Stigmasterol

Squalene (B50732), lanosterol (B50780), cholesterol (B20272), and stigmasterol (B20314) were purchased from Yuanye Biotechnology; cycloartenol (C923402) was purchased from Macklin; and mevinolin (PHR1285), fosmidomycin (F8307), terbinafine (T8826), and ketoconazole (PHR1385) were purchased from Merck.

Methanol, acetonitrile, chloroform, ethanol and n-hexane were purchased from Thermo Fisher Scientific Inc. (Waltham, MA, USA), and all chemical reagents were of HPLC grade. Dioscin (98%), diosgenin (98%), β-sitosterol (98%), stigmasterol (95%), campesterol (98%), cholesterol (98%) and N-methyl-N-(trimethylsilyl) trifluoroacetamide were purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Parvifloside (95%) and protodeltonin (95%) were obtained from Kunming Institute of Botany, CAS (Kunming, China). Detailed information and the structures of eight compounds can be obtained on the NCBI website (https://pubchem.ncbi.nlm.nih.gov/ accessed on 30 July 2021).

GGQLD was prepared using the boiling water extraction method on four dry herbal medicines: Gegen, Huangqin, Huanglian, and Zhigancao. The herbs were mixed in a ratio of 8:3:3:2 and soaked with distilled water (eightfold volume v/w) for 30 min. The mixture was extracted using a decoction pot twice (1 h and 40 min each time), and the supernatants were combined and concentrated to 1 g crude medicine/mL using a rotary evaporator. The crude extract was then preserved at 4 °C for in vitro experiments. Stigmasterol the bioactive ingredients with purities greater than 98%, were provided by Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). The chemical structure of Stigmasterol is presented in Fig. 5A. The HPLC analysis confirmed the puerarin, baicalin, liquiritin, and berberine content in accordance with a previous study [17 (link)]. HPLC analysis was conducted using an Agilent 1200 HPLC1200 (Thermo Fisher Scientific, New York, United States). The detection wavelength for Stigmasterol was set at 210 nm. The decoction was administered orally as a water extract.