In vitro and in vivo antiviral activity of monolaurin against Seneca Valley virus

Inhibition of PRRSV replication by fangchinoline and cepharanthine from medicinal herbs through targeting of the CD163 protein

Pigs are significant sources of food and bioproducts. However, porcine reproductive and respiratory syndrome virus (PRRSV) poses a substantial threat to the global swine industry, leading to considerable economic losses. Efforts are still ongoing to explore effective vaccines or therapeutics to combat this pathogen. Plants stand as one of the richest sources of pharmacologically active natural products, continually furnishing promising antiviral components. This study utilizes computational screening and integrated in vitro and in vivo approaches to identify herbal compounds with anti-PRRSV activity. The binding affinity of these compounds for the CD163 protein is further confirmed through computer-aided drug design and cellular thermal shift assay. Porcine infection and therapeutic interventions studies are performed to comprehensively assess the anti-PRRSV efficacy of herbal formulations. The compounds fangchinoline (EC50 = 2.03 µM) and cepharanthine (EC50 = 1.27 µM) exhibit potent inhibition of PRRSV replication and uniquely target CD163. Furthermore, herbal formulations containing cepharanthine effectively inhibit PRRSV replication in vivo and alleviated symptoms significantly. Targeting CD163 with compounds like fangchinoline and cepharanthine presents a promising strategy for developing anti-PRRSV therapeutics. These findings offer valuable insights for the development of in vivo treatments and highlight the potential of Stephania-derived ingredients in combating PRRSV.

Higher Serum Monolaurin Is Associated with a Lower Risk of COVID-19: Results from a Prospective Observational Cohort Study

The COVID-19 pandemic has stimulated the search for effective preventive and therapeutic agents. In recent years, many studies have considered the effects of different nutrients. This study aimed to investigate the association between serum monolaurin levels and the risk of developing COVID-19 among healthcare workers. In this prospective observational cohort study, 2712 healthcare workers from the University Hospital "Maggiore della Carità" in Novara, Italy were enrolled. Participants underwent blood sampling and were followed up for six months to evaluate the protective role of serum monolaurin against COVID-19 infection. Monolaurin levels were quantified using targeted metabolomic analysis. The study cohort consisted of 1000 individuals with a mean age of 46.4 years, predominantly female. Higher serum monolaurin concentrations were significantly associated with a lower risk of SARS-CoV-2 infection at both 3- and 6-month follow-ups. The optimal cut-off value for serum monolaurin, which provides protective efficacy, was identified as 0.45 µg/mL. Higher serum monolaurin levels appear to be associated with a reduced risk of COVID-19, suggesting its potential as a protective dietary supplement against SARS-CoV-2 infection. This study contributes to the growing body of evidence supporting the role of dietary factors in the management and prevention of infectious diseases and highlights the potential of targeted metabolomics in identifying prophylactic biomarkers.

Activating Esterase D by PFD5 exerts antiviral effect through inhibiting glutathionization of LAMP1 during Senecavirus A infection

Seneca virus A (SVA) is a newly discovered small nucleic acid virus, which can cause swine blister disease (PVD). Currently, there is no drug or vaccine. Studies have shown that SVA relies on the endolysosomal pathway to accomplish intracellular transport and release, and can disrupt lysosomal homeostasis, but its specific mechanism has not been revealed. At present, there is limited research on vaccines and antiviral drugs for it. Esterase D (ESD), a serine hydrolase, is active against many substrates and plays a role in inhibiting viral replication. However, the specific mechanism of the thioesterase activity of ESD in the signaling pathway is unknown. In this study, we synthesized and screened a novel small-molecule ESD activator, FPD5 (4-chloro-2-(5-phenyl-1-(pyridin-2-yl)-4,5-dihydro- 1h -pyrazol-3-yl)phenyl), capable of inhibiting the replication of SVA. To explore the mechanism of action of this process, we demonstrated the direct interaction between ESD and lysosomal membrane protein-1 (LAMP1) by CO-IP; Western blot revealed that FPD5 could activate ESD and exert a protective effect on LAMP1 and lysosomes. The deglutathionization function of ESD was verified by protein glutathione immunoblotting and detection reagents, and the affected cysteine residues were found by point mutation technique. The results showed that FPD5 activated ESD to exert thioesterase activity, reduced glutathionylation cysteine 375 in the LAMP1 and decreased SVA production. This study provides a theoretical basis for the development of small molecule drugs against SVA, and also suggests that the activation of the thioesterase activity of ESD is a new direction for future antiviral drug development.

Development of a water-dispersible antimicrobial lipid mixture to inhibit African swine fever virus and other enveloped viruses

Medium-chain antimicrobial lipids are promising antiviral agents to inhibit membrane-enveloped viruses such as African swine fever virus (ASFV) and influenza A virus (IAV) in livestock applications. However, current uses are limited to feed pathogen mitigation due to low aqueous solubility and the development of water-dispersible lipid formulations is needed for broader application usage. In this study, we report a water-dispersible antimicrobial lipid mixture of monoglycerides and lactylates that can inhibit ASFV and IAV and exhibits antiviral properties in drinking water and feed matrices. The lipid mixture reduced the viral infectivity of membrane-enveloped ASFV and IAV in aqueous solution in a dose-dependent manner but was inactive against non-enveloped encephalomyocarditis virus (EMCV). Additional ASFV experiments supported that the lipid mixture is virucidal, which was corroborated by polymerase chain reaction (PCR) experiments. Feed mitigation experiments demonstrated that the lipid mixture can also inhibit ASFV infectivity and affected the conformational properties of ASFV p72 structural protein in virus-spiked feed. Mechanistic experiments identified that the lipid mixture rapidly disrupted phospholipid membranes in a micelle-dependent manner, which aligns with the virological data while higher concentrations were needed for virucidal activity than for the onset of membrane disruption. These findings support that water-dispersible antimicrobial lipid mixtures can effectively inhibit ASFV and IAV and have practical advantages for drinking water applications compared to existing medium-chain antimicrobial lipid mitigant options that are formulated as dry powders or oils for in-feed applications.

Current alternative therapies for treating drug-resistant Neisseria gonorrhoeae causing ophthalmia neonatorum

Ophthalmia neonatorum is a microbial contraction, damaging eyesight, occurring largely among neonates. Infants are particularly vulnerable to bacterial infections acquired during birth from infected mothers, especially from Neisseria gonorrhoeae and Chlamydia trachomatis. Over the decades, N. gonorrhoeae is alarmingly developing a resistance to most antibiotics currently prescribed. To counter this challenge, it is imperative to find potent and cost-effective therapeutic agents for prophylaxis and treatment, to which the N. gonorrhoeae cannot easily develop resistance. This review showcases alternate therapies such as antimicrobial-fatty acids, -peptides, -nano-formulations etc., currently evident against N. gonorrhoeae-mediated ophthalmia neonatorum, which remains a major cause of ocular morbidity, blindness and even death among neonates in developing countries.

Effects of combined application of benzoic acid and 1-monolaurin on growth performance, nutrient digestibility, gut microbiome and inflammatory factor levels in weaned piglets

BACKGROUND

Our previous study observed that benzoic acid and 1-monolaurin have a synergistic bactericidal effect. Moreover, their improvement effect of benzoic acid and 1-monolaurin on the growth performance and diarrhea of weaned piglets was better than the two feedings alone. However, it is not clear how the combination of benzoic acid and 1-monolaurin affects the growth performance of weaned piglets. Therefore, 100 weaned piglets (mean weight 7.03 ± 1.04 kg, mean weaning age 26 d) were randomly divided into two groups: (1) basal diet control (CON); (2) basal diet supplemented with 0.6% benzoic acid and 0.1% 1-monolaurin (CA). The experiment lasted 28 days after weaning. The effects of benzoic acid and 1-monolaurin supplementation on growth performance, apparent nutrient digestibility, intestinal flora composition and function, and inflammatory factor levels of weaned piglets were investigated.

RESULTS

The feed conversion efficiency of piglets in the CA group between 15 and 28 d and 1 and 28 d after weaning was significantly higher than that in the CON group (P < 0.05). Additionally, the diarrhea proportion and frequency of piglets in the CA group 1-14 days post-weaning were significantly decreased (P < 0.05). The apparent digestibility of dry matter, organic matter and crude protein of piglets in the CA group was significantly higher than the CON group on days 14 and 28 (P < 0.05). The microbial composition in the cecal digesta of piglets was detected. The results indicated that the CA group piglets were significantly supplemented with g_YRC22 at day 14 and g_Treponema, g_Pseudomonas, and g_Lachnobacterium at day 28 (P < 0.05; log LDA > 2). No significant difference was observed between the CON and CA groups in the content of short-chain fatty acids. In addition, serum IL-1β level significantly decreased at day 28 in the CA group compared with the CON group, while serum endotoxin content was significantly reduced at day 14.

CONCLUSION

Therefore, dietary supplementation of 0.6% benzoic acid and 0.1% 1-monolaurin enhanced growth performance and nutrient digestibility, affected gut microflora composition, and decreased systemic inflammatory response and intestinal permeability of weaned piglets. These outcomes provide a theoretical basis for applying of benzoic acid and 1-monolaurin over weaned piglets.

Glycerol Monolaurate Inhibits Wild-Type African Swine Fever Virus Infection in Porcine Macrophages

Naturally abundant antimicrobial lipids, such as fatty acids and monoglycerides, that disrupt membrane-enveloped viruses are promising mitigants to inhibit African swine fever virus (ASFV). Among mitigant candidates in this class, glycerol monolaurate (GML) has demonstrated particularly high antiviral activity against laboratory-adapted ASFV strains. However, there is an outstanding need to further determine the effects of GML on wild-type ASFV strains, which can have different virulence levels and sensitivities to membrane-disrupting compounds as compared to laboratory-adapted strains. Herein, we investigated the antiviral effects of GML on a highly virulent strain of a wild-type ASFV isolate (Armenia/07) in an in vitro porcine macrophage model. GML treatment caused a concentration-dependent reduction in viral infectivity, and there was a sharp transition between inactive and active GML concentrations. Low GML concentrations had negligible effect on viral infectivity, whereas sufficiently high GML concentrations caused a >99% decrease in viral infectivity. The concentration onset of antiviral activity matched the critical micelle concentration (CMC) value of GML, reinforcing that GML micelles play a critical role in enabling anti-ASFV activity. These findings validate that GML can potently inhibit wild-type ASFV infection of porcine macrophages and support a biophysical explanation to guide antimicrobial lipid performance optimization for pathogen mitigation applications.