Bioassay-guided isolation of triterpene from brown alga Padina boergesenii possess anti-inflammatory and anti-angiogenic potential with kinetic inhibition of β-carotene linoleate system

We aimed to investigate the bioassay-guided extraction and characterization of triterpene isolated from brown alga Padina boergesenii in establishing antioxidant, anti-angiogenic and anti-inflammatory activities. The n-hexane defatted methanol crude extract (HDME) was subjected to column chromatography through combination of n-butanol:ethylacetate (BE); chloroform:ethylacetae (CE) and methanol:ethylacetate (ME) solvent system at 1:3 ratio. Five fractions (F1-F5) from each solvent system (BE, CE and ME) was collected and analyzed. Among all, the third fraction from ME (ME-F3) had potential DPPH, deoxyribose and total antioxidant activities (TAA) than CE and BE. Reducing power (RP) of ME-F3 increased with increasing concentrations of triterpene. Saturation curve of triterpene in reduction of β-carotene bleaching at different time-points and at various concentrations have identified kinetic inhibition of free radicals. Antiangiogenic (VEGF) and anti-inflammatory (IL-1β) activities in A498 renal cancer cells have established the potential role of squalene. Molecular characterization by gas chromatography and mass spectrometry has identified the triterpene from ME-F3 fraction.