Sieber Linker

Chemical properties

White to off-white or grey powder

The Uses of Sieber Linker

Sieber linker (3-Hydroxyxanthen-9-one) is a natural product of the trifluoroacetic acid group found in Hypericum sampsonii and Rhachidosorus mesosorus. It has antiplatelet and anti-inflammatory properties. It also inhibits the expression of tumour necrosis factor-α (TNF-α) in mice. The synthesis of TNF-α is inhibited by Sieber linker, which may be due to its ability to inhibit the enzyme phosphodiesterase 4 (PDE4). Sieber linker also inhibits the binding of PDL1 to dinucleotide phosphate (DNP) and has an inhibitory effect on cancer cells. This molecule can be used for the treatment of infectious diseases, such as malaria and tuberculosis, since it inhibits protein synthesis in bacteria.

Synthesis Reference(s)

Tetrahedron, 43, p. 3075, 1987 DOI: 10.1016/S0040-4020(01)86849-6

Purification Methods

Purify the xanthone by chromatography on SiO2 gel with pet ether/*benzene as eluent. Recrystallise it from *benzene or EtOH. The acetate has m 157-158o. [Itoh et al. J Am Chem Soc 107 4819 1985, Davies et al. J Org Chem 23 307 1958]. [Beilstein 18 H 46, 18 I 315, 18 II 29, 21 III/IV 601.]