Isolation and purification of spilanthol from Acmella oleracea flowers by countercurrent chromatography and anti-inflammatory activity

Acmella oleracea (Asteracea) is an exotic plant species that has been adapted to the cultivation conditions in Brazil, thus having wide distribution in the national territory. The chemical marker of the species, spilanthol, is an alkylamide, majority present in the flowers of the plant (Poltronieri, Muller e Poltronieri, 2000). Alkylamides are recognized by their action on CB2 receptors inducing an immunostimulant response, among other properties such as anti-inflammatory, larvicidal, fungicidal and antimicrobial (Barbosa et al. 2016). Because of the potential of this substance, this work seeks to isolate spilanthol by countercurrent chromatography (CCC) technique in order to investigate its anti-inflammatory activity. We obtained crude extracts of A. oleracea by maceration in methanol and performed in vivo nociception assay (2.5% formalin) with crude extracts. The partial results of CCC fractionation, following the literature methodology, were not reproducible. The purity of spilanthol obtained in this study by this technique was 52% against 95% of the literature (Mbenkui et al., 2011). The flower and aerial parts extracts were able to decrease licking time in the second phase of the formalin test. This phase refers to the inflammatory phase. This result infers that it is possible that A. oleracea alkylamides participate in the anti-inflammatory process. Until this stage it was not possible to obtain purified spilanthol. The fractions obtained by CCC did not reach the desired purity, requiring to use other chromatographic techniques to achieve a better purity and then test the pure spilanthol in vivo too. The in vivo test contributes positively to the hypothesis that alkylamides participate in the anti-inflammatory process.

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