Integrative Approaches for the Identification and Localization of Specialized Metabolites in Tripterygium Roots

Abstract

ORCID IDs: 0000-0001-6565-9584 (B.M.L.); 0000-0001-7934-7987 (N.S.); 0000-0002-0600-6847 (D.Š.).Members of the genus Tripterygium are known to contain an astonishing diversity of specialized metabolites. The lack of authentic standards has been an impediment to the rapid identification of such metabolites in extracts. We employed an approach that involves the searching of multiple, complementary chromatographic and spectroscopic data sets against the Spektraris database to speed up the metabolite identification process. Mass spectrometry-based imaging indicated a differential localization of triterpenoids to the periderm and sesquiterpene alkaloids to the cortex layer of Tripterygium roots. We further provide evidence that triterpenoids are accumulated to high levels in cells that contain suberized cell walls, which might indicate a mechanism for storage. To our knowledge, our data provide first insights into the cell type specificity of metabolite accumulation in Tripterygium and set the stage for furthering our understanding of the biological implications of specialized metabolites in this genus.

Integrating pathway elucidation with yeast engineering to produce polpunonic acid the precursor of the anti-obesity agent celastrol

“…Triterpenoid compounds derived from β-amyrin, such as oleanolic acid, are widespread across most orders of higher plants [67]. In T. wilfordii, several oleanane type triterpenoids, many of which contain a carboxylic acid group at the C-29 position [68], have been reported, suggesting that these decorations could be formed by either CYP712K1, CYP712K2 and CYP712K3, or highly similar enzymes. Here, we show that CYP712K1 and CYP712K2 can turn products of TwOSC2 and TwOSC3 into the new compounds, 7, 8 and 9 (Additional file 1: Figure S2).…”

“…Celastrol is a red/orange quinone methide nor-triterpenoid found in the root bark of some genera of Celastraceae, including the traditional Chinese medicinal plant Tripterygium wilfordii [20,21]. However, scalable and reliable sourcing of celastrol or related compounds from plant roots is challenged by slow growth, yield fluctuations and complexity of harvesting branching roots.…”

Biosynthesis of Diterpenoids in Tripterygium Adventitious Root Cultures

“…Hundreds of structurally diverse metabolites have been isolated and characterized from various Tripterygium organs and tissues (Lange et al, 2017). Our adventitious root cultures, in contrast, secreted primarily diterpenoids into the culture medium and, therefore, are an excellent experimental model system in which to study the biosynthesis of these clinically relevant metabolites.…”

The genome analysis ofTripterygium wilfordiireveals TwCYP712K1 andTwCYP712K2responsible for oxidation of friedelin in celastrol biosynthesis pathway

“…Zhou et al (2019) isolated three OSC enzymes from T. wilfordii, of which TwOSC1 and TwOSC3 could convert 2, 3-oxidosqualene into friedelin as a major product, as well as β-amyrin and α-amyrin as minor products. Meanwhile, TwOSC2 catalyzed 2, 3-oxidosqualene into β-amyrin, belonging to oleanane-type triterpenoid which also found in T. wilfordii (Lange et al, 2017;Lv et al, 2019). However, the complete biosynthetic pathway of celastrol is still covered.…”

“…The pharmacological activities of T. wilfordii were mainly attributed to the various compounds accumulate in its root, such as alkaloid, diterpenoids and triterpenoids (Duan et al, 2000;Lv et al, 2019). Celastrol belongs to friedelane-type triterpenoid mainly found in root bark of T. wilfordii (Lange et al, 2017). It has been shown to be effective in the treatment of inflammatory and autoimmune diseases (Ma et al, 2007), anti-tumors (Pang et al, 2019), and as a possible treatment for Alzheimer's disease (Allison et al, 2001).…”