Natural Product Research最新文献

Three new minor steroidal glycosides were isolated from the whole plants of Hoya parasitica (Wall. ex Hornem.) Wight. Their structures were further elucidated as 3β,4α-dihydroxy-5β-spirost-(25)27-en-1β-yl O-α-L-arabinopyranoside (1), 3β-hydroxy-5β-spirost-25(27)-en-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (2), and (23S,24S,25S)-3β,4α,23,24-tetrahydroxy-5β-spirostan-1β-yl O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside (3) through interpretation of the spectroscopic data (one-dimensional and two-dimensional) and mass spectrometry (HR-ESI-MS). To the best of our knowledge, this is the first report of the isolation of spirostane-type steroidal saponins from the Hoya genus.

A new indole compound, N-hydroxy-N-(2-(1-hydroxy-2-methoxy-1H-indol-3-yl)ethyl acetamide (1), together with four known compounds, N-(2-(1H-indol-3-yl)ethylacetamide (2), N-acetylamicoumacin C (3), N-(2-phenylethyl)acetamide (4), and (2 R,3S)-1-(4-hydroxyphenyl)butane-2,3-diol (5) were isolated from Cladosporium sp. SCSIO41205. Their structures were established by detailed analysis of the NMR and HR-ESI-MS data.

Porophyllum ruderale (Jacq.) Cass. (Asteraceae) has antiprotozoal properties and contains extractable phenolic compounds by the maceration method (M). However, new extraction proposals such as ultrasound (U), microwaves (MW), and ultrasound/microwaves (U/MW) have emerged to optimise yields, but it is unknown if these methods modify effectiveness. Therefore, the study consisted of extracting the aerial part of P. ruderale with ethanol using the M, U, MW and U/MW methods to study its composition by RP-HPLC-ESI-MS, its total polyphenol content and its effect against Entamoeba histolytica. The study showed that U, MW and U/MW did not modify the extraction yield compared to M, but they did change the composition and the total polyphenol content. All extracts contain phloretin, caffeic acid 4-O-glucoside, todolactol A, quercetin 3-O-glucoside, quercetin 3-O-rhamnoside, luteolin and 3,7-dimethylquercetin, and affected the growth of E. histolytica. However, M and U extracts were the most effective at 5 mg/mL.

The chemical investigation of the methanolic root extract of Caloncoba glauca (P. Beauv.) Gilg exhibited two new 30-norfriedelane triterpenes, glaucalactones A and B (1-2), together with eight known compounds, caloncobalactone (3), friedelin (4), friedelanol (5), 3-oxo-friedelan-28-oic acid (6), stigmasterol (7), β-sitosterol (8), β-sitosterol-3-O-β-D-glucopyranoside (9) and pentacosanoic acid (10). The structures of the isolates were elucidated by extensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-MS) and by comparison with previously reported data. All the compounds were tested for their antioxidant, antifungal and antibacterial activities. Compound 1 displayed weak antibacterial effect with MIC value of 125 μg/mL against Staphylococcus aureus and Escherishia coli. Compound 6 exhibited moderated antifungal activity against Candida krusei with MIC value of 62.5 μg/mL. All the isolates were found to be inactive as antioxidants in the DPPH, ABTS and FRAP assays.

The genus Stachys L. (Lamiaceae) comprises more than 300 species as annual or perennial herbs or small shrubs, spread in temperate regions of Mediterranean, Asia, America, and Southern Africa. Several species have been used in the traditional medicine to treat stress, skin inflammations, gastrointestinal disorders, asthma, and genital tumours. In the present study the chemical composition of the essential oil from aerial parts of Stachys ocymastrum L. Briq., belonging to section Olisia, endemic of the Western Mediterranean and Greece and collected in Sicily, was analysed by GC-MS. No one report has been previously published on any European accession of this species. The result showed the presence of large quantity of the diterpenoid phytol (23.80%). Other metabolites present in high quantity were β-caryophyllene (17.95%), geranyl-α-terpinene (13.26%) and trans-chrysanthenyl acetate (9.85%). Chemical considerations with respect all the other oils of Stachys taxa, belonging to section Olisia studied so far, were carried out.

Six compounds were isolated from the ethyl acetate extract of endophytic fungus Colletotrichum queenslandicum derived from Morus australis Poir. leaf. Based on NMR and MS data led to characterised of these compounds including one new indole alkaloid Morucolletotricin (1) along with two other indole alkaloids; tryptopol (2) and indole-3-acetic acid (3), phomopyronol (4), 2-(3-aminophenyl)acetic acid (5) and ergosterol (6). phomopyronol (4) and 2-(3-aminophenyl)acetic acid (5) were first reported from Colletotrichum fungi. The cytotoxic activity of compounds 1-6 was evaluated against murine leukaemia P-388 cells and showed that all compounds were moderate cytotoxic. phomopyronol (4) was the most active among the five other compounds with IC₅₀ = 37.17 μg/mL.

One new labdane diterpenoid, tricuspion A (1), as well as five known triterpenoids (2-6) were isolated from Salvia tricuspis Franch (family Labiatae). The structure of tricuspion A was identified by extensive spectroscopic analysis and by comparison with previously reported data. Compounds 1-6 were evaluated for their inhibitory effects on the NO production in LPS-stimulated BV-2 microglia cells, and 1 exhibited potent inhibitory activity with IC₅₀ value of 14.92 ± 0.51 μM. Compound 1 might exert anti-neuroinflammatory activity through inhibiting the excessive production of NO and down-regulating the protein expression of iNOS and COX-2. As such, labdane diterpenoid (tricuspion A) could provide promising anti-neuroinflammatory lead compound for further structural modification.

Six compounds were isolated from the ethyl acetate extract of the stems of Miliusa velutina, including miliutine A acid (1), a new cyclofarnesane sesquiterpenoid; miliutine B methyl ester (2), a cyclofarnesane sesquiterpenoid which was determined the absolute configuration for the first time and four known phenol derivatives (3-6). NMR spectroscopic and mass spectrometry were used for identifying relative configurations. The assignments of the absolute configurations were determined based on Electronic Circular Dichroism (ECD) and NOESY spectra analysis. All six compounds were screened for their in vitro cytotoxic activities against HepG2 cell line using the SRB assay and they showed weak or none activities.

Five new sesquiterpenoids (1-5), elephantmollides A-E, along with four known compounds (6-9), were isolated from the whole plants of E. mollis. Their planar structures were elucidated using the spectroscopic methods, including HRESIMS, IR, UV, and NMR (¹H, ¹³C, DEPT, HSQC, HMBC, ¹H-¹H COSY). The relative configurations of them were partially deduced by the NOESY experiment, and the absolute configurations were assigned by comparing the calculated electronic circular dichroism (ECD) results with the experimental data. In addition, cytotoxic activities of 1-9 against HepG2 cells ware tested, and compounds 1-9 exhibited cytotoxic activities with IC₅₀ values ranging from 6.7 to 25.8 μM.

The phytochemical investigations of the tuber roots of Asparagus flagellaris led to the isolation of a new alkaloid, schweinfurthiamide (1) and eight known compounds. The structures of the isolated compounds were elucidated using spectroscopic techniques 1D and 2D NMR (¹H, ¹³C, COSY, HMBC, HMQC, HSQC-TOCSY). The absolute configuration of 1 was unambiguously determined using DP4+ calculations. Compound 1 showed significant cytotoxicity against MCF-7 (breast cancer), NCI-H460 (lung cancer), and Hela (cervical cancer) cancer cell lines with IC₅₀ values of 1.18 ± 0.02 µM, 2.25 ± 0.19 µM, and 4.23 ± 0.26 µM, respectively and no toxicity against normal human fibroblast (BJ).