Poly-ε-caprolactone based nanoparticles for delivery of genistein in melanoma treatment

Abstract We developed poly-ε-caprolactone (PCL)-based nanoparticles containing D-α-tocopherol polyethylene glycol-1000 succinate (TPGS) or Poloxamer 407 as stabilizers to efficiently encapsulate genistein (GN). Two formulations, referred to as PNTPGS and PNPol, were prepared using nanoprecipitation. They were characterized by size and PDI distribution, zeta potential, nanoparticle tracking analysis (NTA), GN association (AE%), infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). PNTPGS-GN exhibited a particle size of 141.2 nm, a PDI of 0.189, a zeta potential of -32.9 mV, and an AE% of 77.95%. PNPol-GN had a size of 146.3 nm, a better PDI than PNTPGS-GN (0.150), a less negative zeta potential (-21.0 mV), and an AE% of 68.73%. Thermal and spectrometric analyses indicated that no new compounds were formed, and there was no incompatibility detected in the formulations. Cellular studies revealed that Poloxamer 407 conferred less toxicity to PCL nanoparticles. However, the percentage of uptake decreased compared to the use of TPGS, which exhibited almost 80% cellular uptake. This study contributes to the investigation of stabilizers capable of conferring stability to PCL nanoparticles efficiently encapsulating GN. Thus, the PCL nanoparticle proposed here is an innovative nanomedicine for melanoma therapy and represents a strong candidate for specific pre-clinical and in vivo studies.

Strategies towards expansion of chemical space of natural product-based compounds to enable drug discovery

Natural products (NPs) are an excellent source of biologically active molecules that provide many biologically biased features that enable innovative designing of synthetic compounds. NPs are characterized by high content of sp3-hybridized carbon atoms; oxygen; spiro, bridged, and linked systems; and stereogenic centers, with high structural diversity. To date, several approaches have been implemented for mapping and navigating into the chemical space of NPs to explore the different aspects of chemical space. The approaches providing novel opportunities to synthesize NP-inspired compound libraries involve NP-based fragments and ring distortion strategies. These methodologies allow access to areas of chemical space that are less explored, and consequently help to overcome the limitations in the use of NPs in drug discovery, such as lack of accessibility and synthetic intractability. In this review, we describe how NPs have recently been used as a platform for the development of diverse compounds with high structural and stereochemical complexity. In addition, we show developed strategies aiming to reengineer NPs toward the expansion of NP-based chemical space by fragment-based approaches and chemical degradation to yield novel compounds to enable drug discovery