Advances on Antiviral Activity of Morus spp. Plant Extracts: Human Coronavirus and Virus-Related Respiratory Tract Infections in the Spotlight

Abstract

1) Background: Viral respiratory infections cause life-threatening diseases in millions of people worldwide every year. Human coronavirus and several picornaviruses are responsible for worldwide epidemic outbreaks, thus representing a heavy burden to their hosts. In the absence of specific treatments for human viral infections, natural products offer an alternative in terms of innovative drug therapies. (2) Methods: We analyzed the antiviral properties of the leaves and stem bark of the mulberry tree (Morus spp.). We compared the antiviral activity of Morus spp. on enveloped and nonenveloped viral pathogens, such as human coronavirus (HCoV 229E) and different members of the Picornaviridae family-human poliovirus 1, human parechovirus 1 and 3, and human echovirus 11. The antiviral activity of 12 water and water-alcohol plant extracts of the leaves and stem bark of three different species of mulberry-Morus alba var. alba, Morus alba var. rosa, and Morus rubra-were evaluated. We also evaluated the antiviral activities of kuwanon G against HCoV-229E. (3) Results: Our results showed that several extracts reduced the viral titer and cytopathogenic effects (CPE). Leaves' water-alcohol extracts exhibited maximum antiviral activity on human coronavirus, while stem bark and leaves' water and water-alcohol extracts were the most effective on picornaviruses. (4) Conclusions: The analysis of the antiviral activities of Morus spp. offer promising applications in antiviral strategies.

Evaluation of Antiviral, Antibacterial and Antiproliferative Activities of the Endophytic Fungus Curvularia papendorfii, and Isolation of a New Polyhydroxyacid

“…An immunofluorescence analysis (IFA) was used to detect HCoV 229E and FCV F9 protein expression in infected host cells. Briefly, L132 and CRFK cells seeded on 96-well cell culture plates were grown for 24 h at 37 °C in 5% CO 2 [ 30 ]. The cells were then infected with HCoV 229E and FCV F9 virus at MOI 1 and MOI 0.0001 and incubated for 24 h at 33 °C and 37 °C, respectively.…”

“…Briefly, the cells (10 4 cells/well) were grown in 96-well tissue culture plates and incubated for 72 h in the presence of the HCoV 229E or FCV F9, at 33 • C and 37 • C, respectively, in a 5% CO 2 atmosphere with serial 10-fold diluted virus suspensions in order to test multiplicity of infection (MOI), defined as the ratio of infectious virions to cells in a culture, between 0.0001 and 1. This protocol is similar to the article [30] The virus-induced cytopathogenic effect (CPE) was determined after 72 h of infection. By the method of Reed and Muench, the titers were counted as 50% Cell Culture Infectious Doses (CCID 50 )/mL.…”

Potential Natural Products Against Respiratory Viruses: A Perspective to Develop Anti-COVID-19 Medicines

“…rosa and Morus rubra L.) against HCoV-229E has been investigated. Leaf water-alcohol extracts had the best antiviral activity against human coronavirus 229E ( Thabti et al, 2020 ). The structures of natural products against HCoV-229E are shown in Figure 2 .…”

Toxicity as prime selection criterion among SARS-active herbal medications

“…Furthermore, efficacy against airway inflammation (by interruption of NF-κB and JNK/c-Jun signaling) by the Morus constituent Moracin M ( Lee et al, 2016 ) and inhibition of metalloproteinases were seen ( Yiemwattana et al, 2019 ; Wongwat et al, 2020 ). Antiviral activities of Morus alba juice and seed (Kim et al, 2018) as well as specifically activity against human corona virus of Folium Mori have been observed ( Thabti et al, 2020 ). As already stated in the Introduction section, Morus alba is one of the herbal medicines which were successfully used for the therapy of the SARS-CoV infected patients in the 2002/2003 SARS epidemic ( Liu et al, 2006 ; 2012a , 2012b ; Wang et al, 2014 ; Luo et al, 2020 ).…”