Photophysics of Caffeic, Ferulic and Sinapic Acids with α- and β-Cyclodextrins: Spectral and Molecular Modeling Studies

Abstract

Abstract. Encapsulation of caffeic acid (CAA), ferulic acid (FEA) and sinapic acid (SIA) molecules with α-CD and β-CD was studied by UV-visible, fluorescence, time-resolved fluorescence and molecular modelling techniques. This analysis reports the dual emission properties of the above hydroxycinnamic acids (HCAs) in the aqueous cyclodextrin (CD) solution. The shorter wavelength bands originated from the locally excited state and the longer wavelength bands due to the emission from an intramolecular charge transfer (ICT) state. The ratio of the TICT emission to the normal emission increased along with α-CD and β-CD concentration. The guest:host inclusion complexation studies indicates (i) HCAs forms 1:1 inclusion complex and (ii) acrylic group present in the interior part of the CD cavity and OH/OCH 3 groups present in the upper part of the CD cavity. pH studies suggest proton transfer reactions follow the same trend in these molecules. PM3 optimizations were also carried out to assign the encapsulation of the HCA molecules.

Use of Innovative (Micro)Extraction Techniques to Characterise Harpagophytum procumbens Root and its Commercial Food Supplements

“…Compared to the poses found for the harpagoside, none of the two carboxylic acids could establish wide hydrogen‐bond interactions with the hydroxyl groups at the wide rim of the β‐cyclodextrin toroid. It is important to highlight that previous studies also demonstrated that metabolites such as the chlorogenic, vanillic, and sinapinic acids were able to effectively fit and interact with the β‐cyclodextrin (Górnas et al ., ; Rajendiran et al ., ; Xiong et al ., ). It is likely that the great predominance of harpagoside into the mixture elicited a β‐cyclodextrin saturation, thus interfering with the recovery of other components associated with the use of β‐cyclodextrin.…”

Cyclodextrin-Based Delivery Systems and Hydroxycinnamic Acids: Interactions and Effects on Crucial Parameters Influencing Oral Bioavailability—A Review

“…CA αCD [30,[33][34][35][36][37][38] βCD [30,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] HPβCD [30,33,34,44,45,[50][51][52] SBEβCD [53] MβCD [30,45] Crysmeb ® [33,34] DIMEB [54] RAMEB [33,34] γCD [30,36,55,56] Polymeric βCD [57] CGA αCD [31,58] βCD [31,40,42,48,…”

“…FA αCD [33,34,38,[74][75][76][77][78] TRIMEA [54] βCD [28,33,34,38,43,46,49,74,77,79,80] AminoβCD [29,74] HPβCD [33,34,73,78,79,[81][82][83][84] SBEβCD [53] MβCD [78] Crysmeb ® [33,34] DIMEB [54] RAMEB [33,34] γCD [74,77,85] HPγCD [78,84] Polymeric βCD [32] RA αCD [86] βCD [86][87][88][89] HEβCD [86] MβCD [86] Crysmeb ® …”