Photophysical Analysis of Naturally Occurring Coumarins Isolated from The Hydrophobic Phase of Calophyllum inophyllum Leaves

Coumarins are compounds that rapidly observed because of its photochemical and photophysical properties that show excellent potential as laser dyes and fluorescent probes. Recently, four new coumarins naturally occuring from the leaves of Calophyllum inophyllum have been identified. Since structure differences greatly affect the photophysical and photochemical properties, in this research the isolation of coumarin from the leave of C. inophyllum cultivated in Indonesia was carried out. Low polarity solvents such as hexane and chloroform were used for partitioning the crude MeOH extract of C. inophyllum. Methanol extraction of C. inophyllum dry leaves produced 18.76% of crude extract. Solvent partition using hydrophobic solvent, hexane and chloroform gives 5.21% and 0.93% of yield, respectively. Further separation of hexane fraction using SiO2 column collected 8 sub-fractions (FA1 - FA8). Photoluminescence analysis suggested that sub-fractions FA4, FA5, and FA6 gave red fluorescene emission at 672 nm by the excitation wavelength in 400 nm. In contrast, FA3 didn't show that phenomenon. Analysis using LC-QTOF-MS suggested that several coumarin derivatives, that is, isoinophynone, inophyllum C, inophyllum I, 3/5-methylcoumarin, disparfuran B, and inophyllum A were detected in FA4, FA5 and FA6. Further analysis of coumarin framework contribution to the photophysical properties of the fraction is under consideration.