title: Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures.
abstract: The phytoalexin trans-resveratrol, 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol, is a well-known, potent antioxidant having a variety of possible biomedical applications. However, its adverse physicochemical properties (low stability, poor aqueous solubility) limit such applications and its inclusion in cyclodextrins (CDs) has potential for addressing these shortcomings. Here, various methods of the attempted synthesis of inclusion complexes between trans-resveratrol and three methylated cyclodextrins (permethylated α-CD, permethylated β-CD and 2,6-dimethylated β-CD) are described. Isolation of the corresponding crystalline 1:1 inclusion compounds enabled their full structure determination by X-ray analysis for the first time, revealing a variety of guest inclusion modes and unique supramolecular crystal packing motifs. The three crystalline inclusion complexes were also fully characterized by thermal analysis (hot stage microscopy, thermogravimetric analysis and differential scanning calorimetry). To complement the solid-state data, phase-solubility studies were conducted using a series of CDs (native and variously derivatised) to establish their effect on the aqueous solubility of trans-resveratrol and to estimate association constants for complex formation.
authors: Centre for Supramolecular Chemistry Research (CSCR), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
authors: Lee
authors: L
authors: Trollope
authors: Centre for Supramolecular Chemistry Research (CSCR), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
authors: Dyanne L
authors: DL
authors: Cruickshank
authors: Centre for Supramolecular Chemistry Research (CSCR), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
authors: Terence
authors: T
authors: Noonan
authors: Centre for Supramolecular Chemistry Research (CSCR), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
authors: Susan A
authors: SA
authors: Bourne
authors: Department of Drug Sciences, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy.
authors: Milena
authors: M
authors: Sorrenti
authors: Department of Drug Sciences, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy.
authors: Laura
authors: L
authors: Catenacci
authors: Centre for Supramolecular Chemistry Research (CSCR), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
authors: Mino R
authors: MR
authors: Caira
keywords: X-ray structures; cyclodextrin; inclusion complexes; thermal analysis; trans-resveratrol