In vitro cytoprotective potential of ornamental Harpullia pendula highlighting its medicinal value

Abstract

Harpullia pendula F., family Sapindaceae is a small to medium sized rainforest tree. The plant is known as tulipwood or tulip lancewood and is mainly cultivated as ornaments [1]. Leaves and seeds from H. pendula were successively extracted with petroleum ether, chloroform (CHCl3), and methanol (MeOH), the total aqueous methanol extract of the leaves was also prepared. The methanol extract was fractionated on Diaion HP20, compounds were isolated and purified by paper chromatography, Sephadex column and HPLC. The chloroform extract was chromatographed on silica gel column. The study aimed to investigate the direct cell-free radical scavenging activity using the micro-scaled DPPH assay [2] whereas the cell-based anti-oxidative stress activity was tested by the ability to protect murine hepa1c1c7 liver cells against the cell damage induced by t-butyl hydroperoxide (TBHP), assessed by neutral red uptake assay [3]. The total alcoholic extract from the leaves showed potent scavenging of DPPH radical with EC50 of 8.4 µg/ml. The same extract also showed the most potent intracellular protection (71% viability to control) of hepa1c1c7 cells against the strong cell death induced by TBHP. The potency of the fractions obtained by successive extraction was in the order MeOH> aqueous MeOH> CHCl3 recording 30%, 25% and 4% cell viability, respectively, where EC50 against DPPH was calculated as 3.4, 5.3 and 48.6 µg/ml respectively. Column chromatography of the bioactive methanol extract allowed the isolation and identification of flavonoid glucosides and galloyl compounds. Triterpenoids were also isolated from chloroform extract. To the best of knowledge, these data represent the first report of cytoprotective potential of H. pendula leaves extracts and warrant further bioassay-guided fractionation to reveal the bioactive phytochemical(s).