Maytenin Plays a Special Role in the Regulation of the Endophytic Bacillus megaterium in Peritassa campestris Adventitious Roots.

Peritassa campestris (Celastraceae) root bark accumulates potent antitumor quinonemethide triterpenes (QMTs). When grown in their natural habitat, plants of the family Celastraceae produce different QMTs such as celastrol (3) and pristimerin (4). However, when they are inserted in in vitro culture systems, they accumulate maytenin (1) as the main compound. Recently, Bacillus megaterium was detected as an endophytic microorganism (EM) living inside P. campestris roots cultured in vitro. We hypothesized that compound (1) controls EM growth more efficiently, and that the presence of EMs in the root culture causes compound (1) to accumulate. For the first time, this work has explored plant-microorganism interaction in a species of the family Celastraceae by co-culture with an EM. Live endophytic bacteria were used, and QMT accumulation in P. campestris adventitious roots was our main focus. The antimicrobial activity of the main QMTs against endophytic B. megaterium was also evaluated. Our results showed that compound (1) and maytenol (5) were more effective than their precursors QMTs (3) and (4) in controlling the EM. Co-culture of B. megaterium with roots significantly reduced bacterial growth whereas root development remained unaffected. Compound (1) production was 24 times higher after 48 hr in the presence of the highest B. megaterium concentration as compared to the control. Therefore, P. campestris adventitious roots affect the development of the endophyte B. megaterium through production of QMTs, which in turn can modulate production of compound (1).

Cytotoxic Triterpenes from Salacia crassifolia and Metabolite Profiling of Celastraceae Species.

The new pentacyclic triterpene 11ß-hydroxypristimerin (1), along with the known metabolites pristimerin (2), 6-oxopristimerol (3) and vitideasin (4), were isolated from a Salacia crassifolia root wood extract, following a bioassay-guided fractionation approach. Both the extract and the purified triterpenes displayed pronounced cytotoxic activity against human cancer cell lines. The NCI-60 cell line screen revealed that compound 2 was the most active, with a mean GI50 of 0.17 µM, while compound 1 had a mean GI50 of 8.7 µM. A COMPARE analysis of the screening results showed that pristimerin is likely to be the main compound responsible for the cytotoxic activity of the extract (mean GI50 of 0.3 µg·mL−1). A targeted search for pristimerin and related derivatives using LC-MS/MS revealed the presence of pristimerin (2) and 6-oxopristimerol (3) in all Celastraceae species examined and in all plant parts tested, while vitideasin (4) was only detected in the genus Salacia.

Microtropins Q-W, ent-Labdane Glucosides: Microtropiosides G-I, Ursane-Type Triterpene Diglucoside and Flavonol Glycoside from the Leaves of Microtropis japonica.

Microtropins Q-W, (2S,3R)-2-ethyl-2,3-dihydroxybutyrate of various glucosides and glucose, as well as three ent-labdane diterpenoid glucosides, named microtropiosides G, H and I, an ursane-type triterpene diglucoside and a flavonoid glycoside were isolated from the MeOH extract of the leaves of Microtropis japonica. The structure of microtropioside A, also isolated from the branches of M. japonica, was elucidated spectroscopically in a previous experiment and was found to possess a rare seven-membered oxyrane ring. Its structure was confirmed by X-ray crystallographic analysis of its pentaacetate.

[Investigation of metabolites of Triptergium wilfordii on liver toxicity by LC-MS].

In this paper, biomarkers of liver toxicity of Triptergium wilfordii based on metabolomics was screened, and mechanism of liver toxicity was explored to provide a reference for the clinical diagnosis for liver toxicity of Triptergium wilfordii. MS method was carried on the analysis to metabolic fingerprint spectrum between treatment group and control group. The potential biomarkers were compared and screened using the multivariate statistical methods. As well, metabolic pathway would be detailed description. Combined with PCA and OPLS-DA pattern recognition analysis, 20 metabolites were selected which showed large differences between model group and blank group (VIP > 1.0). Seven possible endogenous biomarkers were analyzed and identified. They were 6-phosphate glucosamine, lysophospholipid, tryptophan, guanidine acetic acid, 3-indole propionic acid, cortisone, and ubiquinone. The level changes of above metabolites indicated that the metabolism pathways of amino acid, glucose, phospholipid and hormone were disordered. It is speculated that liver damage of T. wilfordii may be associated with the abnormal energy metabolism in citric acid cycle, amino acid metabolism in urea cycle, and glucose metabolism. It will be helpful to further research liver toxicity ingredients of Triptergium wilfordii.

New dihydro-ß-agarofuran sesquiterpenes from Parnassia wightiana wall: isolation, identification and cytotoxicity against cancer cells.

Five new (4-8) and three known (1-3) dihydro-ß-agarofuran sesquiterpene polyesters were isolated from the whole plants of Parnassia wightiana. The structures of all compounds were elucidated through spectroscopic analysis including 2D-NMR and HR-MS. The absolute configuration of these compounds was established by X-ray diffraction analysis, comparison of NOESY spectra and biogenetic means. The cytotoxities of compounds 2-8 were evaluated in vitro against HL-60, SMMC-7721, A549, MCF-7 and SW480 cell lines. Compounds 5-7 exhibited the highest activities with IC50 values of 11.8-30.1 µM in most cases. The SAR revealed that the introduction of hydroxyl group was able to significantly improve the activities of the compounds for most of the cell lines.