Table 2 Phenolic compounds found at the stingless bee propolis included in this study. The results in mg L⁻¹ are shown as the means of three independent experiments and their respective standard deviations. The different superscript letters in the same line represent significant statistical differences at the ANOVA test at P < 0.05. ND – not detected

Phenolic compounds

 Gallic acid

0.04 ± 0.01^d

0.02 ± 0.01^d

ND

ND

ND

2.06 ± 0.02^a

4.38 ± 0.02^c

0.09 ± 0.01^d

2.57 ± 0.03^b

ND

0.13 ± 0.01^d

 Caffeic acid

ND

ND

ND

ND

ND

0.81 ± 0.01^a

0.07 ± 0.01^d

ND

0.17 ± 0.01^b

0.09 ± 0.01^c

0.06 ± 0.01^d

 Epicatequin

0.07 ± 0.01^e

0.08 ± 0.01^e

0.15 ± 0.01^c

0.13^d

0.14 ± 0.01 ^cd

0.15 ± 0.01^c

0.17 ± 0.01^b

0.2 ± 0.01^a

0.18 ± 0.01^ab

0.18 ± 0.01^b

0.19 ± 0.01^ab

 p-cumaric acid

ND

ND

ND

ND

ND

2.81 ± 0.14^a

0.19 ± 0.01^b

0.19 ± 0.01^b

1.35 ± 0.1^b

0.06 ± 0.01^c

ND

 trans-ferulic acid

ND

0.31 ± 0.02^a

ND

0.07 ± 0.01^d

0.07 ± 0.01 ^cd

ND

0.07 ± 0.01 ^cd

0.08 ± 0.01^c

0.12 ± 0.01^b

0.07 ± 0.01 ^cd

0.07 ± 0.01 ^cd

 Ellagic acid

ND

ND

ND

ND

ND

1.2 ± 0.03^a

0.23 ± 0.01 ^cd

0.2 ± 0.02^d

0.39 ± 0.01^b

ND

0.26 ± 0.01^c

 Rutin

ND

ND

ND

ND

ND

1.52 ± 0.03^a

0.18 ± 0.01^c

ND

0.30 ± 0.03^b

ND

0.17 ± 0.01^c

 Piceatannol

0.11 ± 0.01^e

ND

0.12 ± 0.01^c

0.11 ± 0.01^e

0.12 ± 0.01^c

0.77 ± 0.03^a

0.1 ± 0.011^d

0.1 ± 0.01^f

0.23 ± 0.01^b

0.1 ± 0.01^f

0.11 ± 0.01^d

 Myricetin

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

 Resveratrol

0.07 ± 0.01^c

0.11 ± 0.01^b

0.06 ± 0.01^d

0.06 ± 0.01^d

0.06 ± 0.01^d

0.23 ± 0.01^a

0.06 ± 0.01^d

0.06 ± 0.01^d

0.06 ± 0.01^d

0.06 ± 0.01^d

0.06 ± 0.01^d

 Quercetin

ND

ND

ND

ND

ND

0.16 ± 0.01^a

ND

0.11 ± 0.01^b

0.12 ± 0.0^b

ND

ND

 trans-cinnamic acid

ND

0.14 ± 0.01^d

ND

0.06 ± 0.01 ^g

0.07 ± 0.01^f

1.60 ± 0.02^a

0.19 ± 0.01^c

0.08 ± 0.01^e

0.65 ± 0.03^b

0.05 ± 0.01 ^h

0.06 ± 0.01 ^g

 Naringenin

ND

0.07 ± 0.01^de

0.08 ± 0.01^c

ND

0.07 ± 0.01^e

0.75 ± 0.05^b

0.09 ± 0.01 ^cd

0.11 ± 0.01^c

1.00 ± 0.1^a

ND

ND

 Kaempferol

ND

ND

ND

0.11 ± 0.0^d

0.1 ± 0.01^d

0.32 ± 0.03^a

0.12 ± 0.01 ^cd

0.13 ± 0.01^c

0.210 ± 0.01^b

0.11 ± 0.01^d

ND

 Isoliquiritigenin

0.06 ± 0.01^d

ND

ND

ND

0.08 ± 0.01^c

0.090.01^b

ND

ND

0.09^a

ND

ND

 Formononetin

0.12 ± 0.01^c

ND

ND

ND

ND

45.40 ± 0.36^a

1.28 ± 0.04^b

ND

ND

ND

ND

 Biochanin

0.0 ± 0.013^c

ND

0.02 ± 0.01^c

0.02 ± 0.01^c

0.02 ± 0.01^c

0.48 ± 0.01^b

0.02 ± 0.001^c

0.02^c

0.5 ± 0.04^a

0.02 ± 0.02^c

0.01 ± 0.01^c

 Kaempferide

ND

ND

ND

0.2 ± 0.02^c

ND

0.33 ± 0.31^a

0.2 ± 0.01^c

ND

0.26 ± 0.01^b

ND

ND

 7-hydroxycumarin

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

 Scopoletin

ND

ND

ND

ND

ND

0.1 ± 0.01

ND

ND

ND

ND

ND

 4-methylumbeliferonone

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

 Coumarin

0.1 ± 0.01^de

2.34 ± 0.03^a

0.05 ± 0.01^e

ND

ND

0.69 ± 0.01^b

0.13 ± 0.07^d

0.07 ± 0.01^de

0.28 ± 0.04^c

ND

ND