ANALGESIC, ANTI-INFLAMMATORY AND ANTIDEPRESSANT ACTIVITIES OF TRITERPENE FROM MEIOCARPIDIUM LEPIDOTUM (ANNONACEAE) BARK

ABSTRACT

The traditional phytomedicine: Meiocarpidium lepidotum (Oliv.) Engl. & Diels (Annonaceae) has been used in Fang community to treat illness. This study was designed to verify the antinociceptive, antidepressant, anti-inflammatory and acute toxicity of Meiocarpidium lepidotum (ML) extract in rats and mice. The crude aqueous extract of plant containing triterpene was used in different studies. Phytochemical qualitative analysis was performed using classical and UV methods. The analgesic activity was assessed by employing different pain models, such as tail flick tests for central analgesia, acetic acid-induced writhing (peripheral analgesic model), carrageenan-induced hyperalgesia (inflammation model) in mice. In rats, an antidepressant activity was assessed by swimming test. Our study demonstrated that the crude aqueous extract of ML containing triterpene was not toxic, was capable of preventing nociception, inflammation and depression at a concentration of nearly 1 mg/kg of bodyweight. In mice, ML induced reduction of swelling of the edema paws. This anti-inflammatory effect is similar to the one obtained with 150 mg of acetylsalicylic acid (ASA) and 10 mg of indomethacin for 3 hours. It significantly reduces after 4 hours (p<0.001). The analgesic effect of 1 mg/kg of ML was similar to the effect of 0.1 mg/kg of morphine (Mph) in tail-flick tests (p<0.001) and that of 150 mg of ASA in acetic acid-induced writhing test. In addition, this study showed that 1 mg/kg of ML exhibited antidepressant effect similar to the one obtained with 32 mg/kg of Fluoxetine (p<0.01). To our knowledge, this is the first demonstration of the pronounced analgesic, anti-inflammatory and antidepressant effect of ML in vivo studies. This work validates the traditional use of ML in the Congo Basin forest as phytomedicine.

Key words: Carrageenan, tail flick, Antinociception, Anti-inflammation, Antidepressant, Meiocarpidium lepidotum, Congo Basin Forest.