Antiedematogenic effects of the polar fractions of Persea cordata Mez. (Lauraceae) on microvascular extravasation in rat skin

Abstract

Ethnopharmacological relevancePersea cordata Mez. (Lauraceae) is a medicinal plant used in veterinary ethnopharmacology, which is a popular medicine used as an anti-inflammatory and healing agent, mainly on animal skin diseases, characterized by cutaneous open wounds, in South Brazil. Aim of this studyThe purpose of this study was to investigate a possible antiedematogenic effect of ethyl acetate (EtAc) and butanol (BuOH) polar fractions of Persea cordata on Evans blue dye leakage induced by pro-inflammatory agents in rat skin. Materials and methodsMale Wistar rats (180–200g, n=5–6) were pretreated with a single intraperitoneal administration of EtAc or BuOH (1 to 600mgkg−1) fractions followed by intravenous Evans blue dye injection (1%, 30mgkg−1, i.v.), 60min before the injection of phlogistic agents. Animals received intradermal injections (0.05ml) of carrageenan (CAR, 300µg/site), 48/80 compound (C4880, 10µg/site), histamine (HIS, 0.3µg/site), serotonin (5-HT, 0.01µg/site), dextran (DEX, 200µg/site), bradykinin (BK, 0.003µg/site), capsaicin (CPS, 400µg/site), substance P (SP, 0.003µg/site) or prostaglandin E2 (PGE2 10nmol/site) and they were submitted to euthanasia after 60min. Skin samples were obtained in the extravasation sites of Evans blue dye. Skin fragments were soaked in formamide at 37°C (during 24h) for Evans blue extraction. The amount of dye leakage in the tissue fragment was determined by a spectrophotometer (620nm). ResultsIn a very similar manner in terms of potency and efficacy, systemic administration of EtAc and BuOH fractions caused dose-dependent inhibition of vascular Evans blue dye leakage induced by phlogistic agents in the rat skin. The results obtained (ID50 values in mgkg−1 and maximal inhibition in %) with EtAc fraction, as follows were: CAR (34.42 and 63.0), 4880 (8.52 and 59.1), HIS (21.22 and 66.8), 5-HT (32.99 and 73.4), DEX (41.74 and 67.0), BK (34.03 and 68.0), CPS (100.7 and 77), SP (2.1 and 78.9) and PGE2 (133 and 71.0). BuOH fraction significantly inhibited CAR (25.9 and 70)-, 4880 (36.8 and 66)-, HIS (17.6 and 77)-, 5-HT (32.8 and 56)-, DEX (89.6 and 75)-, BK (28.0 and 66)-, CPS (136.37 and 71)-, SP (5.6 and 78)- and PGE2 (109.64 and 56)-induced VE, respectively. ConclusionSystemic administration of Persea cordata polar fractions exerts a non-specific inhibitory effect on microvascular leakage induced by pro-inflammatory agents in rat skin, probably to interfering with different biological systems involved in the development of the inflammatory process, reinforcing the popular use of Persea cordata as an anti-inflammatory and healing agent for skin.