Saponins and Glycosides

The quinones are generally skin irritants. Some compounds have both toxic and dermatological actions. For example, juglone was known to be toxic as well as to cause dermatitis (170). Other examples were reviewed most recently by Hausen (75). Jones et al. (89) showed that 2,6-dimethoxybenzoquinone, a cytotoxic constituent of the woody stems of Tibouchina pulchra, has an LD50 of 2.5 pg/ml in KB cell culture. 

A few examples are found of the toxicity of some of the phenolics to livestock. The phenol ether, tremetone, from Eupatorium rugosum, caused toxic effects in livestock as did the isoflavones, genistein, and coumestrol (93). 

MacRae and Towers (106) reviewed the biological activities of the lignans and discussed those that are toxic to fungi, insects, and vertebrates, as well as those lignans that are known to have anti-tumor, anti-mitotic, and anti-viral activities. The most studied lignan thus far is podophyllotoxin because of its anti-cancer activity. However, podophyllotoxin is itself toxic (144). 

The pharmacology and percutaneous absorption of common monoterpenes were studied by Schafer and Schafer (160). Among the monoterpenes, the ketones appeared to be more toxic than related compounds. In particular, camphor has been used medically since ancient times. The abuse of camphor and its toxic effects, especially in children, continued to be a problem (7, 69, 87, 88, 95). The toxicology of some borneol isomers (139) and of synthetic camphor (146) has been studied. 

Another monoterpene ketone, thujone, was more toxic than camphor. Arc-tander (6) stated that some authorities considered thujone to be the most toxic 

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Yoshikawa, M., Murakami, T., Ueno, T., Yashiro, K., Hirokawa, N., Murakami, N., Yamahara, J., Matsuda, H., Saijoh, R., and Tanaka, O. (1997b). Bioactive saponins and glycosides. Vlll. Notoginseng (1) New dammarane-type triterpene oligoglycosides, Notoginsenosides-A, -B, -C, and -D, from the dried root of Panax notoginseng (Burk.) F. H. Chen. Chem. Pharm. Bull. 45,1039-1045. 

Yoshikawa M, Murakami T, Ueno T, Kadoya M, Matsuda H, Yamahara J, Murakami N. (1995) Bioactive saponins and glycosides, i. senegae radix. (1) E-senegasaponins a and b and z-senegasaponins a and b, their inhibitory effect on alcohol absorption and hypoglycemic activity. Chem Pharm Bull 43 2115-2122. 

CS021 Murakami, T., J. Nakamura, H. Mat-suda and M. Yoshikawa. Bioactive saponins and glycosides. XV. Saponin constituents with gastroprotective effect from the seeds of tea plant, Camellia sinensis L. var. assamica Pierre, cultivated in Sri Lanka structures of assamsaponins A, B, C, D and E. Chem Pharm Bull 1999 47(12) 1759-1764. 

Yoshikawa, M. et al "Bioactive Saponins and Glycosides...from Seeds of Camellia japonica L. Structures and Inhibitory Activity on Alcohol Absorption," Chem Pharm Bulletin, 1996, vol. 4-1, (10), pp. 1899-1907,... 

Yoshikawa, M. "Bioactive Saponins and Glycosides VI... The Structure-Requirement in Oleanolic Acid Glucuronide-Saponins for the Inhibitory Activity," Chem Pharm Bulletin, 1996 Vol, 44 (10), PP. 1915-1922. 

Yoshikawa, M., T. Murakami, H. Matsuda, et al. 1996. Bioactive saponins and glycosides. II. Senegae Radix. 2) Chemical stmc-tures, hypoglycemic activity, and ethanol absorption-inhibitory effect of E-senegasaponin c, Z-senegasaponin c, and Z-senegins II, III, and IV. Chem. Pharm. Bull. 44(7) 1305-1313. 

Yoshikawa M, Monkawa T, Li N, Nagatomo A et al (2005) Bioactive saponins and glycosides. XXni.l) Triterpene saponins with gastroprotective effect from the seeds of Camellia sinensis -Theasaponins E3, E4, E5, E6, and E7. Chem Phatm Bull 53 1559-1564... 

Yoshikawa M, Monkawa T, Nakamura S et til (2(X)7) Bioactive saponins and glycosides. XXV.l) Acylated oleanane-type triterpene saponins from the seeds of tea plant (Camellia sinensis). Chem Pharm Bidl 55 57-63... 

There has been considerable discussion regarding the mode of action of the sea cucumber and starfish saponins. Both the triterpene and steroidal glycosides inhibit both Na/K ATPase and Ca/Mg ATPase 06) possibly as a result of their aglycone structures. However, their detergent properties cause membrane disruption which will influence the activity of membrane-bound enzymes such as the ATPases. In investigating the actions of saponins on multilamellar liposomes, it was found that cholesterol serves as the binding site for such saponins and that cholesterol-free lip-somes are not lysed by saponins 107). 

Mate contains both caffeine (0.4-2.4%) and theobromine (0.3-0.5%). Also found are triterpene saponins and the caffeic acid derivatives—chlorogenic acid, neochlorogenic acid, and cryptochlorogenic acid. Flavonoids in mate are rutin, isoquercetin, and kaemferol glycosides. A nitrile glycoside, menisdaurin, is also present, which is noncyanogenic. 

Direct injection API-Electrospray MS is capable of analyzing much larger and less volatile substances than either EI/MS or CI/MS. As a result, this method is often used to provide structural information on peptides, proteins, and polymers derived from both natural and synthetic processes it is also useful in the analysis of many natural compounds including molecules such as saponins and flavonol glycosides, derived from plants. When using direct injection API-electrospray, partial purification and EC preparation are performed elsewhere and a collected fraction is dissolved in an appropriate solvent and injected as a bolus into the mass spectrometer (flow or direct injection or syringe infusion). This has an advantage, as the mass... 

In steroidal glycosides, the sugar moiety is joined to the cyclopentanoperhy-drophenanthrene (steroid) nucleus. Steroidal glycosides include the cardeno-lides (cardiac glycosides) and saponins (sapogenic glycosides). 

Glycosides of compounds with a triterpenoid origin include saponins, cardiac glycosides, and glycoalkaloids such as solanine (in potatoes). 

Cell suspension cultures of Gypsophila paniculata and Saponaria officinalis produce very closely related triterpenoid saponins. Pretreatment of cell suspension cultures of G. paniculata with gypsogenin 3,0-glucuxonide (a triterpenoid saponin precursor in G. paniculata) followed by administration of [ C] acetate resulted in a marked reduction in incorporation of radioactivity into saponins and their precursors, but not into sterols and steryl glycosides [26]. Measurements of OSC activities revealed that there was no effect of elicitor treatment on CS levels in either species, but in G. paniculata AS levels went down while in S. officinalis they increased. This suggests that in these two species OSCs are regulating steps in the isoprenoid pathway and control the flux to sterols and triter-penes. 

Glycosides that have soaplike properties are called saponins. Similarly, glycosides that liberate hydrocyanic acid (HCN) on hydrolysis are known as cyanogenic glycosides, and glycosides that have an effect on heart muscle are called cardiac glycosides. 

The aglycone of this type of glycoside is biosynthetically derived from isoprene units. There are two major classes of isoprenoid glycosides saponins and cardiac glycosides. 

A. Some saponins and flavone glycosides of plant origin... 

Secondary plant compounds compounds such as phenols, alkaloids, tannins, organic acids, saponins, terpenes, steroids, essential oils, and glycosides which can deter herbivory and detritivory. 

CD detection for colored derivatives might just as easily be used for structural information about the carbohydrates as well as for their analysis, but so far little attention has been given to either application. Cyclic oligomers of p-D-glucose have important supporting roles to play in analytical applications that are discussed in a later section. The union of chirality in the carbohydrate moiety of a glycoside metabolite with the unsaturation in the base in such compounds as nucleosides and nucleotides, saponins and flavones, etc., is another area that will ultimately be developed for applications of chiroptical detection methods. New and imaginative ideas are needed for the analysis of carbohydrates, and CD should be one of the favored methods. 

Figure 6.4 Chemical structures of estranes, androstanes, cardiac glycosides steroid saponins and steroid alkaloids mentioned in the text.

Plant sterols are products of primary metabolism, but they may also be regarded as direct precursors of many secondary plant metabolites, such as the cardiac glycosides, saponins and steroid alkaloids. All of the compounds mentioned share the same basic skeleton therefore, the accumulation of a particular compound can only be achieved if (1) enzymes with a high degree of substrate specificity are involved in their biosynthesis, (2) metabolites can be channelled efficiently to the respective pathways and (3) products can be transported, sequestered and/or stored in specific compartments. 

Figure 7.11 (Continued) (g) Occurrence of triterpenes and cardiac glycosides. Key to branches leading to families that accumulate triterpenes/triterpene saponins cardiac glycosides. See also legend to (a). (See Plates 14-18 in colour plate section.)...

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