High-resolution Magnetic Data Research Articles

The Architecture of a Root Zone of a Large Magmatic Conduit System From High Resolution Magnetic, Gravity and Petrophysical Data: The Reinfjord Ultramafic Complex

AbstractThe Seiland Igneous Province (SIP) is a large province of mafic and ultramafic (UM) complexes interpreted to be relics of a giant plumbing system feeding the Ediacaran Central Iapetus Magmatic Province. The Reinfjord Ultramafic Complex (RUC) is one of the four major ultramafic complexes of the SIP. The RUC has a younger dunite core surrounded by wehrlite and lherzolite embedded in country rocks consisting of layered gabbros with sub‐horizontal layering and metamorphosed sedimentary rocks. Here, we develop a 3D subsurface model for the RUC using high‐resolution magnetic and gravity data and extensive petrophysical measurements from oriented surface samples and drill core samples. Our model indicates that the RUC narrows in depth, extending a minimum of 1.4 km below sea level, and plunges eastwards below the country rock. This model allows us to decipher the lithologic heterogeneities, and the depth and lateral extent of ultramafic rocks, which we interpret in the context of the geologic history of the area. The RUC is spatially separated from other UM complexes of the SIP and the result of this study indicates a smaller depth extent. Combining these findings with the previously reported distribution of the SIP rocks based on the regional gravity data, we propose that the uplift of the crustal block hosting the RUC is larger than for ultramafic complexes in the northwestern part of the SIP.

Edge detection and depth estimation of Lake Sapanca, Eastern Marmara Region, from high-resolution magnetic data

Edge detection and depth estimation of Lake Sapanca, Eastern Marmara Region, from high-resolution magnetic data

Elemental, phytochemical, and toxicological assessment of Cissus rotundifolia (Forssk.) Vahl

Cissus rotundifolia (Forssk.) Vahl. (Vitaceae) is a wild plant that is commonly used by communities from rural areas as a food and medicine. There are limited studies on the phytochemical composition and the impact of soil quality on the elemental distribution in this plant. In this study, we report a phytochemical analysis to identify the phytocompounds responsible for the reported biological activities of C. rotundifolia. We also examined the impact of soil quality on elemental uptake by the edible parts of C. rotundifolia collected from eight geographical locations in KwaZulu-Natal (South Africa) to assess the nutritional benefits and potential heavy metal toxicities. Three secondary metabolites (stigmasterol, β-sitosterol, and pheophytin a) were isolated, and their structures were characterised by high-resolution mass spectrometry and nuclear magnetic resonance data. The plant was found to contribute adequately to the recommended dietary allowances for essential nutrients without exceeding tolerable upper intake limits and with low concentrations of toxic heavy metals. The average concentrations of microelements in the edible parts were found to be in decreasing order of Fe>Mn>Se>Zn>Cu>Cr>Ni>Co. The bioaccumulation factors indicate that the plant controls the uptake of metals from the soil and would make a good indicator and biological monitor for cadmium toxicity. However, a health risk assessment exposed carcinogenic risks on regular consumption of the plant obtained from sites close to pollution sources, such as roads and landfills. The findings from this study show the synergies when consuming medicinal plants and provide evidence for C. rotundifolia as a nutraceutical. Significance: This study provides additional scientific knowledge on the phytochemical composition of C. rotundifolia. Three phytocompounds (stigmasterol, β-sitosterol, and pheophytin a) were isolated, and their presence may be correlated to this plant’s antidiabetic, anti-inflammatory, and antibacterial properties. This study shows that C. rotundifolia contributes adequately to the recommended dietary allowances for essential elements, and the plant is safe for human consumption if collected from non-polluted sites. The carcinogenic and non-carcinogenic estimates for the toxic metals due to consumption of the plant signify the possibility of developing cancer over time if the plant is consumed frequently from polluted sites.

New Sesterterpenoid from the Marine Fungus Penicillium oxalicum M893

Objectives The aim of the project was the isolation, structural elucidation, and antimicrobial and antifungal activities of compounds from the culture broth of the marine fungus Penicillium oxalicum M893 (isolated from the marine brown alga Spatoglossum sp.). Methods Combined chromatographic techniques were used to isolate antibacterial and antifungal compounds from the MeOH extract Penicillium oxalicum M893. The structures were elucidated by analyses of high-resolution electrospray ionization mass spectral and nuclear magnetic resonance data. The antimicrobial and antifungal effects of compounds were evaluated using the dilution turbidimetric broth method. Results One new sesterterpenoid, oxaliterpenoid (1), and six known compounds, aspergillusidone C (2), nidulin (3), emeguisin B (4), aspergillusether A (5), aspergillusether J (6), and guisinol (7) were isolated from the methanol extract of the culture broth of Penicillium oxalicum M893. All compounds showed potent antibacterial activities against Gram-(+) bacteria, E. faecalis (ATCC299212), S. aureus (ATCC25923), and B. cereus (ATCC14579), and the yeast Candida albicans (ATCC10231), with MIC values ranging from 2 to 128 µg/mL.

Joint Gramian inversion of gravity, magnetic and gravity gradient tensor data for the modelling of Mesoproterozoic iron oxide deposits, southeast Missouri, USA

SUMMARY Within the iron metallogenic province of southeast Missouri, USA, there are several mines that contain not only economic iron resources, magnetite and/or hematite, but also contain rare earth elements, copper and gold. An area including three major deposits, Pea Ridge, Bourbon and Kratz Spring, was selected for detailed modelling for the upper crustal magnetic susceptibility and density structures. For the study area, ground gravity and high-resolution airborne magnetic and gravity gradiometry data sets are available. An efficient and novel joint inversion algorithm for the simultaneous inversion of these multiple data sets is presented. The Gramian coupling constraint is used to correlate the reconstructed density and magnetic susceptibility models. The implementation relies on the structures of the sensitivity matrices and an efficient minimization algorithm to achieve significant reductions in the memory requirements and computational costs. Consequently, it is feasible to use a laptop computer for the inversion of multiple data sets, each containing thousands of data points, for the recovery of models on the study area, each including approximately one million model parameters. This is the first time that these multiple data sets have been simultaneously inverted for this area. The L1-norm stabilizer is used to provide compact and focused images of the ore deposits. For contrast, independent inversions of each data set are also discussed. In general, our results provide new insights about the concealed ore deposits in the Mesoproterozoic basement rocks of southeast Missouri. Both short- and long-wavelength anomalies exist in the recovered models; these provide a high-resolution image of the subsurface. The geometry and physical properties of the known deposits are determined very well. Additionally, some unknown concealed deposits are revealed; these could be economically valuable and should be considered in future geophysical and geological investigations.

Isolation and Quantification of 2-O-Caffeoyl-hydroxycitric Acid, an Active Component in Hot Water Extracts of Coriander (Coriandrum sativum L.), Which Inhibits Degranulation of RBL-2H3 Cells

Objectives: Natural compounds that can effectively prevent and alleviate allergic symptoms, such as hay fever, are widely sought after from sources such as natural ingredients that can be ingested daily. Coriander extracts have been reported to show anti-allergic activity; however, hot water extracts have not been tested previously. Here, we found that a hot water extract of the aerial parts of coriander inhibited the degranulation of rat basophilic leukemia cell line RBL-2H3 cells and identified the active compounds. Methods: Chromatographic methods were used to isolate compounds from the hot water extract of coriander. The chemical structures were elucidated by analyses of high-resolution electrospray ionization mass spectrum and nuclear magnetic resonance spectral data. The degranulation activity of compounds was evaluated using the β-hexosaminidase release assay. Results: We analyzed the components to identify active compounds. 2 S,3 S-2- O-caffeoyl-hydroxycitric acid (1), and 2- O-caffeoyl-hydroxycitric acid 6′- O-methyl ester (2) were isolated from the hot water extract of coriander, and both compounds showed degranulation inhibitory activity in RBL-2H3 cells at a concentration below 2.5 mM. The content of compound 1 in the freeze-dried coriander powder was calculated to be 2.0% via HPLC quantification. Conclusions: Compound 1 was considered to be the primary active contributor in the hot water extract of coriander.

Inner structure of monogenetic Pilot Knob submarine volcano (Austin, Texas) revealed by electrical resistivity tomography and magnetic surveys

Pilot Knob is the eroded and exposed core of an extinct subaqueous to emergent volcano that formed in a shallow Late Cretaceous epicontinental sea in the ancient Gulf of Mexico during the deposition of Austin Chalk Limestone. With the aim of understanding the inner structure of this volcano, we have conducted geophysical surveys (resistivity and magnetometry) to provide an insight into the past eruptive history. High-resolution electrical resistivity and magnetic data reveal, for the first time, a buried tuff mound, an explosion crater, several dikes and vents, basaltic flows, and limestone blocks within the volcano. A combination of geologic and geophysical data suggests that Pilot Knob volcano started with an explosion as a maar-type volcano beneath a shallow sea floor. Then, it likely has evolved into a tuff mound-type volcano with “Surtseyan” eruptions, before finally evolving into an emergent volcanic center. Major resistivity and magnetic anomalies align approximately in the east–west and north–south directions, respectively. Such alignments suggest that Pilot Knob is situated on east–west and north–south fractures, along which its most significant volcanic activity occurred. Results also provide valuable information in delineating tuff mounds and their structural characteristics.

Late-stage structural evolution from near-bottom topographic and magnetic Surveys of Suda Seamount (West Pacific)

The late-stage evolution of seamounts is widespread in the West Pacific and may control the distribution of manganese nodules on the lower seamount flanks and adjacent debris aprons. However, due to the paucity of near-bottom observational data, little research exists specifically focused on the late-stage evolution of seamount structures. To fill this knowledge gap, we systematically investigated the tectonic features and evolution of Suda Seamount based on rock samples, satellite gravity data, and high-resolution magnetic and topographic data surveyed by Autonomous Underwater Vehicle (AUV). We found that the central area of the seamount summit exhibits a negative magnetic anomaly related to a group of minor volcanic structures, while the collapse of volcanic structures on the northeast seamount flank is associated with an extensive positive magnetic anomaly. Surprisingly, a late-stage intrusive dyke with significantly high magnetic susceptibility originates from the lower part of a minor group of volcanic structures but cannot be clearly distinguished below the main summit volcanic structure (hereinafter referred to as the main mound complex). These results demonstrate that at least two late-stage periods of intense magmatic activity occurred during the evolution of the seamount, one centered on the main mound complex and one on the margin of the summit platform. By combining fine-scale topographic and satellite gravity data, we deduce that gravitational slip caused by magma intrusion along a fracture was the main cause of the seamount flank collapse. The late-stage processes resulted in a change in the seamount morphology and distributed clastic rock debris widely along the flanks, which contributed to the uneven distribution of manganese nodules along the lower seamount flanks and determined the distribution of subsequently formed nodules.

Exploratory Mapping of the Geothermal Anomalies in the Neoproterozoic Arabian Shield, Saudi Arabia, Using Magnetic Data

In this paper, certain areas of the Kingdom of Saudi Arabia (KSA) are assessed in order to map potential geothermal energy zones. To evaluate high-resolution aerial magnetic data, spectral depth analysis using a modified centroid approach was used. The calculated geothermal parameters were gridded in order to delineate the regions characterised by a shallow Curie point depth (CPD) and a high geothermal gradient (GG) as well as a high heat flow (HF). The CPD, GG and HF calculated from the analysed data varied in the ranges of 6.0–15.0 km, 40.0–100.0 °C/km and 90.0–270.0 mW/m2, respectively. The obtained results show the concurrence of the positions of shallow CPD (<8.0 km), high GG (>83.5 °C/km) and high HF (>211.0 mW/m2). The geothermal systems that are oriented in the E–W direction are related to the Red Sea tectonics, the tectonic opening of the Red Sea/Gulf of the Suez Rift, hot subterranean anomalies and high enthalpy from radioactive granites. Likewise, the geologic structures (fractures and faults) related to the Red Sea tectonics serve as channels for the movement of hydrothermal fluids and the deposition of associated minerals. All in all, another geophysical study involving deep boreholes, and seismic, magnetotelluric, electromagnetic and geochemical data should be conducted to evaluate and estimate precisely the economic reserves of geothermal resources.

Insights into the deep structure of the Bou Azzer-El Graara inlier (Central Anti-Atlas, Morocco): Inference from high-resolution magnetic data, and geodynamic implications

The Bou Azzer-El Graara inlier (BAEI) in the Central Anti-Atlas has been extensively studied due to its famous Pan-African ophiolite and its great mineral potential. In 1998, an airborne survey was flown over this inlier, providing high-resolution magnetic data. This study is concerned with reinterpreting these data to help elucidate the BAEI structure. For this purpose, the aeromagnetic data were processed through a series of filters and transformations. They were then subjected to a detailed analysis, taking into account the study area geology. Qualitative analysis of the reduced to pole data indicates that the observed anomalies are broadly consistent with outcrops of Precambrian mafic and metavolcanic rocks in the BAEI. The extension of this type of rocks below the Paleozoic sedimentary cover could explain similar anomalies found outside the inlier. Additional analysis of the processed data helped to identify various lineaments and structures organized into two main trends: ENE-WSW and ESE-WNW. Furthermore, the calculation of anomalous source depths by Euler deconvolution from aeromagnetic data shows that these vary between 0 and 1000 m within the inlier. However, deeper sources occur beneath the detached and slightly folded Paleozoic sedimentary deposits in the northern part of the inlier. Moreover, a quantitative interpretation using the 3D inverse method was applied to high-amplitude anomalies associated with the Bou Azzer ophiolite (BAO) and the Foum Zguid great dyke (FZGD). The results indicate that (i) the BAO consists of three north-northeast dipping magnetic bodies, (ii) the FZGD corresponds to a deeply rooted vertical structure with lateral thickness variations and (iii) the NE-SW FZGD structure represents the eastern limit of the BAO as indicated by geological and magnetic data. This suggests that the FZGD fracture may have played an important role during the Pan-African collages as a key structure controlling the oblique suturing of the ophiolite slices.

Appraisal of the magnetic and geothermal anomalies of bornu basin northeast nigeria involving aero-magnetic data

The Bornu Basin in northeast Nigeria was studied using high-resolution airborne magnetic data with the objective of improving the reliability of mapped magnetic and geothermal anomalies, and depth solutions. Necessary enhancement operations like analytic signal (ASIG), upward continuation, depth assessment methods involving standard Euler deconvolution (SED) and source parameter imaging (SPI) as well as spectral analysis applying the centroid technique were applied. The middle and southern parts are dominated by high frequency anomalies as revealed by the ASIG map. Furthermore, the magnetic data, when upward continued to 5 km, revealed avalanche of deeply buried igneous intrusions that created near-surface magnetic sources and geologic structures. Maximum thicknesses of sedimentary series estimated from SED and SPI, are respectively ~5974.7 and ~5885.3 m. These values correlate correlated relatively well with depth to the top boundary (Zt) of ~6550 m obtained from the centroid technique. These depth estimates reveal sequence of thick sediments overlying igneous intrusions and falls under the prospective geothermal anomaly zones characterised by high geothermal gradient (GG) (>55 °C/km) and heat flow (HF) (>130 mW/m2) values. Areas characterised by high geothermal anomalies correspond to igneous intrusion-dominated shallow Curie point depths (CPD or Zb).

New Anti-Inflammatory β-Resorcylic Acid Lactones Derived from an Endophytic Fungus, Colletotrichum sp.

The endophytic fungus Colletotrichum gloeosprioides JS0419, isolated from the leaves of the halophyte Suaeda japonica, produced four new β-resorcylic acid derivatives, colletogloeopyrones A and B (1 and 2) and colletogloeolactones A and B (3 and 4), and seven known β-resorcylic acid lactones (RALs). The structures of these compounds were elucidated via analysis of the high-resolution mass spectrometry and nuclear magnetic resonance data. Compounds 1 and 2 showed a dihydrobenzopyranone ring with a linear C9 side chain, which is rarely observed in RALs. All isolated compounds were evaluated for their anti-inflammatory activities. Colletogloeopyrone A (1), monocillin II (5), and monocillin II glycoside (6) were effective in reducing nitric oxide production without cytotoxicity. They also inhibited the secretion of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), as demonstrated by the expression of mRNA corresponding to IL-6 and TNF-α. Mechanistically, compounds 5 and 6 significantly inhibited the protein expression of nuclear factor-κB, IκBα, IKKα/β, inducible nitric oxide synthase, and cyclooxygenase (COX)-2, whereas compound 1 only inhibited COX-2 expression. This study indicated that RAL-type compounds 1, 5, and 6 demonstrated potential anti-inflammatory activity by inhibiting the synthesis of pro-inflammatory cytokines.

New high resolution aeromagnetic anomaly map of Türkiye and its various derivative-based maps

Since Türkiye's territory is mostly mountainous and forested, earth science studies in these areas have not been completed at an adequate level and with a satisfying resolution. However, due to the long time and cost of collecting measurements from land in large- and medium-scale studies and due to the inability to collect measurements in regular grid intervals in large-scale studies to be carried out on land, an airborne geophysical survey project was conducted in order to collect high-resolution magnetic and radiometric country-scale data. Total magnetic field and radiometry data were collected from the air between 2017 and 2022 within the scope of the country-wide Airborne Geophysics Surveys Project. The data collection flights were carried out in such a way as to follow the topography from an altitude of about 200 m above the ground. The flights were carried out considering the regular geometry of the flight profile and the general geological and tectonic structure of Türkiye in the direction of N-S with one-kilometer profile intervals. A total field magnetic anomaly map was obtained after applying the diurnal, tie line leveling, IGRF (model 2020), and differential reduction to magnetic pole (DRTP) corrections to the magnetic data. For the scope of this study, the total field magnetic anomaly and the regional total field magnetic anomaly maps were presented along with the structural boundary maps (tilt angle (TA), the total horizontal derivative (THDR) and the analytical signal (AS)) derived from these maps. During another stage of the study, the general tectonic structure of Türkiye and structural boundaries obtained from derivative-based maps (AS, TA, and THDR) were compared. General geophysical interpretation was also performed with magnetic-anomaly and derivative-based maps for the three regions characterized by high magnetic anomalies.

Exploratory assessment of geothermal resources in some parts of the Middle Benue Trough of Nigeria using airborne potential field data

Some parts of the Middle Benue Trough (MBT) of Nigeria were evaluated with the aim of detecting prospective geothermal potential regions. Spectral depth analysis using a modified centroid procedure was applied to analyze high-resolution airborne magnetic data. The Curie point depth (CPD) within the study area is in the range of 6.0 and 16 km. It was observed that the Gboko Anticlines (GA) that are interrelated with the Santonian intrusions of Abakaliki Anticlinorium (AA) are characterized by thin CPD (6.0–8.0 km). The mapped geothermal anomalies within the GA with shallow CPD (<8.0 km) are dominated by the high geothermal gradient (GG) (>74 °C/km) and heat flow (HF) (>155 mW/m2) values. The adjoining areas within the study area are defined by medium-deep CPD (8.0–16.0 km), medium–low GG (<74 °C/km), and HF (<155 mW/m2) values. The further integrated geophysical investigation and subsequent exploitation programs should be sited in the delineated GA and adjoining AA

Algicidal characteristics of novel algicidal compounds, cyclic lipopeptide surfactins from Bacillus tequilensis strain D8, in eliminating Heterosigma akashiwo blooms.

Heterosigma akashiwo blooms have caused severe damage to marine ecosystems, the aquaculture industry and human health worldwide. In this study, Bacillus tequilensis D8 isolated from an H. akashiwo bloom area was found to exert high algicidal activity via extracellular metabolite production. This activity remained stable after exposure to different temperatures and light intensities. Scanning electron microscopy observation and fluorescein diacetate staining indicated that the algicidal substances rapidly destroyed algal plasma membranes and decreased esterase activity. Significant decreases in the maximum photochemical quantum yield and relative electron transfer rate were observed, which indicated photosynthetic membrane destruction. Subsequently, the algicidal compounds were separated and purified by high-performance liquid chromatography and identified as three surfactin homologues by interpreting high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy data. Among these, surfactin-C13 and surfactin-C14 exhibited strong algicidal activity against three HAB-causing species, namely, H. akashiwo, Skeletonema costatum, and Prorocentrum donghaiense, with 24 h-LC50 values of 1.2-5.31 μg/ml. Surfactin-C15 showed strong algicidal activity against S. costatum and weak algicidal activity against H. akashiwo but little activity against P. donghaiense. The present study illuminates the algicidal characteristics and mechanisms of action of surfactins on H. akashiwo and their potential applicability in controlling harmful algal blooms.

Magnetic Anomalies of the Tyrrhenian Sea Revisited: A Processing Workflow for Enhancing the Resolution of Aeromagnetic Data

We propose a processing workflow to enhance the information content of aeromagnetic data. Our workflow is based on the downward continuation and subsequent L-transform of magnetic data. This workflow returns a map showing single highs, which correspond to the location of magnetic bodies, and does not need any a priori information about the source magnetization. We validated our workflow using the aeromagnetic anomalies of the Tyrrhenian Sea (Italy), by a comparison of the reprocessed aeromagnetic anomalies with high-resolution shipborne magnetic data in three selected areas. Through this comparison, we show that the proposed processing workflow of aeromagnetic data leads to more accurate interpretative results. Our results indicate that, in areas where higher resolution data are lacking, the reprocessing of aeromagnetic data according to our workflow may be as decisive as to suggest changes to their previous interpretations or, at least, useful for highlighting areas of special interest, deserving to be magnetically explored by a dedicated high-resolution shipborne survey.

Length of day at c . 1.1 Ga based on cyclostratigraphic analyses of the Nanfen Formation in the North China craton, and its geodynamic implications

Length of day (LOD) varies throughout Earth history, dictated in the long term by the retreat of the Moon and growth of Earth's core. Reconstruction of LOD in deep time has greatly benefited from analyses of the orbital cycle from geological records. The Precambrian database, however, is very limited. Here we present a cyclostratigraphic study on c. 1.1 Ga laminated argillaceous limestones of the Nanfen Formation from the North China craton. Milankovitch cycles are successfully recognized from the consistent cyclical variations of the high-resolution magnetic susceptibility data measured on drillcores from the Nanfen Formation. Sedimentary cycles with wavelengths of 12.45, 10.72 and 9.96 m in three drillcores are interpreted as 405 kyr eccentricity cycles. An obliquity period of 20.9–21.4 kyr and a precession period of 12.7–16.0 kyr are also identified. The Earth–Moon distance and LOD are thus estimated at 3.43 ± 0.04 × 10 8 m and 18.94 ± 0.39 h, respectively. Our new results together with the data previously published reveal an important discontinuity between 1.9 and 1.4 Ga in the evolutionary trend of the LOD. We suggest that Earth's core grew rapidly during the interval, which significantly changed the moment of inertia of the Earth–Moon system, and tidal dissipation again ruled the LOD variations after that stage. Supplementary material: A description of the calculation method, magnetic susceptibility data, anisotropy of magnetic susceptibility data and supplementary figures are available at https://doi.org/10.6084/m9.figshare.c.6086544

High-resolution imaging of subsurface infrastructure using deep learning artificial intelligence on drone magnetometry

The use of drones fo r geophysical data acquisition and artificial intelligence (AI) for geophysical data processing, imaging, and interpretation are active focus areas in current industry and academic applications. Unlocking their cumulative potential in single-focus applications can have a transformative impact, possibly leading to dramatic cost reductions in key use cases and new application areas for enhanced actionable business intelligence. We present field study results from Texas and California that show the potential for imaging pipelines and other subsurface infrastructure by using AI-based methods on high-resolution aboveground magnetic data. The superior resolution and interpretability over conventional geophysical inversion is demonstrated. The method has the potential to provide actionable intelligence in several business-use cases for detecting and characterizing pipelines, crossing zones for multiple pipes, etc. at dramatically reduced costs. The advanced algorithms and workflows used resulted in a 100-fold increase in efficiency and delivered results in two days compared to what could take several months using generally available open-source deep learning AI workflows and software. Future direction of development is to validate against excavation-/drill-bit-/inline-tool-based ground truth and further extend and develop this process to deliver near real-time results. The techniques used are general and can be applied to other geophysical data including seismic, electromagnetic, and gravity at various scales and resolution.

Lignans and Other Compounds From the Roots of Pandanus tonkinensis and Their Lipid Peroxidation Inhibitory Activity

A new phenylpropane (1) and 9 known (2-10) compounds were isolated from the methanol extract of Pandanus tonkinensis roots. Their chemical structures were determined as (7 S)-2,6-dimethoxyphenyl-7,9-propanediol-1 -O-β-D-glucopyranoside (1), isorhapontigenin (2), pinoresinol-4,4′-di -O-β-D-glucoside (3), isoeucommin A (4), pinoresinol-4′ -O-β-D-glucoside (5), acanthoside B (6), eucommin A (7), urolignoside (8), benzyl O-α-L-arabinopyranosyl-(1→6) -β-D-glucopyranoside (9), and (6 S,9 S)-roseoside (10) by comprehensive analysis of high-resolution electron spray ionization mass spectrum and nuclear magnetic resonance spectral data, as well as by comparison of their spectral data with those reported in the literature. In addition, the stereochemistry of 1 was successfully determined by both theoretical and calculated CD spectra. All the isolates were tested for their lipid peroxidation inhibitory effects by in vitro assay. Compounds 2-7 exhibited significantly lipid peroxidation inhibitory effects with IC50 values of 21.3 ± 1.7, 61.9 ± 3.9, 57.5 ± 5.5, 10.4 ± 0.7, 28.9 ± 0.3, 54.2 ± 3.5 µM, respectively, compared to that of the positive control, trolox (31.4 ± 2.2 µM).

Phytochemical Profiling and Isolation of Bioactive Compounds from Leucosidea sericea (Rosaceae).

In the study, ultraperformance liquid chromatography–quadrupole time-of-flight–mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4–6, seven pentacyclic triterpenoids 7–13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16–22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC50 values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.