Related Experiment Video

Updated: Aug 15, 2026

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
14:22

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development

Published on: April 15, 2013

A study of free radical release from beta-cyclodextrin-anticancer pro-drugs adducts in water

Enzo Castagnino1, Michela Cangiotti, Serena Tongiani

  • 1Pharmaceutical Chemistry Institute, Università degli Studi Carlo Bo, Piazza Rinascimento, 6, 61029 Urbino, Italy. castagnino@uniurb.it

Journal of Controlled Release : Official Journal of the Controlled Release Society
|October 26, 2005
PubMed

Insights

Beta-cyclodextrin stabilizes cancer-fighting carbon radicals by forming a cage, preventing premature reactions. This enhances the delivery of radical-affording substances (RAS) for improved chemotherapy.

Area of Science:

  • Medicinal Chemistry
  • Biophysical Chemistry
  • Cancer Research

Background:

  • Novel cancer chemotherapy strategies explore radical-affording substances (RAS) as pro-drugs to induce tumor cell apoptosis.
  • A key challenge is the rapid reaction of radical species with their environment before reaching tumor cells.
  • Developing effective transport systems for RAS in biological media is crucial.

Purpose of the Study:

  • To investigate the stabilization effect of beta-cyclodextrin on carbon-centered radicals generated from mercaptopyridine congeners.
  • To evaluate beta-cyclodextrin's potential as a therapeutic system for delivering RAS.

Main Methods:

  • Electron Paramagnetic Resonance (EPR) spectroscopy was used to study aqueous solutions of N-acyloxy-pyridinethione analogues in the presence of beta-cyclodextrin.
  • Photochemical generation of alkyl radicals was employed.

Main Results:

  • Alkyl radicals formed an adduct with beta-cyclodextrin, acting as a cage that prevented interaction with the aqueous medium.
  • Beta-cyclodextrin demonstrated a delay in radical generation, suggesting an interaction with the mercaptopyridine moiety responsible for initiating the radical event.

Conclusions:

  • Beta-cyclodextrin effectively stabilizes carbon-centered radicals, offering a potential solution for targeted delivery in cancer chemotherapy.
  • The cage effect and delayed radical generation by beta-cyclodextrin enhance the therapeutic potential of RAS.

More Related Videos

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling09:33

Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling

Published on: March 20, 2018

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions10:53

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions

Published on: October 10, 2016

Related Concept Videos

Radical Autoxidation01:20

Radical Autoxidation

The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
Radical Reactivity: Overview01:11

Radical Reactivity: Overview

Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired molecule. These three...
Radical Formation: Addition00:47

Radical Formation: Addition

Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Radical Reactivity: Steric Effects01:10

Radical Reactivity: Steric Effects

The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic factors, steric factors also account...
Radical Chain-Growth Polymerization: Overview01:10

Radical Chain-Growth Polymerization: Overview

Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
Radical Reactivity: Electrophilic Radicals01:02

Radical Reactivity: Electrophilic Radicals

Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a low‐energy SOMO, which interacts...