Piceid

All of the solvents, salts, acids and bases were of analytical grade and were purchased from Sigma-Aldrich-Merck (Darmstadt, Germany) or Carlo Erba (Milan, Italy). (Poly)phenol standards used for identification and quantification purposes with HPLC-MS/MS were as follows: protocatechuic acid, gallic acid, (+)-gallocatechin, (−)-epigallocatechin, caftaric acid, (+)-catechin, (−)-epicatechin, trans-coutaric acid, astringin, trans-fertaric acid, 2,6-dihydroxybenzoic acid, 4-hydroxybenzoic acid, chlorogenic acid, caffeic acid, vanillic acid, rutin, piceid, coumaric acid, sinapic acid, ferulic acid, luteolin, quercetin, apigenin, kaempferol, procyanidin B1 (Sigma-Aldrich-Merck, Darmstadt, Germany) and procyanidin B2 (Extrasynthese, Genay Cedex, France).

The following reagents were used during the process: dimethyl sulfoxide (DMSO), phosphate buffered saline (PBS), caffeine, 4-phenylbutyrate, glycine betaine, (±) catechin, (−) epicatechin, (−) gallocatechin gallate, epigallocatechin gallate, luteolin, kaempferol, resveratrol, piceid, caffeic acid phenethyl ester (CAPE), curcumin and α-tocopherol were supplied by Sigma-Aldrich (St. Louis, MI, USA). OptiCHO free serum media and l-glutamine were supplied by Thermo Fisher Scientific (Ulm, Germany). Further well known chaperon chemicals were also assessed as reference (Appendix B).
The cell line used was a stable recombinant DG44 CHO cell line that expressed an IgG monoclonal antibody, provided by Fujifilm Diosynth. This cell line was then left to grow in suspension in an OptiCHO™ free serum media in a 125 mL Erlenmeyer Flask (Corning, NY, USA) containing 33 mL of culture media, supplemented with 8 mM l-glutamine and 100 mg/L hygromycin B. Culture was maintained in a Infors HT Multitron cell shaking incubator (Bottmingen, Switzerland) set at 130 rpm with 5% CO₂ modified atmosphere at 37 °C. Cells were seeded into new media at 0.2 × 10⁶ viable cells/mL every three to four days for a maximum of 16 passages prior to use.

Plant samples were freeze-dried for 48 hours, and dry weight was determined according to the volume-to-mass ratio of 1:10. Methanol was added to extract stilbene substances for 24 hours in dark. Then, the methanol extract was filtered through a 0.22-μm membrane film. High-performance liquid chromatography (HPLC) was conducted using a Nexera UHPLC LC-30A (Shimadzu, Japan). The gradient used was consistent with previous research methods [127 ]. Standard samples of trans-resveratrol (CAS: 501-36-0), piceid (CAS: 27208-80-6), piceatannol (CAS: 10083-24-6), pterostilbene (CAS: 537-42-8), and ε-viniferin (CAS: 62218-08-0) (Sigma–Aldrich, USA) were used to confirm retention times.

P. cuspidatum was obtained from Gwang-Myoung (Korea) in April 2019. The P. cuspidatum root sample was pulverized to an 80 mesh size using the DA280-S grinder (Daesung Artlon, Korea), and freeze dried (Ilshin, Korea) to obtain powder. ABTS was obtained from Wako Industries, Ltd. (Japan). Folin-Ciocalteu reagent, potassium ferricyanide, trichloroacetic acid, ferric chloride, butylated hydroxyanisole, ascorbic acid, EDTA, IBMX, glycerol, MTT, dimethyl sulfoxide, dexamethasone, emodin, piceid, and resveratrol were obtained from Sigma Chemical Co., LLC. FBS and DMEM were obtained from Gibco Laboratory (USA). Antibodies against PPARγ (#2435), C/EBPα (#8178), FAS (#3180), ACC (#3676), NF-kB (Phospho-p38 (#9212), p38 (#9211), Phospho-ERK (#4370), ERK (#9102), Phospho-JNK (#9251), JNK (#9252), and β-actin (#4970), as well as anti-rabbit IgG (#7074) and anti-mouse IgG (#7076), were purchased from Cell Signaling Technology (USA). An anti-SREBP1-c (ab28481) antibody was obtained from Abcam Inc. (USA).