Plant steroids

Plant safety Plant sites Plant steroids Plant tissue Plan tvax PLASDOC Plasdone Plasma... 

A. Molecular Ion Because of low volatility, most steriods are derivatized before analysis by GC/MS. Molecular ions are usually observed for steriods sufficiently volatile to be analyzed underivatized by GC/MS (see Figure 31.1) Some important steroids in urine include estrone, estradiol, estriol, pregnanediol, and 17-ketosteroids. which can be analyzed by GC/MS as the TMS or the MO-TMS derivatives. The plant steroids, such as camposterol, ergosterol. stigmasterol, cholestanol, and sitosterol, are generally analyzed as the TMS derivatives. 

Brassinosteroids (BR) are a group of plant steroid hormones that help to regulate many aspects of plant growth and development. Several P450s have been... 

Historically, this lack of competition is probably responsible for the flies total dependency on the cactus The flies somehow lost the biochemical machinery needed for conversion of common plant steroids into those steroids they require. The loss went unnoticed, because the cactus provided an assured source of steroids the flies were still able to utilize. However, no other available plants provide these unusual steroids, so they must now consume senita cactus to survive. 

Cyclopamine also interferes with cholesterol metabolism that results in decreased cholesterol synthesis and the accumulation of late biosynthetic intermediates. Cyclopamine was evaluated as an inhibitor of multi-drug resistance in tumor cells. Intrinsic or acquired resistance of tumor cells to cytotoxic drugs is a major cause of failure of chemotherapy. Both cyclopamine and the spirosolane alkaloid tomatidine from tomatoes act as potent and elfective chemosensitizers in multidrug-resistant cells (Lavie et ah, 2001). Therefore, plant steroidal alkaloids, such as cyclopamine and tomatidine, or their analogs, may serve as chemosensitizers in combination with chemotherapy and conventional cytotoxic drugs for treating multidrug-resistant cancers. 

Simons V et al (2006) Dual effects of plant steroidal alkaloids on Saccharomyces cerevisiae. Antimicrob Agents and Chemother 50 2732... 

May 1994 both exclusive and typical of terrestrial plants Steroids pol vdroxvlated ... 

Figure 22-9 Structures and routes of biosynthesis for a few plant steroids.

K. Nakanishi, Past and present studies with ponasterones, the first insect molting hormones from plants , Steroids, 1992, 57, 649-657. 

Markovic-Housley, Z., Degano, M., Lamba, D. et al. 2003. Crystal structure of a hypoallergenic isoform of the major birch pollen allergen Bet v 1 and its likely biological function as a plant steroid carrier. J Mol Biol 325 123-133. 

Corbiere, C., Liagre, B., Bianchi, A., Bordji, K., Dauca, M., Netter, P. and Beneytout, J.L. (2003) Different contribution of apoptosis to the antiproliferative effects of diosgenin and other plant steroids, hecogenin and tigogenin, on human 1 547 osteosarcoma cells. International Journal of Oncology 22(4), 899-905. 

BRs are specific plant steroid hormones that are essential for normal plant development (Adam and Schneider, 1999 Adam et al, 1999 Bishop and Koncz, 2002 Asami et al, 2005). They act on different levels in multiple... 

Bishop, G.J. (2007) Refining the plant steroid hormone biosynthesis pathway. Trends Plant Sci. 12, 377-80. 

Bishop, G.J. and Koncz, C. (2002) Brassinosteroids and plant steroid hormone signaling. Plant Cell, 14, 97-110. 

Crude fats and oils consist primarily of glycerides. However, they also contain many other hpids in minor quantitites. Com oil, for example, may contain glycerides plus phosphoUpids, glycolipids, many isomers of sitosterol and stigmasterol (plant steroids), several tocopherols (vitamins E), vitamin A, waxes, unsaturated hydrocarbons such as squalane and dozens of carotenoids and chlorophyll compounds, as well as many products of decomposition, hydrolysis, oxidation, and polymerization of any of the natural constituents. 

The only report of the presence of a steroidal saponin is proved by Khafegi et al. [166] from the alcoholic extract of A. alexandrinus. Two saponins, a glucoside of the (22)-fiirostene type (I) and its isomer pseudosapogenin (II) have been isolated. Fig (2). Both furnish a red colour with Erlich reagent, that characterizes these types among the plant steroids. 

---