RP-HPLC-UV-ESI-MS phytochemical analysis of fruits of Conocarpus erectus L.

Previous work revealed that the defatted methanol (MeOH) extract of fruits of Conocarpus erectus L. (Combretaceae family) exhibited antioxidant, antibacterial and anti-cancer activities. In further studies of this valuable plant, the defatted MeOH extract of C. erectus fruits was subjected to chromatographic fractionation in a silica gel glass column followed by reversed-phase high-performance liquid chromatography-ultraviolet-electrospray ionisation spectrometry analysis (RP-HPLC-UV-ESI-MS). The major and sharp peaks in each sample were identified or tentatively identified based on matching with some standard compounds and a review of the literature. Ellagic acid, vescalagin/castalagin isomer and di-(hexahydroxy diphenoyl) galloyl hexose isomer were tentatively identified as major components with many hydrolysable types of tannins on the basis of a comparison of its mass patterns with relevant items in the literature. Gallic acid, kaempferol 3-O-β-d-glucopyranoside and quercetin 3-O-β-d-glucopyranoside were identified on the basis of matching retention time (t R ) and mass spectra with the standards. Polymethoxylated flavonoid isomers were also tentatively identified. The antioxidant properties of all samples were found to be associated with the total content of phenolic compounds. This may be considered as the first detailed phytochemical report in identifying the phytochemicals in C. erectus fruits. Due to the high antioxidant activity exhibited by both the crude MeOH extract and its fractions, it could be used as an effective natural antioxidant after further in vitro and in vivo studies. © 2014 Institute of Chemistry, Slovak Academy of Sciences.