Anti-Neurodegenerative Biflavonoid Glycosides from Impatiens balsamina

Systematic investigation of the material basis, effectiveness and safety of Thesium chinense Turcz. and its preparation Bairui Granules against lung inflammation

BACKGROUND

Thesium chinense Turcz. (Named as Bai Rui Cao in Chinese) and its preparations (e.g., Bairui Granules) have been used to treat inflammatory diseases, such as acute mastitis, lobar pneumonia, tonsillitis, coronavirus disease 2019 (COVID-19), and upper respiratory tract infection. However, the material basis, pharmacological efficiency, and safety have not been illustrated.

METHODS

Anti-inflammatory activity-guided isolation of constituents has been performed using multiple column chromatography, and their structures were elucidated by NMR spectroscopy and ECD calculations. The inhibitory effects on lung inflammation and safety of the crude ethanol extract (CE), Bairui Granules (BG), and the purified active constituents were evaluated using lipopolysaccharide (LPS)-stimulated acute lung inflammation (ALI) mice model or normal mice.

RESULTS

Seven new compounds (1-7) and fifty-six known compounds (8-63) were isolated from T. chinense, and fifty-four were reported from this plant for the first time. The new flavonoid glycosides 1-2, new fatty acids 4-5, new alkaloid 7 as well as the known constituents including flavonoid aglycones 8-11, lignans 46-54, alkaloids 34 and 45, coumarins 57, phenylpropionic acids 27, and simple aromatic compounds 39, 44 and 58 exhibited anti-inflammatory activity. Network pharmacology analysis indicated that anti-inflammation of T. chinense was attributed to flavonoids and alkaloids by regulating inflammation-related proteins (e.g., TNF, NF-κB, TGF-β). Furthermore, constituents of T. chinense including kaempferol-3-O-glucorhamnoside (KN, also named as Bairuisu I, 19), astragalin (AG, Bairuisu II, 12), and kaempferol (KF, Bairuisu III, 8), as well as CE and BG could alleviate lung inflammation caused by LPS in mice by preventing neutrophils infiltration and the expression of the genes for pro-inflammatory cytokines NLRP3, caspase-1, IL-1β, and COX-2. After a 28-day subacute toxicity test, BG at doses of 4.875 g/kg and 9.750 g/kg (equivalent to onefold and twofold the clinically recommended dose) and CE at a dose of 11.138 g/kg (equivalent to fourfold the clinical dose of BG) were found to be safe and non-toxic.

CONCLUSIONS

The discovery of sixty-three constituents comprehensively illustrated the material basis of T. chinense. T. chinense and Bairui Granules could alleviate lung inflammation by regulating inflammation-related proteins and no toxicity was observed under the twofold of clinically used doses.

Neurotrophic phenolic glycosides from the roots of Armoracia rusticana

Armoracia rusticana P. G. Gaertner. belongs to the Brassicaceae family and has aroused scientific interest for its anti-inflammatory and anticancer activities. In a continuing investigation to discover bioactive constituents from A. rusticana, we isolated 19 phenolic glycosides including three undescribed flavonol glycosides and one undescribed neolignan glycoside from MeOH extract of this plant. Their structures were elucidated based on NMR spectroscopic analysis (1H, 13C, 1H-1H COSY, HSQC, and HMBC), HRESIMS, and chemical methods. The determination of their absolute configuration was accomplished by ECD and LC-MS analysis. All the compounds were assessed for their potential neurotrophic activity through induction of nerve growth factor in C6 glioma cell lines and for their anti-neuroinflammatory activity based on the measurement of inhibition levels of nitric oxide production and pro-inflammatory cytokines (i.e., IL-1β, IL-6, and TNF-α) in lipopolysaccharide-activated microglia BV-2 cells.

Japonins A-D, cyathane diterpenoids with neurite outgrowth-promoting activity isolated from Onychium japonicum using NMR and MS/MS-based molecular networking

Guided by MS/MS-based molecular networking strategy, four new cyathane diterpenoids japonin A-D (1-4), together with the known analogues (5 and 6), have been isolated from aerial parts of Onychium japonicum. The structures of the new compounds were elucidated through a combination of NMR and MS experiments. Through single-crystal X-ray diffraction analysis, and comparison of experimental and calculated computational electronic circular dichroism (ECD) spectra, the absolute configurations of compounds 1-4 were determined. The new compound 1 showed promoting effects on the differentiation of PC12 at a concentration of 40 μM.

Structure Revision of Anti-Inflammatory Indole Alkaloids with a 1,2-Benzisoxazole Ring

(R)- and (S)-2-(benzo[d]isoxazol-3-yl)-2-ethylindolin-3-one [(±)-1] were previously isolated from NIRAM, a natural blue dye from Polygonum tinctorium, and their structures were initially proposed to possess a 1,2-benzisoxazole ring. In this study, the structures of (±)-1 were revised to have an indole-anthranilic acid fused tetracyclic ring rather than the 1,2-benzisoxazole ring by reanalysis of one-dimensional (1D) and two-dimensional (2D) NMR followed by density functional theory (DFT) chemical shift calculation, DP4+ technique, and ECD simulation.

Perplexing Polyphenolics: The Isolations, Syntheses, Reappraisals, and Bioactivities of Flavonoids, Isoflavonoids, and Neoflavonoids from 2016 to 2022

Flavonoids, isoflavonoids, neoflavonoids, and their various subcategories are polyphenolics-an extensive class of natural products. These compounds are bioactive and display multiple activities, including anticancer, antibacterial, antiviral, antioxidant, and neuroprotective activities. Thus, these compounds can serve as leads for therapeutic agents or targets for complex synthesis; they are coveted and routinely isolated, characterized, biologically evaluated, and synthesized. However, data regarding the compounds' sources, isolation procedures, structural novelties, bioactivities, and synthetic schemes are often dispersed and complex, a dilemma this review aims to address. To serve as an easily accessible guide for researchers wanting to apprise themselves of the latest advancements in this subfield, this review summarizes seventy-six (76) articles published between 2016 and 2022 that detail the isolation and characterization of two hundred and forty-nine (249) novel compounds, the total and semisyntheses of thirteen (13) compounds, and reappraisals of the structures of twenty (20) previously reported compounds and their bioactivities. This article also discusses new synthetic methods and enzymes capable of producing or modifying flavonoids, isoflavonoids, or neoflavonoids.

Impatiens balsamina: An updated review on the ethnobotanical uses, phytochemistry, and pharmacological activity

ETHNOPHARMACOLOGICAL RELEVANCE

Impatiens balsamina is an annual herb of the Balsaminaceae family, which is cultivated extensively in Asia as an ornamental plant. Notably, as a folk medicine, I. balsamina has been long prescribed for the treatment of rheumatism, isthmus, generalized pain, fractures, inflammation of the nails, scurvy, carbuncles, dysentery, bruises, foot diseases, etc. AIM OF THE STUDY: The paper overviews comprehensive information on ethnobotanical uses, phytochemistry, pharmacological activity, and toxicity of I. balsamina, aiming at laying a sturdy foundation for further development of I. balsamina.

MATERIALS AND METHODS

Research information was acquired through electronic databases such as Web of Science, PubMed, SciFinder, ScienceDirect, Google Scholar, and CNKI with the keyword "Impatiens balsamina ".

RESULTS

Briefly, more than 307 natural compounds have been separated and identified from various medicinal parts of I. balsamina, which are classified into diverse groups, like flavonoids, naphthoquinones, coumarins, terpenoids, sterols, phenols, fatty acids and their ester, naphthalene derivatives, nitrogen-containing compounds, polysaccharides, and other compounds. In particular, 2-methoxy-1,4-naphthoquinone, one of the naphthoquinones, is the predominant and most representative component. Moreover, I. balsamina furnishes numerous and complicated pharmacological activities, including antimicrobial, antiallergic, antipruritic, antitumor, antioxidant, anti-inflammatory, immunomodulatory, anti-hepatic fibrosis, insecticidal, and anthelmintic as well as enzyme-inhibiting activities, etc. Toxicological studies have shown that the hexane extract of the stems and leaves was less toxic, and the hydroalcoholic extract of stems was more toxic.

CONCLUSIONS

The paper contributes to updating the ethnobotanical uses, phytochemistry, pharmacological activity, and toxicity of I. balsamina, which offer abundant information for future investigations and applications of I. balsamina.

Plastome evolution and phylogenomics of Impatiens (Balsaminaceae)

This study reported seven new plastomes from Impatiens and observed three highly variable regions for phylogeny and DNA barcoding, which resolved the relationships among sections of subgenus Impatiens. Impatiens L. (Balsaminaceae, Ericales) is one of the largest and most diverse genera of angiosperms, widely known for its taxonomic difficulty. In this study, we reevaluated the infrageneric relationships within the genus Impatiens, using complete plastome sequence data. Seven complete plastomes of Impatiens (representing 6 species) were newly sequenced and characterized along with 20 previously published plastomes of other Impatiens species, plus 2 plastomes of outgroups (Hydrocera triflora, Balsaminaceae; Marcgravia coriacea, Marcgraviaceae). The total size of these 29 plastomes ranged from 151,538 bp to 152,917 bp, except 2 samples of Impatiens morsei, which exhibited a shorter length and lost some genes encoding NADH dehydrogenase subunits. Moreover, the number of simple sequence repeats (SSRs) ranged from 51 to 113, and the number of long repeats from 17 to 26. In addition, three highly variable regions were identified (trnG-GCC (The previous one), ndhF-rpl32-trnL-UGA-ccsA, and ycf1). Our phylogenomic analysis based on 80 plastome-derived protein-coding genes strongly supported the monophyly of Impatiens and its two subgenera (Clavicarpa and Impatiens), and fully resolved relationships among the six (out of seven) sampled sections of subgenus Impatiens. Overall, the plastome DNA markers and phylogenetic results reported in this study will facilitate future identification, taxonomic and DNA barcoding studies in Impatiens as well as evolutionary studies in Balsaminaceae.

Phytochemicals targeting nitric oxide signaling in neurodegenerative diseases

Neurodegenerative diseases are a set of diseases in which slow and progressive neuronal loss occurs. Nitric oxide (NO) as a neurotransmitter performs key roles in the stimulation and blockade of various inflammatory processes. Although physiological NO is necessary for protection against a variety of pathogens, reactive oxygen species-mediated oxidative stress induces inflammatory cascades and apoptosis. Activation of glial cells particularly astrocytes and microglia induce overproduction of NO, resulting in neuroinflammation and neurodegenerative disorders. Hence, inhibiting the overproduction of NO is a beneficial therapeutic approach for numerous neuroinflammatory conditions. Several compounds have been explored for the management of neurodegenerative disorders, but they have minor symptomatic benefits and several adverse effects. Phytochemicals have currently gained more consideration owing to their ability to reduce the overproduction of NO in neurodegenerative disorders. Furthermore, phytochemicals are generally considered to be safe and beneficial. The mechanisms of NO generation and their implications in neurodegenerative disorders are explored in this review article, as well as several newly discovered phytochemicals that might have NO inhibitory activity. The current review could aid in the discovery of new anti-neuroinflammatory drugs that can suppress NO generation, particularly during neuroinflammatory and neurodegenerative conditions.

Hot off the press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as chlorfortunone A from Chloranthus fortunei.

Structure Revision of Balsamisides A-D and Establishment of an Empirical Rule for Distinguishing Four Classes of Biflavonoids

Balsamisides A-D (1-4) are anti-inflammatory and neurotrophic biflavonoidal glycosides originally proposed to possess an epoxide functionality at the C-2/C-3 position. However, there are inconsistencies in their 13C NMR chemical shift values with those of previously reported analogs, indicating that reanalysis of NMR data for structures of 1-4 is necessary. Computational methods aided by the DP4+ probability technique and ECD calculations enabled structural reassignment of 1-4 to have a 2,3-dihydro-3-hydroxyfuran (3-DHF) instead of an epoxide. Additionally, two new biflavonoidal glycosides, balsamisides E and F (14 and 18), possessing a 2,3-dihydro-2-hydroxyfuran (2-DHF) and a 1,4-dioxane ring, respectively, were characterized by conventional NMR and MS data analysis as well as DP4+ and ECD methods. Systematic 13C NMR analysis was performed on the four aforementioned classes of biflavonoids with a 2- or 3-DHF, epoxide, or 1,4-dioxane. As a result, diagnostic 13C NMR chemical shift values of C-2/C-3 for rapid determination of these four biflavonoid classes were formulated, and based on this first empirical rule for (bi)flavonoids eight previously reported ones were structurally revised.

Procyanidins and Phlobatannins from the Twigs of Rosa multiflora and Their Neuroprotective Activity

Three new procyanidins (1-3), two new phlobatannins (6 and 7), a new flavan-3,4-diol glycoside (9), and a new neolignan glycoside (10), along with three previously reported compounds (4, 5, and 8) were isolated from the twigs of Rosa multiflora. The chemical structures of the new compounds (1-3, 6, 7, 9, and 10) were characterized by spectroscopic data interpretation, including NMR (¹H and ¹³C NMR, ¹H-¹H COSY, HSQC, HMBC, and NOESY) and HRESIMS analysis. Experimental ECD data analysis was conducted to assign the absolute configurations of the new compounds (1-3, 6, 7, 9, and 10). The absolute configuration of the sugar moieties was verified through a chiral derivatization method and LC-MS analysis. All the isolated compounds (1-10) were evaluated for their anti-neuroinflammatory activity based on inhibitory effects on nitric oxide production using a lipopolysaccharide-stimulated murine microglia BV-2 cell line and for their neurotrophic effects on nerve growth factor induction in C6 glioma.

Complete Chloroplast Genomes and Comparative Analyses of Three Ornamental Impatiens Species

Impatiens L., the largest genus in the family Balsaminaceae with approximately 1,000 species, is a controversial genus. Due to the conflict of morphological features and insufficient genomic resources, the studies of systematic evolution and understanding of taxonomic identification are considered to be very limited. Hence, we have sequenced the complete chloroplast genomes of three ornamental species (Impatiens balsamina, I. hawkeri, and I. walleriana), and compared them with previously published wild species data. We performed a detailed comparison of a highly similar basic structure, size, GC content, gene number, order, and functional array among them. Similarly, most divergent genes were detected from previous work in the literature. The mutational regions containing highly variable nucleotide hotspots were identified and may be used as potential markers for species identification and taxonomy. Furthermore, using whole chloroplast genome data to analysis the phylogenetic relationship of the Balsaminaceae species, we found that they were all part of a single clade. The three phenotypically different ornamental species were clustered together, suggesting that they were very likely to be closely related. We achieved and characterized the plastid genome structure, identified the divergence hotspots, and determined the phylogenetic and taxonomic positions of the three cultivated species in the Impatiens genus. The results may show that the chloroplast genome can be used to solve phylogenetic problems in or between the Impatiens genus and also provide genomic resources for the study of the Balsaminaceae family’s systematics and evolution.

Quality consistency evaluation of commercial Impatiens Caulis by integrating UPLC-QTOF-MS/MS chemical profiling and UPLC-DAD multi-components quantification approaches

In this study, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) and ultra-high performance liquid chromatography coupled with photo-diode array spectrometry (UPLC-DAD) were firstly integrated to qualitatively characterize the chemical profiles and quantitatively determine the major components in Impatiens Caulis (IC), a Chinese medicinal herb derived from the dried stem of Impatiens balsamina. The qualitative analysis revealed that there was no difference in chemical profiles of twenty commercial IC samples. A total of 45 components were characterized, there in 5 naphthoquinones, 3 coumarins, 5 phenolic acids, 12 flavonoids and 3 other compounds were identified definitely. However, the quantitative results showed a significant difference in these IC samples. In particular, the highest content of total quantified compounds was even 9.49 times of the lowest one. Furthermore, the average contents of these quantified compounds in twenty commercial IC samples had high values of relative standard deviation (RSD) ranged from 15.64% to 98.76%, suggesting a poor quality consistency in these commercial IC samples. Therefore, efficacy related chemical markers as well as the cultivation region, harvest time and/or post-harvest handling of IC should be further investigated for ensuring its quality and efficacy consistency.

Glycosylated constituents isolated from the trunk of Abies holophylla and their anti-inflammatory and neurotrophic activity

Eleven previously undescribed glycosylated compounds with phenolic (abeoside A-F), monoterpenyl (abeoside G and H), or 2-heptanyl (abeoside I-K) aglycone, and twenty one reported compounds were isolated from the trunk of Abies holophylla. The structures of the previously undescribed compounds were elucidated on the basis of the conventional NMR and HRMS data analysis, and the absolute configuration of sugar units were assigned by chiral derivatization and LC-MS analysis. All the isolated compounds were evaluated for their anti-neuroinflammatory and neurotrophic activities. Among the evaluated compounds, twelve compounds including abeoside A, B, E, G, H, J, and K exhibited strong anti-neuroinflammatory activities with IC₅₀ values of 4.6-18.2 μM by inhibiting production of LPS-induced NO levels, and abeoside C and 1-O-[(S)-oleuropeyl]-β-D-glucoside showed powerful effects on the stimulation of NGF secretion levels with 157.09 ± 8.53% and 154.74 ± 1.24%, respectively.

Proceedings of Chemistry, Pharmacology, Pharmacokinetics and Synthesis of Biflavonoids

Biflavonoids, composed of two monoflavonoid residues, occur naturally in angiosperms, bryophytes, ferns, and gymnosperms. More than 592 biflavonoids have been structurally elucidated, and they can be classified into two groups of C-C and C-linear fragments-C, based on whether the linker between the two residues contains an atom. As the linker can be established on two arbitrary rings from different residues, the C-C type contains various subtypes, as does the C-linear fragment-C type. Biflavonoids have a wide range of pharmacological activities, including anti-inflammatory, antioxidant, antibacterial, antiviral, antidiabetic, antitumor, and cytotoxic properties, and they can be applied in Alzheimer's disease and Parkinson's disease. This review mainly summarizes the distribution and chemistry of biflavonoids; additionally, their bioactivities, pharmacokinetics, and synthesis are discussed.

Comparative chloroplast genome analysis of Impatiens species (Balsaminaceae) in the karst area of China: insights into genome evolution and phylogenomic implications

BACKGROUND

Impatiens L. is a genus of complex taxonomy that belongs to the family Balsaminaceae (Ericales) and contains approximately 1000 species. The genus is well known for its economic, medicinal, ornamental, and horticultural value. However, knowledge about its germplasm identification, molecular phylogeny, and chloroplast genomics is limited, and taxonomic uncertainties still exist due to overlapping morphological features and insufficient genomic resources.

RESULTS

We sequenced the chloroplast genomes of six different species (Impatiens chlorosepala, Impatiens fanjingshanica, Impatiens guizhouensis, Impatiens linearisepala, Impatiens loulanensis, and Impatiens stenosepala) in the karst area of China and compared them with those of six previously published Balsaminaceae species. We contrasted genomic features and repeat sequences, assessed sequence divergence and constructed phylogenetic relationships. Except for those of I. alpicola, I. pritzelii and I. glandulifera, the complete chloroplast genomes ranging in size from 151,366 bp (I. alpicola) to 154,189 bp (Hydrocera triflora) encoded 115 distinct genes [81 protein-coding, 30 transfer RNA (tRNA), and 4 ribosomal RNA (rRNA) genes]. Moreover, the characteristics of the long repeat sequences and simple sequence repeats (SSRs) were determined. psbK-psbI, trnT-GGU-psbD, rpl36-rps8, rpoB-trnC-GCA, trnK-UUU-rps16, trnQ-UUG, trnP-UGG-psaJ, trnT-UGU-trnL-UAA, and ycf4-cemA were identified as divergence hotspot regions and thus might be suitable for species identification and phylogenetic studies. Additionally, the phylogenetic relationships based on Maximum likelihood (ML) and Bayesian inference (BI) of the whole chloroplast genomes showed that the chloroplast genome structure of I. guizhouensis represents the ancestral state of the Balsaminaceae family.

CONCLUSION

Our study provided detailed information about nucleotide diversity hotspots and the types of repeats, which can be used to develop molecular markers applicable to Balsaminaceae species. We also reconstructed and analyzed the relationships of some Impatiens species and assessed their taxonomic statuses based on the complete chloroplast genomes. Together, the findings of the current study might provide valuable genomic resources for systematic evolution of the Balsaminaceae species.

Nitric Oxide as a Target for Phytochemicals in Anti-Neuroinflammatory Prevention Therapy

Nitric oxide (NO) is a neurotransmitter that mediates the activation and inhibition of inflammatory cascades. Even though physiological NO is required for defense against various pathogens, excessive NO can trigger inflammatory signaling and cell death through reactive nitrogen species-induced oxidative stress. Excessive NO production by activated microglial cells is specifically associated with neuroinflammatory and neurodegenerative conditions, such as Alzheimer’s and Parkinson’s disease, amyotrophic lateral sclerosis, ischemia, hypoxia, multiple sclerosis, and other afflictions of the central nervous system (CNS). Therefore, controlling excessive NO production is a desirable therapeutic strategy for managing various neuroinflammatory disorders. Recently, phytochemicals have attracted considerable attention because of their potential to counteract excessive NO production in CNS disorders. Moreover, phytochemicals and nutraceuticals are typically safe and effective. In this review, we discuss the mechanisms of NO production and its involvement in various neurological disorders, and we revisit a number of recently identified phytochemicals which may act as NO inhibitors. This review may help identify novel potent anti-inflammatory agents that can downregulate NO, specifically during neuroinflammation and neurodegeneration.

Complete chloroplast genomes of Impatiens cyanantha and Impatiens monticola: Insights into genome structures, mutational hotspots, comparative and phylogenetic analysis with its congeneric species

Impatiens L., the largest genus in the family Balsaminaceae with approximately 1000 species, is a controversial and complex genus that includes many economically important species well known for medicinal and ornamental values. However, there is limited knowledge of molecular phylogeny and chloroplast genomics, and uncertainties still exist at a taxonomic level. In this study, we have assembled four chloroplast genomics specimens of Impatiens cyanantha and Impatiens monticola, which are found at the different altitudes of Guizhou and Yunnan in China, and compared them with previously published three wild Balsaminaceae species (Impatiens piufanensis, Impatiens glandlifera, and Hydrocera triflora). The complete chloroplast genome sequences ranged from 152,236 bp (I. piufanensis) to 154,189 bp (H. triflora) and encoded 115 total distinct genes, of which 81 were protein-coding, 30 were distinct transfer RNA genes(tRNA), and 4 were ribosomal RNA genes (rRNA). A comparative analysis of I. cyanantha (Guizhou) vs. I. cyanantha (Yunnan) and I. monticola (Guizhou) vs. I. monticola (Yunnan) revealed minor changes in lengths; however, similar gene contents, gene orders, and GC contents existed among them. Interestingly, highly coding and non-coding genes, and regions matK, psbK, atpH-atpI, trnC-trnT, petN, psbM, atpE, rbcL, accD, psaL, rps3-rps19, ndhG-ndhA,rpl16, rpoB, ndhB, ndhF, ycf1, and ndhH were found, which could be suitable for identification of species and phylogenetic studies. During the comparison between I. cyanantha (Guizhou) and I. cyanantha (Yunnan), we observed that the rps4, ycf2, ndhF, ycf1, and rpoC2 genes underwent positive selection. Meanwhile, in the comparative study of I. monticola (Guizhou) vs. I. monticola (Yunnan), The accD and ycf1 genes were positively selected. Additionally, phylogenetic relationships based on maximum likelihood (ML) and Bayesian inference (BI) among whole chloroplast genomes showed that a sister relationship with I. monticola (Guizhou) and I. monticola (Yunnan) formed a clade with I.piufanensis proving their close connection. Besides, I.cyanantha (Guizhou) and I. cyanantha (Yunnan) formed a clade with I. glandlifera. Along with the findings and the results, the current study might provide valuable significant genomic resources for systematics and evolution of the genus impatiens in different altitudes of regions.

Neurotrophic and anti-neuroinflammatory constituents from the aerial parts of Coriandrum sativum

In the course of our continuing search for biologically active compounds from medicinal sources, we investigated the MeOH extract of the aerial parts of Coriandrum sativum Linn. An extended phytochemical investigation of the aerial parts of C. sativum led to the isolation and identification of seven compounds (1-7) including two new isocoumarin glycosides (1-2) and a new phenolic glycoside (5). The chemical structures of the new compounds (1, 2, and 5) were elucidated by analysis of 1D and 2D NMR (¹H and ¹³C NMR, COSY, HSQC, and HMBC) and HRESIMS data as well as by using chemical methods. All the isolates were evaluated not only for their potential neurotrophic activity by means of induction of nerve growth factor (NGF) in C6 glioma cells but also for production of nitric oxide (NO) levels in lipopolysaccharide (LPS)-activated murine microglia BV-2 cells to assess their anti-neuroinflammatory activity. Compounds 1-3 and 7 were stimulants of NGF release, with levels of NGF stimulated at 127.23 ± 1.89%, 128.22 ± 5.45%, 121.23 ± 6.66%, and 120.94 ± 3.97%, respectively. Furthermore, the aglycones of 1 and 2 (1a and 2a) showed more potent NGF secretion activity and anti-neuroinflammatory effect than did their glycosides (1a : 130.81 ± 5.45% and 2a : 134.44 ± 5.45%).

Three New Oleanane-Type Triterpenoidal Glycosides from Impatiens balsamina and Their Biological Activity

Three new oleanane-type triterpenoidal glycosides, imbalosides A-C (1-3), were isolated from the white flowers of Impatiens balsamina. The structures of these phytochemical constituents (1-3) were elucidated through 1D and 2D Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) data analyses followed by chemical methods. All the characterized compounds (1-3) were evaluated for their antiproliferative activity against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and BT549) and their anti-neuroinflammatory activity on the basis of inhibition levels of nitric oxide (NO) in the lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cell lines.

Radiolytic Cyclization Products of Phloridzin as Potent Anti-Glycation Agents

The current research examined for radiolytic structure modification and improved bioefficacy of phloridzin by γ-ray, subsequent to a 50 kGy irradiation dose. Structures of the unusual degraded products phlorocyclin, isophlorocyclin, and radiophlorisin were determined spectroscopically, by detailed nuclear magnetic resonance (NMR) and mass spectrometry (MS). Additionally, absolute configuration of the novel cyclized phlorocyclin and isophlorocyclin were proposed by circular dichroism (CD) spectrum analysis. Among the compounds tested, phlorocyclin and isophlorocyclin exhibit potent antidiabetic complication capacities toward advanced glycation end products (AGEs) formation inhibition assay, with IC₅₀ values of 9.1±0.5 and 13.8±0.7 μM, respectively. Furthermore, the predominantly formed products phlorocyclin and isophlorocyclin exerted significantly enhanced DPPH radical scavenging activity compared to the parent phloridzin. These results indicate that γ-ray mediated cyclization of phloridzin exerts a positive influence on the bioactivity.

LR-HSQMBC versus LR-selHSQMBC: Enhancing the Observation of Tiny Long-Range Heteronuclear NMR Correlations

The detection of ultra-long-range (⁴J_CH and higher) heteronuclear connectivities can complement the conventional use of HMBC/HSQMBC data in structure elucidation NMR studies of proton-deficient natural products, where two-bond and three-bond correlations are usually observed. The performance of the selHSQMBC experiment with respect to its broadband HSQMBC counterpart is evaluated. Despite its frequency-selectivity nature, selHSQMBC efficiently prevents any unwanted signal phase and intensity modulations due to passive proton-proton coupling constants typically involved in HSQMBC. As a result, selHSQMBC offers a significant sensitivity enhancement and provides pure in-phase multiplets, improving the detection levels for short- and long-range cross-peaks corresponding to small heteronuclear coupling values. This is particularly relevant for experiments optimized to small ⁿJ_CH values (2-3 Hz), referred to as LR-selHSQMBC, where key cross-peaks that are not visible in the equivalent broadband LR-HSQMBC spectrum can become observable in optimum conditions.

Unraveling Plant Natural Chemical Diversity for Drug Discovery Purposes

The screening and testing of extracts against a variety of pharmacological targets in order to benefit from the immense natural chemical diversity is a concern in many laboratories worldwide. And several successes have been recorded in finding new actives in natural products, some of which have become new drugs or new sources of inspiration for drugs. But in view of the vast amount of research on the subject, it is surprising that not more drug candidates were found. In our view, it is fundamental to reflect upon the approaches of such drug discovery programs and the technical processes that are used, along with their inherent difficulties and biases. Based on an extensive survey of recent publications, we discuss the origin and the variety of natural chemical diversity as well as the strategies to having the potential to embrace this diversity. It seemed to us that some of the difficulties of the area could be related with the technical approaches that are used, so the present review begins with synthetizing some of the more used discovery strategies, exemplifying some key points, in order to address some of their limitations. It appears that one of the challenges of natural product-based drug discovery programs should be an easier access to renewable sources of plant-derived products. Maximizing the use of the data together with the exploration of chemical diversity while working on reasonable supply of natural product-based entities could be a way to answer this challenge. We suggested alternative ways to access and explore part of this chemical diversity with in vitro cultures. We also reinforced how important it was organizing and making available this worldwide knowledge in an "inventory" of natural products and their sources. And finally, we focused on strategies based on synthetic biology and syntheses that allow reaching industrial scale supply. Approaches based on the opportunities lying in untapped natural plant chemical diversity are also considered.

Natural disesquiterpenoids: an update

This review highlights the progress on the isolation, bioactivity, biogenesis and total synthesis of dimeric sesquiterpenoids since 2010.

Total synthesis of wikstrol A and wikstrol B

The first total synthesis of wikstrol A and wikstrol B was achieved by employing aldol reaction, Sharpless asymmetric dihydroxylation, regioselective iodination, Sonogashira coupling, and rhodium-catalyzed oxidative coupling as key steps. The structure of the key intermediate for wikstrol A was confirmed via its derivative by single-crystal X-ray analysis.

Chemical constituents of the root bark of Ulmus davidiana var. japonica and their potential biological activities

The root bark of Ulmus davidiana var. japonica (Ulmaceae), commonly known as yugeunpi, has been used as a traditional Korean medicine for the treatment of gastroenteric and inflammatory disorders. As part of continuing projects to discover bioactive natural products from traditional medicinal plants with pharmacological potential, phytochemical investigation of the root bark of this plant was carried out. This led to the successful isolation of a new chromane derivative (1) and 22 known compounds: catechin derivatives (2-5), megastigmane glycoside (6), dihydrochalcone glycosides (7 and 8), flavanone glycosides (9 and 10), coumarins (11 and 12), lignan derivatives (13-17), and phenolic compounds (18-23). The structure of the new compound (1) was determined with 1D and 2D NMR spectroscopy and HR-ESIMS, and its absolute configurations were achieved by chemical reactions and the gauge-including atomic orbital (GIAO) NMR chemical shifts calculations. All the isolated compounds were evaluated for their potential biological activities including neuro-protective, anti-neuroinflammatory, and anti-Helicobacter pylori activities. Among the isolates, compounds 1, 8, and 20 displayed stronger potency by causing a greater increase in the production and the activity of nerve growth factor (NGF) in C6 glioma cells (147.04 ± 4.87, 206.27 ± 6.70, and 143.70 ± 0.88%, respectively), whereas compounds 11, 14, and 19 inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine microglial cells (IC₅₀ of 18.72, 12.31, and, 21.40 µM, respectively). In addition, compounds 1, 11, 18, and 20 showed anti-H. pylori activity with MIC values of 25 or 50 µM against two strains of H. pylori 51 and 43504. These findings provide scientific evidence that supports the traditional usage of U. davidiana var. japonica root bark in the treatment of gastroenteric and inflammatory disorders.

Securinega Alkaloids from the Twigs of Securinega suffruticosa and Their Biological Activities

Seven new Securinega alkaloids, securingines A-G (1-7), together with seven known analogues (8-14), were isolated from the twigs of Securinega suffruticosa. Their chemical structures were elucidated by a combined approach of spectroscopic analysis, chemical methods, ECD calculations, and DP4+ probability analysis. The full NMR assignments and the absolute configuration of compound 8 are also reported. In addition, all the isolated phytochemicals (1-14) were assessed for their cytotoxic, anti-inflammatory, and potential neuroprotective activities. Compound 4 showed cytotoxic activity (IC₅₀ values of 1.5-6.8 μM) against four human cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15). Compounds 3, 10, 12, and 13 showed potent inhibitory effects on nitric oxide production (IC₅₀ values of 12.6, 12.1, 1.1, and 7.7 μM, respectively) in lipopolysaccharide-stimulated murine microglia BV-2 cells. Compound 5 exhibited a nerve growth factor production effect (172.6 ± 1.2%) in C6 glioma cells at 20 μg/mL.

Beauvetetraones A–C, phomaligadione-derived polyketide dimers from the entomopathogenic fungus, Beauveria bassiana

Beauvetetraones A–C, phomaligadione-derived polyketide dimers, were isolated from the entomopathogenic fungus Beauveria bassiana using LC/MS-guided isolation and their putative biosynthetic pathway is proposed.

Rare Thioglycosides from the Roots of Wasabia japonica

Six new thioglycosides (1-6) were characterized from the roots of Wasabia japonica along with a known analogue (7). Of these compounds, 1-3 possess a disulfide bridge connecting the carbohydrate motif and the aglycone, which is extremely rare in Nature. In particular, compound 1 forms an unusual 1,4,5-oxadithiocane ring system. The structures of the isolated compounds were determined through conventional NMR and HRMS data analysis procedure, and computational methods with advanced statistics were used for the configurational assignments of 1 and two pairs of inseparable epimers, 2/3 and 4/5. All compounds were evaluated for their anti-inflammatory, neuroprotective, and cytotoxic activities, with 1 showing weak anti-inflammatory activity (IC₅₀ 41.2 μM).

Secoiridoid Glycosides from the Twigs of Ligustrum obtusifolium Possess Anti-inflammatory and Neuroprotective Effects

Two new secoiridoid glycosides, obtusifolisides A and B (1, 2), together with 7 known secoiridoid glycosides (3-9) were isolated from the twigs of Ligustrum obtusifolium. The chemical structures of new compounds were determined by a spectroscopic data analysis, including one and two dimensional (1D-, 2D)-NMR, High resolution-MS, and experiments involving chemical reactions. The isolated secoiridoid glycosides were evaluated for their anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated BV-2 murine microglia cells. Compounds 2, 5, 6, 8, and 9 significantly reduced the production of nitric oxide (NO), with IC₅₀ values of 5.45, 11.17, 14.62, 15.45, and 14.96 µM, respectively. None of the compounds were toxic to the cells. Additionally, we evaluated the neuroprotective effects of compounds 1-9 on nerve growth factor (NGF) induction in a C6 rat glioma cell line. Compounds 2 and 6 upregulated NGF secretion to 155.56±7.16%, and 139.35±11.65%, respectively, without significant cell toxicity.

Multi-Target Screening and Experimental Validation of Natural Products from Selaginella Plants against Alzheimer's Disease

Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder which is considered to be the most common cause of dementia. It has a greater impact not only on the learning and memory disturbances but also on social and economy. Currently, there are mainly single-target drugs for AD treatment but the complexity and multiple etiologies of AD make them difficult to obtain desirable therapeutic effects. Therefore, the choice of multi-target drugs will be a potential effective strategy inAD treatment. To find multi-target active ingredients for AD treatment from Selaginella plants, we firstly explored the behaviors effects on AD mice of total extracts (TE) from Selaginella doederleinii on by Morris water maze test and found that TE has a remarkable improvement on learning and memory function for AD mice. And then, multi-target SAR models associated with AD-related proteins were built based on Random Forest (RF) and different descriptors to preliminarily screen potential active ingredients from Selaginella. Considering the prediction outputs and the quantity of existing compounds in our laboratory, 13 compounds were chosen to carry out the in vitro enzyme inhibitory experiments and 4 compounds with BACE1/MAO-B dual inhibitory activity were determined. Finally, the molecular docking was applied to verify the prediction results and enzyme inhibitory experiments. Based on these study and validation processes, we explored a new strategy to improve the efficiency of active ingredients screening based on trace amount of natural product and numbers of targets and found some multi-target compounds with biological activity for the development of novel drugs for AD treatment.