Electronic structure and optical properties of some anthocyanins extracted from grapes

The pallet of applications of natural dyes and pigments is continuously extending as a stringent need to meet the challenges arisen from sustainable development, particularly related to replacing synthetic chemicals by eco-friendly renewable raw materials. In this respect, the well known nutritive and therapeutic properties demonstrated by anthocyanin compounds present in selective plant extracts of numerous fruits, vegetables and flowers could be largely complemented by their characteristics as chromophores and fluorophores with high potential in promising applications in bio-imaging for diagnostic and therapy, but also in electronic and photonic devices, solar cells, etc. In this context, this paper proposes an improved protocol for extraction and HPLC detection of anthocyanins from black grapes. Moreover, in order to exploit their potential to be applied as chromatic and fluorescence molecular probes, the electronic properties have been studied by correlating spectral characteristics with trichromatic parameters, combined with quantum chemistry computation.

► An improved extraction/purification protocol for anthocyanins from grapes given. ► Chromatic characteristics evaluation based on CIE-L*a*b* trichromatic system. ► Electronic properties calculated in terms of HOMO–LUMO energy gap splitting. ► Demonstration that anthocyanins are promising candidates for NLO applications.