Polyalthia longifolia leaves methanolic extract targets entry and budding of viruses-an in vitro experimental study against paramyxoviruses

Nephroprotective potential of Polyalthia longifolia roots against vancomycin-induced renal toxicity in experimental animals

This study was done to investigate the possible nephroprotective effect of an ethanolic root extract of Polyalthia Longifolia (PL) on vancomycin-induced nephrotoxicity using curative and protective models. Vancomycin (150 mg/kg, intravenous) was given to healthy Wistar albino rats in the curative model before the start of treatment, whereas the protective group received vancomycin at the conclusion of the 10-day treatment procedure. Animals were divided into six groups for both models; group I served as the normal control, while groups II, III, IV, V, and VI were kept as toxic control, standard (selenium, 6 mg/kg), LDPL (low dose of PL 200 mg/kg), HDPL (high dose of PL 400 mg/kg), and HDPL + selenium (interactive) groups, respectively. Renal biomarkers [(uric acid, creatinine, blood urea nitrogen (BUN), serum proteins], and blood electrolyte levels were measured for all tested groups. When compared to the vancomycin group, the HDPL significantly (p < 0.01) showed greater effectiveness in lowering the BUN, potassium, and calcium levels. Additionally, in the curative model, there was a significant (p < 0.05) decrease in the blood levels of uric acid, creatinine, BUN, potassium, and calcium in the animals who received the combination of selenium and HDPL. Both LDPL and HDPL did not provide any distinguishable effect in the protective model, but groups that received HDPL with selenium did provide detectable protection by significantly lowering their levels of uric acid, BUN, serum potassium, and total serum protein in comparison to the vancomycin control group. These findings indicate that, whether administered before or after renal damage is induced, the Polyalthia longifolia root extract provided only modest protection to nephrons, which require selenium support to prevent vancomycin-induced kidney damage.

Antiviral activities of Polygonum perfoliatum L. extract and related phenolic acid constituents against hepatitis B virus

Chronic hepatitis B virus (HBV) infection is an important public health problem. Polygonum perfoliatum L. is a traditional medicinal herb and has been reported to have pharmacological activities such as anti-inflammatory, antibacterial, and antiviral. In this study, the antiviral activities and mechanisms of Polygonum perfoliatum L. extract against HBV and the effective components were investigated. The results showed that the total extract of Polygonum perfoliatum L. reduced the levels of HBV e antigen (HBeAg) secretion and the viral covalently closed circular DNA (CCC DNA) formation, but had little or no negative effects on viral capsid assembly and pregenomic RNA packaging. Further fractionation showed that the water extract (WE) fraction exerted comparable anti-HBV activities with the total extract, especially in inhibiting the CCC DNA formation and HBeAg production, indicating that the effective antiviral components are mainly distributed in this fraction. Further study showed that the phenolic acids constituents, protocatechuic acid, and gallic acid, but not ethyl caffeate, which is reported enriched in the WE fraction, showed strong anti-HBV activities in inhibiting viral core DNA synthesis, CCC DNA formation, and HBeAg production. These results suggested that the Polygonum perfoliatum L. total extract and the related phenolic acids like protocatechuic acid and gallic acid could inhibit HBV replication and also indicated the potential utility of Polygonum perfoliatum L. and related constituents as sources of novel antivirals against HBV.

Antiviral Properties of Polyphenols from Plants

Polyphenols are active substances against various types of viral infections. Researchers have characterized methods of how to isolate polyphenols without losing their potential to formulate pharmaceutical products. Researchers have also described mechanisms against common viral infections (i.e., influenza, herpes, hepatitis, rotavirus, coronavirus). Particular compounds have been discussed together with the plants in the biomass in which they occur. Quercetin, gallic acid and epigallocatechin are exemplary compounds that inhibit the growth cycle of viruses. Special attention has been paid to identify plants and polyphenols that can be efficient against coronavirus infections. It has been proven that polyphenols present in the diet and in pharmaceuticals protect us from viral infections and, in case of infection, support the healing process by various mechanisms, i.e., they block the entry into the host cells, inhibit the multiplication of the virus, seal blood vessels and protect against superinfection.

Antiviral Effectivity of Favipiravir Against Peste Des Petits Ruminants Virus Is Mediated by the JAK/STAT and PI3K/AKT Pathways

Peste des petits ruminants virus (PPRV), belonging to the genus Morbillivirus in the family Paramyxoviridae, causes severe infectious disease in small ruminants and has been rapidly spreading in many parts of Africa, the Middle East, and Asia. Although vaccination is considered to be an effective means of controlling PPR, the heat-sensitive nature of the vaccines against PPRV greatly limits their application in areas with a hot climate. In the present study, we investigated the anti-PPRV effects of favipiravir and sought to identify the underlying mechanisms in vitro using the Vero cell line. MTT assays, Western blotting, indirect immunofluorescence assays, virus plaque formation assays, and qRT-PCR were used to assess the effects of favipiravir on the life cycle of PPRV and the expression of RNA-dependent RNA polymerase (RdRp). Additionally, the expression levels of JAK1, STAT1, phosphorylated (p)-STAT1, PI3K, AKT, and p-AKT, as well as those of signaling molecules acting downstream of the JAK/STAT and PI3K/AKT signaling pathways, were determined by Western blotting and qRT-PCR. The results indicated that, in PPRV-infected, favipiravir-treated Vero cells, the attachment, invasion, replication, and release of PPRV were significantly inhibited, as was the expression of RdRp, when compared with that in untreated PPRV-infected cells. Furthermore, in favipiravir-treated cells, the expression of JAK1 and STAT1 was downregulated, whereas that of p-STAT1 was significantly upregulated. Similarly, the expression levels of PKR, IRF9, ISG54, and MxA proteins that are associated with innate antiviral activity in host cells were also markedly increased. Moreover, with favipiravir treatment, the expression of PI3K and p-AKT and the p-AKT/AKT ratio were significantly decreased, whereas the expression of AKT was noticeably upregulated. The expression of GSK3, NF-κB p65, p-NF-κB p65, and BAD was also increased with favipiravir treatment, while the expression of CREB, p-CREB, p-GSK3, and Bcl-2 was slightly decreased. In addition, all the p-GSK3/GSK3, p-CREB/CREB, p-NF-κB/NF-κB, and p-BAD/BAD ratios were significantly reduced in favipiravir-treated cells. These results implied that the antiviral effectivity of favipiravir against PPRV is mediated by the JAK/STAT and PI3K/AKT pathways and that favipiravir has potential for use as an effective antiviral agent against PPRV.

Antiviral activity of Apigenin against buffalopox: Novel mechanistic insights and drug-resistance considerations

We describe herein that Apigenin, which is a dietary flavonoid, exerts a strong in vitro and in ovo antiviral efficacy against buffalopox virus (BPXV). Apigenin treatment was shown to inhibit synthesis of viral DNA, mRNA and proteins, without affecting other steps of viral life cycle such as attachment, entry and budding. Although the major mode of antiviral action of Apigenin was shown to be mediated via targeting certain cellular factors, a modest inhibitory effect of Apigenin was also observed directly on viral polymerase. We also evaluated the selection of drug-resistant virus variants under long-term selection pressure of Apigenin. Wherein Apigenin-resistant mutants were not observed up to ~ P20 (passage 20), a significant resistance was observed to the antiviral action of Apigenin at ~ P30. However, a high degree resistance could not be observed even up to P60. To the best of our knowledge, this is the first report describing in vitro and in ovo antiviral efficacy of Apigenin against poxvirus infection. The study also provides mechanistic insights on the antiviral activity of Apigenin and selection of potential Apigenin-resistant mutants upon long-term culture.