Antinociceptive and anti-inflammatory activity of extracts and α-pyrones isolated from Cantinoa stricta

Abstract

Abstract The present study aimed to evaluate the composition of the crude extracts obtained from the leaves of Cantinoa stricta (Lamiaceae) and explore the antinociceptive and anti-inflammatory activity of these extracts and two isolated compounds: anamarine (ANA) and 10-epi-olguine (eOL). Different extracts were obtained from the leaves of C. stricta and compared by NMR data. Crude ethanolic extract (EEt) and dichloromethane extract (DCM) were selected for the pharmacological tests in mice. The oral administration of EEt and DCM in male Swiss mice significantly reduced the second phase of formalin-induced nociception, lipopolysaccharide (LPS)-induced mechanical hyperalgesia, and carrageenan (Cg)-induced edema. ANA and eOL, the major compounds in EEt and DCM extracts, administered orally or locally (in the paw), also reduced the LPS-induced mechanical hyperalgesia and the Cg-induced edema without changing the thermal acute nociception or the motor performance of the animals. These isolated compounds did not change the mechanical hyperalgesia induced by tumor necrosis factor-α, interleukin-1β, prostaglandin E2, dibutyryl cyclic AMP, or forskolin but reversed the hyperalgesia induced by dopamine, epinephrine, and phorbol 12-myristate 13-acetate. The mechanical hyperalgesia induced by epinephrine was reversed in male but not in female mice, in which this response is not dependent on protein kinase C. These results suggest that C. stricta extracts possess antinociceptive and anti-inflammatory activity which is, at least partially related to the presence of ANA and eOL. Differently from the known analgesics, these substances seem to exert their action mainly interfering with the sympathetic component of pain, possibly with protein kinase C.