Comparison of Biochemical Constituents and Contents in Floral Nectar of Castanea spp

Castanea crenata honey reduces influenza infection by activating the innate immune response

Influenza is an acute respiratory disorder caused by the influenza virus and is associated with prolonged hospitalization and high mortality rates in older individuals and chronically ill patients. Vaccination is the most effective preventive strategy for ameliorating seasonal influenza. However, the vaccine is not fully effective in cases of antigenic mismatch with the viral strains circulating in the community. The emergence of resistance to antiviral drugs aggravates the situation. Therefore, developing new vaccines and antiviral drugs is essential. Castanea crenata honey (CH) is an extensively cultivated food worldwide and has been used as a nutritional supplement or herbal medicine. However, the potential anti-influenza properties of CH remain unexplored. In this study, the in vitro and in vivo antiviral effects of CH were assessed. CH significantly prevented influenza virus infection in mouse Raw264.7 macrophages. CH pretreatment inhibited the expression of the viral proteins M2, PA, and PB1 and enhanced the secretion of proinflammatory cytokines and type-I interferon (IFN)-related proteins in vitro. CH increased the expression of RIG-1, mitochondrial antiviral signaling (MAVS) protein, and IFN-inducible transmembrane protein, which interferes with virus replication. CH reduced body weight loss by 20.9%, increased survival by 60%, and decreased viral replication and inflammatory response in the lungs of influenza A virus-infected mice. Therefore, CH stimulates an antiviral response in murine macrophages and mice by preventing viral infection through the RIG-1-mediated MAVS pathway. Further investigation is warranted to understand the molecular mechanisms involved in the protective effects of CH on influenza virus infection.

The chemical composition of pollen, staminate catkins, and honey of Castanea sativa Mill

The chemical composition of pollen and honey primarily depends on the botanical and geographical origin of the species, as well as other factors – climatic conditions, soil type, plant species, etc. The present study was to knowledge the biochemical profile of pollen, staminate catkins, and honey samples of Castanea sativa Mill. which were examined under conditions of Ukraine. Proteins are the major components of pollen and staminate catkins (169.0 ±1.60 g.kg-1 and 69.8 ±1.67 g.kg-1, respectively), while saccharides are predominant in honey samples (38.0 ±1.32 g.kg-1 fructose, 32.5 ±0.68 glucose g.kg−1 and 6.1 ±0.06 g.kg-1 sucrose). Glutamic acid (13.30 g.kg-1), aspartic acid (13.05 g.kg-1), and proline (12.45 g.kg-1) were predominant nonessential amino acids in the chestnut pollen. The content of macro and microelements was found in the pollen and staminate catkins much higher than in the honey. All Castanea sativa samples are a very valuable source of potassium as the main mineral element contained in pollen (7400 mg.kg-1), staminate catkins (7760 mg.kg-1), and honey (981 mg.kg-1). Microelements such as manganese and iron prevailed in pollen (478 mg.kg-1 Mn and 461 mg.kg-1 Fe), and staminate catkins (247 mg.kg-1 Mn and 109 mg.kg-1 Fe), and heavy metals (Hg, Sr, Sn, Sb, Li) are present only in the pollen samples with the most abundant Sr (12.8 mg.kg-1) and Sn (1.9 mg.kg-1) content and can be used as indicator suggesting the environmental pollution status in the region. Regarding the vitamin content, vitamin C was the most represented in all samples. Obtained results indicate that chestnut is species with important constituents such as amino acids and vitamins, with low content of heavy metals and high content of biogenic elements that may be used in phytotherapy and phytopharmacology.