Ethnopharmacological relevance-Paullinia pinnata L. (Sapindaceae) is an African woody vine, traditionally used for the treatment of itch and pain-related conditions such as rheumatoid arthritis. Aim-This work evaluates, in vitro and in vivo, the anti-inflammatory and analgesic effects of aqueous (AEPP) and methanol (MEPP) extracts from Paullinia pinnata leaves. Methods-AEPP and MEPP (100, 200 and 300 mg/kg/day) were administered orally in monoarthritic rats induced by a unilateral injection of 50 μl of Complete Freund's Adjuvant (CFA) in the ankle joint. During the 14 days of treatment, pain and inflammation were evaluated alternatively in both ankle and paw of the CFA-injected leg. Malondialdehyde (MDA) and glutathione (GSH) levels were assessed in serum and spinal cord. Histology of smooth tissue of the paw was also analyzed. For in vitro studies, AEPP and MEPP (10, 30 and 100 μg/ml) were

AEPM and MEPM given orally are effective in inhibiting mechanical hyperalgesia in persistent inflammatory pain caused by CFA. Their mechanisms of action seem to involve an interaction with PKC, PKA and nitric oxide pathways. These extracts might be devoid of hepatotoxic effects.

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BackgroundThe leaves of Oxyanthus pallidus Hiern (Rubiaceae) are extensively used in the west region of Cameroon as analgesic. These leaves are rich in cycloartanes, a subclass of triterpenes known to possess analgesic and anti-inflammatory properties. The present study aimed at evaluating the analgesic properties of three cycloartanes isolated from Oxyanthus pallidus leaves as well as their aglycones and acetylated derivatives.MethodsThree cycloartanes OP3, OP5 and OP6 obtained by successive chromatography of the crude methanol extract of the leaves were hydrolysed to yield respective aglycone AOP1, AOP2, AOP3 and acetylated to HOP1, HOP2 and HOP3 respectively. Formalin-induced pain model was used to evaluate the acute anti-nociceptive properties of these cycloartanes (5 mg/kg, p.o) in mice and to determine the structure-activity relationship. Acute (24 h) and chronic (10 days) anti-hyperalgesic and anti-inflammatory activities of OP5 were evaluated at the doses of 2.5 and 5 mg/kg/day administered orally. OP6 was also evaluated in acute experiments. The antioxidant and hepato-protective activities of OP5 were evaluated at the end of the chronic treatment.ResultsThe mixture and the individual isolated cycloartanes significantly inhibited both phases of formalin-induced pain with percentage inhibition ranging from 13 to 78 %. Acid hydrolysis did not significantly affect their antinociceptive activities while acetylation significantly reduced the effects of these compounds during the second phase of pain. OP5 and OP6 induced acute anti-hyperalgesic activity in formalin-induced mechanical hyperalgesia but not an anti-inflammatory effect. Repeated administration of OP5 for 10 days did not induce any anti-hyperalgesic effect. The evaluation of in vivo antioxidant properties showed that OP5 significantly reduced malondialdehyde and increased superoxide dismutase levels in liver without significantly affecting other oxidative stress and hepatotoxic parameters. Chronic administration of OP5 did not cause gastric ulceration.ConclusionCycloartanes isolated from Oxyanthus pallidus possess analgesic effects but lack anti-inflammatory activities. This analgesic effect especially on inflammatory pain may be due to the presence of hydroxyl group in front of the plane. OP5 is devoid of ulcerogenic effect and possess antioxidant properties that might be of benefit to its analgesic properties.

BackgroundBoerhavia coccinea (Nyctaginaceae) is an herbaceous plant used for the treatment of pain. The aim of this study was to evaluate the antinociceptive and anti-inflammatory activities of the aqueous (AEBC) and ethanol (EEBC) extracts of Boerhavia coccinea as well as the major fractions (F1, F2 and F3) from EEBC.MethodsThe antinociceptive effect of the extracts and fractions was evaluated using formalin test. AEBC, EEBC and F1 were selected and further evaluated acutely (24 h) and chronically (16 days) in Complete Freund’s Adjuvant (CFA)-induced persistent inflammatory pain for their antihyperalgesic and anti-inflammatory effects. They were administered orally (100 and 200 mg/kg/day) from 48 h following the intraplantar injection of 100 µL of CFA. After the 16 days of chronic treatment, rats’ spinal cord and brain were collected for the evaluation of oxidative stress parameters namely nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT).ResultsAEBC, EEBC and F1 significantly inhibited the first and second phases of the formalin-induced pain. They significantly reduced the hyperalgesia both in acute and chronic treatments. These extracts showed no acute anti-inflammatory effect. AEBC and EEBC exhibited anti-inflammatory activities after repeated administration. AEBC, EEBC and F1 significantly reduced MDA level and significantly increased SOD and catalase activities, mainly in the spinal cord. AEBC and EEBC also reduced the NO production in the spinal cord.ConclusionsBoerhavia coccinea extracts and F1 possess potent antinociceptive activity which is not related to their anti-inflammatory properties. Their antioxidant effects may contribute to these activities in chronic treatment.

Pain treatment is one of the most challenging situations of the modern medicine. To overcome the actual limitations, new strategies should be developed and phytotherapy represents a promising alternative. Boerhavia coccinea is a medicinal plant used for the treatment of pain. The present work was undertaken to evaluate the antinociceptive effects of crude aqueous extract of the leaves of Boerhavia coccinea (AE) on acute pain and examine its mechanism of action. The analgesic effect of AE was evaluated at doses 50, 100, 200 and 400 mg/kg using the formalin-induced nociception in mice. The specific analgesic effect of AE was verified by testing its effect of AE on the sleep induced by diazepam. The anti-inflammatory effects of AE were also tested in vivo (100 and 200 mg/kg) on CFA-induced inflammation and in vitro