Phytochemical study of Swertia longifolia (Boiss.)

Plants of the genus Swertia (Gentianaceae) have been used in traditional medicine for many years. These herbs taste extremely bitter and have been mainly used for the treatment of hepatic, choleric and inflammatory diseases such as hepatitis, cholecystitis, pneumonia, osteomyelitis, dysentery, scabies, spasm, pain and neurastenia. In this genus, many components such as iridoids, xanthones, flavonoids, polyphenolic compounds and so on have been isolated and their biological activities investigated. They were described as antidepressant, antipsychotic, antidiabetic and hepatoprotective. It is also reported that xanthones and xanthone glycosides are most active compounds. Because of these biological abilities and in our course to a better knowledge of endemic plants of Flora Iranica, Swertia longifolia (Boiss.) that grows in the northern parts of Iran was studied. Dried and milled aerial parts of plant were continuously extracted in a soxhlet apparatus with petroleum ether (bp. 60-80) and then with ethanol. Ethanolic extract after concentration was poured into aqueous acetic acid 4% and filtered. The clarified acidic aqueous solution was subsequently extracted with chloroform, ethyl acetate and n-buthanol. N-buthanol extract was chromatographed over Sephadex LH-20 and eluted with methanol. The main fractions were chromatographed on Silica and then C18. This process yielded 7 components. They were identified as 1 iridoid glycoside, 1 secoiridoid glycoside, 2 xanthones and 2 xanthone glycosides by means of their UV, MS, 1H-NMR and 13C-NMR data. Since there are xanthones and xanthone glycosides in Swertia longifolia, it is expected that this plant has interesting pharmacological activities.