[Two new sesquiterpenes in Qi-nan Aquilariae Lignum Resinatum].

This study aimed to investigate the chemical constituents of supercritical extract from Qi-nan Aquilariae Lignum Resinatum by silica gel column chromatography, thin-layer chromatography, and semi-preparative high-performance liquid chromatography. One new elemane-type and one new eudesmane-type sesquiterpene compounds were isolated from the extract, and their structures were identified by MS, UV, IR, NMR, and ECD spectroscopic techniques, and named aquqinanol C(1) and aquqinanol D(2). Both compounds are novel compounds. The neuroprotective effect of the compounds on CORT-induced PC12 cell damage was determined in vitro. The results showed that compounds 1 and 2 exhibited a certain protective effect against CORT-induced damage in PC12 cells.

Cadinane-Type Sesquiterpenoids with Cytotoxic Activity from the Infected Stems of the Semi-mangrove Hibiscus tiliaceus.

Eight new cadinane sesquiterpenoids (1-8), along with two known compounds (9 and 10), were isolated from infected stems of the semi-mangrove plant, Hibiscus tiliaceus. The structures of compounds 1-8 were elucidated through the analysis of their 1D and 2D NMR and MS data, and their absolute configurations were determined by comparing their experimental and calculated ECD spectra and by single-crystal X-ray diffraction. The two confused known compounds (9 and 10) were resolved using single-crystal X-ray crystallography. Compounds 1-3 have novel norsesquiterpene carbon skeletons arising from a ring contraction rearrangement. All obtained isolates were evaluated against the HepG2 and Huh7 cell lines, and compounds 1b, 2b, 4, 6, and 8 showed cytotoxic activity toward both cell lines, with IC50 values ranging from 3.5 to 6.8 µM.

Cadinane-type sesquiterpenoid dimeric diastereomers hibisceusones A-C from infected stems of Hibiscus tiliaceus with cytotoxic activity against triple-negative breast cancer cells.

Three new cadinane-type sesquiterpenoid dimeric diastereomers (1-3) named hibisceusones A-C were obtained from the infected stems of Hibiscus tiliaceus. The structures were determined by NMR spectroscopy and MS techniques, and the absolute configurations were assigned by ECD and single-crystal X-ray diffraction techniques. Compounds 1-3 are diastereomers, and contain a 1,4-dioxane ring linearly fused to different cadinane-type polycyclic skeletons. This is the first time that such a structure has been identified in natural products. Compounds 1-3 exhibited cytotoxic activities, and 2 showed a significantly high anti-triple-negative breast cancer (TNBC) effect. The anti-cancer effect of compound 2 was 3-4 fold higher than that of 1 and 3. The anti-cancer effect was generated via the induction of the apoptosis of the MDA-MB-231 cells by inhibiting the PI3Kα pathway.

Moschamindole induces glioma cell apoptosis by blocking Mia40-dependent mitochondrial intermembrane space assembly and oxidative respiration.

Glioblastoma multiforme (GBM) is the most frequent, lethal, and aggressive tumor of the central nervous system in adults. In this study, we found for the first time that moschamindole (MCD), a rare phenolic amide with 8/6/6/5/5 rings, is a major bioactive constituent derived from Phragmites communis Trin (Poaceae) that exhibits a potential cytotoxic effect on both TMZ-resistant GBM cell lines and xenograft models. MCD-induced intrinsic apoptosis signals and mitochondrial dysfunction were confirmed by cell cycle arrest, caspase-3/7 activation, and membrane potential depolarization. Furthermore, investigations exploring the mechanism showed that MCD specifically inhibits Mia40-mediated oxidative folding of mitochondrial intermembrane space (IMS) proteins via PCR assay and immunoblot analysis. MCD relies on its positive charge to associate with mitochondrial oxidative respiration, thus blocking energy metabolism and inducing apoptosis. Overexpression and upregulation of Mia40 were proven to reverse MCD-induced apoptosis and were correlated with the chemoresistance of GBM in vitro and in vivo, respectively. Taken together, our study demonstrates that Mia40 is a potential target of the chemoresistance of glioblastoma and suggests that MCD might be a potential agent for the individualized treatment of chemoresistant GBM based on mitochondrial metabolic characteristics and Mia40 expression.

A Review on Phytochemicals of the Genus Maytenus and Their Bioactive Studies.

The genus Maytenus is a member of the Celastraceae family, of which several species have long been used in traditional medicine. Between 1976 and 2021, nearly 270 new compounds have been isolated and elucidated from the genus Maytenus. Among these, maytansine and its homologues are extremely rare in nature. Owing to its unique skeleton and remarkable bioactivities, maytansine has attracted many synthetic endeavors in order to construct its core structure. In this paper, the current status of the past 45 years of research on Maytenus, with respect to its chemical and biological activities are discussed. The chemical research includes its structural classification into triterpenoids, sesquiterpenes and alkaloids, along with several chemical synthesis methods of maytansine or maytansine fragments. The biological activity research includes activities, such as anti-tumor, anti-bacterial and anti-inflammatory activities, as well as HIV inhibition, which can provide a theoretical basis for the better development and utilization of the Maytenus.

Natural Nitrogenous Sesquiterpenoids and Their Bioactivity: A Review.

Nitrogenous sesquiterpenoids fromnatural sourcesare rare, so unsurprisingly neither the potentially valuable bioactivity nor thebroad structural diversity of nitrogenous sesquiterpenoids has been reviewed before. This report covers the progressduring the decade from 2010 to February 2020 on the isolation, identification, and bioactivity of 391 nitrogen-containing natural sesquiterpenes from terrestrial plant, marine organisms, and microorganisms. This complete and in-depth reviewshouldbe helpful for discovering and developing new drugs of medicinal valuerelated to natural nitrogenous sesquiterpenoids.

A new bis-γ-pyrone polypropionate from a marine pulmonate mollusc Onchidium struma.

A new bis-γ-pyrone polypropionate compound onchidione II (1), together with three known compounds, was isolated from a marine pulmonate mollusc Onchidium struma, collected at Hainan Island of China. The structure of new compound was determined by extensive spectroscopic analyses including IR, 1D and 2D NMR techniques, and chemical methods. Compounds 1-4 were evaluated for their cytotoxicity against human tumor cell lines HepG-2, A549, and MCF-2. The results showed that compounds 1 and 2 were moderate cytotoxic against HepG-2, A549, and MCF-2 cell lines, with IC50 values from 13.2 to 22.4 µM.

Five New Cucurbitane-Type Triterpenoid Glycosides from the Rhizomes of Hemsleya penxianensis with Cytotoxic Activities.

Five new cucurbitane-typetriterpenoid glycosides, named Xuedanoside F-J (1-5), were obtained from the rhizomes of Hemsleya penxianensis (Xue dan), which belongs to the family of Cucurbitaceae. These new compounds were elucidated byspectroscopic analysis, including 1D, 2D NMR, and HR-ESI-MS spectra. Additionally, all the isolates were evaluated for cytotoxicity against three human cancer cell lines (Hela, MCF-7, and A-549) with the IC50 ranging from 2.25 to 49.44 µM in vitro with treatment 48 h and showed low cytotoxicity in human normal liver L-02 cells (IC50 > 50 µM). Compound 5 showed the most significant cytotoxic activity with the IC50 value of 2.25, 4.72, and 5.33 µM in 48 h, respectively.

A Review on Daphnane-Type Diterpenoids and Their Bioactive Studies.

Natural daphnane diterpenoids, mainly distributed in plants of the Thymelaeaceae and Euphorbiaceae families, usually include a 5/7/6-tricyclic ring system with poly-hydroxyl groups located at C-3, C-4, C-5, C-9, C-13, C-14, or C-20, while some special types have a characteristic orthoester motif triaxially connectedat C-9, C-13, and C-14. The daphnane-type diterpenoids can be classified into five types: 6-epoxy daphnane diterpenoids, resiniferonoids, genkwanines, 1-alkyldaphnanes and rediocides, based on the oxygen-containing functions at rings B and C, as well as the substitution pattern of ring A. Up to now, nearly 200 daphnane-type diterpenoids have been isolated and elucidated from the Thymelaeaceae and Euphorbiaceae families. In-vitro and in-vivo experiments of these compounds have shown that they possess a wide range of biological activities, including anti-HIV, anti-cancer, anti-leukemic, neurotrophic, pesticidal and cytotoxic effects. A comprehensive account of the structural diversity is given in this review, along with the cytotoxic activities of daphnane-type diterpenoids, up to April 2019.

[Chemical constituents from green walnut husks and their antitumor activity in vitro].

Fourteen chemical constituents, including 5-hydroxy-4-methoxy-1-tetralone(1), 4,8-dihydroxy-1-tetralone(2), 4,5-dihydroxy-α-tetralone(3), blumenol B(4), dehydrovomifoliol(5), megastigm-5-ene-3,9-diol(6), juglanin B(7), blumenol C(8), loliolide(9), oleracone B(10), syringarsinol(11), pinoresinol(12), methyl 4-hydroxy-3-methoxybenzoate(13), and isovanillic acid(14), were isolated from the dichloromethane fraction of 95% methanol extract of green walnut husks by silica gel and MCI column chromatography, and Pre-HPLC. Their structures were determined by spectroscopic methods, such as NMR, MS and so on. Among them, compounds 1, 4-6, 8-13 were isolated from the green walnut husks for the first time, and compounds 4-6, 8, 10, 12, 13 were isolated from the Juglans genus for the first time. All of isolates were detected their inhibitory activities against HeLa, HGC-27 and Ht-29 cell lines by the MTT assay. The result showed that compounds 2, 3, 7, 9 and 11 exhibited inhibitory activity against the tested cell line. The IC_(50) of 7 were 26.5, 9.0, 25.4 µmol·L~(-1), respectively.

A new steroidal saponin from Polygonatum sibiricum.

A new furostan type steroidal saponin, kingianoside Z (1), along with four known compounds (2-5), was isolated from the ethanolic extract of Polygonatum sibiricum Delar. ex Redoute. Their structures were determined by spectroscopical method and by comparison with previously reported spectroscopic data. Compounds 3-5 showed significant cytotoxicity against HepG2 cell lines with IC50 values of 14.2, 12.1 and 8.5 µM, respectively.

Two new daphnane diterpenes from the roots of Stelleropsis tianschanica.

Two new daphnane diterpenes named tianchaterpenes A and B were isolated from the roots of Stelleropsis tianschanica. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses and HRESIMS. Compounds 1 and 2 were evaluated for their cytotoxic activities against HeLa and HCT-8 cell lines. The results showed that all compounds displayed weak cytotoxicities to the HeLa cells and were inactive to the HCT-8 cells.

New Naphthalene Derivatives from the Bulbs of Eleutherine americana with Their Protective Effect on the Injury of HUVECs.

Five new naphthalene derivatives, named Eleutherols A⁻C (1⁻3) and Eleuthinones B⁻C (4,5), together with three known compounds were isolated from the bulbs of Eleutherine americana. Their structures were elucidated on the basis of spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR techniques. These compounds exhibited a potent effect against the injury of human umbilical vein endothelial cell (HUVECs) induced by high concentrations of glucose in vitro.

[A new naphthalene derivative from bulbs of Eleutherine americana].

A new naphthalene derivative and three known compounds were isolated from the petroleum ether extract of the bulbs of Eleutherine americana by using various chromatographic techniques, such as column chromatography over silica gel and semi-preparative HPLC. Their structures were elucidated by spectroscopic date (MS, UV, IR, NMR), which were identified as eleutherol B (1), 4,8-dihydroxy-3-methoxy-1-methylanthraquinone-2-carboxylic acid methyl ester (2), 8-hydroxy-3,4-dimethoxy-1-methylanthraquinone-2-carboxylic acid methyl ester (3), and isoeleutherine (4). Compound 1 is a new compound. The diastolic blood vessels activity of compound 1 and 2 were potent, reaching 82.5% and 85.3% at the concentration of 10 µmol·L⁻¹, which were basically the same as that of the positive drug tanshinone ⅡA.

Cassane-type diterpenes from Caesalpinia minax induce apoptosis in pituitary adenoma: structure-activity relationship, ER stress and Wnt/ß-catenin pathways.

Plant-derived natural products have been the highly significant sources of novel antitumor agents. The cassane-type diterpenes of genus Caesalpinia have been reported to bear antiproliferative activities toward different types of cancer cells. In this study, we evaluated the antineoplasmic activities of 16 natural origin cassane-type diterpenes isolated from the CHCl3 extract of the seeds of C. minax in pituitary adenomas cells and identified caesalpin G (CAG) showed the strongest cytotoxicity. Moreover, we further investigated the structure-activity relationship and molecular mechanism of these derivatives systematically. The results confirmed the unsaturated lactone-type ring, hydroxyl at C-7, and alkenyl at C-11 or C-14 functionality as critical for anticancer activity in this family of natural products. In addition, the mechanism experiments also demonstrated unfolded protein response and ER stress and Wnt/ß-catenin pathway were involved in the CAG-induced apoptosis.

Soulieoside O, a new cyclolanostane triterpenoid glycoside from Souliea vaginata.

A new cyclolanostane triterpenoid glycoside, soulieoside O (1), together with 25-O-acetylcimigenol-3-O-ß-d-xylopyranoside (2) and cimigenol-3-O-ß-d-xylopyranoside (3), was isolated from the rhizomes of Souliea vaginata. Their structures were characterized by spectroscopic analysis and chemical methods. The new compound showed moderate inhibitory activity against three human cancer cell lines with IC50 values of 9.3-22.5 µM.

Oleanane triterpene saponins with cardioprotective activity from Clinopodium polycephalum.

Two new triterpene saponins, clinopodiside VI (1) and saikosaponin c (2), along with six known saikosaponins (3-8), were isolated from the plant of Clinopodium polycephalum. Compounds 1-3 showed moderate inhibition against H9c2 cell damage induced by H2O2.

New Cassane Diterpenoids from Caesalpinia sappan and their Antiplasmodial Activity.

One new cassane diterpene possessing an unusual N bridge between C-19 and C-20 named caesalsappanin R (1), as well as another new diterpene caesalsappanin S (2), were isolated from the seeds of Caesalpinia sappanwith methanol extract. Their structures were determined by spectroscopic analysis and examined alongside existing data from prior studies. Their biological activities were profiled by their antiplasmodial activity.

[A new triterpenic acid from the roots of Rosa laevigata].

This study was designed to investigate triterpenoids from the roots of Rosa laevigata Michx. The silica gel column chromatography was used to separate the chemical constituents from the roots of Rosa laevigata Michx. HPLC was used to analyze its purity and chemical constitution. Spectroscopy methods were used to determine their structures. Five constituents were isolated and identified as19α-OH-3ß-E-feruloyl corosolic acid (1), 23-hydroxy-tormentic acid (2), 2α, 3ß, 19α, 23- tetrahydroxy-12-en-28-oleanolic acid (3), 2α, 3α, 20ß- trihydroxyurs-13 (18)-en-28-oic-acid (4), 2α, 3ß, 20ß-trihydroxyurs-13 (18)-en-28-oic-acid (5). Compound 1 was assigned as a new compound, compounds 4, 5 were obtained from the genus Rosa for the first time.

[Chemical constituents from roots of Stelleropsis tianschanica].

The constituents from 95% ethanol extract of the roots of Stelleropsis tianschanica were purified by column chromatography techniques, leading to the isolation of 17 compounds. Their structures were elucidated by spectroscopic dataas 5'-methoxy lariciresinol(1), pinoresinol(2), daphnoretin(3), acutissimalignan B(4),(+)-secoisolariciresinol(5),(+)-epipinoresinol(6), 7-methyi-daphnoretin(7), thero-8S-7-methoxysyringylglycerol(8), 1-O-methyl-guaiacylglycerol(9), 2R-22'-ferulic acid ester-2,3-dihydroxypropyl ester(10), vesiculosin(11), 4ß,5ßH-guai-9,7(11)-dien-12,8-olide-1α,8α-diol(12),(-)-nortrachelogenin(13), 4α,5ßH-guai-9,7(11)-dien-12,8-olide-1α,8α-diol(14), matairesinol(15), lariciresinol(16)and isolariciresinol(17). Among them, compounds 1-13 wereobtained for the first time fromthe genus Stelleropsis. Compounds 3, 7, 10-14 were tested for their activation of orphan nuclear receptor TR3 with the immunofluorescence technology in 50 µmol•L⁻¹. The results showed that compound 10 displayed moderate activity with the activity ratio of 76.38%, and the others were only about 50.0%.