Luteolin

The 26 Chinese prickly ash peels materials were collected from eight provinces of China (the main production areas: Guide, Xunhua, Hanyuan, Jiuzhaigou, Wenxian, Wudu, Qin’an, Fengxian, Fuping, Hengshan, Hancheng, Yongji, Lingbao, Jiaocheng, Shexian, Zaozhaung and Laiwu) at different altitudes (201–2188 m) from July to August 2020 (Figure 1). The 26 samples were divided into 6 groups based on the geographical location and altitude of the sample collection sites, as shown in Table S1. Under the premise of protecting local germplasm resources, Chinese prickly ash mature fruits from each location were collected in three replicates, and the distance between each plant was more than 50 m. Fruits without pests and mechanical damage were dried in the laboratory at room temperature until they reached a constant weight.
A total of 15 flavonoid compound standards (hyperoside, luteolin, kaempferol, quercitrin, catechin, rutin, chlorogenic acid, quercetin, hesperetin, apigenin, peonidin O-hexoside, peonidin 3-O-glucoside, cyanidin 3-O-glucoside, cyanidin O-syringic acid, cyanidin 3-O-galactoside) were bought (Beijing Solarbio Science & Technology, Beijing, China). HPLC-grade methanol, acetic acid and acetonitrile were bought (TEDIA Chemical Co., Ltd., Fairfield, OH, USA). Deionized water (18 MΩ cm) was used to prepare aqueous solutions (MilH-Q Advantage A1, Millipore, Billerica, MA, USA).

Hexane and methanol were purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China and ethyl acetate and ethanol from Hunan Huihong Reagent Co., Ltd. (Hunan, China). Folin-Ciocalteu reagent and vanillin were purchased from Coolaber Science and Technology, Beijing, China. DPPH, ABTS, and T-AOC (FRAP), apigenin, (+)-catechin, gallic acid, glucose, kaempferol, quercetin, luteolin, naringenin, and rutin, were all purchased from Solarbio Life Sciences, Beijing, China. HPLC grade acetic acid and acetonitrile were purchased from Tianjin Kemiou Chemical Reagent Co., Ltd. (Tianjin, China).

Plantago asiatica L. (3777555) was purchased from Traditional Chinese Medicine Market (Harbin, China). Luteolin, scutellarein, and caffeic acid were purchased from Solarbio Company (Purity ≥ 99%). Male or female clean Kunming mice (18–22 g) and clean Wistar rat (180–200 g) were obtained from the Department of Animal Center, Harbin Medical University (Harbin, China).

Syringa oblata Lindl. was growing naturally on the campus of Northeast Agricultural University (N 45°44′33.64″, E 126°43′22.07″) in Harbin, Heilongjiang Province of China, and were authenticated by Professor Xiuju Wu from College of Life Sciences, Northeast Agricultural University. The raw materials were dried, pulverized, sifted through an 80-mesh sieve, and stored at 4°C before use. Voucher specimens were deposited at the Department of Animal Pharmacy, Northeast Agricultural University. Rutin, luteolin, oleanolic acid, and kaempferol standards (purity≥98%) were purchased from the Beijing Solarbio Science & Technology Co., Ltd. (Beijing, China). L-proline, L-lysine, 1,2-propanediol, glycerol, glycol, 1,4-butanediol, methanol, and other chemicals were obtained from the Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). D101 macroporous resin was procured from the Tianjin BSF Resin Technology Co. Ltd. (Tianjin, China).