Evaluation of Anti-Inflammatory and Analgesic Effects of Calendula officinalis Extracts in Mice

Abstract

Background: Calendula officinalis (marigold) is a widely cultivated medicinal plant traditionally used for centuries to treat various ailments due to its therapeutic properties. Aims: This study aimed to evaluate the anti-inflammatory and analgesic effects of ethanolic and ethyl acetate extracts of Calendula officinalis in mice. Study Design: Randomized, controlled, parallel-group, blinded preclinical study. Place and Duration of Study: Ecosystem and Environmental Sciences Team & Laboratory of Pharmacology, Neurobiology, Anthropology and Environment, between September 2025 and April 2026. Methodology: A total of 36 adult male Swiss mice were randomly allocated into six groups (n = 6 per group): control (saline), positive controls (acetylsalicylic acid, morphine, or diclofenac depending on the test), and four treatment groups receiving ethanolic extract (100 and 200 mg/kg, p.o.) or ethyl acetate extract (100 and 200 mg/kg, p.o.). Analgesic activity was assessed using the acetic acid-induced writhing test, formalin-induced paw licking test, and hot-plate test. Anti-inflammatory activity was evaluated using the xylene-induced ear edema model. Results: Both extracts exhibited significant dose-dependent analgesic and anti-inflammatory activities. In the acetic acid-induced writhing test, inhibition of nociception reached 61.59 ± 2.47% for the ethanolic extract and 71.44 ± 2.73% for the ethyl acetate extract at 200 mg/kg. In the formalin test, both extracts significantly reduced licking time in both early and late phases. The hot-plate test showed increased latency, particularly with the ethyl acetate extract, indicating central analgesic activity. In the xylene-induced ear edema model, both extracts significantly reduced inflammation, which was confirmed by histological analysis showing decreased edema and leukocyte infiltration. Conclusion: Calendula officinalis extracts possess significant antinociceptive and anti-inflammatory properties, likely related to their rich phenolic and flavonoid content. The ethyl acetate extract demonstrated comparatively greater pharmacological activity.