RESUMO
Antiplasmodial and analgesic effects of crude ethanol extract of Piper guineense was investigated in mice. The antiplasmodial and analgesic efficacy of the extract was judged on its ability to reduce parasitemia and writhing, respectively, in mice. The antiplasmodial screening involved treating infected mice with 200, 400, and 600 mg/kg body weight of extract while the positive control group was given standard artesunate drug. The analgesic test was carried out by administering 1000, 1500, and 2000 mg/kg body weight of extract to three groups of healthy mice, respectively, after induction of pain with 0.75% acetic acid. The positive control group was given aspirin drug. Parasitemia was reduced by 28.36%, 43.28%, and 62.69% in a dose-dependent pattern in the curative test which was significantly different (P < 0.05) from 96.03% of the standard drug. The reduction of writhing by mice given the extract was also dose-dependent (36.29, 45.43, and 59.07%). Aspirin drug was however more effective (86.36%). The extract was safe at 2000 mg/kg body weight. Phytochemical screening revealed the presence of flavonoids, tannins, phlobatannins, terpenoids, and coumarins. Result obtained in this study demonstrated the efficacy of ethanol extract of Piper guineense as an antiplasmodial and analgesic agent.
RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Clausena lansium (Fool's Curry Leaf) is used for various ethnomedical conditions in some countries, including bronchitis, malaria, viral hepatitis, acute and chronic gastro-intestinal inflammation, and as a spicy substitute of the popular Curry leaf tree (Murraya koenigii). AIM OF THE STUDY: This study was to evaluate the ethnomedical uses of the stem bark in inflammatory conditions, hepatotoxicity and to determine the anti-diabetic and anti-trichomonal properties of the plant. MATERIALS AND METHOD: Anti-trichomonal, in vivo and in vitro antidiabetic and insulin stimulating, anti-inflammatory, hepatoprotective and anti-oxidant activities using Trichomonas gallinae, glucose loaded rats and in vitro insulin secreting cell line (INS-1 cell), carrageenin-induced rat paw oedema, CCl(4)-induced hepatotoxicity and DPPH scavenging ability methods respectively for the extracts and some isolates were determined. RESULTS: A dichloromethane extract was superior over methanolic extract with respect to an anti-trichomonal activity which was measured after 24 and 48 h. The isolated compounds imperatorin and 3-formylcarbazole had the main anti-trichomonal activity (LC(50)s of 6.0, 3.0 and 3.6, 9.7 microg/mL after 24 and 48 h, respectively). Methanolic extract (100 mg/kg) induced maximum and significant (p<0.05) anti-hyperglycaemic activity of 15.8% at 30 min and a 38.5% increase in plasma insulin at 60 min, compared to control. The increase in plasma insulin after 60 min, compared to 0 min, was 62.0% (p<0.05). The significant 174.6% increase of insulin release from INS-1 cells (in vitro) at 0.1 mg/ml indicates that it mediates its antidiabetic action mainly by stimulating insulin release. Imperatorin and chalepin were the major active constituents increasing in vitro insulin release to 170.3 and 137.9%, respectively. 100 mg/kg of the methanolic extract produced an anti-inflammatory activity after 4 h. A sedative effect was not observed. 100 and 200 mg/kg of methanolic extract administered i.p., reduced CCl4-induced hepatotoxicity firstly by 5.3 and 8.4% reduction in phenobarbitone-sleeping time respectively, secondly by reversing the reduction in serum liver proteins by 7.0-8.8%, serum AST, ALT and ALP activities by 27.7-107.9% and thirdly by diminishing increased values of plasma AST, ALT and ALP activities by 13.2-83.8%. The extract exhibited antioxidant activities. CONCLUSION: The hepatoprotective activity of C. lansium is partly due to its anti-oxidant and anti-inflammatory properties and confirms its folkloric use in the treatment of gastro-intestinal inflammation, bronchitis and hepatitis. In addition the use of C. lansium stem bark would be useful in diabetes and trichomoniasis.