Flavonols (kaempeferol, quercetin, myricetin) contents of selected fruits, vegetables and medicinal plants

The concentrations of flavonols (kaempeferol, quercetin, myricetin) were determined in 22 plant materials (9 vegetables, 5 fruits, and 8 medicinal plant organs). The materials were extracted with acidified methanol (methanol/HCl, 100: 1, v/v) and analyzed by reverse phase high-performance liquid chromatographic (RP-HPLC) with UV detection. The total flavonols contents varied significantly (P < 0.05) among vegetables, fruits and medicinal plant organs ranged from 0 to 1720.5, 459.9 to 3575.4, and 2.42 to 6125.6 mg kg(-1) of dry matter, respectively. Among vegetables, spinach and cauliflower exhibited the highest amounts of flavonols (1720.5 and 1603.9 mg kg-1, respectively), however, no flavonols were detected in garlic. Within fruits, highest level of flavonols was observed in strawberry (3575.4 mg kg(-1)), whereas, the lowest in apple fruit (459.9 mg kg(-1)). Of the medicinal plant organs, moringa, and aloe vera leaves contained the highest contents of flavonols (6125.6 and 1636.04 mg kg(-1)), respectively, whereas, lowest was present in barks (2.42-274.07 mg kg(-1)). Overall, leafy green vegetables, soft fruits and medicinal plant leaves exhibited higher levels of flavonols. (c) 2007 Elsevier Ltd. All rights reserved.