1 research outputs found
Water-Soluble Pd<sub>8</sub>L<sub>4</sub> Self-assembled Molecular Barrel as an Aqueous Carrier for Hydrophobic Curcumin
A tetrafacial
water-soluble molecular barrel (<b>1</b>) was synthesized by
coordination driven self-assembly of a symmetrical tetrapyridyl donor
(<b>L</b>) with a <i>cis</i>-blocked 90° acceptor
[<i>cis</i>-(en)Pd(NO<sub>3</sub>)<sub>2</sub>] (en = ethane-1,2-diamine).
The open barrel structure of (<b>1</b>) was confirmed by single
crystal X-ray diffraction. The presence of a hydrophobic cavity with
large windows makes it an ideal candidate for encapsulation and carrying
hydrophobic drug like curcumin in an aqueous medium. The barrel (<b>1</b>) encapsulates curcumin inside its molecular cavity and protects
highly photosensitive curcumin from photodegradation. The photostability
of encapsulated curcumin is due to the absorption of a high proportion
of the incident photons by the aromatic walls of <b>1</b> with
a high absorption cross-sectional area, which helps the walls to shield
the guest even against sunlight/UV radiations. As compared to free
curcumin in water, we noticed a significant increase in solubility
as well as cellular uptake of curcumin upon encapsulation inside the
water-soluble molecular barrel (<b>1</b>) in aqueous medium.
Fluorescence imaging confirmed that curcumin was delivered into HeLa
cancer cells by the aqueous barrel (<b>1</b>) with the retention
of its potential anticancer activity. While free curcumin is inactive
toward cancer cells in aqueous medium at room temperature due to negligible
solubility, the determined IC<sub>50</sub> value of ∼14 μM
for curcumin in aqueous medium in the presence of the barrel (<b>1</b>) reflects the efficiency of the barrel as a potential curcumin
carrier in aqueous medium without any other additives. Thus, two major
challenges of increasing the bioavailability and stability of curcumin
in aqueous medium even in the presence of UV light have been addressed
by using a new supramolecular water-soluble barrel (<b>1</b>) as a drug carrier