RESUMO
BACKGROUND: Stevia serrata Cav. (Asteraceae), widely found in Guatemala, is used to treat gastrointestinal problems. The aim of this study was to demonstrate the antinociceptive and anti-inflammatory effects of the essential oil (EO) and the mechanism of action. METHODS: EO was tested in chemical (capsaicin- and glutamate-induced licking response) or thermal (hot plate) models of nociception at 10, 30 or 100 mg/kg doses. The mechanism of action was evaluated using two receptor antagonists (naloxone, atropine) and an enzyme inhibitor (L-NAME). The anti-hyperalgesic effect was evaluated using carrageenan-induced nociception and evaluated in the hot plate. RESULTS: All three doses of EO reduced licking response induced by glutamate, and higher doses reduced capsaicin-induced licking. EO also increased area under the curve, similar to the morphine-treated group. The antinociceptive effect induced by EO was reversed by pretreatment of mice with naloxone (1 mg/kg, ip), atropine (1 mg/kg, ip) or L-NAME (3 mg/kg, ip). EO also demonstrated an anti-hyperalgesic effect. The 100 mg/kg dose increased the latency time, even at 1 h after oral administration and this effect has been maintained until the 96th hour, post-administration. CONCLUSIONS: Our data suggest that essential oil of S. serrata presents an antinociceptive effect mediated, at least in part, through activation of opioid, cholinergic and nitrergic pathways.
RESUMO
Los oligoelementos son importantes constituyentes nutricionales de las hierbas comestibles. Se colectaron 11 especies, nueve nativas (Amaranthus hybridus, Cnidoscolus aconitifolius, Crotalaria longirostrata, Dysphania ambrosioides, Lycianthes synanthera, Sechium edule, Solanum americanum, S. nigrescens, S. wendlandii) y dos introducidas (Moringa oleifera, Spinacea oleracea) en dos regiones de Guatemala. Se prepararon muestras de la hierba seca, cocida y de caldo de hierba fresca. Se cuantificaron por espectrofotometría de absorción atómica los macro (N, P, K) y oligoelementos (Ca, Mg, Na, Cu, Zn, Mn), taninos por espectrofotometría y oxalatos por permanganimetría. El contenido de oligoelementos es diverso, para Zn, la hierba control S. oleracea contienen buena cantidad (90-140 ppm); de las nativas D. ambrosioides (130-160 ppm) y A. hybridus (70-80 ppm) tienen la mayor cantidad. Respecto a Fe las hierbas control tienen buena composición (S. oleracea, 220-280 ppm y M. oleifera, 105-135 ppm); de las nativas A. hybridus (90-240 ppm), C. aconitifolius (75-185 ppm) y L. synanthera (75-140 ppm) tienen buenas concentraciones. Se encontraron niveles elevados de oxalatos en S. oleracea (67.30 (5.51) mg/g), L. synanthera (56.30 (9.67) mg/g) y S. nigrescens (33.6 (5.48) mg/g); en las demás hierbas se encontraron niveles menores. Los niveles de taninos fueron bajos (0.1-0.8 mg/g) para todas las especies. Se demuestra que cuatro especies nativas tienen un buen contenido de oligoelementos y presentan valores menores de antinutricionales que los controles.
Trace elements are important nutritional constituents from edible herbs. Eleven species were collected in two regions of Guatemala, nine native (Amaranthus hybridus, Cnidoscolus aconitifolius, Crotalaria longirostrata, Dysphania ambrosioides, Lycianthes synanthera, Sechium edule, Solanum americanum, S. nigrescens, S. wendlandii) and two introduced (Moringa oleifera, Spinacea oleracea). Dry, cooked and broth samples were prepared. By atomic absorption spectrometry, macro (N, P, K) and trace elements (Ca, Mg, Na, Cu, Zn, Mn) were quantified, tannins by spectrophotometry, and oxalates by permanganometry. Trace elements content is diverse, for Zn, control herb S. oleracea contained high quantity (90-140 ppm); from the natives D. ambrosioides (130-160 ppm) and A. hybridus (70-80 ppm) contained high amounts. For Fe, control herbs had high composition (S. oleracea, 220-280 ppm, M. oleifera, 105-135 ppm); from the natives A. hybridus (90-240 ppm), C. aconitifolius (75-185 ppm) and L. synanthera (75-140 ppm) had the highest amounts. High levels of oxalates were demonstrated in S. oleracea (67.30 (5.48) mg/g), L. synanthera (56.30 (9.67) mg/g), and S. nigrescens (33.6 (5.48) mg/g); from the others levels.
