Records of Natural Products Articles

Three new chromone glycosides, named 2-methyl-5-hydroxyl-4-chromone-7-O-β-D-glucuronide (1), 2-ethyl-5-hydroxyl-4-chromone-7-O-β-D-glucuronide (2) and 1-acetyl-3-C-β-D-glucopyranosyl-5-methyl-phloroglucinyl-6-O-β-D-glucopyranoside (6), together with eight known compounds were isolated from the water extract of Dryopteris crassirhizoma Nakai，and the water extract preparation process is consistent with Lianhua Qingwen capsule. All the chemical structures of new compounds were characterized by 1D and 2D NMR spectra as well as high resolution mass and IR spectra. The chemical structures of known compounds were characterized by NMR spectra along with comparison of their spectroscopic data with those reported in the literature. The binding ability of these compounds to 3CL hydrolase of SARS-COV-2 was evaluated by molecular docking. The results showed that the chromone glycosides with glucuronic acid fragment had good docking effect with 3CL hydrolase and this indicated the chromone glucuronides could be further studied as potential antiviral compounds.

A new (1) and five known (2-6) bromophenols were isolated from the organic extract of the marine red alga Symphyocladia latiuscula.  Their structures were assigned by interpretation of NMR and MS data, and these compounds were determined as 2,3,5′-tribromo-3′,4,4′,5-tetrahydroxy-diphenylmethane (1), 2-methoxy-3-bromo-5-hydroxymethylphenol (2), 5-(2,3-dihydroxybenzyl)-3,4-dibromobenzene-1,2-diol (3), 5-(2-bromo-3,4-dihydroxy-6-(methoxymethyl)benzyl)-3,4-dibromobenzene-1,2-diol(4), methyl 2-(3,5-dibromo-4-hydroxybenyl) acetate (5), and 3,4-dibromo-5-(methoxymethyl)benzene-1,2-diol (6). All these compounds were evaluated for DPPH radical scavenging activity, and they displayed potent antioxidant activity with IC50 values ranging from 9.6 to 31.5 μM. These compounds also showed moderate ABTS radical scavenging activity with TEAC value ranging from 2.1 to 3.0 mM. The results suggested that these bromophenols or the marine red alga S. latiuscula may have potential application in food as natural antioxidants.

Oxidative stress is one of the leading causes that contribute to the pathogenesis of chronic diseases based on the imbalance between free radicals and the antioxidant defense system. Here, Syzygium jambos (L.) Aston, a traditional herb used to treat various diseases, was evaluated using RAW264.7 macrophages with lipopolysaccharide (LPS)-stimulation to demonstrate its effects and find a new therapy for oxidative stress. This study proved that Syzygium jambos leaf extract exerted its ability to protect cells against oxidative stress via activating the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway to suppress reactive oxygen species (ROS) production. Moreover, the extract also attenuated the nitric oxide (NO) production and the nitric oxide synthase (iNOS) expression, suggesting an anti-inflammatory response. In addition, four active compounds, including gallic acid, quercetin, myricetin, and caffeic acid, were isolated from ethyl acetate fraction using column chromatography. The structure of compounds was analyzed based on one-dimensional nuclear magnetic resonance (1D-NMR) and compared to literature data. Their biological activity was confirmed by promoting the induction of HO-1. Hence, this study provides the initial evidence of Syzygium jambos leaves protective effects and highlights its potential as an antioxidant agent.

A new isobenzofuranone derivative, (R)-3-acetyl-[5,7]-dimethoxy-3H-isobenzofuran-l-one (1), together with six known compounds, (R)-3-acetyl-7-hydroxy-5-methoxy-3H-isobenzofuran-l-one (2), banksialactone D (3), (3R,4S)-3,8-dihydroxy-3-hydroxymethyl-6-methoxy-4,5-dimethyl-isochroman-1-one (4), 1-O-[α-L-rhamnopyranosyl]-2,5-dimethyl-3-phenol (5), p-hydroxybenzaldehyde (6), 2-(4-hydroxyphenyl) ethanol (7), were isolated from Arctic fungus Gyoerffyella sp. CPCC 401434. Their structures and absolute configurations were elucidated by the analysis of spectroscopic data, electronic circular dichroism, and comparison with reported literature data. Herein, all compounds were reported for the first time from the genus Gyoerffyella and their cytotoxic and antibacterial activities.

The secondary metabolites of the strain Penicillium sp. LPFH-Q3 isolated from the sea sediment were investigated. A new eremophilane sesquiterpene, named penicisepene (1), along with seven known compounds (2-8) was obtained. The structures of the metabolites were elucidated based on spectroscopic analysis including 1H NMR, 13C NMR, 1H-1H COSY, HSQC, HMBC, NOESY, and the MS data. The absolute configuration of 1 was established via comparison of the experimental and density functional theory predicted ECD data. Compound 1, an eremophilane sesquiterpene containing a hexenic acid, was scarcely found in nature. Besides, the NMR data of 3 and 4 in methanol-d4 were reported for the first time. Biological evaluation showed that compounds 1, 3, and 4 showed inhibitory activity comparable to the positive control quercetin (16.7 uM) on NO production in LPS-activated RAW 264.7 macrophages with IC50 values of 13.2, 10.6, 17.9 uM, respectively.

A new megastigmane glycoside, namely (9S)-O-β-D-glucopyranosyl-2,5-megastigmen-4-one (1), along with seven known bibenzyls (2-8) were isolated from the aerial stems of Dendrobium henanense. Their structures were elucidated by spectroscopic and mass-spectrometric analyses, including 1D-, 2D-NMR and HR-MS. The anti-inflammatory activities of compounds 1-8 evaluated its anti-inflammatory activity by inhibiting the production of inflammatory cytokines such as NO, TNF-α and IL-6 in LPS-stimulated RAW264.7 macrophages. Compounds 3, 4, 6-8 exhibited moderated anti-inflammatory activity with IC50 values of below 100 µΜ.

Abstract: The fungal strain Aspergillus sp. LPFH-6 was cultured on solid rice medium with the addition of artificial salt. The culture medium was extracted with the solvent EtOAc to afford an extract, which was separated by various chromatographic techniques to give 8 compounds (1-8). The structures were determined by extensive analyses of the spectroscopic data including 1D (1H and 13C NMR), 2D NMR (1H-1H COSY, HSQC, HMBC, NOESY), and the MS data. Compound 1 was identified to be a highly conjugated compound that contained a rare 5-(2-methoxyphenyl)penta-2,4-dienal moiety. The known compounds were identified as yaminterritrem B (2), butyrolactone I (3), butyrolactone V (4), sulochrin (5), monomethylsulochrin (6), questinol (7), and 7-hydroxyemodin (8). Bioasasy showed that compounds 2-4 and 8 displayed better a-glucosidase inhibitory activity than the positive control acarbose with IC50 values of 0.25, 0.09, 0.12, and 0.27 mM, respectively.

Astragalus L., is the most populated plant genus on the planet. It has found use in folk medicine to treat many different forms of ailment. However, the toxicity studies of the genus and the chemicals isolated from it, are scarce and the toxicological profile is largely unknown. Caenorhabditis elegans has been used in multiple scientific disciplines. Its ease of use, genetic similarity to humans in many pathways, connectome and nervous system and resistance to environmental stress make it among the best organisms for toxicity testing. The present study used C. elegans chemotaxis responses, and micronucleus generation, to evaluate the potential neurotoxicity of some selected cycloartane-type glycosides; astragalosides IV (1) and VI (2), astrasieversianin II (3), baibutoside (4), and macrophyllosaponins B (5) and D (6), in the short- and long-term domain, along with long-term genotoxicity testing. The results indicate long-term chemotaxis inhibition by compounds 1, 2, 3 and 5, whereas only compound 3 inhibited chemotaxis in the short-term. Compound 1 was found to significantly increase micronucleus generation at the highest tested dose. The study demonstrates the usefulness of the Nematode Chemotaxis and in vivo Micronucleus Assays for the determination of the toxicity of natural products, while illuminating the points of consideration that future studies may be designed to address.

Thymbra spicata subsp. spicata L. is a member of the Lamiaceae family, which is used in Türkiye against various health issues among other uses. The main components of T. spicata essential oil (TE) were identified as carvacrol (52.3%) and p-cymene (21.1%) using GC-FID and GC/MS. The in vitro effects of TE on Miapaca-2 and HUVEC cell lines were reported for the first time. The initial results showed that TE applied to Miapaca-2 cell lines at concentrations of ≥62.18 g/mL for 48 hours could reduce cell growth and induce apoptosis. The application of relatively high concentrations of TE (≥82.91 g/mL) significantly (P<0.001) suppressed cell growth. Administration of relatively high TE concentrations (≥82.91 g/mL) significantly (P<0.001) suppressed cell growth. Concentrations of TE lower than 20.73 g/mL did not affect the viability of the HUVEC cell line in 48 hours. The IC50 value for Miapaca-2 cells was 62.18 µg/mL, and HUVEC cells’ IC50 value was 263.97 µg/mL for 48h. The number of apoptotic cells in Miapaca-2 (55±5%) and HUVEC (38.33±6%) were significantly higher (P<0.001). Significantly lower migration rates (P<0.001) were seen for Miapaca-2 (52±5%) and HUVEC cell lines (64±1.67%).  

A new γ-lactone compound, trichonafurin A (1), was obtained from the culture of Trichoderma atroviride ZW-7, an endophyte of the marine brown alga Sargassum thunbergii. Its structure was unambiguously assigned by detailed interpretation of 1D/2D NMR and HRESIMS data. Trichonafurin A (1) exhibited moderate cytotoxicity against HeLa and HepG2 cell lines with IC50 values of 20.2 and 32.1 μM, respectively.

 A new ingenane diterpenoid, named ingenol-20-laurate (1), and two known analogues (ingenol-20-palmitate (2), ingenol-20-pentadecanoate (3)) and an ent-abietane diterpenoid (euphopilolide, 4) were isolated from the whole plants of Euphorbia jolkinii. The structure of compound 1 was elucidated by HRESIMS and 2D NMR methods. The cytotoxicities of compound 1 against SMMC-7721, MDA-MB-231, and SW480 cell lines were 27.22±0.58, 17.69±0.29 and 16.19±0.77 μM, respectively.

A novel phenanthrene compound, diphenanthrin (1), and an undescribed alkaloid compound, N-chloromethylstephenanthrine (2), together with two known compounds (3-4) were isolated from the EtOH extract of the roots of Stephania tetrandra. Their structures were elucidated by 1D and 2D NMR, mass spectroscopy and comparison of NMR data with those of known compounds. In anti-inflammatory assay,  compounds 3 and 4 showed the inhibitory effects on NO production, with IC50 values of 41.51 ± 0.20 and 23.87 ± 2.12 μM.

Ten secondary metabolites, including one new monoterpene rhamnoside (1), five terpenoids (2–6), two nucleosides (7–8), and two phenylethanoid glycosides (9–10) were isolated from the roots of Rehmannia glutinosa. Their structures were determined by spectroscopic analysis such as NMR and HR-ESI-MS. In the tyrosinase inhibitory assay, compounds 2, 6 and 8 showed inhibition against tyrosinase. Compounds 1, 4, 5, 6, 9 and 10 are being reported in the genus Rehmannia for the first time.

In this study, the essential oils (EOs) of flowers from German chamomile (GCEOs 1-5) Matricaria chamomilla L., Roman chamomile (RCEOs 1-2) Chamaemelum nobile (L.) All, and Chinese chamomile (CCEO-1) or “Juhua” Chrysanthemum morifolium Ramat were characterized by GC-FID and GC-MS analysis. EOs were tested for biting deterrence/repellency against Aedes aegypti and hybrid imported fire ants and for toxicity against Anastrepha suspensa. GCEOs 1-5 were characterized by the higher contents of α-bisabolol oxide A (43%-66%) and α-bisabolol oxide B (10%-16%) whereas isobutyl angelate (16%-17%), 2-butenyl angelate (12%-13%), isoamyl tiglate (11%-12%), 3-methyl pentylangelate (8%-11%), and trans-pinocarveol (6%-7%) were major compounds of RCEOs 1 and 2. The CCEO-1 was rich in borneol (31%), ar-curcumene (12%), bornyl acetate (7%) and intermedeol (5%). Biting deterrence of GCEO-2 and -3, and CCEO-1 was similar to N,N-diethyl-3-methylbenzamide (DEET) whereas the activity of the other EOs was lower than DEET against Ae. aegypti. The activity of pure compounds α-bisabolol and 1,6-dioxaspiro[4.4]non-3-en-2-one from German chamomiles was also similar to DEET against Ae. aegypti. Repellency of German chamomile EO, GCEO-F against hybrid imported fire ants was higher whereas the activity of Roman chamomile EO, RCEO-PT was lower than DEET. All EOs, GCEO-4, RCEO-2, and CCEO-1 were toxic against female A. suspensa. Further research using intensive in vivo bioassays will be conducted to explore the potential of these natural products in insect pest management strategies.

Aim of the study is to evaluate the potential use of Thymus capitatus (L.) Hoffm. & Link and Origanum dubium Boiss. essential oils and their major constituents; thymol and carvacrol in cancer therapies. For this aim hMSC-telo1 cells and their tumorigenic counterpart were exposed to varying concentrations of Thymus capitatus (L.) Hoffm. & Link and Origanum dubium Boiss. essential oils, thymol and carvacrol and cellular viability and proliferation have been evaluated by MTT assay. TUNEL assay has used for evaluation of apoptosis. Study suggested that, Thymus capitatus (L.) Hoffm. & Link essential oil and thymol have an enhancer effect once combined with conventional chemotherapeutic agents. 0.005 v/v % of Thymus capitatus (L.) Hoffm. & Link, 0.005 v/v % and 0.05 v/v % of thymol showed enchancer effect by sparing the normal hMSC-telo1 cells from the cytotoxicity of Deferasirox while these combinations were cytotoxic towards tumorigenic hMSC-telo1 cells.