Biosynthesis of Sterols and Triterpenes in Cell Suspension Cultures of Uncaria tomentosa

Abstract

;Pectin administered to Uncaria tomentosa cell suspension cultures, was found to increase the production of triterpene acids (ursolic and oleanolic acid), however, neither growth nor sterol accumulation were affected. Cell cultures showed that pectin treatment caused a rapid threefold increase in the activities of enzymes involved in the biosynthesis of C 5 and C 30 isoprenoid, such as isopentenyl diphosphate isomerase and squalene synthase. The activity of a farnesyl diphosphatase, which could divert the flux of farnesyl diphosphate to farnesol, was two times lower in elicited than in control cells. Elicited cells also transformed more rapidly a higher percentage of [5-3 H]mevalonic acid into triterpene acids. Interestingly, addition of terbinafine, an inhibitor of squalene epoxidase, to elicited cell cultures inhibited sterol accumulation while triterpene production was not inhibited. These results suggest that in U. tomentosa cells, both the previously mentioned enzymes and those involved in squalene 2,3-oxide formation play an important regulatory role in the biosynthesis of sterols and triterpenes.

Induced accumulation of oleanolic acid and ursolic acid in cell suspension cultures of Uncaria tomentosa

“…Elicitation with citrus pectin, as previously reported (Flores-Sa´nchez et al 2002), did not provoke changes in the growth characteristics of U. tomentosa cell cultures.…”

“…The extracts were evaporated under vacuum, dissolved in 0.5 ml methanol, and analysed by HPLC and TLC as previously described (Flores-Sa´nchez 2002). Ursolic and oleanolic acids, from 40 mg extract, were purified by TLC and analysed by 1 H NMR on a 300 MHz Varian Mercury spectrometer, measuring the methyl signal integrals at d 1.14 for oleanolic acid and d 1.08 for ursolic acid in CDCl 3 with tetramethylsilane as reference.…”

“…Addition of elicitors may be successful in terms of the role of triterpenes as chemical defence against pathogens and herbivores. Yeast extracts and oligogalacturonide-rich fractions have induced the production of secondary metabolites (Flores-Sa´nchez et al 2002, Yoon et al 2000 which is mediated by jasmonates (Mueller et al 1993). Carbohydrates serve as carbon sources and also show several effects as signal compounds for secondary metabolite production (Rothe et al 2001).…”

Gene regulation patterns in triterpene biosynthetic pathway driven by overexpression of squalene synthase and methyl jasmonate elicitation in Bupleurum falcatum

“…Similar result was obtained in P. ginseng overexpressing SS (PgSS1) gene (Lee et al 2004). It has been suggested that active biosynthesis of triterpenes occurs when sterol formation has been sacrificed (Flores-Sánchez et al 2002).…”

Metabolic analysis of elicited cell suspension cultures of Cannabis sativa L. by 1H-NMR spectroscopy

“…Pectin suspensions from Citrus fruits (87% galacturonic acid and 8.7% methoxy groups, Sigma) were prepared according to the method of Flores-Sanchez et al (2002).…”