A Validated RP-HPLC–DAD Method for Analyzing Flavonoids in Caatinga Brazilian Green Propolis from Mimosa tenuiflora Produced by Apis mellifera

There are several types of propolis in Brazil produced by Apis mellifera Linnaeus, 1758, Apidae, with the green propolis from the Caatinga biome standing out for its high flavonoid content. In this study, we describe the isolation of flavonoids from Brazilian green propolis of Caatinga Mimosa tenuiflora (Willd.) Poir., Fabaceae, and the development of a reliable RP-HPLC quantitative method. This method uses a Shim-pack VP-ODS column (250 × 4.6 mm i.d., 5 μm) with nonlinear gradient elution and UV detection at 280 nm. Additionally, a sample preparation method for extracting flavonoids using 96% ethanol and caffeic acid as the internal standard was employed. The developed method demonstrated excellent detection response, with limits of detection and quantification ranging from 0.65–2.08 µg/ml and 1.97–6.31 µg/ml, respectively. The maximum relative standard deviation was 4.61%. Thirteen flavonoids were quantified, including santin, ermanin, sakuranetin, quercetin-3-methyl ether, viscosine, eriodictyol-5-O-methyl ether, isokaempferide, kaempferide, penduletin, quercetin-3,6,7-trimethyl ether, cirsimaritin, 3,3'-O-dimethylquercetin, and luteolin. The developed method met all the parameters set by international guidelines for analytical method development. It is reliable for the quality control of M. tenuiflora green propolis and its related products.