Apolipoprotein E LDL receptor-binding domain-containing high-density lipoprotein: A nanovehicle to transport curcumin, an antioxidant and anti-amyloid bioflavonoid

AbstractCurcumin is an antioxidant and anti-inflammatory bioflavonoid that has been recently identified as an anti-amyloid agent as well. To make it more available in its potent form as a potential amyloid disaggregation agent, we employed high-density lipoproteins (HDL), which are lipid–protein complexes that transport plasma cholesterol, to transport curcumin. The objective of this study was to employ reconstituted HDL containing human apoE3 N-terminal (NT) domain, as a vehicle to transport curcumin. The NT domain serves as a ligand to mediate binding and uptake of lipoprotein complexes via the low-density lipoprotein receptor (LDLr) family of proteins located at the cell surface. Reconstituted HDL was prepared with phospholipids and recombinant apoE3-NT domain in the absence or presence of curcumin. Non-denaturing polyacrylamide gel electrophoresis indicated that the molecular mass and Stokes' diameter of HDL bearing curcumin were ~670kDa and ~17nm, respectively, while electron microscopy revealed the presence of discoidal particles. Fluorescence emission spectra of HDL bearing (the intrinsically fluorescent) curcumin indicated that the wavelength of maximal fluorescence emission (λmax) of curcumin was ~495nm, which is highly blue-shifted compared to λmax of curcumin in solvents of varying polarity (λmax ranging from 515–575nm) or in aqueous buffers. In addition, an enormous enhancement in fluorescence emission intensity was noted in curcumin-containing HDL compared to curcumin in aqueous buffers. Curcumin fluorescence emission was quenched to a significant extent by lipid-based quenchers but not by aqueous quenchers. These observations indicate that curcumin has partitioned efficiently into the hydrophobic milieu of the phospholipid bilayer of HDL. Functional assays indicated that the LDLr-binding ability of curcumin-containing HDL with apoE3-NT is similar to that of HDL without curcumin. Taken together, we report that apoE-containing HDL has a tremendous potential as a ‘nanovehicle’ with a homing device to transport curcumin to target sites

Optimal Production of <i>Ganoderma formosanum</i> Mycelium with Anti-Melanogenic Activity

Ganoderma formosanum is a medicinal mushroom endemic to Taiwan. The extraction of G. formosanum mycelium using ethyl acetate showed a significant reduction of melanin activity due to the inhibition of tyrosinase. To optimize the production of G. formosanum mycelium with anti-melanogenic activity, different variables (carbon sources and concentrations, initial pH value, and temperature) were investigated. According to the results, the optimal conditions included the utilization of 50 g/L lactose as the carbon source at pH 7 and 25 °C for 9 days. Afterward, the G. formosanum ethanolic extracts-optimized (GFE-O) was used to study the anti-melanogenic activity in vitro and in vivo. In B16-F10 melanoma cells treated with GFE-O (0.1 mg/mL), the intracellular melanin content was reduced to 76% compared to the control group. By applying GFE-O (0.05 mg/mL) in vivo on zebrafish embryo, hypopigmentation was observed, and the melanin content was reduced to 62% compared to the control with no toxicological effects. The results showed that the optimal inoculation conditions can provide the basis for future large-scale production of G. formosanum mycelium to maximize the extraction of anti-melanogenic ingredients