Ultrasound-assisted extraction versus traditional Soxhlet apparatus for the obtention of polyphenols, carotenoids and tocopherols from Tagetes erecta L. flowers

BACKGROUND Tagetes erecta L., commonly known as American marigold, serves as a food plant used for the extraction of carotenoids such as lutein, employed both as culinary ingredient in certain dishes and for its ornamental and medicinal applications. Two extraction techniques, Soxhlet and ultrasound-assisted extraction (UAE), were used on two cultivars (yellow and orange) of T. erecta. Polyphenols were quantified using HPLC-tandem mass spectrometry, whereas carotenoids and tocopherols were determined using HPLC-diode array detection. Biological activity for antioxidant and antiglycation properties was carried out. RESULTS The best extraction yield was obtained for UAE (7.51% and 6.83% for yellow and orange flowers), corresponding with the largest amounts of polyphenols quantified. The highest content of tocopherols was obtained in the yellow cultivar extracted by Soxhlet (6499.3 ± 21.2 and 4671.0 ± 92.9 mg kg−1 dry extract for α- and γ-tocopherol). The antioxidant potential resulted higher in the orange Soxhlet extract, whereas the yellow Soxhlet extract displayed the best antiglycation activity (median 50% inhibitory concentration of 25.3 ± 3.3 μg mL−1). CONCLUSION Both extraction techniques showed interesting results in terms of bioactivity and compounds obtention.