Francis Desire Tatsinkou Bomba1, Bibiane Aimee Wandji1, Basile Nganmegne Piegang1, Maurice Ducret Awouafack2, Dharmarajan Sriram3, Perumal Yogeeswari3, Albert Kamanyi1, Telesphore Benoit Nguelefack4. 1. Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. 2. Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. 3. Neuropathic Pain Research Laboratory, Department of Pharmacy, Birla Institute of Technology & Science-Pilani, Hyderabad Campus, R.R. District, 500078 Andhra Pradesh, India. 4. Laboratory of Animal Physiology and Phytopharmacology, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon. Electronic address: nguelefack@yahoo.fr.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous maceration from the stem barks of Petersianthus macrocarpus (P. Beauv.) Liben (Lecythidaceae) is taken orally in the central Africa for the management of various ailments, including pain. AIM OF THE STUDY: This work was carried out to evaluate in mice, the antinociceptive effects of the aqueous and methanol extracts of the stem bark of P. macrocarpus. MATERIALS AND METHODS: The chemical composition of the aqueous and methanol extracts prepared as cold macerations was determined by high performance liquid chromatography coupled with mass spectrometry (LCMS). The antinociceptive effects of these extracts administered orally at the doses of 100, 200 and 400 mg/kg were evaluated using behavioral pain model induced by acetic acid, formalin, hot-plate, capsaicin and glutamate. The rotarod test was also performed at the same doses. The oral acute toxicity of both extracts was studied at the doses of 800, 1600, 3200 and 6400 mg/kg in mice. RESULT: The LCMS analysis revealed the presence of ellagic acid as the major constituent in the methanol extract. Both extracts of P. macrocarpus significantly and dose dependently reduced the time and number of writhing induced by acetic acid. They also significantly inhibited the two phases of formalin-induced pain. These effects were significantly inhibited by a pretreatment with naloxone, except for the analgesic activity of the methanol extract at the earlier phase. In addition, nociception induced by hot plate, intraplantar injection of capsaicin or glutamate was significantly inhibited by both extracts. Acute toxicity test showed no sign of toxicity. CONCLUSION: These results demonstrate that aqueous and methanol extracts of P. macrocarpus are none toxic substances with good central and peripheral antinociceptive effects that are at least partially due to the presence of ellagic acid. These extracts may induce their antinociceptive effect by interfering with opioid, capsaicin and excitatory amino acid pathways.
ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous maceration from the stem barks of Petersianthus macrocarpus (P. Beauv.) Liben (Lecythidaceae) is taken orally in the central Africa for the management of various ailments, including pain. AIM OF THE STUDY: This work was carried out to evaluate in mice, the antinociceptive effects of the aqueous and methanol extracts of the stem bark of P. macrocarpus. MATERIALS AND METHODS: The chemical composition of the aqueous and methanol extracts prepared as cold macerations was determined by high performance liquid chromatography coupled with mass spectrometry (LCMS). The antinociceptive effects of these extracts administered orally at the doses of 100, 200 and 400 mg/kg were evaluated using behavioral pain model induced by acetic acid, formalin, hot-plate, capsaicin and glutamate. The rotarod test was also performed at the same doses. The oral acute toxicity of both extracts was studied at the doses of 800, 1600, 3200 and 6400 mg/kg in mice. RESULT: The LCMS analysis revealed the presence of ellagic acid as the major constituent in the methanol extract. Both extracts of P. macrocarpus significantly and dose dependently reduced the time and number of writhing induced by acetic acid. They also significantly inhibited the two phases of formalin-induced pain. These effects were significantly inhibited by a pretreatment with naloxone, except for the analgesic activity of the methanol extract at the earlier phase. In addition, nociception induced by hot plate, intraplantar injection of capsaicin or glutamate was significantly inhibited by both extracts. Acute toxicity test showed no sign of toxicity. CONCLUSION: These results demonstrate that aqueous and methanol extracts of P. macrocarpus are none toxic substances with good central and peripheral antinociceptive effects that are at least partially due to the presence of ellagic acid. These extracts may induce their antinociceptive effect by interfering with opioid, capsaicin and excitatory amino acid pathways.