The Influence of Surface Charge on the Antiviral Effect of Curcumin Loaded in Nanocarrier System.

BACKGROUND: Curcumin is a well-documented bioactive compound present in Curcuma sp., a tropical, medicinal plant. This substance exhibits broad-spectrum biological activities, including antivirus. Despite the lack of pharmaceutical properties of curcumin limits its clinical use. OBJECTIVE: This study aims to produce curcumin nanoemulsion with different surface charge (curcumin (+) nanoemulsion and curcumin (-) nanoemulsion) and to evaluate its physical characteristics, in vitro cell cytotoxicity, and antiviral activity against dengue virus (DENV) 1 and 2. METHODS: Two forms of nanoemulsion were prepared, which were differed from their surface charge through spontaneous procedure resulting in similar characteristics except for the zeta potential value. Cytotoxicity was determined using the RT-PCR method in the A549 cell line, and anti- DENV properties were determined by calculation of inhibitory concentration 50 (IC50) value. RESULTS: The positive charge of curcumin-loaded nanoemulsion showed a better effect in reducing the viral replication represented by a lower IC50 value. In addition, DENV-1 was more sensitive and responsive to curcumin as compared to DENV-2. CONCLUSION: Positive surface charge of curcumin-loaded nanoemulsion improves the antiviral effect of the curcumin, suggesting a promising approach for alternative treatment for dengue virus infection.

Relationship of Agaricus bisporus mannose-binding protein to lectins with ß-trefoil fold.

Agaricus bisporus mannose-binding protein (Abmb) was discovered as part of the mushroom tyrosinase (PPO3) complex, but its function in the mushroom has remained obscure. The protein has a ß-trefoil structure that is common for Ricin-B-like lectins. Indeed, its closest structural homologs are the hemagglutinin components of botulinum toxin (HA-33) and the Ricin-B-like lectin from Clitocybe nebularis (CNL), both of which bind galactose, and actinohivin, a recently discovered mannose-binding lectin from actinomycetes. Here we show that Abmb is evolutionarily related to them, which are lectins with a ß-trefoil fold. We also show for the first time that Abmb can exhibit typical lectin agglutination activity but only when in the complex with mushroom tyrosinase. This is unexpected and unique because the two proteins are not evolutionarily related and have different activities. Lectin and tyrosinase major role in defense mechanism as well as Abmb and PPO3 gene regulation during the early stages of the development of mushroom fruiting bodies suggested that Abmb has likely a function in defense against bacterial infection and/or insect-induced damage.

Antiviral Action of Curcumin Encapsulated in Nanoemulsion against Four Serotypes of Dengue Virus.

BACKGROUND: Curcumin has been used as a traditional medicine showing antiinflammatory, antimicrobial, and antiviral properties. Despite the promising potentials, curcumin-based drug development is hindered due to its poor solubility and cell uptake. OBJECTIVE: This study aims to produce curcumin nanoemulsion (nanocurcumin) and evaluate its physical characteristics and in vitro cell cytotoxicity and antiviral activity against dengue virus (DENV). METHODS: Nanocurcumin was generated by self-nanoemulsion technique. Cytotoxicity was determined using MTT assay in A549 cell line. Anti-DENV properties were determined by calculation of inhibitory concentration 50 (IC50) and plaque assay. RESULTS: The resulting nanoemulsion showed uniform droplet size distribution with the average droplet size of 40.85 ± 0.919 nm. Nanocurcumin exhibited higher cell cytotoxicity compared to curcumin solution and may be explained by better cell uptake. Nanocurcumin treatment suppressed DENV growth, although no significant difference observed compared to the curcumin solution counterpart. Greater virus reduction was observed for DENV-1 and DENV-2. CONCLUSION: The synthesis of nanocurcumin improved curcumin physicochemical properties with potential as antiviral against DENV.

Agaricus bisporus mannose binding protein is not an agglutinating protein.

Agaricus bisporus mannose binding protein (Abmb) demonstrates permeability to epithelial monolayer barrier of the intestine, resistance to gastrointestinal tract conditions and to proteolysis therefore it holds potential as a drug carrier for oral route administration. Abmb also display antiproliferative activity to breast cancer cells and stimulation of immune system thus could potentially be also developed for therapeutic purpose. It is not immunogenic or toxic thereby safe for use. In this paper we further provide evidence that Abmb also lacks of agglutinating activity despite sharing high structural homology to lectins. Abmb is thereby the only mannose specific binding protein that is not member of lectin family. This evidence provides further support on the use of Abmb as pharmaceutical or medicinal agent. Its molecular globularity that may contribute to its lack of agglutination capacity was also evaluated.

Orf239342 from the mushroom Agaricus bisporus is a mannose binding protein.

A recently discovered lectin-like protein from mushroom tyrosinase designated as orf239342 inhibits proliferation of the MCF-7 breast cancer cells. This characteristic is likely derived from its ability to recognize sugar entity on the cell surface. Thereby, the binding specificity of orf239342 to sugars was studied. Orf239342 was found to bind specifically to mannose upon analysis with the surface plasmon resonance technique. Finally, our in vitro study showed that mannose impeded orf239342 ability to inhibit proliferation of the MCF-7 breast cancer cells, providing further evidence for the mannose binding onto the protein. Our finding is a breakthrough to characterise orf239342 i.e. to define its functioning in the mushroom, association to the tyrosinase, or even possible application in breast cancer therapy. In addition, the finding allows the more appropriate designation of the protein as Agaricus bisporus mannose binding-protein (AbMb).