W van Uden

Increased podophyllotoxin production in Podophyllum hexandrum cell suspension cultures after feeding coniferyl alcohol as a β-cyclodextrin complex

SummaryCell suspension cultures, derived from roots of Podophyllum hexandrum Royle (Berberidaceae), accumulate podophyllotoxin. In this study the use of β-cyclodextrin in feeding the poorly water-soluble precursor coniferyl alcohol to these cultures is described. By complexation with β-cyclodextrin, a solution of 3 mM coniferyl alcohol could be fed, resulting in enhanced podophyllotoxin accumulation. The same concentration of non-complexed suspended coniferyl alcohol had only little effect on the podophyllotoxin accumulation. β-Cyclodextrin itself was proven to be non-toxic for the cells. It did not influence the podophyllotoxin content and it was not metabolized or used as a carbon source by the cells. For comparison, coniferin, the water-soluble β-D-glucoside of coniferyl alcohol, was also fed in the same concentration. The effect of coniferin on the podophyllotoxin accumulation was stronger than that of coniferyl alcohol complexed with β-cyclodextrin, but coniferin is not commercially available.

Stability of artemisinin in aqueous environments: Impact on its cytotoxic action to Ehrlich ascites tumour cells

We have recently shown artemisinin to be cytotoxic against Ehrlich ascites tumour cells. The aim of this study was to investigate the stability of this compound in the aqueous environment of the in‐vitro Ehrlich ascites tumour cell system (RPMI 1640 cell culture medium supplemented with 10% foetal bovine serum (RPMI/FBS) with reference to its cytotoxic action.

Isolation of Two Cytotoxic Diterpenes from the Fern Pteris multifida

From aerial parts of the fern Pteris multifida Poir. (Polypodiaceae) two diterpenes, entkaurane- 2β,16α-diol and ent-kaur-16-ene-2β,15α-diol, were isolated by repeated column chromatography using silica gel and silica gel impregnated with silver nitrate. The structures were confirmed by spectroscopic methods. Both compounds showed a moderate cytotoxicity to Ehrlich ascites tumour cells

Callitris spp. (Cypress Pine): In Vivo and In Vitro Accumulation of Podophyllotoxin and Other Secondary Metabolites

The name Callitris is derived from the Greek word kallistos, and means most beautiful (Dallimore and Jackson 1966). It was first named by Ventenat in 1808 (Adams and Simmons 1987), and is a relatively small genus that belongs to the division of Gymnospermae, order Coniferales, family Cupressaceae (Sporne 1969). Appreciable nomenclature complexities occur and therefore the reports on the number of Callitris species varies. Figures of 13, 14, 15, 16, and 20 species have been mentioned by several authors (Li 1953; Dallimore and Jackson 1966; Gadek and Quinn 1983; Krussmann 1985; Adams and Simmons 1987; Evans 1989). In the Index Kewensis the names of 39 species are listed (Hooker and Jackson 1895).