Binding of Clitoria ternatea L. flower extract with α-amylase simultaneously monitored at two wavelengths using a photon streaming time-resolved fluorescence approach

Graham Hungerford*, M. Adilia Lemos, Boon-Seang Chu

*Corresponding author for this work

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    The binding of an extract from the flowers of Clitoria ternatea L. to the digestive enzyme α-amylase was investigated. This extract is a mixture of flavonoids, including anthocyanins, and has been previously shown to inhibit the activity this enzyme. This has implications for modulating starch digestion. Since the extract contains a mixture of flavonoids, including anthocyanins, in order to investigate the kinetics, we made use of time-resolved fluorescence to simultaneously monitor two different emission bands emanating from the extract. This measurement was enabled by the use of a “photon streaming” approach and changes in fluorescence lifetime and intensity were used to follow the interaction. A longer wavelength band (655nm) was ascribed to anthocyanins in the mixture and these were observed to bind at a rate an order of magnitude slower than other flavonoids present in the extract, monitored at a shorter wavelength (485 nm). Changes in the fluorescence emission of the extract upon binding were further assessed by the use of decay associated spectra.
    Original languageEnglish
    Pages (from-to)108-113
    Number of pages6
    JournalSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
    Early online date30 Nov 2018
    Publication statusPublished - 15 Mar 2019


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