Identification of the Components in a Vaccinium oldhamii Extract Showing Inhibitory Activity against Influenza Virus Adsorption

Abstract

We previously reported that extracts from plants of the Ericaceae genus Vaccinium, commonly known as the kind of blueberry, inhibited the early steps of influenza virus (IFV) infection to host cells, and that the activity was correlated with the total polyphenol content. Particularly potent inhibitory activity was observed for Vaccinium oldhamii. In this study, we identified the active components in Vaccinium oldhamii involved in the inhibition of IFV infection. We sequentially fractionated the Vaccinium oldhamii extract using a synthetic adsorbent resin column. High inhibitory activity was observed for the fractions eluted with 30%, 40%, and 50% ethanol, and three peaks (peak A, B, and C) considered to represent polyphenols were identified in the fractions by HPLC analysis. Among these peaks, high inhibitory activity was detected for peak A and B, but not for peak C. These peaks were analyzed by LC/MS, which revealed that peak A contained procyanidin B2 and ferulic acid derivatives, whereas peak B contained two ferulic acid O-hexosides, and peak C contained quercetin-3-O-rhamnoside and quercetin-O-pentoside-O-rhamnoside. It is already known that these polyphenols have anti-IFV activity, but we speculate that ferulic acid derivatives are the major contributors to the inhibition of the early steps of IFV replication, such as either adsorption or entry, observed for Vaccinium oldhamii.

Network Pharmacology Analysis on the Mechanism of Huangqi Sijunzi Decoction in Treating Cancer-Related Fatigue

“…e IL-17 signaling pathway is a classical important pathway related to immune responses, apoptosis, and tumorigenesis [46]. Animal experiments have shown that the main active ingredients of HQSJZD, that is, quercetin, luteolin, and kaempferol, can reduce the expression of TNF-α and IL-17 [47], thus improving the tumor microenvironment to effectively relieve CRF. Moreover, it has been revealed by KEGG pathway enrichment analysis that HQSJZD acts on EGFR, MMPS, and ERBB2 to improve bladder cancer-related fatigue and on EGFR, MET, ERBB2, and PI3K-Akt to improve non-small cell lung cancer-related fatigue.…”

Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus

“…However, quercetin glycosides showed weak activity in this study. Although anti-influenza activity of quercetin was reported previously [ 78 , 86 ], it was suggested in this study that this activity was due to the suppression of influenza replication inside the cells and not due to the inhibition of virus infection to the host cells [ 98 ].…”

Polyphenols as promising biologically active substances for preventing SARS-CoV-2: A review with research evidence and underlying mechanisms

“… (Palamara et al , 2019) Flavonoids Elderberry and blueberry Several blueberry varieties exert anti-influenza viral activities, especially viral adsorption, which positively correlated with the total polyphenol content in Madin-Darby canine kidney cells. ( Sekizawa et al , 2019 ) …”