Natural Product Research最新文献

The chemical investigation of the methanol extract of the roots of Caloncoba lophocarpa (Oliv.) Gilg. exhibited a new 30-norfriedelane triterpenoid, laphocarpanol (1), together with seven known compounds, caloncobalactone (2), friedelin (3), friedelanol (4), asperphernamate (5), stigmasterol (6), sitosterol (7) and sitosterol-3-O-β-D-glucopyranoside (8). The structures of the compounds 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 antifungal and antibacterial activities. Compound 1 displayed weak antibacterial effect with MIC value of 62.5 μg/mL against Shigella flexineri. All the isolates were found to be inactive against the tested fungal strains.

The study aims to evaluate the Quorum Sensing (QS) system inhibition against some Gram-positive and Gram-negative bacteria detected by molecular modeling of R. cathartica L. plant extract. R. cathartica L. methanol extract was evaluated in vitro. R. cathartica L. extract was observed to have antimicrobial activity against Gram-positive and Gram-negative bacteria at different rates (11.3 mm-16 mm). The inhibitory effect of R. cathartica L. extract on P. aeruginosa PAO1 (elastase 61%, pyocyanin 18%, and biofilm 61%) was recorded moderately. Phytochemical analysis revealed that the main component of the extract is kaempferol. Therefore, the binding potential of kaempferol on QS system receptors was investigated via molecular docking. Computational analysis showed that kaempferol can inhibit the QS system by preventing competitive ligands from connecting to LasR. It may provide a new way to use R. cathartica L. seed extract as a green antibacterial agent.

Grevillosides R-S (1-2), two new glucosides of 5-alkylresorcinol derivatives, were isolated from the roots of Ardisia crispa (Thunb.) A. DC. The structures of grevillosides R-S (1-2) were determined by 1D and 2D NMR, HR-MS, UV, IR experiments and by comparison of their spectroscopic and physical data with literature values. In this paper, grevillosides R-S (1-2) were tested for their radical-scavenging activity (DPPH and ABTS) and α-glucosidase inhibitory activity in vitro. Grevillosides R-S (1-2) exhibited weak DPPH radical-scavenging activity with IC₅₀ values of 72.3 and 485.2 μM, respectively. Grevillosides R-S (1-2) exhibited no inhibitory activity against α-glucosidase.

Two rarely occurring diphenylheptanoid-phenylheptanoid hybrid dimers (1 and 2) and one new oxygenated fatty acid (3), as well as two known fatty acid analogues (4 and 5), were isolated from the 70% EtOH extract of the pollen of Typha angustifolia. Their planar structures were established by interpretation of MS and NMR spectroscopic data, and the absolute configurations of 1 and 2 were determined by Mosher's method and quantum chemical TD-DFT calculations of ECD spectra. An in vitro anti-diabetic evaluation of these isolates revealed that compounds 1 and 2 exhibited promising inhibitory activity against α-glucosidase with IC₅₀ values of 11.85 ± 0.69 and 17.06 ± 3.08 μM, respectively. It is the first report on both diphenylheptanoid constituents and α-glucosidase inhibitors from the title plant, which represents a significant phytochemical progress of this herbal species and may serve as a reference for its future medicinal applications.

The manuscript describes the synthesis of eight Novel 1,2,4-triazine and 1,2-diazino derivatives having the 5-nitro isatin moiety. Antiradical and anticancer activities were evaluated using the DPPH method and the MTT assay against breast cancer (MCF-7) cell lines. The compound with the strongest antioxidant and anticancer properties after 24 h was compound 9 (1,2,4-triazine-3-thione) but after 48 h, compound 7 (1,2,4- triazine-3-ol) with good anticancer activity while compound 11 (1,2-diazino) after 72 h.

Two new 2-arylbenzo[b]furans (1-2) and ten known compounds (3-12) were identified from the 95% EtOH extract of the branches and leaves of Itea indochinensis for the first time. Their structures were determined mainly based on extensive analyses of UV, IR, 1D/2D NMR and HRMS spectra. The results of MTT assays demonstrated the anti-tumor potential of compound 1 with good selectivity, which displayed moderate inhibitory effects on proliferation of SK-hep-1 cells with IC₅₀ value of 22.3 μM, while weak inhibitory effect on proliferation of HepG2 cells with an inhibition rate of 25% at 20 μM, and no obviously inhibitory effect on proliferation of A549 cells at 20 μM. In addition, compound 1 exhibited its significant scavenging capacity on ABTS^·+ free radical with an IC₅₀ value of 0.11 mg/mL, while weak scavenging effects on DPPH and O₂^·- radicals with scavenging ratios of 32.93% and 21.49% at 1 mg/mL, respectively.

Alpinia nelumboides Nob.Tanaka, T.T.K.Van & V.Hoang is the new Alpninia species discovered in Vietnam in 2023. Herein, we first hydrodistillated its pseudo-stems and rhizomes to obtain its essential oils, PS-EO and RH-EO. Their volatile compounds and total polyphenols were analysed by gas chromatography-mass spectrometry and the Folin-Ciocalteu method, respectively. Antioxidant activities were determined using four different approaches. The results showed that PS-EO and RH-EO contained 40 and 31 compounds, accounting for 99.78% and 99.45% of their compositions, respectively. The contents of polyphenols and monoterpenes in PS-EO were higher than in RH-EO. RH-EO displayed weaker scavenging activities (17.40-19.53%) than PS-EO (30.81-44.08%). PS-EO also showed higher ferric and cupric reducing powers, with EC₅₀ values of 3.50-5.30 mg/mL smaller than RH-EO's EC₅₀ values of 19.0-23.0 mg/mL. These results first revealed the phytochemical profile and antioxidant activities of EOs from A. nelumboides.

There is growing evidence that bioactive substances produced by microbial endophytes have applicability in medicine, agriculture and industry. To enrich the bioactive substances, in our search for new bioactive metabolites from fungi Aspergillus, the phytochemical reinvestigation on the Aspergillus sp. 0338 was carried out, and this led to the isolation of three new (1-3) and five known alkaloids (4-8). Their structures were elucidated by spectroscopic analysis, including extensive 1D and 2D NMR techniques, as well as comparison with literature values. Additionally, compounds 1-3 were evaluated for their anti-MRSA activities. The results revealed that compounds 1-3 exhibited good inhibitions with IZD of 15.2 ± 1.8, 14.6 ± 2.0, and 13.4 ± 2.2 mm, respectively.

A rapid, precise, accurate, and cost-effective liquid chromatography-mass spectrometer method was developed by using a novel extraction technique for the simultaneous quantification of major oleane derivatives: arjunetin, arjungenin, arjunolic acid, and arjunic acid of Terminalia arjuna in infused edible oil. An innovative idea was implemented to extract the active phytoconstituents from the oil matrix based on the freezing point of oils and extraction solvent. The developed method was validated for all four active compounds in the linear working range of 0.47-1.72 µg/mL, 0.845-2.93 µg/mL, 1.73-5.95 µg/mL and 0.62-2.22  µg/mL with good correlations value (r²) more than 0.99 for arjunetin, arjungenin, arjunolic acid, and arjunetin, respectively. Furthermore, the HPTLC method was also developed for the quick identification of all four active markers along with other phytoconstituents infused in oil.

(+)-Usnic acid (UA), a natural dibenzofuran derivative, abundantly produced by lichens and possess wide number of biomedical applications including antibacterial, anti-inflammatory, anti-oxidant and anticancer activities. In the present study, as series of usnic acid derivatives (3a-3i) were synthesised using Mannich reaction assessed for their antioxidant, α-glucosidase, and anticancer activities. The in vitro antioxidant activity showed that compound 3d displayed potent antioxidant activity by scavenging the activities of DPPH and ABTS⁺. The compounds 3d and 3e showed potent cytotoxic activity against HepG2 cancer cells by arresting the cell cycle at S phase and regulating the Bax/BcL2 expression and subsequently induce the apoptosis. Overall, the results clearly indicated that (+)-usnic acid derivatives bearing secondary amines are useful scaffolds for the development of drug candidates for treatment of oxidative stress mediated cancer and metabolic disorders.