Three new ring-A modified ursane triterpenes from Davidia involucrata

The triterpenoids and sesquiterpenoids from the plant of Agrimonia pilosa

A phytochemistry of the whole plant of Agrimonia pilosa led to the discovery of two new nortriterpenoids, agrimonorterpenes A and B (1 and 2), together with one known triterpenoid fupenzic acid (3) and seven known sesquiterpenoids (4-10). The new structures were determined as 19α-hydroxy-2-oxo-nor-A (3)-urs-11,12-dien-28-oic acid (1) and 2, 19β-dihydroxy-3-oxo-23-noroleana-1, 4, 12-trien-28-oic acid (2) by the spectroscopic data of UV, IR, HR-ESI-MS, and NMR. Notably, the structure of 1 possessed a rare five-membered A ring. And this is the first time to discover the sesquiterpenoids (4-10) from A. pilosa. Compound 3 displayed the selective cytotoxicity against HCT116, BGC823, and HepG2 cell lines with the IC₅₀ values of 16.31 μM, 21.94 μM, and 23.40 μM, respectively.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Ellagitannins of Davidia involucrata. I. Structure of Davicratinic Acid A and Effects of Davidia Tannins on Drug-Resistant Bacteria and Human Oral Squamous Cell Carcinomas

We isolated a new ellagitannin, davicratinic acid A (5), together with four known ellagitannins, davidiin (1), granatin A (2), pedunculagin (3), and 3-O-galloylgranatin A (4), from an aqueous acetone extract of dried Davidia involucrata leaves. The known ellagitannins were identified based on spectroscopic data. The structure of davicratinic acid A (5), a monomeric ellagitannin possessing a unique, skew-boat glucopyranose core, was established based on spectroscopic data. Additionally, we examined the effects of several tannins with good yields from this plant on drug-resistant bacteria and human oral squamous cell carcinomas, and found that davidiin (1) exhibited the most potent antibacterial and antitumor properties among the tannins examined.

Chemically Diverse Secondary Metabolites fromDavidia involucrata(Dove Tree)

Dove tree,Davidia involucrataBaill. which is endemic in western China, is not only one of the best known relict species of the tertiary, but also a famous ornamental plant with dove-shaped flowers. A diverse array of secondary metabolites have been isolated and identified fromDavidia involucrata. The 58 structures of the secondary metabolites were presented and classified as triterpenoids, tannins, phenolic compounds, lignans, flavonoids, alkaloids, and sterol. In addition, the biosynthetic route of some triterpenoids was proposed. Moreover, the advances in the discovery of unprecedented compounds and uncovering of notable bioactivities were highlighted in this review.

Cytotoxic 24-nor-ursane-type triterpenoids from the twigs of Mostuea hirsuta

Two new 24-nor-ursane-type triterpenoids, 2α,3β,19α-trihydroxy-24-norurs-4(23),12-dien-28-oic acid (1) and 3β-acetoxy-2α,19α-dihydroxy-24-norurs-4(23),12-dien-28-oic acid (2), along with 15 known compounds were isolated from the methanol extract of the twigs of Mostuea hirsuta. While 2-hydroxymethylbenzamide (13) was isolated for the first time from the natural source, compounds 3–12 are reported here for the first time from the genus Mostuea. Their structures were elucidated by means of spectroscopic analyses including 1D- and 2D-NMR spectroscopy, high-resolution mass spectrometric data as well as comparison with data from the literature. Compounds 1, 2, 4–9 and 13 were tested against bacteria, fungi and plant pathogen oomycetes by the paper disk agar diffusion assay resulting in missing to low activities corresponding with minimum inhibitory concentrations (MICs) > 1 mg mL–1. However, the respective compounds 1, 2, 8, 9 and 13 exhibited moderate cytotoxic activity against the human Caucasian prostate adenocarcinoma cell line PC-3, with IC50 10.6–16.5 μm compared to the standard doxorubicin with IC50 0.9 μm.

Five new taraxerene-type triterpenes from the branch barks of Davidia involucrata

Five new taraxerene-type triterpenes, 2-nor-D-friedoolean-14-en-28-ol (1), 2-nor-d-friedoolean-14-en-3α,28-diol (2), 6α-hydroxy-2-nor-D-friedoolean-14-en-3,21-dione (3), 6α,11α,29-trihydroxy-D-friedoolean-14-en-3,16,21-trione (4), and 6α,23,29-trihydroxy-D-friedoolean-14-en-3,16,21-trione (5), were isolated from the MeOH extract of the branch barks of Davidia involucrata, together with five known compounds. Their structures were elucidated by means of various spectroscopic analyses. Five of the identified compounds showed moderate cytotoxicities against the cell proliferation of SGC-7901, MCF-7, and BEL-7404.