Sesquiterpenes and nor sesquiterpenes from Schefflera leucantha R.Vig. (Araliaceae)

One new nor sesquiterpenes, Schesesquiterpene (1), together with nine reported sesquiterpenes and nor sesquiterpenes (2–10) were obtained from Schefflera leucantha R.Vig. (Araliaceae). The structures were determined according to spectroscopic data analysis and chemical evidence. Noteworthily, Compound 7 was isolated as a new natural product, and other compounds (2–6 and 8–10) were obtained from the family Araliaceae for the first time.     

Chemical constituents from the fungus Stereum sp. YMF1.04183

The chemical constituents of the basidiomycete Stereum sp. YMF1.04183 were studied. Three new sesquiterpenes, stereumenes A–C (1–3), were isolated and identified from the EtOAc extract of Stereum sp. YMF1.04183 culture broth. Stereumene B showed weak nematicidal activity against Caenorhabditis elegans.     

Chemical constituents from Hovenia dulcis Thunb. And their chemotaxonomic significance

Phytochemical investigations on the fruit stalks and seeds of the plant Hovenia dulcis Thunb. led to the isolation of twenty-one compounds, including three triterpenes (1–3), two sterols (4–5), five flavonoids (6–10), two sesquiterpenes (11–12), one lignan (13), two phenylpropanoids (14–15), four benzoic acid derivatives (16–19), one acid amide (20) and one cerebroside (21). The structures of these compounds were elucidated on the basis of spectroscopic analysis and comparison with previous literatures. Among them, ten compounds (4, 11–12, 14–20) were isolated from familiy Rhamnaceae, two (13, 21) from the genus Hovenia, and three (5, 8, 10) from the species Hovenia dulcis Thunb. for the first time, respectively. The chemotaxonomic significance of these isolates was also discussed.     

Chemical constituents from Valeriana officinalis L. var. Iatifolia Miq. and their chemotaxonomic significance

Twenty-one compounds, including four monoterpenoids (1–4) (two new natural products, 1 and 2), four sesquiterpenes (5–8), two iridoids (9 and 10), four steroids (11–14), five phenolic compounds (15–19), and two alkaloids (20 and 21), were isolated from the roots of Valeriana officinalis L. var. Iatifolia Miq. Their chemical structures were established by spectroscopic methods and further confirmed by comparison with published data in the literature. Among them, eight compounds (1, 2, 6–8, 13, 18, and 21) are being reported from the family Valerianaceae for the first time, and compounds 9–12 were obtained from V. officinalis for the first time. The chemotaxonomic significance of the isolated compounds is discussed.     

Chemotaxonomic significance of sesquiterpenes and amide derivatives from Chloranthus angustifolius Oliv.

Phytochemical investigation of the aerial parts of Chloranthus angustifolius Oliv. (Chloranthaceae) resulted in the isolation and characterization of seven sesquiterpenes (1–7) and six amide derivatives (8–13). All structures were established based on analysis of their spectroscopic data. This is the first report of compounds 2 and 8–13 from the family Chloranthaceae, and the first report of compounds 3–5 from C. angustifolius. Moreover, the chemotaxonomic significance of these compounds was summarized.     

Terpenoids from Russula lepida and R. amarissima (Basidiomycota,Russulaceae)

Four aristolane sesquiterpenes were isolated from the fruiting bodies of Russula lepida and R. amarissima, namely (1R,2S)-1,2-dihydroxyaristolone (6), (2S,11S)-2,12-dihydroxy-aristolone (7), (1R,2S,11S)-1,2,12-trihydroxyaristolone (8), (1S,2S,11S)-1,2,12-trihydroxy-aristolone (9). In addition, a seco-cucurbitane triterpene, i.e. 3,4-secocucurbita-4,24E-diene-3-hydroxy-26-carboxylic acid (14) was isolated from both species. The configuration at C-2 of the already known rulepidol (2-hydroxyaristolone, 5) was corrected as S instead of R. Several more aristolane and nardosinane sesquiterpenes, as well as cucurbitane triterpenes, already reported both from European and Chinese samples of R. lepida, were also isolated. Compound 14 showed moderate cell growth inhibitory activity.     

Phytochemical investigation on the fruiting body of Russula aruea Pers

Phytochemical investigation of ethyl acetate fraction from Russula aruea Pers fruiting body led to the isolation and identification of one new isolactarane sesquiterpene (1) and 11 known compounds, including four sesquiterpenes (2-5), four sterols (6–9), one allitol (10), and two fatty acids (11–12). The structure of compound 1 was elucidated by means of spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, and X-Ray experiments. Compounds 1–3 and 5–12 are herein reported for the first time from Russula genus, while compound 4 is firstly described in R. aruea. The sesquiterpenes in R. aruea could serve as chemotaxonomic markers.     

Rare hydroperoxyl guaianolide sesquiterpenes from Pulicaria undulata

Pulicaria species, such as Pulicaria undulata, are rich in sesquiterpene lactones. The methylene chloride/methanol (1:1) extract of P. undulata resulted in the isolation of new sesquiterpenes (1–4), as well as previously reported metabolites (5–14). Structures were elucidated by spectroscopic analyses. Using a mouse peritoneal macrophage bioassay, lipopolysaccharide-induced nitric oxide inhibition was observed with the eudesman-type sesquiterpene 1β,4β-dihydroxy-5αH,7αH,8α-guaia-10(14),11(13)-dien-8β,12-olide (11) at an EC₅₀ of 7.2 μM.     

Phytochemical and chemotaxonomic studies on Pteris wallichiana J. Agardh

A systematic phytochemical investigation of Pteris wallichiana J. Agardh resulted in the isolation of twenty compounds, including five sesquiterpenes (1–5), six flavonoids (6–11), seven phenolic acids (12–18) and two fatty acids (19 and 20). Their structures were deduced from MS, NMR and ORD data. This is the first report of compounds dehydropterosin B (2), (2R,3S)-pterosin C (4), (2R,3R)-pterosin L (5), apigenin (6), luteolin (7), luteolin-7-O-glucoside (10), caffeic acid (13), vanillin (14), 3,4-dihydroxybenzaldehyde (15), chlorogenic acid (17), 3,5-dicaffeoylquinic acid (18), suberic acid (19) and azelaic acid (20) from P. wallichiana and of compounds 15, 19 and 20 from the family Pteridaceae. Furthermore, a chemotaxonomic study of the isolates was performed.     

Sesquiterpenes from Curcuma zedoaria rhizomes and their cytotoxicity against human gastric cancer AGS cells

Curcuma zedoaria rhizome (Zingiberaceae) is a well-known traditional medicinal plant used in Ayurvedic and traditional Chinese medicine to treat various cancers. This study aimed to identify the cytotoxic components from C. zedoaria rhizomes that act against gastric cancer, which is the third leading cause of death from cancer worldwide because the MeOH extract of C. zedoaria rhizome was found to show a cytotoxic effect against gastric cancer AGS cells. Repeated column chromatography and semi-preparative HPLC purification were used to separate the components from the C. zedoaria MeOH extract. Two new sesquiterpenes, curcumenol-9,10-epoxide (1) and curcuzedoalide B (2), and 12 known related sesquiterpenes (3–14) were isolated from the C. zedoaria MeOH extract. The structures of new compounds were determined by 1D and 2D NMR spectroscopic experiments and HR-ESIMS, and quantum chemical ECD calculations. The cytotoxic effects of the isolated compounds were measured in human gastric cancer AGS cells using an MTT cell viability assay. Compounds 9, 10, and 12 exhibited cytotoxic effects against gastric cancer AGS cells, with IC₅₀ values in the range of 212–392 μM. These findings provide further experimental scientific evidence to support the traditional use of C. zedoaria rhizomes for the treatment of cancer. Curcumenol (9), 4,8-dioxo-6β-methoxy-7α,11-epoxycarabrane (10), and zedoarofuran (12) were identified as the main cytotoxic components in C. zedoaria rhizomes.     

Eudesmanolide sesquiterpenes and protein tyrosine phosphatase 1B inhibitory ent-kaurene diterpenes from aerial parts of Indonesian Wedelia prostata

Seven eudesmanolide sesquiterpenes (1–7) and two ent-kaurene diterpenes (8 and 9) including two new (9R)-eudesman-9,12-olides, named wedelolides I and J (1 and 2), were isolated from the aerial parts of Indonesian Wedelia prostata. The structures of 1 and 2 were assigned based on their spectroscopic data. Diterpenes 8 and 9 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with IC₅₀ values of 8.3 and 28 μM, respectively. Among sesquiterpenes 1–7, compound 4, wedelolide D, exhibited 32% inhibitory activity against PTP1B at 20 μM.     

Eremophilane sesquiterpenes from the endophyte Microdiplodia sp. KS 75-1 and revision of the stereochemistries of phomadecalins C and D

Two new eremophilane sesquiterpenes, compounds 1 and 2, were isolated from the endophytic fungus Microdiplodia sp. KS 75-1, together with the known compounds phomadecalins C (3) and D (4). Their structures were determined by extensive 1D– and 2D–NMR and MS spectral analyses. The previously reported stereochemistry at C-8 of 3 and 4 were revised on the basis of NOEs experiments. Compounds 1 and 2 showed antimicrobial activity against Pseudomonas aeruginosa.     

Chemical constituents of the Piper crocatum leaves and their chemotaxonomic significance

Chemical study of Piper crocatum leaves has led to isolation of a new megastigmane glucoside isomer (18), along with 23 known compounds including fifteen phenolic compounds (1–15), two monoterpenes (16 and 17), three sesquiterpenes (19–21), a phenolic amide glycoside (22), a neolignan (23), and a flavonoid C-glycoside (24). Structures of these compounds were identified via spectroscopic methods and compared with those reported in the literature. Seven compounds (7, 11, 13, 14, 17, 20, and 24) from the P. crocatum species and 17 others (1–6, 8–10, 12, 15–16, 18–19, and 21–23) from the Piper genus and Piperaceae family were isolated and reported for the first time. Furthermore, this study discusses chemotaxonomic relations between P. crocatum and other Piper species.     

New eudesmane sesquiterpenes from the marine-derived fungus Penicillium thomii

Four new eudesmane-type sesquiterpenes thomimarines A–D (1–4) were isolated from the marine-derived fungus Penicillium thomii. Their structures were established based on spectroscopic methods. The absolute configurations of 1–4 were determined by time-dependent density functional theory (TD-DFT) calculations of ECD spectra. Inhibitory effects of compounds 1, 2 and 4 on NO production in LPS-induced RAW 264.7 murine macrophages were evaluated.     

Eudesmane-type sesquiterpenes and aporphine-type alkaloids from Fissistigma maclurei

The phytochemical investigation of the stems of Fissistigma maclurei Merr. led to the isolation of a new eudesmane-type sesquiterpene 6α,12-dihydroxy-4(15)-eudesmen- 1-one (1), together with seven known eudesmane-type sesquiterpenes (2–8) and four known aporphine-type alkaloids (9–12). The structures of these compounds were elucidated using comprehensive spectroscopic methods. All compounds were isolated from the F. maclurei for the first time. The chemotaxonomic significance of the isolates was also discussed.     

Four new sesquiterpenoids as natural nitric oxide (NO) inhibitors from the rhizomes of Curcuma phaeocaulis

A new norsesquiterpene named phaeocaulisin N (1), and three new guaiane-type sesquiterpenes named phaeocaulisins O–Q (2–4), together with a known norsesquiterpene (5) were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were established based on extensive spectroscopic analysis. Compounds 1 and 5, as far as we know, are the first example of 13-norguaiane-type sesquiterpenes isolated from the genus Curcuma. All of the isolated compounds were tested for inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages. Compound 1 showed strong inhibitory activity on nitric oxide production with IC₅₀ value of 3.58 ± 0.17 μM.     

Understanding dihydro-β-agarofuran sesquiterpenes from Tripterygium hypoglaucum as the modulators of multi-drug resistance in HepG2/Adr cells

Multi-drug resistance (MDR) is one of the dominant reasons for the failure of cancer chemotherapy. P-glycoprotein (P-gp) over-expression in the plasma membrane of drug-resistant tumor cells promotes the efflux of chemotherapeutic agents and plays a significant role in MDR. Several investigations have suggested that dihydro-β-agarofuran sesquiterpenes are the potential modulators of MDR. However, their cellular mechanism in regulating P-gp has not been fully explored. Seven dihydro-β-agarofuran sesquiterpenes (1–7) from Tripterygium hypoglaucum was evaluated for the chemoreversal activity of HepG2/Adr cells. 1, 2, 4, 5, and 7 were active with reversal fold ranging from 47.68 to 456.90. The image-based high-screening indicated that all of the active compounds were capable of decreasing the efflux of doxorubicin (Dox). The most potent 4 did not affect the expression or subcellular distribution of P-gp. P-gp ATPase activity was stimulated by 4 in a dose-depend manner, suggesting that 4 may be the substrate of P-gp. The docking data implied that 4 took PHE 979, PHE 332, and GLN 986 to bind with P-gp. Taken together, the results demonstrated that dihydro-β-agarofuran sesquiterpenes from T. Hypoglaucum were the substrate of P-gp and potential modulators of MDR.     

Sesquiterpenes from the roots of Illicium dunnianum

Six allo-cedrane sesquiterpenes, four seco-prezizaane-type sesquiterpenes, two monocyclofarnesane sesquiterpenes, together with four known sesquiterpenes, were isolated from the roots of Illicium dunnianum. The structures were elucidated by spectroscopic methods including 1D and 2D NMR. The absolute configuration of 10 was determined by a CD experiment. Compounds 11 and 13 showed potent activities against the release of β-glucuronidase in rat polymorphonuclear leukocytes induced by platelet-activating factor in vitro, with IC₅₀ values of 2.10 ± 0.40 and 1.93 ± 0.57 μM, respectively. All compounds were evaluated for cytotoxicities against five human cancer cell lines (A549, Bel-7402, BGC-823, HCT-8, and A2780) in the MTT assay, but none of them exhibited activity at concentrations tested (10⁻⁵–10⁻⁷ M).     

Antifungal trichothecene sesquiterpenes obtained from the culture broth of marine-derived Trichoderma cf. brevicompactum and their structure-activity relationship

Two new trichothecene sesquiterpenes, trichobreols D (1) and E (2), were isolated from the culture broth of marine-derived Trichoderma cf. brevicompactum together with trichobreol A (3). The structures of 1 and 2 were assigned on the basis of their spectroscopic data. Compound 1 inhibited the growth of two yeast-like fungi, Candida albicans and Cryptococcus neoformans, with equivalent MIC values (6.3 μg/mL), while 2 gave MIC values of 12.5 and 25 μg/mL, respectively. The antifungal activities of five semisynthetic derivatives (4–8) prepared from 3 were evaluated and compared to investigate the preliminary structure-activity relationship.     

Five new germacrane sesquiterpenes with anti-inflammatory activity from Salvia petrophila

Five new germacrane sesquiterpene lactones, petrophins A–E (1–5), were isolated from the whole herbs of Salvia petrophila. The structures were established using spectroscopic analysis (1D and 2D NMR, HR-ESI-MS) and compatible with values in the literature. These sesquiterpenes are unusual with an endocyclic double bond in the γ-lactone ring. All the isolated compounds were evaluated for their inhibitory effects on the LPS-induced nitric oxide production using murine macro-phage RAW264.7 cells.