Effect of liposomal complexes of quercetin-rich flavonoids from French Marigold (Tagetes patula L.) on Jurkat cell viability

Background: Natural polyphenols are naturally used in traditional medicine to treat various diseases. Despite their healthful properties, ingesting phenolic compounds in food form does not provide a sufficient concentration for systemic therapeutic effects due to their low solubility in water, poor absorption, and fast metabolism. This problem has been solved by creating various composite pharmaceuticals from phenolic compounds using different methods to stabilize polyphenols. Objective: The purpose of this study was to assess the effects of the DPPA (1,2-palmitoyl phosphatidic acid) and DPPC (dipalmitoyl phosphatidylcholine) liposomes on the protective effects of a quercetin-rich flavonoid fraction extracted from French Marigold (Tagetes patula L.) on the viability of Jurkat cells. The study will examine both intact cells and cells that have been incubated under oxidative stress conditions.   Materials and Methods: Quercetin-rich flavonoid fraction was extracted from a French Marigold (Tagetes patula L.) by thin-layer chromatography (TLC), High-pressure liquid chromatography (HPLC), and Liquid Chromatography-Mass Spectrometry (LC-MS) methods. Extract alone and in complex with dipalmitoyl phosphatidylcholine (DPPC) and 1,2- dipalmitoyl phosphatidic acid (DPPA) liposomes were added to the Jurkat cells culture at a rate of 2 mg/mL−1.The 3-(4,5-dimethylthiazol-2)-2,5-diphenyltetrazolium bromide (MTT) test assayed Cell viability by evaluating cellular dehydrogenase activity. Results: Flavonoids were separated and identified in the marigold extracts by TLC, HPLC, and LC-MS methods. The spectrophotometric absorption spectrum of the quercetin-rich flavonoid fraction extracted from French Marigold (Tagetes patula L.) shows two peaks corresponding to benzoyl (254nm) and cinnamyl (375nm) aromatic rings. In the complex of quercetin-rich flavonoid fraction with DPPC and DPPA liposomes, the spectrophotometric absorption peak at 254nm was not detected, while the absorption intensity of the peak at 375nm was sharply reduced. The quercetin-rich flavonoid fraction alone and in combination with DPPC liposome increased intact and incubated under low- and high-intensity oxidative stress conditions Jurkat cells’ viability but did not reveal effect in combination with DPPA liposome. Conclusions: The quercetin-rich flavonoid fraction extracted from French Marigold (Tagetes patula L.) forms stable complexes with DPPC and DPPA liposomes that allow the storage of high content of phenolic compounds in lipid nanocapsules. The use of the liposomal system in the pharmaceutical and food industry allows for carried and controlled bioactive-compound release, which is considered one of the main strategies to improve and enhance the quality of food, providing preventative healthcare for the population and decreasing the risk of disease. Keywords: bioactive-compound, polyphenols, Quercetin, Liposomes, Jurkat cells, therapeutic effects, pharmaceuticals