Tailor-Made Deep Eutectic Solvents for Simultaneous Extraction of Five Aromatic Acids from Ginkgo biloba Leaves

Ginkgo bilobaleaves have various health benefits due to the presence of bioactive compounds such as polyprenyl acetates, flavonoids, and terpene trilactones. However, there is little literature reported on the aromatic acids inGinkgo bilobaleaves. In this work, five aromatic acids including shikimic acid (SA), 6-hydroxykynurenic acid (6-HKA), protocatechuic acid (PA), gallic acid (GAA), andp-hydroxybenzoic acid (PHBA) were simultaneously extracted fromGinkgo bilobaleaves by employing the green deep eutectic solvents (DESs). A DES tailor-made from xylitol, glycolic acid and 1,5-pentanedioic acid at a molar ratio of 1:3:1 with 50% (w/w) water addition, named as NGG50, gave higher extraction yields for the five aromatic acids. Main factors affecting the extraction process were further optimized. The highest extraction yields of SA, GAA, 6-HKA, PA, and PHBA were 94.15 ± 0.96 mg/g, 332.69 ± 5.19 μg/g, 25.90 ± 0.61 μg/g, 429.89 ± 11.47 μg/g and 67.94 ± 0.37 μg/g, respectively. The NGG50-based extraction process developed here was a successful attempt of simultaneously extracting five aromatic acids fromGinkgo bilobaleaves for the first time, which could provide a new exploitation direction ofGinkgo bilobaleaves.Keywords:deep eutectic solvents;Ginkgo bilobaleaves;simultaneous extraction;shikimic acids;6-hydroxykynurenic acid