Nicotinamide

Aβ_1-42 (Shanghai GL Bio-Chem Ltd.) and hexafluoroisopropanol (HFIP, Shanghai Aladdin Bio-Chem Technology Co., Ltd.) were used to synthesize Aβ oligomers. The formula consists of Gastrodia elata Blume, Curcuma longa L., Punica granatum L., Morus alba Linn., Lycium barbarum L, Ginkgo biloba, Rhodiola rosea, and Alpinia oxyphylla Miq. The herbs were purchased from Beijing Tongrentang Pharmaceutical Co. Ltd. Dulbecco’s modified Eagle’s medium (DMEM) was purchased from Hyclone (United States). Penicillin, streptomycin, and trypsin were purchased from Beyotime Biotechnology (China). Phosphate buffered saline (PBS) was purchased from Solarbio Life Sciences (China), and 3-(4,5-dimethyl-2-thiazolyl)- 2,5-diphenyl-2-H-tetrazolium bromide (MTT) was bought from Sigma (United States). Amyloid beta A4 rabbit antibody (Catalog No: A17911) and GSK3β rabbit antibody (Catalog No: A11731) were purchased from Wuhan ABclonal Biotech Co., Ltd. The standard products of salidroside, umbelliferone, gastrodin, and nicotinamide were purchased from Yuanye Biotechnology Co., Ltd. (China). Acetonitrile and methanol were supplied by Merck KGaA (Darmstadt, Germany). Formic acid of chromatographic grade was purchased from Aladdin (Shanghai, China). Ultrapure water was prepared by a water purification system (Milli-Q Integral 5). All other chemicals were of analytical grade.

Puerarin, streptozotocin, nicotinamide, and citrate buffer were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Metformin was purchased from Youcare Pharmaceutical Group Co., Ltd. Male Sprague–Dawley rats were purchased from Vital River (Weitong Lihua) Laboratory Animal Technology Co., Ltd. (Beijing, China). The rodent chow diet was purchased from Keao Xieli Feed Co., Ltd. (Beijing, China). The required glassware was purchased from Sichuan Shubo (Group) Co., Ltd. (Chongzhou, China). The polypropylene consumables were purchased from Axygen Biotechnology (Hangzhou) Co., Ltd. (Hangzhou, China). The automatic biochemical analyser (URIT8026, URIT Medical Electronics, Guizhou, China) was used to measure the serum biochemical parameters. The ELISA kits used to measure oxidative stress markers (glutathione (GSH), malonaldehyde, and total antioxidant capacity) were purchased from Jiangsu Meimian industrial Co., Ltd. (Jiangsu, China) and proinflammatory markers (IL-1β, IL-6, and TNF-α) were purchased from Thermo Fisher Scientific (China) Co., Ltd. (Shanghai, China). FilterMax™ F-3-Multi-Mode Microplate Reader (Molecular Devices, LLC. San Jose, CA, USA) was used to measure the absorbance/fluorescence of the test solutions. The histology of the pancreas was observed using a microscope slide scanner PANNORAMIC MIDI II (3DHISTECH Ltd., Budapest, Hungary).