Antinociceptive effects of ethanolic extract from the flowers of Acmella oleracea (L.) R.K. Jansen in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: In Brazil, Acmella oleracea (L.) R.K. Jansen, popularly known as "jambu", has been used by some communities from Amazon region to treat toothache. In this study we examined the antinociceptive effect of the ethanolic extract obtained from the flowers of Acmella oleracea (EEAO) in animal models of nociceptive (chemical and thermal) and neuropathic (partial sciatic nerve ligation) pain. MATERIALS AND METHODS: Adult male mice were treated by intraperitoneal route (i.p.) with EEAO before the induction of nociceptive response by formalin, capsaicin and cinnamaldehyde, thermal heat hyperalgesia (hot plate test) and mechanical allodynia (traumatic sciatic nerve injury). Acute toxicity and non-specific sedative effects were evaluated. RESULTS: EEAO (10, 30 and 100 mg/kg) reduced both neurogenic and inflammatory phases of the formalin- and also capsaicin- and cinnamaldehyde-induced orofacial nociception. Interestingly, EEAO at 100mg/kg (i.p.) also reversed capsaicin-induced heat hyperalgesia assessed as the latency to paw withdrawal in the hot plate test. Also in the hot plate test, paw withdrawal latency was increased by EEAO (100 mg/kg) and this response was only partially reversed by naloxone. Furthermore, EEAO (100 mg/kg) also reduced mechanical allodynia caused by partial sciatic nerve ligation for 3 h. The estimated LD50 value was 889.14 mg/kg and EEAO did not alter the locomotion of animals in the open-field test. CONCLUSION: Taken together, our data show that EEAO produces prevalent antinociceptive effects and does not cause adverse effects. The presence of N-alkylamides, including spilanthol, suggests that the therapeutic effect of EEAO is related to its highest anesthetic activity.

Structure of a galactoarabinoglucuronoxylan from tamarillo (Solanum betaceum), a tropical exotic fruit, and its biological activity.

Tamarillo (Solanum betaceum) is a tropical exotic fruit whose polysaccharides were extracted from the ripe pulp. After various purification steps, homogeneous fractions (designated PTW, STK-1000R and PF) were analyzed by sugar composition, HPSEC, methylation and NMR spectroscopy analysis. The results showed that the fraction PTW consisted of a linear arabinan with (1→5)-linked α-l-arabinofuranosyl units. Fractions designated as STK-1000R and PF contained galactoarabinoglucuronoxylans, with (1→4)-linked ß-d-Xylp residues in the backbone, carrying branches exclusively at O-2. The polysaccharide in STK-1000R is less branched than that in the PF fraction (∼20.0% and 36.5%, respectively), with side-chains formed by (1→5)-linked α-l-Araf residues and (1→4)-linked α-d-GlcpA residues and with non-reducing end units formed by α-l-Araf, ß-Arap, ß-d-Galp, α-d-GlcpA and 4-O-Me-α-d-GlcpA. Intraperitoneal administration of the STK-1000R fraction in mice significantly reduced the number of abdominal constrictions induced by 0.6% acetic acid and the inflammatory phase of nociception induced by 2.5% formalin, indicating that that fraction has an antinociceptive effect on inflammatory pain models.