Spiranthera odoratissima A. St. Hil. (manacá) is used in folk medicine to treat renal and hepatic diseases, stomachache, headaches and rheumatism. A central nervous system (CNS) depressant effect of the hexane fraction from the ethanolic extract of this plant has been described. β-caryophyllene, the main component of this essential oil, is a sesquiterpene compound with anti-inflammatory properties that has been found in essential oils derived from several medicinal plants. This work is aimed to evaluate the pharmacological activity of the essential oil obtained from S. odoratissima leaves (EO) and its major component on the murine CNS; we aimed to evaluate a possible anxiolytic-like effect and the underlying mechanisms involved. In an open field test, EO (500 mg/kg) and β-caryophyllene (50, 100 and 200 mg/kg) increased the crossing frequency (P<0.05) and, EO (250 and 500 mg/kg) and β-caryophyllene (200 mg/kg) increased the time spent in the center (P<0.05) without altering total crossings of the open field. EO and β-caryophyllene did not alter the number of falls in the rota-rod test (P>0.05). In the pentobarbital-induced sleep test, EO (500 mg/kg) and β-caryophyllene (200 and 400 mg/kg) decreased the latency to sleep (P<0.05), and EO (125, 250 and 500 mg/kg) (P<0.001) and β-caryophyllene (200 and 400 mg/kg) (P<0.05 and P<0.001) increased the sleep time. In anxiety tests, EO (500 mg/kg) and β-caryophyllene (100 and 200 mg/kg) increased head-dipping behavior (P<0.05) in the hole-board test, entries (P<0.05) into and time spent (P<0.05) on the open arms of the elevated plus maze (EPM), and number of transitions (P<0.05) and time spent in the light compartment (P<0.05) of a light-dark box (LDB). We further investigated the mechanism of action underlying the anxiolytic-like effect of EO and β-caryophyllene by pre-treating animals with antagonists of benzodiazepine (flumazenil) and 5-HT(1A) (NAN-190) receptors prior to evaluation using EPM and LDB. The anxiolytic-like effects of EO were significantly reduced by pre-treatment with NAN-190 (P<0.05) but not flumazenil (P>0.05). The anxiolytic-like effects of β-caryophyllene were not blocked by either NAN-190 or flumazenil (P>0.05). In conclusion, these results suggest that the essential oil derived from S. odoratissima produces an anxiolytic-like effect without altering motor performance and that this effect is mediated by 5-HT(1A) but not via benzodiazepine receptors. In addition, the major component, β-caryophyllene, also has an anxiolytic-like effect that may contribute to the effects of EO, but this effect does not seem to be mediated via 5-HT(1A) or benzodiazepine receptors.

These data indicate that the extract of Lafoensia pacari A. St.-Hil. possesses antidepressant-like properties in mice.

The antinociceptive and antiinflammatory properties of the neolignan, grandisin, isolated from Virola surinamensis (Myristicaceae) were investigated. Grandisin (GRA) is present in several plant species from Brazil used in popular medicine for the treatment of disorders such as colic, inflammation, rheumatism, dyspepsia and liver dysfunction. These studies demonstrated that GRA is able to inhibit the acetic acid-induced writhing in mice dose-dependently, and that this effect is not caused by motor incoordination or sedation due to depressant effect in the CNS. Through the formalin test the antiinflammatory activity of GRA was characterized, this substance reduced the time licking the paw by 60.5% (only in the second phase (inflammatory pain). This activity was also verified by the oil-induced ear oedema test, where GRA 10.0 mg/kg reduced the oedema by 36.4%. The results suggest that GRA has antinociceptive effects arising from antiinflammatory activity.

No abstract

Synadenium umbellatum Pax., popularly known in Brazil as “cola-nota,” “avelós,” “cancerola,” and “milagrosa”, is a plant species used in folk medicine for the treatment of inflammation, pain, and several diseases. This study aimed to investigate the antinociceptive and anti-inflammatory activities of the ethanolic extract from Synadenium umbellatum Pax. leaves (EES) and its hexane (HF), chloroform (CF), and methanol/water (MF) fractions using the acetic acid-induced abdominal writhing test, formalin-induced paw licking test, tail flick test, croton oil-induced ear edema test, and carrageenan-induced peritonitis test. EES and MF reduced the number of acetic acid-induced abdominal writhes, while CF and HF did not. EES effect on acetic acid-induced abdominal writhing was reversed with a pretreatment with naloxone. EES reduced licking time in both phases of the formalin-induced paw licking test, but did not prolong the latency in the tail flick test. These results show that EES presented antinociceptive activity, probably involving the opioid system, anti-inflammatory activity in the croton oil-induced ear edema test, and leukocyte migration into the intraperitoneal cavity. MF also presented anti-inflammatory activity in the croton oil-induced ear edema test. In conclusion, EES and MF have antinociceptive activity involving the opioid system and anti-inflammatory activity.