Emodin

Emodin, genipin, chlorogenic acid, cimigenoside, and ginsenoside Rb1 were purchased from ChemFaces (Hubei, China). Imiquimod (IMQ) was obtained from 3M Health Care (Leicestershire, England). High glucose Dulbecco's modified Eagle's medium (DMEM) was acquired from WelGENE Inc. (Gyeongsangbuk, Korea). Fetal bovine serum (FBS) and antibiotics were supplied by Invitrogen Inc. (Carlsbad, CA, USA). U0126, SB202190, SP600125, cryptotanshinone, and wortmannin were obtained from Sigma-Aldrich (St. Louis, MO, USA). Human CXCL8, CXCL10, and mouse IFN-γ, IL-1β, IL-6 ELISA kits were purchased from KOMA Biotech Inc. (Seoul, Korea). The human CCL20 ELISA kit was bought from R&D system (Minneapolis, MN, USA). The antibodies for phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated p38 (p-p38), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), phosphorylated Akt (p-Akt), phosphorylated mammalian target of rapamycin (p-mTOR), ERK, p38, JNK, STAT3, Akt, and mTOR were obtained from Cell Signaling Technology (Danvers, MA, USA). The antibodies against keratin 16 (K16) and K17 were procured from Abcam (Cambridge, MA, USA). HRP-conjugated anti-β-actin was supplied by Sigma-Aldrich (St. Louis, MO, USA).

Vanicoside A and vanicoside B were isolated earlier from rhizomes of Reynoutria sachalinensis (F.Schmidt) Nakai, according procedure described in [32 (link)]. The structures of vanicoside B and vanicoside A were identified using 1H and 13C NMR and HR-MS-qTOF MS analysis and presented in the above article [32 (link)]. Emodin, piceid, epigallocatechin gallate, procyanidin B2, procyanidin C1, were purchased in ChemFaces (Wuhan, China), procyanidin B2 3,3′-di-O-gallate was purchased in Albtechnology (HongKong) and resveratrol, epicatechin, epicatechin gallate in MilliporeSigma (St. Louis, MO, USA) and their purity verified using HPLC and exceeded 98%.

Rhein (CFN99157, purity 98%), emodin (CFN98834, 99%), chrysophanol (CFN98751, 98%), aloe-emodin (CFN98749, 98%), and physcion (CFN98848, 98.5%) were obtained from ChemFaces (Hubei, China). RPE components were quantified using an HPLC 1290 system (Agilent, Santa Clara, CA, USA) at the Korea Basic Science Institute (Seoul, Republic of Korea). RPE (10 μL, 20 mg/mL) was separated on a Kinetex C18 column (4.6 × 250 mm, 5 µm, Phenomenex, Torrance, CA, USA) at a flow rate of 1 mL/min. Mobile phases A and B consisted of 0.1% phosphoric acid and acetonitrile, respectively. The solvent gradient components were as follows: 40–50% (B) for 50 min, 50–100% (B) for 20 min, and equilibration for 5 min. The column temperature was maintained at 25 °C. Rhein, emodin, chrysophanol, aloe-emodin, and physcion were detected at 278 nm wavelength. The concentrations of the compounds in RPE were calculated using standard curves.