Green Extraction and Optimization of Lutein From <i>Tagetes erecta</i> by Ultrasound‐Assisted Extraction Method and Identification by High‐Performance Liquid Chromatography Method

ABSTRACT Lutein, an essential nutrient, is present (0.01%–0.5%) in marigold flowers ( Tagetes erecta L.) and has been associated with benefits for eye health, including protection against age‐related macular degeneration. Green extraction methods and green solvents have been reported to extract high yields of lutein, maintain purity, and reduce environmental impact compared to conventional methods. This study aims to extract lutein from marigold flowers using green extraction methods (maceration, soxhlet, and ultrasound‐assisted extraction [UAE]) and green solvents (isopropyl alcohol [IPA], ethanol, 2‐methyltetrahydrofuran [2‐MeTHF], dimethyl carbonate [DC], and cyclopentyl methyl ether [CPME]). Using the Box–Behnken design (BBD), the selected method was optimized and evaluated for lutein extraction and antioxidant activity. The optimal conditions for the ultrasound extraction method are ultrasonic power (100 W), extraction time (2.5 min), and a solid‐to‐solvent ratio (5%). Lutein was quantified by HPLC with a mobile phases of acetonitrile and methanol (40:60) at 450 nm. The UAE method using 2‐MeTHF showed the highest lutein yield (41.5 ± 1.4 µg/mL), surpassing hexane (25.8 ± 1.9 µg/mL) and other green solvents. By optimizing the extraction method, significant improvements were achieved in both lutein extraction yield (10%) and antioxidant activity (93.78%). The lutein yield increased 240.96‐fold, as compared to reported values.