Mehdi Ait Laaradia, Amina Ettitaou, Khadija Oubella, Jawad Laadraoui, Zineb El Gabbas, Adil El Housseini, Youssef El Joud, Moulay Abdelmonaim El Hidan, Loubna Elyazouli, Ait Baamrane Moulay Abdeljalil, Toulon Oulaid, Abderrahman Chait
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.