Caryophyllaceae saponins

Since cancer chemotherapeutics were reported to exert part of their pharmacological effect by triggering apoptotic cell death, the search for apoptosis-inducing compounds in tumor cells have become useful for the development of anticancer drugs. There were few reports on the apoptotic activity of saponins, except those on ginsenosides. We will present here recent results obtained with other saponins from Liliaceae, Mimosaceae, Araliaceae, and Caryophyllaceae. 

The last review on the Caryophyllaceae family was published almost two decades ago [1]. Since then, purification and structural elucidation techniques have changed enormously. Many of the earlier chemical studies have been reinvestigated and new findings published. The present review deals with the chemistry of the triterpenoid saponins of Caryophyllaceae family with special emphasis on recent developments in purification techniques and structural study aspects. 

Fig. (1). The aglycones of the triterpenoid saponins from Caryophyllaceae family.

Two acylated saponins, tram- and cw-/ -methoxycinnamoyl triterpene glycosides, have recently been isolated from Silene jenisseensis (Caryophyllacea) [71]. Since these saponins contain quillaic acid as their aglycone (Fig. 11), they should be expected to have immunostimulating properties. However, no apparent immunostimulating activity was detected by an in vitro chemiluminescent granulocyte assay [4,71]. 

One characteristic of many (but not all) saponins is their capacity to rupture erythrocytes (red blood corpuscles). By measuring the change in absorbance of the supernatant of an erythrocyte suspension after hemolysis, the saponin content can be calculated. Various amounts of the saponin-containing product or extract are mixed with a suspension of washed erythrocytes in isotonic buffer at pH 7.4. After 24 h, the mixture is centrifuged and hemolysis is indicated by the presence of hemoglobin (red) in the supernatant. In the European Pharmacopoeia, the quantity in milliliters of ox blood (diluted 1 50) that is totally hydrolysed by 1 g of test substance is measured. As a standard, the saponin mixture from the roots of Gypsophila paniculata (Caryophyllaceae) has by definition an activity of 30 000 units. 

Saponins (Glycosylated Triterpene Steroids) Common constituents of flowering plants, among others from the Aceraceae, Caryophyllaceae, and Sapindaceae families. 

Adjuvant activity has also been observed with saponins from Gypsophila and Saponaria (Caryophyllaceae) whereas it was absent with other saponin containing extracts prepared from Soya Alfalfa Chenopodium quinoa and Glycyrrhiza radix [15]. Since the strongest adjuvant activity was observed with saponins from Quillaja saponaria we will describe the activities associated with saponins from this species. 

Triterpenoid saponins are mainly found in dicotyledons in the plant kingdom. Approximately, 60 families of this taxon produce this type of saponin, including Apiaceae, Araliaceae, Caryophyllaceae, Fabaceae, Primulaceae, Ranuncu-laceae, and Theaceae [17]. 

As it can be clearly seen Fig. 2 that Gypsophila species (Caryophyllaceae) are an especially rich source of triterpenoidal saponins [18-20]. Gypsophila saponins are of interest in terms of their applications in vaccines [21]. Saponi-num album (Merck) is a complex mixture of triterpenoid saponins from Gypsophila paniculata and Gypsophila anostii which used to be commercially... 

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