Antinociceptive and antianxiety activity of hydroethanolic extracts of three impatiens species in mice

Abstract

The plants of the Impatiens L. (Balsaminaceae) have been used for a long time in folk medicine in different painful conditions, and to treat rheumatism, isthmus and crural aches, fractures, superficial infections, fingernail inflammation. This study was undertaken to determine the pharmacological profile of hydroethanolic extracts from Impatiens glandulifera, I. noli-tangere and I. parviflora. A range of behavioral assessments was applied to evaluate the effects of obtained extracts i.e. measurement of body temperature, tests of locomotor activity and motor coordination, nociceptive reaction and anxiety-like behavior. Hydroethanolic extracts were analyzed for total polyphenol (TPC), flavonoid (TFC), flavones/flavonols (TFFC), and flavonones/dihydroflavonols (TFDC) content. Our results show that the extracts from Impatiens species contain high levels of TPC, TFC, TFFC, and TFDC. Oral (i.e., by gavage) administration of Impatiens L. extracts (except for I. nolitangere) presented an antinociceptive or/and anti-inflammatory activity in the writhing test. The antinociceptive effect of I. parviflora leaves (100 mg/kg) and I. glandulifera flowers (100 mg/kg) was reversed by naloxone. I. glandulifera flowers and roots extracts (100 mg/kg) increased the reaction time to the thermal stimulus in the hot-plate test. All extracts from I. glandulifera (100 mg/kg) showed antianxiety effect in the elevated plus-maze test. It is worth noting that none of the extracts, at the highest used dose - 0.1 ED50 (200 mg/kg), caused coordination impairments or myorelaxation as measured in the rota-rod and chimney tests. These results seem to suggest that the tested extracts are not neurotoxic. These findings show the potential use of hydroethanolic extracts from different parts of I. glandulifera as phytomedicine.