Screening of neuraminidase inhibitory activities of some medicinal plants traditionally used in Lingnan Chinese medicines

Jiawei Liu,Kaotan Chen,Weiling Zhuo,Ailin Liu,Li Gao,Weiwen Chen,Mian Zu,Huan Min

doi:10.1186/s12906-018-2173-1

Abstract

BackgroundNeuraminidase (NA) is one of the key surface protein of the influenza virus, and has been established as a primary drug target for anti-influenza therapies. This study aimed to screen bioactive herbal extracts from some medicinal plants traditionally used in Lingnan Chinese Medicines by NA activity high-throughput screening assay.MethodsOne hundred ninety herbal extracts from 95 medicinal plants collected in Guangzhou were screened for their potential inhibitory activities against A (H1N1) influenza neuraminidase, and the most active extracts were further evaluated for their anti-influenza virus activities using virus-induced cytopathic effect (CPE).ResultsAmong the tested 190 herbal extracts, 14 extracts inhibited significantly NA activity (IC50 < 40 μg/mL), and the extracts 1–5, which were obtained from Amomurn villosum Lour, Melaphis chinensis (Bell) Baker, Sanguisorba officinalis and Flos Caryophylli, showed potent inhibitory activity against NA with IC50 values ranging from 4.1 to 9.6 μg/mL. Moreover, the most bioactive extracts 1–5 were found to protect MDCK cells from A (H1N1) influenza virus infection with very low cytotoxicity to the host cells (EC50 values ranged from 1.8 to 14.1 μg/mL, CC50 values ranged from 97.0 to 779.2 μg/mL, SI values ranged from 14 to 438). In addition, quantitative RT-PCR analysis showed that the extracts 1–5 inhibited viral RNA synthesis in a dose-dependent manner.ConclusionWe performed in vitro screening of anti-neuraminidase activities of herbal extracts from medicinal plants used in Lingnan Chinese Medicines, and the results indicate that some bioactive extracts are worth further studies to identify the bioactive components responsible for anti-influenza virus activities, to elucidate their modes of action and finally determine their clinical potentials.

Highlights

Neuraminidase (NA) is one of the key surface protein of the influenza virus, and has been established as a primary drug target for anti-influenza therapies
The results showed that these herbal extracts significantly inhibited the NA activity and the replication of influenza viruses, and exhibited very low cytotoxicity to the host cells
We first examined the ability of 190 organic extracts from 95 medicinal plants to inhibit NA activity by in vitro screening assay

Summary

Introduction

Neuraminidase (NA) is one of the key surface protein of the influenza virus, and has been established as a primary drug target for anti-influenza therapies. NA plays a critical role for virus replication and spread in infected tissues during infection, and has been well established as a primary drug target for anti-influenza therapies [5, 6]. Some potent NA inhibitors, including oseltamivir, zanamivir, laninamivir and peramivir, have been designed and applied in clinical treatments [7, 8]. Resistance to these NA inhibitors has been extensively reported [9,10,11]. Medicinal plants may be a probable source for the discovery of natural NA inhibitors and might provide leads to develop the NA inhibitors [12]

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