Fast isolation of cytotoxic compounds from the native Chilean species Gypothamnium pinifolium Phil. collected in the Atacama Desert, northern Chile

Abstract

Gyphothamnium pinifolium Phil. is an evergreen Chilean native bush with white–violet flowers growing in Paposo valley in the cost of the Atacama Desert. The combination of high-speed counter-current chromatography (HSCCC) and medium pressure column chromatography allowed the fast isolation and purification of one rare phenolic derivative: 2-Nor-1,2-secolycoserone, one 5-methyl-coumarin: Aphyllodenticulide, one ent-labdane: ent-labda-8,13-E-diene-15-ol (compounds 1–3) and a inseparable mixture of common sterols (mainly composed of lupeol and taraxerol) from this Chilean species. In order to prepare the main individual compounds, a rapid enrichment step (only 100min) was achieved by HSCCC using the solvent system n-hexane: ethyl acetate: acetonitrile 5:2:5 v:v:v, followed by a fast final purification step of the mentioned compounds by normal phase medium pressure column chromatography (MPC). The isolated compounds were evaluated against breast cancer MCF-7 cells, showing good cytotoxic activity (<50% cell viability at 100μM). Besides, compound 1 showed the best cytotoxicity, (IC50=15.12μM), but was also toxic against its normal counterpart MCF-10F cells (IC50=13.79μM). Based on these results, it is concluded that HSCCC is a viable separation method for the purification of novel compounds from Gyphotamnium pinifolium with cytotoxic activity in cancer cells. Furthermore, the X-ray crystal-structure for compound 2 is reported in this paper for the first time.