Isolation of new polyacetylenes from the roots of Eurycoma longifolia via high-speed counter-current chromatography

- Five new polyacetylenes were isolated from Eurycoma longifolia for the first time.
- Application of preparative high-speed counter-current chromatography enabled preparation of longifolione C in large quantity (up to 317 mg in one run).
- The relative configuration of γ-lactone ring of the isolated polyacetylenes was assigned by their specific rotation values and comparison to the known compound saccopetrin A.

Eurycoma longifolia is a tropical plant of diverse applications in folk medicine, which occurs in Southeast Asia. In this study, pre-purified fraction (0.86 g) of the crude extracts from the roots of E. longifolia, was subjected to preparative high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 5:2:5:2 (v/v). Longifolione A (1, 19 mg, purity 96.0%) and longifolione C (3, 317 mg, purity 96.2%), together with longifolione B (2, purity 77.6%) were isolated in one run. The whole mobile and stationary phase was then blown out, concentrated in vacuo, and subjected to second HSCCC purification. Using HEMWat at a volume ratio of 6:1:6:1.2 (v/v), this fraction yielded two more new polyacetylenenes, longifolione D (4, 5 mg purity 94.5%) and longifolione E (5, 33 mg purity 96.3%). All of these five compounds are new natural products and isolated from E. longifolia for the first time. The established protocol for large-scale isolation of these polyacetylenes from E. longifolia was simple, efficient, and economical.