2D Nuclear Magnetic Resonance Research Articles

New acylphloroglucinols from a crude acetone extract of Eucalyptus camaldulensis Dehnh. leaf

Acylphloroglucinols are well-known Eucalyptus secondary metabolites which exhibit a variety of structures and bioactivities. The investigation of a crude acetone extract of Eucalyptus camaldulensis leaves led to the isolation of two new acylphloroglucinols, eucalypcamals O and P (1 and 2) together with seven phloroglucinols (3–9), and a benzene derivative (10). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy. The absolute configurations of compounds 1 and 2 were established by comparison of experimental and calculated electronic circular dichroism (ECD) data. In the putative biosynthetic pathway, eucalypcamals O and P should be derived from hetero-Diels-Alder reaction between grandinol and trans-isoeugenol.

Determination of in situ hydrocarbon contents in shale oil plays. Part 2: Two-dimensional nuclear magnetic resonance (2D NMR) as a potential approach to characterize preserved cores

Determination of the in situ hydrocarbon content and occurrence characteristics of shale oil reservoirs is crucial for reserve prediction and efficient development. Although many scholars have studied the fluid saturation of conventional coring shale using solvent and thermal extraction methods, with time consuming and only volumes or mass of oil and water were given, which could not reveal the occurrence characteristics of oil and water in samples. This study proposes a two-dimensional (2D) nuclear magnetic resonance (NMR) T1–T2 mapping method to systematically assess the in situ water and oil content, distribution, and their evaporative loss laws of preserved shales. Sixty preserved shales with different maturities were selected from the first member of the Qingshankou Formation in the northern Songliao Basin, China. Each preserved sample was divided into two parts and analyzed using a high-frequency (22 MHz) NMR and Dean–Stark extraction respectively. Furthermore, a time-elapsed NMR T1–T2 mapping was performed on a preserved shale core sample after varying the exposure times in an open environment. Results show that T1–T2 mapping can be used to determine the porosity, water and oil contents, and saturations of preserved shales. Oil content measured using T1–T2 mapping was consistent with that obtained by Dean–Stark extraction, with a correlation coefficient (R2) as high as 90% when crude oils of varying maturities were used for NMR calibration.The T1/T2 of oil inpreserved shale showed a negative trend with maturity, and the T2 of oil was often higher than that of water, indicating oil is enriched in the relative macropores. After exposing the preserved shale to open air for 150–200 h, 1) the total loss ratio of oil and water was approximately 80%; 2)the fluid evaporation loss rate follows the orders: oil > water and fluids in larger pores > smaller pores; 3)the free oil content decreased by approximately 92%, whereas the absorbed oil content varied slightly. As a nondestructive, rapid, and minimal sample preparation method, 2D NMR can efficiently assess both fluids content and distribution of a core sample in only 5 min, thus displaying its great advantages and applications for preserved shales with fast fluid evaporation to determine the in situ fluid content.

Chemical constituents and their anti-neuroinflammatory activities from the bark of Taiwan incense cedar, Calocedrus formosana

One undescribed C40 terpenoid, calomacroquinoic acid; four undescribed diterpenes, 5α,6α-epoxy-7α-hydroxyferruginol, 15-ethoxysugiol, 7-methoxy-6,7-secoabieta-8,11,13-triene-6,12-diol, and ethyl 7,8-secoabieta-11,14-dioxo-7-ate; two compounds isolated from Nature for the first time, 6β,7α-dihydroxyferruginol and 12-O-methyltaxochinon; and six known compounds were successfully identified from the bark of Taiwan incense cedar Calocedrus formosana. Structures of all isolates were elucidated by physical data (appearance, ultraviolet, infrared, specific rotation, and X-ray) and spectroscopic data (1D and 2D nuclear magnetic resonance, and high-resolution electron ionization mass spectrometry). The biosynthetic pathway of calomacroquinoic acid is also described in the current study. Nitric oxide production in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells was inhibited by 6,7-dehydroferruginol, 7α,11-dihydroxy-12-methoxy-8,11,13-abietriene, and trans-communic acid. Altogether, the bark of C. formosana possessed several potential natural therapeutics against inflammation-related neuronal diseases.

Anti-inflammatory properties of novel galloyl glucosides isolated from the Australian tropical plant Uromyrtus metrosideros

Two new galloyl glucosides, galloyl-lawsoniaside A (4) and uromyrtoside (6), were isolated from the polar fraction of Uromyrtus metrosideros leaf extract along with another four previously identified phytochemicals (1, 2, 3, and 5). The structures of these six compounds were characterised using low and high-resolution mass spectrometry (L/HRMS) and 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy. These compounds were not toxic to human peripheral blood mononuclear cells (PBMCs) at 10 μg/mL over 24 h, yet showed significant in vitro suppression of proinflammatory cytokines involved in the pathogenesis of inflammatory bowel disease (IBD). Specifically, the release of interferon γ (IFN-γ), interleukin (IL)-17A, and IL-8 from phorbol myristate acetate/ionomycin (P/I) and anti-CD3/anti-CD28-activated cells were significantly suppressed by compounds 4 and 5. Interestingly, no effect on tumour necrosis factor (TNF) release was observed. These results show that the newly characterised compound 4 has promising cytokine suppressive properties, which could be further investigated as a candidate for IBD treatment.

Synthesis and evaluation of benzoylbenzofurans and isoflavone derivatives as sirtuin 1 inhibitors with antiproliferative effects on cancer cells

Isoflavone derivatives were prepared from benzoylbenzofuran precursors. The synthesized compounds were analyzed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, as well as high-resolution mass spectrometry (HRMS) to confirm their structures. The benzoylbenzofuran and isoflavone analogues were evaluated for inhibition of sirtuin 1 (SIRT1) and cell proliferation in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Several isoflavone and benzoylbenzofuran derivatives exhibited potent antiproliferative effects against the MDA-MB-231 cancer cell line. Most of the isoflavone derivatives attenuated SIRT1 activity to below 50%. The most active compounds were the isoflavone quinones 38, 39, and 40, at IC50 values of 5.58 ± 0.373, 1.62 ± 0.0720, and 7.24 ± 0.823 μM, respectively. Importantly, the most active compound, 6-methoxy-4′,6′-dimethylisoflavone-2′,5′-quinone (39) displayed SIRT1 inhibitory activity comparable to that of the reference compound, suramin. The in silico docking simulations in the active site of SIRT1 further substantiated the experimental results and explored the binding orientations of potent compounds in the active site of the target.

Antimicrobial and Cytotoxic Cyathane-Xylosides from Cultures of the Basidiomycete Dentipellis fragilis.

In our continued search for biologically active metabolites from cultures of rare Basidiomycota species, we found eight previously undescribed cyathane-xylosides from submerged cultures of Dentipellis fragilis, which were named dentifragilins A–H. In addition, the known cyathane derivatives striatal D and laxitextine A were isolated. All compounds were characterized by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) as well as by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Several of the compounds exhibited significant activities in standardized cell-based assays for the determination of antimicrobial and cytotoxic effects. The discovery of cyathanes in the genus Dentipellis has chemotaxonomic implications, as this class of diterpenoids has already been shown to be characteristic for mycelial cultures of the related genera Hericium and Laxitextum, which are classified as Dentipellis in the family Hericiaceae.

Lupeol and pristimerin do not inhibit activation of the human sperm CatSper Ca(2+)-channel.

Opposing findings have been published on the regulation of the sperm-specific Ca 2+ channel CatSper (cation channel of sperm) in human sperm cells by the plant triterpenoids lupeol and pristimerin. While the original study on this topic found these triterpenoids to act as potent inhibitors of human CatSper, subsequent studies have failed to replicate such an inhibitory effect. It has been suggested that these issues could in part be due to purity issues and/or batch variation between the plant-derived extracts of lupeol and pristimerin obtained for the studies. The aim of this study was to elucidate this controversy by investigating the batches of lupeol and pristimerin used in our previous study with state-of-the-art 1H-, 13C- and 2D-nuclear magnetic resonance (NMR) methods to reveal potential purity and/or batch variation issues. When comparing the NMR-spectra obtained from 1H-NMR and 13C-NMR with previously published NMR-spectra for lupeol and pristimerin, we could confirm that both the lupeol and pristimerin batch were ≥95 % pure. These results confirm the validity of the findings in our previous study for lupeol and pristimerin, showing that lupeol and pristimerin do not inhibit activation of CatSper in human sperm. In conclusion, using 1H-, 13C- and 2D-NMR methods, we confirm that the lupeol and pristimerin batches used in our previous study were ≥95 % pure and thereby fail to identify any purity issues and/or batch variation that could explain the observed inability of lupeol and pristimerin to inhibit activation of CatSper in human sperm.

(R)-13aα-Densiindolizidine, A New Phenanthroindolizidine Alkaloid From Cryptocarya densiflora Blume (Lauraceae) and Molecular Docking Against SARS-CoV-2

Cryptocarya densiflora Blume (Lauraceae) is an evergreen tree widely distributed throughout the hills and mountain forests up to 1500 m in Malaysia and Indonesia. The plant has been reported to contain phenanthroindolizidine-type of alkaloids. In the present work, a new phenanthroindolizidine alkaloid named ( R)-13a α-densiindolizidine, was isolated from the dichloromethane (DCM) extract of the leaves. The structure of the alkaloid was established based on 1D and 2D nuclear magnetic resonance (NMR) and liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) analysis. ( R)-13a α-densiindolizidine displayed binding interactions with crucial amino acid residues in the active sites ofsevere acute respiratory syndrome coronavirus 2 Mpro (SARS-CoV-2 Mpro) and RNA-dependent protease (RdRp) in silico, whilst fulfilling theabsorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria and Lipinsky's rule, thus revealing its potential as a lead compound.

Simplex centroid mixture design, DI-ESI-MS, and chemometric analysis-guided isolation of parinarioidin C from bark of Brosimum parinarioides (Moraceae)

Brosimum parinarioides , a plant species native to the Amazonian region, is used in folk medicine for the treatment of several diseases. However, knowledge regarding its phytochemical content is scarce. In order to investigate the phytochemical composition of B. parinarioides , an integrative approach based on simplex-centroid design, direct infusion electrospray ionization mass spectrometry (DI-ESI-MS), and chemometric analysis was adopted. According to simplex-centroid design, dichloromethane (DCM), ethyl acetate (AcOEt), and ethanol-based (EtOH) extracts were prepared and analyzed using DI-ESI-MS, and their chemical profile was submitted to principal component analysis (PCA) and hierarchical cluster analysis (HCA). The AcOEt extract from the bark was obtained on a large scale and subjected to chromatographic separation. The multivariate analysis indicated the formation of three groups and highlighted isoliquiritigenin ( 1 ), licoagrochalcone A ( 2 ), caffeic acid glucoside ( 3 ), epicatechin-glycoside ( 4) , caffeic acid ( 5 ), and one unknown compound, as being responsible for the segregation of these groups. Thus, the new compound was isolated and characterized using 1D and 2D nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (HR-MS) as parinarioidin C ( 10 ). In addition, parinarioidin A ( 6 ), parinarioidin B ( 7 ), 3- O -caffeoylquinic acid ( 8 ), and kanzonol C ( 9 ) were tentatively identified based on manual interpretation of MS/MS spectra. Overall, the integrative approach proposed in the study provided a simple and effective model to dereplicate known compounds and guide the isolation of a new compound from a native amazon species, thus improving the knowledge regarding the phytochemical content of B. parinarioides . • One new compound was isolated from Brosimum parinarioides. • Nine phenolic compounds were identified based on the MS/MS data. • This study provided an effective model to guide the isolation of new natural products.

Evaluation of Antiproliferative Activity of Lac Dye Fractions against MDA-MB-231 and SiHa Cell Lines.

Laccifer lacca (Kerr) produces a mixture of polyhydroxy anthraquinones (laccaic acid) known as lac dye. Literature suggests that these laccaic acids have a structural resemblance with the anticancer drug Adriamycin (ADR). Hence, they may possess potential anticancer activity. This study was designed to explore the in vitro anticancer activity of the three fractions of lac dye, i.e., chloroform (C), methanol (M), and water (W) fractions, and isolation of constituents from bioactive fraction. SRB (Sulforhodamine B) assay method was employed to evaluate the inhibitory action of all three fractions. However, only methanolic showed promising inhibitory action with GI50 <10; this runs in parallel with Adriamycin inhibition (GI50 <10). Two active constituents of the methanolic extract were isolated using column chromatography and were characterized using UV (UV visible spectrophotometer), IR (Infrared spectroscopy), NMR (nuclear magnetic resonance), and mass spectrometry methods. The final structure of the isolated constituents (laccaic acid D and laccaic acid B) was confirmed by 13C and 2D NMR data. Conclusively, only the methanol fraction (M) showed promising anticancer activity against in vitro MDAMB- 231 and SiHa cell lines compared to the standard adriamycin.

Conformational Properties and Putative Bioactive Targets for Novel Thiosemicarbazone Derivatives.

The structure assignment and conformational analysis of the thiosemicarbazones, DKI21 and DKI24, were performed through homonuclear and heteronuclear 2D Nuclear Magnetic Resonance (NMR) spectroscopy (2D-COSY, 2D-NOESY, 2D-ROESY, 2D-HSQC, and 2D-HMBC) and quantum mechanics (QM) calculations, using Functional Density Theory (DFT). In addition, utilizing a combination of 2D-NOESY and 2D-ROESY spectra an exo structure was established for both of the analogs. This experimental results were confirmed by theoretical mechanistic studies, as the lowest minima conformations derived through DFT calculations were compatible with the spatial correlations observed in the 2D-NOESY and 2D-ROESY spectra. Finally, molecular binding experiments were performed to detect the potential targets for DKI21 and DKI24, derived from SwissAdme. In silico molecular binding experiments showed favorable binding energy values for the most of the enzymes studied. The ADMET calculations, using the preADMET and pKCSm software, showed that the two molecules appear as possible drug leads.

Epoxinnamide: An Epoxy Cinnamoyl-Containing Nonribosomal Peptide from an Intertidal Mudflat-Derived Streptomyces sp.

Cinnamoyl-containing nonribosomal peptides (CCNPs) form a unique family of actinobacterial secondary metabolites and display various biological activities. A new CCNP named epoxinnamide (1) was discovered from intertidal mudflat-derived Streptomyces sp. OID44. The structure of 1 was determined by the analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) data along with a mass spectrum. The absolute configuration of 1 was assigned by the combination of advanced Marfey’s method, 3JHH and rotating-frame overhauser effect spectroscopy (ROESY) analysis, DP4 calculation, and genomic analysis. The putative biosynthetic pathway of epoxinnamide (1) was identified through the whole-genome sequencing of Streptomyces sp. OID44. In particular, the thioesterase domain in the nonribosomal peptide synthetase (NRPS) biosynthetic gene cluster was proposed as a bifunctional enzyme, which catalyzes both epimerization and macrocyclization. Epoxinnamide (1) induced quinone reductase (QR) activity in murine Hepa-1c1c7 cells by 1.6-fold at 5 μM. It also exhibited effective antiangiogenesis activity in human umbilical vein endothelial cells (IC50 = 13.4 μM).

Machine Learning Optimization of Lignin Properties in Green Biorefineries

Novel biorefineries could transform lignin, an abundant biopolymer, from side-stream waste to high-value-added byproducts at their site of production and with minimal experiments. Here, we report the optimization of the AquaSolv omni biorefinery for lignin using Bayesian optimization, a machine learning framework for sample-efficient and guided data collection. This tool allows us to relate the biorefinery conditions like hydrothermal pretreatment reaction severity and temperature with multiple experimental outputs, such as lignin structural features characterized using 2D nuclear magnetic resonance spectroscopy. By applying a Pareto front analysis to our models, we can find the processing conditions that simultaneously optimize the lignin yield and the amount of β-O-4 linkages for the depolymerization of lignin into platform chemicals. Our study demonstrates the potential of machine learning to accelerate the development of sustainable chemical processing techniques for targeted applications and products.

High-performance thin-layer chromatography – antibacterial assay first reveals bioactive clerodane diterpenes in giant goldenrod (Solidago gigantea Ait.)

The present work introduces a high-performance thin-layer chromatography (HPTLC)–direct bioautography method using the Gram-positive plant pathogenic bacterium, Rhodococcus fascians. The screening and isolation procedure comprised of a non-targeted high-performance thin-layer chromatography-effect-directed analysis (HPTLC–EDA) against Bacillus subtilis, B. subtilis subsp. spizizenii, R. fascians, and Aliivibrio fischeri, a targeted HPTLC–mass spectrometry (MS), and bioassay-guided column chromatographic (preparative flash and semi-preparative HPLC) fractionation and purification. The developed new separation methods enabled the discovery of four bioactive cis-clerodane diterpenes, solidagoic acid H (1), solidagoic acid E (2), solidagoic acid I (3), and solidagoic acid F (4), in the n-hexane extract of giant goldenrod (Solidago gigantea Ait.) leaf for the first time. These compounds were identified by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. The initially used HPTLC method (chloroform – ethyl acetate – methanol 15:3:2, V/V/V) was changed (to n-hexane – isopropyl acetate – methanol – acetic acid 29:20:1:1, V/V/V/V) to achieve the separation of the closely related isomer pairs (1–2 and 3–4). Compounds 1 and 3 exhibited moderate antibacterial activity against the Gram-positive B. subtilis subsp. spizizenii and R. fascians bacterial strains in microdilution assays with half-maximal inhibitory concentration (IC50) values in the range of 32.3–64.4 µg/mL. The mass spectrometric fragmentation of the isolated compounds was interpreted and their previously published NMR assignments lacking certain resonances were completed.

Chemical constituents from the bulbs of Lilium davidii var. unicolor and anti-insomnia effect

In this work, twenty-five water-soluble constituents were isolated from the bulbs of Lilium davidii var. unicolor, including two new compounds termed liliumtides A and B (1–2), and seventeen known compounds (3–4, 6–13, 15, 17, 21–25) isolated from the genus of Lilium for the first time. Their structures were established using high-resolution electrospray ionization mass spectroscopy and 1D and 2D nuclear magnetic resonance data. To confirm furtherly the absolute configuration of liliumtide A, and to accumulate enough sample to study the anti-insomnia effect, a total synthesis for liliumtide A was achieved by four steps. The pentobarbital-induced sleeping time test showed that compared with the blank control group, the liliumtide A decreased sleep latency and significantly increased the sleep time. These results suggested that liliumtide A could be investigated as a natural anti-insomnia lead compound in the pharmaceutical and food industries.

Study on fluid mobility in sandwich-type shale oil reservoir using two-dimensional nuclear magnetic resonance approaches

ABSTRACT Regarding sandwich-type shale oil reservoir characterized by diversified lithologies and complex fluid mobility, we combined one- and two-dimensional (1D and 2D) nuclear magnetic resonance (NMR) core analysis techniques to quantitatively study the movable oil and fluid saturations of rock samples with different lithologies. First, we used 2D T1-T2 NMR to analyze the spectrum curve of the dolomitic mudstone and siltstone samples from a sandwich-type shale oil reservoir at initial and oil-saturated states. We evaluated the occurrence of movable oil saturations in source and reservoir rocks. Then, we analyzed samples of the siltstone serving as the reservoir rock using a centrifuge combined with 1D NMR approach to evaluate the characteristics of movable fluid saturations inside the reservoir. The results showed that the samples of dolomitic mudstone serving as the source rock in the sandwich-type shale oil reservoir in the Lucaogou Formation in Jimsar had the occurrence of kerogen and bitumen signals, the development of small- and medium-scale organic matter pores, and an average movable oil saturation of 15.6%. The siltstone serving as the reservoir rock had an average movable oil saturation of 53.8%, and its movable fluid saturation was positively correlated with porosity and permeability. For samples whose porosity was greater than 12% and permeability was greater than 0.1 mD, their movable fluid saturations usually were higher than 40%. Therefore, siltstone was the preferable diagenetic facies for the development of high-quality reservoirs.

Structural characterization and antioxidant and anti-inflammatory activities of new chemical constituent from the seeds of bambara groundnut (Vigna subterranea (L.) Verdc.)

ABSTRACT A new compound (C20H18O9) was isolated from bambara groundnut seeds (Vigna subterranea (L.) Verdc.) and identified as a luteolin glycoside based on 1H, 13C and 2D nuclear magnetic resonance spectroscopy data and previously reported data. This compound exhibited similar scavenging activity for DPPH radical to Trolox and had a higher inhibitory effect on superoxide anion radicals than gallic acid and Trolox. C20H18O9 exhibited an inhibitory effect on DPPH and superoxide anion radicals, with IC50 values of 2.25 ± 0.14 µg/mL and 9.8 ± 0.3 µg/mL, respectively. However, C20H18O9 displayed low activities for FRAP and metal chelation. C20H18O9 had a higher inhibitory effect on lipoxygenase (IC50 = 2.16 ± 0.14 µg/mL) than nordihydroguaiaretic acid but had a lower inhibitory effect on xanthine oxidase than allopurinol. These results indicate that bambara groundnut seeds can be natural sources of antioxidants for humans and can serve as lipoxygenase inhibitor to reduce inflammation.

Optimization and Characterization of a Novel Exopolysaccharide from Bacillus haynesii CamB6 for Food Applications.

Extremophilic microorganisms often produce novel bioactive compounds to survive under harsh environmental conditions. Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, are functional biopolymers that act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermophilic Bacillus haynesii CamB6 from a slightly acidic (pH 5.82) Campanario hot spring (56.4 °C) located in the Central Andean Mountains of Chile. Physicochemical properties of the EPS were characterized by different techniques: Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), 1D and 2D Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps. GPC and HPLC analysis showed that the EPS is a low molecular weight heteropolymer composed of mannose (66%), glucose (20%), and galactose (14%). FTIR analysis demonstrated the polysaccharide nature (–OH groups, Acetyl groups, and pyranosic ring structure) and the presence of different glycosidic linkages among sugar residues, which was further confirmed by NMR spectroscopic analyses. Moreover, D-mannose α-(1→2) and α-(1→4) linkages prevail in the CamB6 EPS structure. TGA revealed the high thermal stability (240 °C) of the polysaccharide. The functional properties of the EPS were evaluated for food industry applications, specifically as an antioxidant and for its emulsification, water-holding (WHC), oil-holding (OHC), and flocculation capacities. The results suggest that the study EPS can be a useful additive for the food-processing industry.

New polyketides from the liquid culture of Diaporthebreyniae sp. nov. (Diaporthales, Diaporthaceae).

During the course of a study on the biodiversity of endophytes from Cameroon, a fungal strain was isolated. A multigene phylogenetic inference using five DNA loci revealed that this strain represents an undescribed species of Diaporthe, which is introduced here as D.breyniae. Investigation into the chemistry of this fungus led to the isolation of two previously undescribed secondary metabolites for which the trivial names fusaristatins G (7) and H (8) are proposed, together with eleven known compounds. The structures of all of the metabolites were established by using one-dimensional (1D) and two-dimensional (2D) Nuclear Magnetic Resonance (NMR) spectroscopic data in combination with High-Resolution ElectroSpray Ionization Mass Spectrometry (HR-ESIMS) data. The absolute configuration of phomopchalasin N (4), which was reported for the first time concurrently to the present publication, was determined by analysis of its Rotating frame Overhauser Effect SpectroscopY (ROESY) spectrum and by comparison of its Electronic Circular Dichroism (ECD) spectrum with that of related compounds. A selection of the isolated secondary metabolites were tested for antimicrobial and cytotoxic activities, and compounds 4 and 7 showed weak antifungal and antibacterial activity. On the other hand, compound 4 showed moderate cytotoxic activity against all tested cancer cell lines with IC50 values in the range of 5.8-45.9 µM. The latter was found to be less toxic than the other isolated cytochalasins (1-3) and gave hints in regards to the structure-activity relationship (SAR) of the studied cytochalasins. Fusaristatin H (8) also exhibited weak cytotoxicity against KB3.1 cell lines with an IC50 value of 30.3 µM. Graphical abstract.

Isolation of New Constituents from Whole Plant of Salsola imbricata Forssk. of Saudi Origin.

This work describes the first report of the known glycosidic constituents β-sitosterol-3-O-β-d-glucoside-6′-palmitate (1), β-sitosterol-3-O-β-d-glucoside (2), momor-cerebroside I (3), phytolacca cerebroside (4), 1,2-di-O-palmitoyl-3-O-(6-sulfoquinovopyranosyl)-glycerol (5), isorhamnetin-3-robinobioside (6), and isorhamnetin-3-rutinoside (7) from the plant Salsola imbricata Forssk. grown in the eastern region of Saudi Arabia. The structures of the isolated compounds were elucidated from extensive 1D and 2D nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC–MS), liquid chromatography-mass spectrometry (LC–MS), and chemical analyses. Compound 1 is reported for the first time from the Amaranthaceae family. In addition to the isolated and identified fatty alcohols, compounds 3, 4, 5, and 6 are also reported for the first time from the genus Salsola. The findings of this study suggest a contribution of the isolated compounds to the various biological activities reported for this plant.