Bioactivity and Botanical Origin of Austroplebeia and Tetragonula Australian Pot-Pollen

Abstract

Antibacterial properties, antioxidant activity, and bioactive components were measured in ethanolic and methanolic extracts of pot-pollen from Australian stingless bees (Meliponini) Austroplebeia australis, Tetragonula carbonaria, and Tetragonula hockingsi. Tetragonula hockingsi pot-pollen presented the highest flavonoid, polyphenol, and protein concentrations in both ethanolic and methanolic extracts. The antioxidant activity was positively correlated with the polyphenol content. All three pot-pollen extracts were active against both Gram-positive (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Enterobacter cloacae, Escherichia coli, Pseudomonas aeruginosa), with lower minimum inhibitory concentration (MIC) values found in ethanolic extracts than in methanolic extracts. Ethanolic extracts of Tetragonula hockingsi pot-pollen showed the lowest MIC values. A palynological study identified the botanical origin of Australian pot-pollen. We suggest pot-pollen is a food that increases the value of stingless bee products in Australia.