Antiviral activity of natural products particularly Australian native fruits against human coronavirus 229e

Abstract

With the emergence of several airborne respiratory infectious diseases like SARS, MERS, and COVID-19 in the past decade, the need for more and better treatment options for such viral infections has increased rapidly. Most of these infections have been reported to be caused by viruses that belong to the family Coronaviridae. All the members of this family have a crown-like appearance and adopt a more or less similar mechanism of infection. Among these viruses, HCoV-229e is a virus that has existed for a long period and is responsible for the common cold. Despite its commonness, HCoV-229e has been reported to cause severe life-threatening infections in immunocompromised individuals as well as infants and the elderly. It accounts for the highest mortality rate among non-SARS and non-MERS coronaviruses. Each year thousands of people get infected by HCoV-229e yet there is a lack of appropriate treatment or vaccine. The need for proper therapy has led to the exploitation of plants that have been shown antiviral properties in the past. Based on previous studies, the project focuses on different food components mainly Australian native fruits and vegetables which have anti-oxidant, anti-microbial and anti-inflammatory properties. The study included selection of Kakadu plum (KP), Illawara plum (IP), lemon aspen (LA), Davidson plum (DP) and native currant (NC) extracts based on their availability in the laboratory and analysis of their antiviral activity at various concentrations, on the late phase of HCoV-229e infection using a liquid-media based assay on the host MRC-5 cells. A total of 10 extracts were tested which included both aqueous and ethanol solutions for each fruit except lemon aspen which was not soluble in water, thus DMSO was used to dissolve lemon aspen. The absorbance value was low for most of the fruit extracts in almost all the concentrations except for ethanolic extract solution of Illawarra plum at 1500μg/ml and 375μg/ml for aqueous solution of Native currant at a virus concentration of 10-2. The extracts of Lemon aspen and Davidson plum were eliminated as the initial assays indicated that they were comparatively less active than others. The IC50 values for the antiviral activity were calculated for mostly the active extracts and statistical analyses were performed. Illawarra extract (IP/OH) exhibited an IC50 value of 135.39μg/ml and the water extract of Native currant (NC/W) had a comparatively lower IC50 value of 108.14μg/ml. The results from the anti-inflammatory NO assay was rejected due to the error in LPS readings.

Date of Thesis submission	2024
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Chun Guang Li (Supervisor) & Deep Bhuyan (Supervisor)