Biotransformation of cycloartane-type triterpenes by the fungus Glomerella fusarioides

Dentatacid A: An Unprecedented 2, 3-Seco-arbor-2, 3-dioic Triterpenoid from the Invasive Plant Euphorbia dentata, with Cytotoxicity Effect on Colon Cancer

Euphorbia dentata Michx. is an invasive plant species in China, known for its toxicity and potential to reduce crop yields, posing numerous threats. To gain a deeper understanding of this invasive plant, phytochemical methods were employed to isolate 13 terpenoids (1-11, 19, 20) and 7 sterols (12-18) from the ethanol extract of E. dentata, identifying one new compound and 19 known compounds. Within spectroscopic methods such as NMR, HR-ESI-MS, and ECD, the structures and absolute configurations of these compounds were established. Among them, dentatacid A (11) possesses an unprecedented 2, 3-seco-arbor-2, 3-dioic skeleton within the potential biosynthetic pathway proposed. Dentatacid A also exhibited excellent anti-proliferative activity against the HT-29 (human colorectal adenocarcinoma) cell line, with an IC50 value of 2.64 ± 0.78 μM, which was further confirmed through network pharmacology and molecular docking. This study significantly expands the chemical diversity of E. dentata and offers new insights into the resource utilization and management of this invasive plant from the perspective of natural product discovery.

Phytochemical and biological studies on rare and endangered plants endemic to China. Part XXV. Structurally diverse triterpenoids and diterpenoids from two endangered Pinaceae plants endemic to the Chinese Qinling Mountains and their bioactivities

A joint phytochemical investigation on the MeOH extracts of the twigs and needles of two endangered Pinaceae plants endemic to the Chinese Qinling Mountains, Picea neoveitchii (an evergreen spruce) and Larix potaninii var. chinensis (a deciduous larch), led to the isolation and characterization of 34 and 24 structurally diverse terpenoids, respectively. Among them, seven are previously undescribed, including a picane-type [i.e., 14(13 → 12)abeo-12αH-serratane] (neoveitchin A) and a serratane-type (neoveitchin B) triterpenoids, and an abietane-type (neoveitchin C) as well as four labdane-type (potalarxins A-D) diterpenoids. Their structures and absolute configurations were established by extensive spectroscopic methods and/or X-ray diffraction analyses. All isolates were evaluated for their inhibitory activities against the human protein tyrosine phosphatase 1B (PTP1B). Serrat-14-en-3α,21β-diol, betulinic acid, 3β-hydroxy-11-ursen-13(28)-olide, ursolic acid, and oleanolic acid were found to have considerable inhibitory effects against PTP1B, with IC₅₀ values ranging from 1.1 to 18.1 μM. The interactions of the bioactive triterpenoids with PTP1B were thereafter performed by employing molecular docking studies. In addition, 7-oxo-dehydroabietic acid (an abietane-type diterpenoid) and mangiferonic acid (a cycloartane-type triterpenoid) inhibited acetyl-coenzyme A carboxylase 1 (ACC1), with IC₅₀ values of 3.4 and 6.6 μM, respectively.

Antitumor Profile of Carbon-Bridged Steroids (CBS) and Triterpenoids

This review focuses on the rare group of carbon-bridged steroids (CBS) and triterpenoids found in various natural sources such as green, yellow-green, and red algae, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in amoebas, fungi, fungal endophytes, and plants. For convenience, the presented CBS and triterpenoids are divided into four groups, which include: (a) CBS and triterpenoids containing a cyclopropane group; (b) CBS and triterpenoids with cyclopropane ring in the side chain; (c) CBS and triterpenoids containing a cyclobutane group; (d) CBS and triterpenoids containing cyclopentane, cyclohexane or cycloheptane moieties. For the comparative characterization of the antitumor profile, we have added several semi- and synthetic CBS and triterpenoids, with various additional rings, to identify possible promising sources for pharmacologists and the pharmaceutical industry. About 300 CBS and triterpenoids are presented in this review, which demonstrate a wide range of biological activities, but the most pronounced antitumor profile. The review summarizes biological activities both determined experimentally and estimated using the well-known PASS software. According to the data obtained, two-thirds of CBS and triterpenoids show moderate activity levels with a confidence level of 70 to 90%; however, one third of these lipids demonstrate strong antitumor activity with a confidence level exceeding 90%. Several CBS and triterpenoids, from different lipid groups, demonstrate selective action on different types of tumor cells such as renal cancer, sarcoma, pancreatic cancer, prostate cancer, lymphocytic leukemia, myeloid leukemia, liver cancer, and genitourinary cancer with varying degrees of confidence. In addition, the review presents graphical images of the antitumor profile of both individual CBS and triterpenoids groups and individual compounds.

Biotransformations of diterpenoids and triterpenoids: a review

During the past few years, research has focused on the microbial transformation of a huge variety of organic compounds to obtain compounds of therapeutic and/or industrial interest. Microbial transformation is a useful tool for organic chemists looking for new compounds, as a consequence of the variety of reactions for natural products. Terpenoids are a large family of natural products exhibiting a wide range of biological activities such as antibiotics, anti-inflammatory, anti-HIV and anti-tumor effects; hypotensive agents; sweeteners; insecticides; anti-feedants; phytotoxic agents; perfumery intermediates; and plant growth hormones. This article describes the biotransformation products of diterpenoids and triterpenoids in a variety of biological media. Emphasis is placed on reporting the metabolites that may be of special interest as well as the practical aspects of this work in the field of microbial transformations. This review covers the literature from 1991 to 2012.

Microbial transformation of cycloastragenol

The microbial transformation of cycloastragenol by the fungi Cunninghamella blakesleeana NRRL 1369 and Glomerella fusarioides ATCC 9552, and the bacterium Mycobacterium sp. NRRL 3805 were investigated. Both fungi mainly provided hydroxylated metabolites together with products formed by cyclization, dehydrogenation and Baeyer-Villiger oxidation resulting in a ring cleavage. The bacteria yielded only a single oxidation product, namely, 3-oxo-cycloastragenol. Structures of the metabolites were elucidated by 1-D ((1)H,(13)C), 2-D NMR (COSY, HMBC, HMQC) and HRMS analyses.

Hydroxylation of Diosgenin by Absidia coerulea

Microbial transformation of diosgenin (1) using Absidia coerulea yielded five new polar metabolites, which were identified as (25 R)-spirost-5-en-3β,7β,12β,25α-tetrol (2), (25 S)-spirost-5-en-3β,7α,12β,25β-tetrol (3), (25 S)-spirost-5-en-3β,7β,12β,25β-tetrol (4), (25 R)-spirost-5-en-3β,7α,12β,25α-tetrol (5), and (25 R)-spirost-5-en-3β,7β,12β,24β-tetrol (6). Their structures were established on the basis of mass spectrometry and multi-dimensional NMR spectroscopy. The characteristic transformations observed were C-7α, C-7β, C-12β, C-24β, C-25α, and C-25β hydroxylation. The cytotoxicity of compounds 1–6 was evaluated against the human myelogenous leukemia K562 cell line and squamous cell carcinoma KB parental cell lines. Compounds 2–6 exhibited weak cytotoxicity against K562 and KB cells and were less potent than the parent compound 1.

Triterpenoids and aromatics from Derris laxiflora

Seven new compounds, O-trans-cinnamoylglutinol (1), 22β-hydroxy-12-oleanen-3-one (2), 15α,16α-epoxy-12-oleanen-3-one (3), 29-hydroxy-12-oleanene-3,22-dione (4), 22β,29-dihyroxy-12-oleanen-3-one (5), 2,3-(methylenedioxy)-4-methoxy-5-methylphenol (8), and 2,3,6-trimethoxy-5-methylphenol (9), as well as two first isolated from natural sources, 25-cycloartene-3,24-dione (6) and 24ξ-hydroxy-25-cycloarten-3-one (7), were characterized from Derris laxiflora. The structures of these compounds were determined by analysis of their spectroscopic data.