Phytochemical Constituents of Propolis Flavonoid, Immunological Enhancement, and Anti-porcine Parvovirus Activities Isolated From Propolis

South African Propolis: Anti-Helicobacter pylori Activity, Chemistry, and Toxicity

Propolis, a resin-like substance produced by bees, has previously shown antimicrobial activity against the ulcer-causing gut pathogen Helicobacter pylori. South African propolis, however, was yet to be investigated. This study aimed to investigate a comprehensive range of South African propolis for its antimicrobial activity against H. pylori and to investigate toxicity. A total of 51 samples were collected from around South Africa and comparatively analysed with three Brazilian samples. The antimicrobial broth microdilution assay was used to determine the minimum inhibitory concentration (MIC) of ethanolic propolis extracts against three clinical H. pylori strains. A total of 27 South African propolis extracts presented antimicrobial activity better than that of the Brazilian samples (MIC ≤ 0.51 mg/mL). Samples with the best anti-H. pylori activity were selected for chemical analysis using ultra-performance liquid chromatography-mass spectrometry. The compounds pinocembrin, 3-O-acetylpinobanksin, and pinobanksin were found to be the most abundant. All propolis extracts investigated in this study were considered non-toxic (mortality < 50%) when investigated using the brine shrimp lethality assay. This study demonstrates the in vitro potential of utilizing propolis for treating H. pylori infections and highlights the possible compounds responsible for the activity observed.

Effects of propolis extract supplementation in breeder and broiler diets and it's in ovo injection on immune status, blood parameters, vaccine-antibody response and intestinal microflora of broiler chick

This study evaluated the effects of dietary propolis extract supplementation and in-ovo propolis injection on the immune status, blood parameters, vaccine-antibody response, and intestinal microflora of broiler chickens. A total of 600 Ross 308 broiler chicks were used. Breeder diets were supplemented with 400 ppm propolis extract (P) or left unsupplemented (C) during weeks 38-39. Eggs from the control group (C) were divided into four groups, with in-ovo injections of 400 ppm propolis extract (C-iP) or physiological saline (C-iS) on day 18 of incubation. Untreated eggs formed the control (C-C) or propolis-supplemented (P-C) groups. Chicks were fed either a basal diet (C) or a diet supplemented with 400 ppm propolis extract (P), forming six experimental groups: C-C, C-P, P-C, P-P, C-iP, and C-iS, with 10 replicates per group (10 chicks per replicate). Propolis supplementation significantly increased immunoglobulin levels (IgA, IgG, IgM) compared to the control group. Although it positively affected certain blood parameters, no significant differences were found in post-vaccination antibody titers. The C-C group had the highest total antioxidant levels, while total oxidant levels and oxidative stress index were lowest in the P-P group. Despite positive effects on blood parameters and intestinal microflora, no significant improvements in growth performance were observed. Nevertheless, propolis extract shows potential as an immune enhancer for broiler chickens through parental feeding, standard diets, or in-ovo injection.

Investigating small molecules in propolis as Nipah virus glycoprotein (NiV-G) inhibitors through molecular interaction studies

Despite the significant fatality rates associated with Nipah virus (NiV) outbreaks in South Asia, including Bangladesh, and India, till today, there is no approved medications to treat it. In this context, small molecules in propolis were computationally screened through pharmacokinetic and toxicity studies followed by molecular docking and dynamics simulation with Nipah virus glycoprotein (NiV-G protein) to assess their anti-Nipah potential. A thorough literature analysis was performed to identify antiviral compounds in propolis from a pool of 84 experimental articles. Following ADMET analysis, 27 molecules out of 34 were docked against NiV-G and compared with a control ligand, ribavirin, which is an investigational drug against Nipah. The molecular docking revealed that bauer-7-en-3β-yl acetate (BA) and moronic acid (MA) bound more strongly to the active site of NiV-G than ribavirin and other ligands. Investigation of root-mean-square deviation (RMSD), root mean square fluctuations (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), molecular surface area (MolSA), binding free energy (MM-PBSA), the complexity of hydrogen bonds (HBs), and secondary structure of ligand-target interactions for 100 ns by molecular dynamics (MD) simulation study further supported the docked complex's stability and compactness. Therefore, the in silico molecular interaction analysis reports that both molecules may be the possible candidates against Nipah infection.

Antiviral alternatives against important members of the subfamily Parvovirinae: a review

Parvoviruses are responsible for multiple diseases, and there is a critical need for effective antiviral therapies. Specific antiviral treatments for parvovirus infections are currently lacking, and the available options are mostly supportive and symptomatic. In recent years, significant research efforts have been directed toward understanding the molecular mechanisms of parvovirus replication and identifying potential targets for antiviral interventions. This review highlights the structure, pathogenesis, and treatment options for major viruses of the subfamily Parvovirinae, such as parvovirus B19 (B19V), canine parvovirus type 2 (CPV-2), and porcine parvovirus (PPV) and also describes different approaches in the development of antiviral alternatives against parvovirus, including drug repurposing, serendipity, and computational tools (molecular docking and artificial intelligence) in drug discovery. These advances greatly increase the likelihood of discoveries that will lead to potent antiviral strategies against different parvovirus infections.

Inactivated herpes simplex virus-1 vaccine formulated in aqueous and alcoholic extracts of propolis boosts cellular and IgG responses

Objectives

In this study, the adjuvant activity of aqueous and alcoholic extracts of propolis was examined on the inactivated herpes simplex virus-1 (HSV-1).

Materials and Methods

BALB/C mice were administered with inactivated (HSV-1; the KOS strain) plus alcoholic and aqueous extracts, followed by assessment of the cellular and humoral immune responses.

Results

Alcoholic and aqueous extracts, as an adjuvant, revealed a significant increase in lymphocyte proliferation and cytotoxic T lymphocyte (CTL) responses versus the HSV-1 group. In addition, HSV-1 plus alcoholic extract showed a remarkable increase in IFN-γ cytokine and IFN-γ/IL-4 ratio. On the other hand, both alcoholic and aqueous extracts in the HSV-1 vaccine suppressed the IL-4 cytokine response as compared with the HSV-1 vaccine. In addition, HSV-1 plus alcoholic extract showed a significant increment in IgG1, IgG2a, and IgG2b isotypes as compared with the HSV-1 vaccine.

Conclusion

Propolis extracts seem to modulate the immune response against inactivated HSV-1 model and can be used as a suitable vaccine adjuvant or a component of a complex adjuvant against infectious diseases.

Propolis as a Potential Therapeutic Agent to Counteract Age-Related Changes in Cartilage: An In Vivo Study

Aging is intricately linked to chronic low-grade systemic inflammation, which plays a significant role in various age-related conditions, including osteoarthritis (OA). The aging process significantly influences the development of OA due to alterations in cartilage composition, reduced proteoglycan content, dysregulation of growth factor signaling, and heightened oxidative stress. Propolis, a natural product renowned for its potent antioxidant and anti-inflammatory properties, has the potential to mitigate age-induced changes in cartilage. The primary objective of this study was to rigorously assess the impact of in vivo propolis treatment on the histopathological characteristics of knee articular cartilage in senescent rats. This study involved a cohort of twenty male Sprague-Dawley rats, randomly allocated into four distinct groups for comparative analysis: YR (control group consisting of young rats), SR (senescent rats), SR-EEP (senescent rats treated with an ethanolic extract of propolis, EEP), and SR-V (senescent rats administered with a control vehicle). This study employed comprehensive histological and stereological analyses of knee articular cartilage. Propolis treatment exhibited a significant capacity to alleviate the severity of osteoarthritis, enhance the structural integrity of cartilage, and augment chondrocyte density. These promising findings underscore the potential of propolis as a compelling therapeutic agent to counteract age-related alterations in cartilage and, importantly, to potentially forestall the onset of osteoarthritis.

The antimicrobial peptide MetchnikowinII enhances Ptfa antigen immune responses against avian Pasteurella multocida in chickens

Immunostimulants and vaccines are the main means for controlling infectious diseases and searching highly effective and low toxic immunestimulants has always been the focus of researchers. The MetchnikowinII (MetII) had been expressed by us and exhibited both antibacterial and antifungal activities, in this study, we evaluated its potential for an adjuvant effect. In chickens, antigen-specific immunoglobulin Gs (IgGs) were increased after MetII adjuvanted vaccination using the Ptfa protein. Compared to group Ptfa + iFA, which was only adjuvanted with incomplete Freund's adjuvant (iFA), the antibody titers of the group Ptfa + iFA + Met20 μg·mL-1 (PFM20) and Ptfa + iFA + Propolis (PFP) significantly increased (P<0.05). Likewise, Interleukin-2 (IL-2) and Interferon-γ (IFN-γ) cytokines in group Ptfa + iFA + Met20 μg·mL-1 (PFM20) and Ptfa + iFA + Propolis (PFP) were significantly higher than those of the other three experimental groups (P<0.05). The stimulation index (SI) value in chickens of group PFM20 was significantly higher than that of the other four experimental groups (P<0.05). Chickens that received MetII adjuvanted vaccinations benefitted from higher protection rate (88%) when challenged with Pasteurella multocida (P. multocida), which was significantly higher than those of group PF and PFP (P<0.05). These results suggested that the antimicrobial peptide MetII may play an adjuvant role in the immune response in chickens but need a proper usage, because the higher usage of 40 μg·mL-1 and 60 μg·mL-1 resulted poor effect. Whether MetII could be a potential adjuvant or a biomolecule as part of a complex adjuvant for vaccines needs more experimental evidence, the study still provides an examples for understanding vaccine adjuvants.

Antiviral Potential of Specially Selected Bulgarian Propolis Extracts: In Vitro Activity against Structurally Different Viruses

Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched with enzymes and bee saliva. It also contains various essential oils, vitamins, mineral salts, trace elements, hormones, and ferments. It has been found that propolis possesses antimicrobial, antiviral, and anti-inflammatory properties. We have studied the antiviral activity of six extracts of Bulgarian propolis collected from six districts of Bulgaria. The study was conducted against structurally different viruses: human coronavirus strain OC-43 (HCoV OC-43) and human respiratory syncytial virus type 2 (HRSV-2) (enveloped RNA viruses), human herpes simplex virus type 1 (HSV-1) (enveloped DNA virus), human rhinovirus type 14 (HRV-14) (non-enveloped RNA virus) and human adenovirus type 5 (HadV-5) (non-enveloped DNA virus). The influence of the extracts on the internal replicative cycle of viruses was determined using the cytopathic effect (CPE) inhibition test. The virucidal activity, its impact on the stage of viral adsorption to the host cell, and its protective effect on healthy cells were evaluated using the final dilution method, making them the focal points of interest. The change in viral infectivity under the action of propolis extracts was compared with untreated controls, and Δlgs were determined. Most propolis samples administered during the viral replicative cycle demonstrated the strongest activity against HCoV OC-43 replication. The influence of propolis extracts on the viability of extracellular virions was expressed to a different degree in the various viruses studied, and the effect was significantly stronger in those with an envelope. Almost all extracts significantly inhibited the adsorption step of the herpes virus and, to a less extent, of the coronavirus to the host cell, and some of them applied before viral infection demonstrated a protective effect on healthy cells. Our results enlarge the knowledge about the action of propolis and could open new perspectives for its application in viral infection treatment.

Improvement influenza vaccine immune responses with traditional Chinese medicine and its active ingredients

The current influenza vaccines are unable to provide effective protection in many cases, like influenza viruses strain antigenic drift or shift, and the influenza continues to cause significant annual morbidity and mortality. Improving the immune response to influenza vaccination is an unmet need. Traditional Chinese medicine (TCM) and its active ingredients are commonly known to have immunomodulatory properties. We therefore compared influenza vaccination alone or formulated with Astragali Radix (Huangqi in Chinese), and several representative ingredients of TCM, including lentinan (polysaccharide), panax notoginseng saponins (saponin), breviscapine (flavone), andrographolide (terpenoid), and a Chinese herbal compound (kangai) for their potential to enhance immune responses to influenza vaccine in mice. We found that all these TCM-adjuvants were able to increase hemagglutination inhibition (HAI) antibody titers, splenocyte proliferation, splenic T cell differentiation, bone marrow dendritic cell maturity, and both Th1 and Th2 cytokine secretion of influenza vaccine to varying degrees, and that had the characteristics of no excessive inflammatory responses and bidirectional regulation simultaneously. Taken together, our findings show that Astragali Radix exerts a more comprehensive effect on vaccine immunity, on both innate and adaptive immunity. The effects of lentinan and andrographolide on adaptive immunity were more significant, while the effects of breviscapine on innate immunity were stronger, and the other two TCM adjuvants were weaker. As the first report of a comprehensive evaluation of TCM adjuvants in influenza vaccines, the results suggest that TCM and their active ingredients are good candidates for enhancing the immune response of influenza vaccines, and that suitable TCMs can be selected based on the adjuvant requirements of different vaccines.