Lecithin/chitosan nanoparticle drug carrier improves anti-tumor efficacy of Monascus pigment rubropunctatin.

Rubropunctatin, a metabolite isolated from the fungi of the genus Monascus, is a natural lead compound applied for the suppression of tumors with good anti-cancer activity. However, its poor aqueous solubility has limited its further clinical development and utilization. Lecithin and chitosan are excellently biocompatible and biodegradable natural materials, which have been approved by the FDA as drug carrier. Here, we report for the first time the construction of a lecithin/chitosan nanoparticle drug carrier of the Monascus pigment rubropunctatin by electrostatic self-assembly between lecithin and chitosan. The nanoparticles are near-spherical with a size 110-120 nm. They are soluble in water and possess excellent homogenization capacity and dispersibility. Our in vitro drug release assay showed a sustained release of rubropunctatin. CCK-8 assays revealed that lecithin/chitosan nanoparticles loaded with rubropunctatin (RCP-NPs) had significantly enhanced cytotoxicity against mouse mammary cancer 4T1 cells. The flow cytometry results revealed that RCP-NPs significantly boosted cellular uptake and apoptosis. The tumor-bearing mice models we developed indicated that RCP-NPs effectively inhibited tumor growth. Our present findings suggest that lecithin/chitosan nanoparticle drug carriers improve the anti-tumor effect of the Monascus pigment rubropunctatin.

Continuous cultivation of Arthrospira platensis for phycocyanin production in large-scale outdoor raceway ponds using microfiltered culture medium.

In the present study, the effect of filtrating algal culture medium for reuse by using microfiltration membranes on microalgal growth, microbiological contamination, and phycocyanin production of Arthrospira platensis was investigated. Results showed that microfiltered culture medium affected microalgal growth, microbiological contamination, and phycocyanin production of A. platensis significantly. Microfiltered culture medium could enhance biomass production, photosynthesis, and phycocyanin accumulation and decrease microbiological contamination during continuous cultivation of A. platensis compared to the control. The profile of microbial communities, which contained the 10 phyla of microorganisms including bacteria and microzooplanktons, was identified for the first time for industrial algae systems of A. platensis with extreme conditions (salt-alkaline stress conditions). The application of the established strategy can enhance phycocyanin production of A. platensis while mitigating microbiological contamination.