ABSTRACT
This study describes the antinociceptive activity of extracts (methanolic (ME) and acetonic (AE)) and two phenolic compounds, 3,4,3'-trimethoxyflavellagic acid (1) and 3,4,3'-trimethoxy flavellagic acid 4'-O-glucoside (2), from Plinia glomerata leaves, against different experimental models of pain in mice. When evaluated against writhing test, by i.p. route, ME and AE presented calculated ID(50) values (and respective confidence interval) of 3.28 (1.63-6.61) and 24.79 (16.57-37.09) mg/kg, respectively. Given by the oral route at 500 mg/kg, AE and ME extracts inhibited the abdominal constrictions by 60.5% and 35.3%, respectively. In the formalin test (10 mg/kg, i.p.), AE inhibited both phases of pain (45.6% in the first phase; 99.8% in the second phase) whereas ME inhibited 47.8% the first phase, and 92.6% the second phase. In the capsaicin test both extracts showed activity, with calculated ID(50) values of 6.56 (5.69-7.56) and 7.68 (4.94-11.93) mg/kg for AE and ME, respectively. When evaluated against the hot-plate test, both extracts demonstrated activity, but only in high doses. Compound 2, when evaluated against the formalin test (10 mg/kg, i.p.), inhibited both phases of pain (77.6%, first phase; 62%, second phase) whereas 1 inhibited only the first phase, with inhibition of 70%. When tested in the capsaicin and glutamate tests, at 10 mg/kg, i.p., 1 and 2 caused inhibitions of 41.5% and 37.9%, and 37.7% and 54.5%, respectively. These results confirm previous studies carried out by our research group regarding the antinociceptive properties of P. glomerata, stimulating other studies on mechanism of action as well as the determination of additional active principles in this plant.
Subject(s)
Analgesics/pharmacology , Ellagic Acid/analogs & derivatives , Myrtaceae/chemistry , Phenols/pharmacology , Acetic Acid , Acetone , Analgesics/isolation & purification , Analgesics, Opioid/pharmacology , Animals , Capsaicin , Ellagic Acid/isolation & purification , Ellagic Acid/pharmacology , Formaldehyde , Glutamic Acid , Hot Temperature , Injections, Intraperitoneal , Male , Methanol , Mice , Morphine/pharmacology , Pain Measurement/drug effects , Phenols/isolation & purification , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Leaves/chemistry , SolventsABSTRACT
The present study describes the analgesic activity of extracts and some fractions obtained from Erythrina crista-galli leaves in different in vivo analgesic models, using mice as experimental animals. The results showed that extract E(2) was the most active, inhibiting 48% of the abdominal constrictions when evaluated against the writhing test at 10 mg kg(-1), intraperitoneal. It also caused dose-dependent inhibition in the same model, with a calculated ID(50) value and respective confidence interval of 10 (9-14) mg kg(-1), and was more potent than reference drugs. Administered orally, E(2) caused potent antinociceptive action, with a calculated ID(50) value of 35 (26-47) mg kg(-1). The fractions F(1) and F(2) obtained from E(2) were evaluated against the writhing test at 10 mg kg(-1), causing inhibitions of 41 and 88%, respectively. The most active fraction, F(2), presented ID(50) calculated value of 3 (2-4) mg kg(-1), being about 7-fold more active than the reference drugs (acetyl salicylic acid and acetaminophen). In the formalin test, F(2) inhibited both phases of pain (44%, first phase; 58%, second phase). However, in contrast to the results observed for E(2), it was not active against the hot-plate test. The phytochemical results showed that at least four main components are present in F(2), which show a positive reaction of terpenes with TLC spray reagents.
Subject(s)
Analgesics, Non-Narcotic/pharmacology , Erythrina/chemistry , Pain Measurement/drug effects , Plant Extracts/pharmacology , Analgesics, Non-Narcotic/chemistry , Animals , Male , Mice , Plant Components, Aerial/chemistry , Plant Extracts/chemistry , Plants, Medicinal/chemistry , Random AllocationABSTRACT
The present work describes the antinociceptive properties and chemical composition of the aerial parts of Plinia glomerata (Myrtaceae). Both of the extracts evaluated, acetonic and methanolic, showed potent antinociceptive action, when analyzed against acetic acid-induced abdominal constrictions in mice, with calculated ID50 (mg/kg, i. p.) values of 24.8 and 3.3, respectively. Through usual chromatographic techniques with an acetonic extract, the following compounds were obtained: 3,4,3'-trimethoxy flavellagic acid (1), 3,4,3'-trimethoxy flavellagic acid 4'-O-glucoside (3) and quercitrin (4), which were identified based on spectroscopic data. Compounds 1 (ID50 = 3.9 mg/kg, i. p., or 10.8 micromol/kg) and 3 (ID50 = 1.3 mg/kg or 2.5 micromol/kg) were notably more active than some well-known analgesic drugs used here for comparison.