Hypolipidemic and Antithrombotic Effect of 6'-O-Caffeoylarbutin from Vaccinium dunalianum Based on Zebrafish Model, Network Pharmacology, and Molecular Docking

Vaccinium dunalianum leaf buds make one of the most commonly used herbal teas of the Yi people in China, which is used to treat articular rheumatism, relax tendons, and stimulates blood circulation in the body. In addition, 6'-O-caffeoylarbutin (CA) is a standardized extract of V. dunalianum, which has been found in dried leaf buds, reaching levels of up to 31.76%. Because of the uncommon phenomenon, it is suggested that CA may have a potential therapeutic role in hyperlipidemia and thrombosis. This study was designed to study the efficacy of CA on treating hyperlipidemia and thrombosis and the possible mechanisms behind these effects. Hyperlipidemia and thrombosis zebrafish models were treated with CA to observe variations of the integrated optical density within the vessels and the intensity of erythrocyte staining within the hearts. The possible mechanisms were explored using network pharmacology and molecular docking. The results demonstrate that CA exhibits an excellent hypolipidemic effect on zebrafish at concentrations ranging from 3.0 to 30.0 μg/mL and shows thrombosis inhibitory activity in zebrafish at a concentration of 30.0 μg/mL, with an inhibition rate of 44%. Moreover, network pharmacological research shows that MMP9, RELA, MMP2, PRKCA, HSP90AA1, and APP are major targets of CA for therapy of hyperlipidemia and thrombosis, and may relate to pathways in cancer, chemical carcinogenesis-receptor activation, estrogen signaling pathway, and the AGE-RAGE signaling pathway in diabetic complications.

Phenolic Constituents, Antioxidant and Cytoprotective Activities, Enzyme Inhibition Abilities of Five Fractions from Vaccinium dunalianum Wight

The bud of Vaccinium dunalianum Wight has been traditionally consumed as health herbal tea by “Yi” people in Yunnan Province, China, which was locally named “Que Zui tea”. This paper studied the chemical constituents of five fractions from Vaccinium dunalianum, and their enzyme inhibitory effects of α-glucosidase and pancreatic lipase, antioxidant activity, and cytoprotective effects on H₂O₂-induced oxidative damage in HepG2 cells. The methanol extract of V. dunalianum was successively partitioned with petroleum ether (PF), chloroform (CF), ethyl acetate (EF), n-butanol (BF), and aqueous (WF) to obtain five fractions. The chemical profiling of the five fractions was analyzed by ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry (UHPLC-MS/MS), and 18 compounds were tentatively identified. Compared to PF, CF, BF and WF, the EF revealed the highest total phenols (TPC) and total flavonoids (TFC), and displayed the strongest enzyme inhibition ability (α-glucosidase and pancreatic lipase) and antioxidant capacity (DPPH, ABTS and FRAP). Furthermore, these five fractions, especially EF, could effectively inhibit reactive oxygen species (ROS) production and cell apoptosis on H₂O₂-induced oxidative damage protection in HepG2 cells. This inhibitory effect might be caused by the up-regulation of intracellular antioxidant enzyme activity (CAT, SOD, and GSH). The flavonoids and phenolic acids of V. dunalianum might be the bioactive substances responsible for enzyme inhibitory, antioxidant, and cytoprotective activities.

Phenolic constituents, antioxidant activity and neuroprotective effects of ethanol extracts of fruits, leaves and flower buds from Vaccinium dunalianum Wight

Vaccinium dunalianum Wight is an important healthy tea resource in China with health benefits. The chemical compositions and the possible bioactive substances in its fruits, leaves and flower buds extracts (FE, LE and FBE) were identified and characterized by UHPLC-HRMS/MS. Consequently, FE, LE and FBE were rich in phenolic and flavonoid compounds. Among them, 21 compounds were identified, and the main components were chlorogenic acid, quinic acid and 6'-O-caffeoylarbutin. Furthermore, their neuroprotection and mechanism on H₂O₂-induced neurotoxicity in PC12 cells were investigated. All the different concentrations of FE, LE and FBE were apparently inhibited the H₂O₂-induced ROS generation and apoptosis on PC12 cells. FBE showed stronger neuroprotective activity against H₂O₂-induced PC12 cell damage than those of FE and LE. The mechanism of neuroprotective effect might be related to the upregulation of endogenous antioxidant enzymes expressions and activation of the Nrf2/HO-1 signaling pathway.