee edema 4 h after the zymosan knee injection. The treatment with the EEPV significantly inhibited the CFA-induced edema, mechanical and cold hyperalgesia, and NAG and MPO. The EEPV also significantly inhibited carrageenan-induced leukocyte rolling and adhesion. The present study revealed, for the first time, the antiarthritic and antinociceptive effects of the EEPV.

Delta-3-carene (CAR), a monoterpene derived from plant essential oils, exhibits promising biological properties, including anti-inflammatory, antioxidative, anxiolytic, and antimicrobial activities. Therefore, this study aimed to investigate the anti-inflammatory effects of CAR by analyzing the activity of this terpene on leukocyte activation through the evaluation of cell migration in in vitro and in vivo models. Cell viability analysis demonstrated that CAR (3, 10, 30, and 90 μg/mL) exerted no cytotoxic effects and significantly reduced in vitro neutrophil chemotaxis toward N-formylmethionyl-leucyl-phenylalanine (fMLP). Furthermore, CAR decreased phagocytosis in zymosan-stimulated neutrophils in vitro. In Swiss mice, oral CAR treatment, at doses of 25, 50, and 100 mg/kg, reduced inflammatory and antinociceptive parameters in zymosan-induced peritonitis, carrageenan-induced paw edema and mechanical hyperalgesia, and nociception induced by acetic acid and formalin models. In the persistent inflammation model (for 21 days) induced by complete Freund’s adjuvant (CFA), daily CAR treatment (50 mg/kg) reduced paw edema and mechanical hyperalgesia in all evaluated times at 6, 11, 16, and 21 days after CFA-induced inflammation. In conclusion, our data demonstrated that CAR modifies acute and chronic inflammatory responses, highlighting its potential therapeutic application in managing inflammation and pain.