Botanical source investigation and evaluation of the effect of seasonality on Brazilian propolis from Apis mellifera L

Bees generally use different botanical sources of resins for the production of propolis. The elucidation of botanical sources of propolis and identification of the effects of seasonality on the chemical profile of propolis are recognized as two important aspects in the development of a high quality product. Thus, our objective was to elucidate the botanical source and identify the effect of the seasons on the chemical profile of propolis produced in southern Brazil. The chemical profile of the samples was analysed by spectrophotometric and chromatographic techniques and the results were coupled to multivariate analysis. Field observation of the foraging behaviour of Apis mellifera L. revealed its preference for the Baccharis dracunculifolia DC. species. p-Coumaric acid, 3, 4-dicaffeoylquinic acid, 3, 5-dicaffeoylquinic acid, drupanin, and artepillin C which were identified in both plant and propolis samples. Moreover, higher artepillin C amounts have been detected in samples collected in the summer and autumn, while the main compounds of p-coumaric acid and quercetin were available in spring and winter sampled propolis, respectively. Baccharis dracunculifolia has been identified as a plant species preferred by A. mellifera in foraging resin for the production of propolis in southern Brazil. The contents of balsam, total phenolic compounds, and flavonoids varied significantly over the seasons, with values above the minimum required by the legislation, thus assuring a quality pattern for this biomass. The financial support by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) is acknowledged (Process n° 473494/2013-2). This study was partially funded by Project PropMine, funded by the agreement between Portuguese Fundação para a Ciência e a Tecnologia and Brazilian CNPq (Process n° 490383/2013-0). The owners of the Apiário Real® Com-pany are also acknowledged for their logistical support and the supply of propolis samples. The authors also wish to thank the “Financiamento do Plano Estratégi-co de Unidades de I&D” of UID/BIO/04469/2013 unit. The researcher fellowship from CNPq on behalf of M. Maraschin is also acknowledged.