Background: Flavonoids as secondary metabolites of plants fulfill various functions in cell
protection. They are of a considerable scientific interest because of their potentially medical use due to
their anticancer, chemoprotective, antimicrobial, antiallergic, anti-inflammatory and antiviral activities.
Objective: The study aimed to develop a new UHPLC-UV method for morin and 2 other structurally
related flavonoids - naringenin and kaempferol as the structural similarity of huge numbers of flavonoids
does not limit their various biological functions and activities.
Methods: Separation of morin and 2 other structurally related flavonoids - naringenin and kaempferol -
was achieved by using BEH C18 (1.7 µm, 2.1 x 50 mm) analytical column (Waters® Acquity UPLC)
and a mobile phase composed of 0.05%v/v Formic acid in water and acetonitrile in proportion of 77:23
v/v and pumped at a flow rate of 0.4 ml/min. Column temperature was set at 25 ºC and samples were
analyzed (3 µl injection volume) at a wavelength of 340 nm. Waters® Xevo G2-S QToF coupled with
Waters® Acquity UPLC system with binary Solvent Manager (I-Class) via electrospray ionization (ESI)
interface was used to confirm the identity of the peaks in biological samples.
Results: A rapid and simple UHPLC-UV separation of morin, kaempferol and naringenin is documented
including methods validation. The developed method was applied to measuring morin,
kaempferol and naringenin in human plasma after a solid phase extraction. Additionally, stability of
morin in tissue culture medium was verified. The extraction method and UHPLC-UV elution conditions
described provide a practical means to analyze morin, kaempferol and naringenin in biological matrices.
Conclusion: The developed method is fast and highly sensitive. Moreover, the flavonoids used were
stable in human plasma for more than 10 days.