The determination of the minimal inhibitory concentration (MIC) was conducted by broth microdilution, with the microplates sealed and incubated at 35 °C for 24–72 h. The MIC was defined as the smallest concentration able to inhibit the click here growth of microorganisms. The result was expressed as the average of three separate tests (Souza, Stamford, Lima, & Trajano, 2007). The antibacterial and antifungal activities were interpreted based on the following parameters: from no growth to 0.5 mg mL−1, excellent/optimal activity; from no growth to 0.6–1.5 mg mL−1, moderate activity; from no growth to over 1.6 mg mL−1, low activity

(Houghton, Howes, Lee, & Steventon, 2007). Chloramphenicol (0.1 mg mL−1) and nystatin (100 IU mL−1) were used for the negative control, and for the positive control, the inoculation was performed using only DMSO. CT99021 order The analyses were made in triplicate and the results expressed as the average ± standard deviation. The analyses of correlations (p ⩽ 0.05) between the pollen, phenolic compounds and ABTS were investigated by multivariate statistical analysis in PAST 2.17. A total of 22 pollen types, belonging to 16 different botanical families, were identified in the honey samples (Table 1). Five pollen types that were lacking an established botanical affinity were named “Undetermined”. The Fabaceae family stood out in the pollen spectrum with six recognised pollen types. The high

pollen diversity found in the honeys reflects the flora diversity filipin of Amazonas state, a feature that favours the production of honeys with different characteristics. The pollen type Clidemia from the Melastomataceae family was identified in six of the seven samples analysed. It is present in both state regions in which the honey samples were collected, with the smallest occurrence (1.34%) in CAD3 and the largest occurrence (90.96%) in CAD4 ( Table 1). These data show that the bees M. s. merrilae collect material from species of the Melastomataceae family; however, plants from this family are often polliniferous and have a low nectar production. Clidemia and Miconia (Melastomataceae)

constitute important protein sources for Meliponini, and their pollen grains are harvested by several stingless bee species in the Amazon. Moreover, Melastomataceae is typically found in vegetable formations in the Amazon rain forest. Its flowers show poricidal anthers, and they are therefore visited primarily by bees able to vibrate the anthers in a phenomenon known as buzz pollination, which is characteristic of bees such as Bombus and Xylocopa ( Renner, 1989). The honey samples collected in SAD1, CAD2 and CAD4, representing the two state regions analysed had Clidemia pollen in quantities greater than 65% of the overall identified pollen. In the analysed honey samples, no secondary pollen types were found, and the percentages of the important minor pollen and minor pollen were low.