Poncirin

Solvents of analytical grade were obtained from VWR International s.r.l. (Milan, Italy).
Tween 20, ascorbic acid, Folin–Ciocalteu reagent, sodium carbonate, butylated hydroxytoluene (BHT), propyl gallate, 2,2-diphenyl-1-picrylhydrazyl (DPPH), tripyridyltriazine (TPTZ), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) solution, β-carotene, linoleic acid, Orlistat, Trizma base, 4-nitrophenyl octanoate (NPC), maltose, α-amylase from porcine pancreas, α-glucosidase from Saccharomyces cerevisiae, o-dianisidine dihydrochloride, and peroxidase/glucose oxidase (PGO) were purchased from Sigma–Aldrich S.p.a. (Milan, Italy).
Acarbose from Actinoplanes sp. was obtained from Serva (Heidelberg, Germany). Caffeic acid, protocactechuic acid, p-coumaric acid, chlorogenic acid, vanillic acid, eriocitrin, gallic acid, apigenin, didymin, quercetin, hesperidin, neohesperidin, neoeriocitrin, naringin, narirutin, sinensetin, tangeretin, rutin, quercetin-O-glucoside, genistin, poncirin, luteolin, kaempferol, hesperetin, rhamnetin, umbelliferone, isopimpinellin, and bergapten were purchased from Sigma–Aldrich Chem. Co. (Milwaukee, WI, USA). Acetonitrile, formic acid, methanol, and water were HPLC-grade solvents, obtained from Carlo Erba Reagents (Milano, Italia).

CGX, which consisted of 13 kinds of herbal plants that complied with the Korean Pharmacopoeia standards, was manufactured by Kyung-bang Pharmacy according to the guidelines of the Korean Food and Drug Administration (Table 1). To confirm the chemical composition of CGX, ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS, Thermo Scientific, Waltham, CA, United States) was performed according to a previous study (Kim et al., 2014 (link)). The chromatogram indicated that the main chemical components of CGX were scopoletin, liquiritin, naringin, esculetin, rosmarinic acid, salvianolic acid B, poncirin, and tanshinone IIA (Sigma Aldrich, MO, United States, Figures 1A–C).

Samples of Ganpu tea and the corresponding raw materials (including Pu-erh tea and GCP) were provided by Xinhui Hele Tea Art Co. Ltd. (Jiangmen, China). The reference standards of gallic acid, caffeine, hesperidin, naringin, neohesperidin, rutin, rhoifolin, and synephrine were obtained from the National Institute for Control of Biological and Pharmaceutical Products of China (Beijing, China). Naringenin, poncirin, nobiletin, sinensetin, tangeretin, and mass spectrometry (MS) grade formic acid were purchased from Sigma-Aldrich (St. Louis, MO, USA). Hesperetin and N-methyltyramine were acquired from Sinova (Shenzhen, China). MS-grade acetonitrile was purchased from Fisher Scientific (Pittsburgh, PA, USA). Water used in the experiment was distilled and further purified with a Milli-Q system (Millipore, Milford, MA, USA). All other reagents used were of analytical grade.