Evaluation of analgesic and anti-inflammatory activities of Warionia saharae essential oil

Abstract

Warionia saharae Benth & Coss (W.s) (Asteraceae) is a monospecific genus endemic to Algeria and Morocco. Its leaves are used in their traditional medicine, such as gastrointestinal and inflammatory diseases; for instance, rheumatoid arthritis treatment. In this work, our team investigated the anti-inflammatory and analgesic effects of essential oil extracted from the dried upper parts of Warionia saharae based on different standard experimental test models. The analgesic activity was assessed by central and peripheral models, such as “hot plate” and “writhing” tests on Swiss albino mice. The hot plate test used latency measurements to assess acute cutaneous pain sensitivity, as a result; the latency of the hind-paw pain response was by licking and either shaking or jumping, those occurrences were recorded. Writhing test as a chemical method used to induce pain of peripheral origin in mice by injecting acetic acid intraperitoneally (IP). This results in characteristic stretching behavior of the animals (cramps and contortions). The evaluation of the analgesic activity, shows that the essential oil of this plant induces a decrease in the number of abdominal cramps in the contortion test and a maximum inhibition of pain. As for the anti-inflammatory effect, it was studied by the “paw edema” test, a phlogogenic agent (formaldehyde) was used to stimulate inflammation in the paws of mice. Anti-inflammatory properties can be observed by inhibiting this edema compared to the standard drug Diclofenac. In conclusion, Warionia saharae essential oil (75 mg/kg) showed a strong anti-inflammatory and analgesic activities which supports the conventional use of this plant in traditional medicine.