Resveratrol-Loaded Attalea funifera Oil Organogel Nanoparticles: A Potential Nanocarrier against A375 Human Melanoma Cells.

This study aimed to evaluate Attalea funifera seed oil with or without resveratrol entrapped in organogel nanoparticles in vitro against A375 human melanoma tumor cells. Organogel nanoparticles with seed oil (SON) or with resveratrol entrapped in the seed oil (RSON) formed functional organogel nanoparticles that showed a particle size <100 nm, polydispersity index <0.3, negative zeta potential, and maintenance of electrical conductivity. The resveratrol entrapment efficiency in RSON was 99 ± 1%. The seed oil and SON showed no cytotoxicity against human non-tumor cells or tumor cells. Resveratrol at 50 µg/mL was cytotoxic for non-tumor cells, and was cytotoxic for tumor cells at 25 µg/mL. Resveratrol entrapped in RSON showed a decrease in cytotoxicity against non-tumor cells and cytotoxic against tumor cells at 50 µg/mL. Thus, SON is a potential new platform for the delivery of resveratrol with selective cytotoxic activity in the treatment of melanoma.

Lithium bioaccumulation in Lentinus crinitus mycelia grown in media with different lithium sources and pH values.

Lentinus crinitus bioaccumulates lithium in mycelia, but bioaccumulation may be affected by pH of the culture medium. Lithium is used in clinical practice as a mood stabilizer and antidepressant. This study aimed to assess the effect of culture medium pH and lithium source (LiCl or Li2CO3) on lithium bioaccumulation in vegetative mycelia of L. crinitus grown in malt extract broth. Lentinus crinitus U9-1 was cultured in malt extract broth supplemented with Li2CO3 or LiCl (50 mg L-1 lithium) in the pH range of 3.0 to 6.0. The pH was adjusted using HCl solution. The results showed that medium pH affected mycelial biomass production, lithium bioaccumulation in mycelial biomass, and lithium transfer from the culture medium to mycelial biomass. The effect of lithium source on the bioaccumulation capacity of mycelial biomass varied according to pH. At pH 4.0, both lithium sources stimulated mycelial biomass production compared to the control without the addition of lithium. At pH 5.5, Li2CO3 provided the highest lithium bioaccumulation in mycelial biomass. Lithium transfer from the culture medium to mycelia was highest in Li2CO3-supplemented cultures at pH 4.5. LiCl reduced hyphal width compared with Li2CO3 and the control. However, pH and lithium sources did not affect the formation of clamp connections in hyphae. For the first time, the influence of the pH of the culture medium on lithium bioaccumulation by Lentinus crinitus is reported. Finally, we conclude that the culture medium pH affected lithium transfer and bioaccumulation in mycelial biomass differently depending on the lithium source. Additionally, we report the presence of clamp connections in the hyphae of L. crinitus as an indicator of even growth.

Long-term cryopreservation of Lentinus crinitus strains by wheat grain technique.

Lentinus crinitus (Basidiomycota: Polyporales) is a saprophytic fungus with biotechnological importance described more than 20 years ago. However, there are few studies on the long-term preservation of this basidiomycete. Cryopreservation is a long-term storage technique that reduces the metabolic activity of microorganisms, but its success depends on the adjustment of the freezing process, the cryoprotectants, and the protective substrates for each species. This study aimed to assess the mycelial viability and genetic stability of L. crinitus strains cryopreserved at -86 °C for two years by the wheat grain technique using different cryoprotectants and freezing methods. Three strains of L. crinitus (U9-1, U13-5, and U15-12) were subjected to different concentrations and types of cryoprotectants (dimethyl sulfoxide, glycerol, glucose, and sucrose), freezing methods such as immediate freezing from 25 to -86 °C and progressing freezing from 25 to -86 °C in a freezing container with isopropyl alcohol to control the rate of cell freezing at -1 °C min-1, protective substrate (wheat grain and 2% malt extract agar), and cryopreservation period (1, 6, 12, and 24 months). After thawing, samples were evaluated for mycelial viability, time to mycelial recovery, mycelial stability, and genetic stability of the fungus. All techniques achieved effective cryopreservation at -86 °C, mainly with the wheat grain technique. All cryoprotectants (3.5% glycerol, 1.5% dimethyl sulfoxide, 25% sucrose, and 5% glucose), freezing methods (immediate and gradual), and protective substrate (wheat grain and malt extract agar) were effective for cryopreservation of the three L.crinitus strains in an ultra-low temperature freezer for two years. Mycelial viability, mycelial stability, and genetic stability of the fungus were not affected after two-year cryopreservation, evidencing the robustness of the long-term cryopreservation technique and the fungus.

In vitro and in silico studies of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitory activity of the cowpea Gln-Asp-Phe peptide.

Previous studies have shown that cowpea protein positively interferes with cholesterol metabolism. In this study, we evaluated the ability of the fraction containing peptides of <3 kDa, as well as that of the Gln-Asp-Phe (QDF) peptide, derived from cowpea ß-vignin protein, to inhibit HMG-CoA reductase activity. We established isolation and chromatography procedures to effectively obtain the protein with a purity above 95%. In silico predictions were performed to identify peptide sequences capable of interacting with HMG-CoA reductase. In vitro experiments showed that the fraction containing peptides of <3 kDa displayed inhibition of HMG-CoA reductase activity. The tripeptide QDF inhibits HMG-CoA reductase (IC50 = 12.8 µM) in a dose-dependent manner. Furthermore, in silico studies revealed the binding profile of the QDF peptide and hinted at the molecular interactions that are responsible for its activity. Therefore, this study shows, for the first time, a peptide from cowpea ß-vignin protein that inhibits HMG-CoA reductase and the chemical modifications that should be investigated to evaluate its binding profile.