Isolation and structure of some constituents of the Australian medicinal plant Tinospora smilacina ('snakevine')

The structures of a number of compounds isolated from the stems of Tinospor a smilacina (known as 'snakevine') have been determined. The known clerodan e-type compound columbin is a major component, and two new minor compounds incorporate a heavily oxygenated tetrahydrofuran ring in place of the furan ring of columbin. The lignan isolariciresinol is also shown to be a minor component, along with dihydrosyringenin. The traditional medicinal use of t he vine, particularly in countering snake venom, may be associated primaril y with the presence of columbin.