Propolis SJ1
Propolis is a chemically complex biomass produced by honeybees (Apis mellifera) from plant resins
added of salivary enzymes, beeswax, and pollen. Recent studies classified Brazilian propolis into 12 groups based on
physiochemical characteristics and different botanical origins. Since propolis quality depends, among other variables, on
the local flora which is strongly influenced by (a)biotic factors over the seasons, to unravel the harvest season effect on
the propolis' chemical profile is an issue of recognized importance. For that, fast, cheap, and robust analytical techniques
seem to be the best choice for large scale quality control processes in the most demanding markets, e.g., human health
applications. UV-Visible (UV-Vis) scanning spectrophotometry meets those prerequisites and was adopted, affording a spectral
dataset containing the chemical profiles of hydroalcoholic extracts of sixty five propolis samples collected over the
distinct seasons of year 2014, in southern Brazil. Descriptive and classification models were built following a
chemometrics approach, i.e. principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used, by
using bioinformatics tools supported by scripts written in the R language. The spectrophotometric profile approach associated
with chemometric analyzes allowed identifying a different pattern in samples of propolis produced
during the summer season over the other seasons. Importantly, the discrimination based on PCA could
be improved by using the dataset of the fingerprint region of phenolic compounds (λ = 280-350ηm), suggesting that besides
the biological activities presented by those secondary metabolites, they are also relevant for the discrimination and
classification of that complex matrix through bioinformatics tools.