Pollen Residues in Commercial Propolis Products Reveal Gaps in Processing and Quality Standardization

Propolis is a natural product widely used in pharmaceutical and nutraceutical formulations, whose quality and bioactivity are closely related to botanical origin and processing conditions. Current quality control protocols are primarily based on physicochemical parameters, which provide limited information on botanical traceability and processing efficiency. This study applied palynological analysis to evaluate fifteen commercial propolis solutions marketed in northeastern Brazil, including brown, green, and red propolis, in order to characterize pollen residues and assess their relevance for pharmacognostic quality evaluation. Pollen grains were detected in most samples, and 75 pollen types belonging to 19 botanical families were identified, with predominance of Fabaceae, Asteraceae, Myrtaceae, and Rubiaceae. Brown propolis formulations exhibited higher pollen richness and greater heterogeneity, whereas green propolis samples showed lower diversity and higher relative frequencies of a few pollen types. Marked variation in pollen abundance was observed among samples, including high pollen frequencies in products described as filtered extracts, suggesting differences in processing efficiency. Palynological analysis, therefore, provides complementary pharmacognostic information for assessing botanical origin, processing consistency, and quality control of commercial propolis products.