Gastroprotective 2-(2-phenylethyl)chromone-sesquiterpene hybrids from the resinous wood of Aquilaria sinensis (Lour.) Gilg.

Six previously unprecedented 2-(2-phenylethyl)chromone-sesquiterpene hybrids, aquisinenins A-F (1 - 6), were isolated from the resinous wood of Aquilaria sinensis by a LC-MS-guided fractionation procedure. Their structures were determined by extensive spectroscopic analysis (1D and 2D NMR, UV, IR, and HRMS) and experimental and computed ECD data. Compounds 1 - 6 were rare dimeric 2-(2-phenylethyl)chromone-sesquiterpene derivatives featuring 5,6,7,8-tetrahydro-2-(2-phenylethyl)chromone hybridized with different sesquiterpene (eudesmane/guaiane type) moieties via ester bond. Furthermore, all the isolated compounds were evaluated for their protective effects on taurocholic acid (TCA)-induced GES-1 cell injury. The most effective aquisinenin F (6) was used to elucidate the involved mechanism on protection against TCA-induced gastric mucosal damage. Our results indicated that 6 protected against gastric mucosal cell insult by downregulation of the ER stress triggered by TCA.

[Chemical constituents of diterpenoids from Boswellia carterii].

This paper explored the chemical constituents of Boswellia carterii by column chromatography on silica gel, Sephadex LH-20, ODS column chromatography, and semi-preparative HPLC. The structures of the compounds were identified by physicochemical properties and spectroscopic data such as infrared radiation(IR), ultra violet(UV), mass spectrometry(MS), and nuclear magnetic resonance(NMR). Seven diterpenoids were isolated and purified from n-hexane of B. carterii. The isolates were identified as(1S,3E,7E,11R,12R)-11-hydroxy-1-isopropyl-4,8,12-trimethyl-15-oxabicyclo[10.2.1]pentadeca-3,7-dien-5-one(1),(1R,3S,4R,7E,11E)-4,8,12,15,15-pentamethyl-14-oxabicyclo[11.2.1]hexadeca-7,11-dien-4-ol(2), incensole(3),(-)-(R)-nephthenol(4), euphraticanoid F(5), dilospirane B(6), and dictyotin C(7). Among them, compounds 1 and 2 were new and their absolute configurations were determined by comparison of the calculated and experimental electronic circular dichroisms(ECDs). Compounds 6 and 7 were obtained from B. carterii for the first time.

Phenolic Glucosides from the Leaves of Vitex negundo var. cannabifolia.

Four new phenolic glucosides, cannabifolins G-J (1-4), together with four known ones (5-8), were isolated from the leaves of Vitex negundo var. cannabifolia. Their structures were established by comprehensive analysis of 1D and 2D NMR data and comparison of their spectroscopic and physical data with the literature values. Compound 7 exhibited weak inhibition of nitric oxide production stimulated by lipopolysaccharide in BV-2 microglial cells with IC50 value of 132.8 µM.

[Quality standard of Lobeliae Chinensis Herba].

In light of related methods in Chinese Pharmacopoeia(2020 edition), this study established the quality standard for Lobeliae Chinensis Herba. The TLC identification method was established with silica gel GF_(254) thin layer plate, diosmin standard, linarin standard, and the reference material of Lobeliae Chinensis Herba. The loss on drying, total ash, acid-insoluble ash, and ethanol-soluble extracts of 18 batches of Lobeliae Chinensis Herba samples were determined according to the general principles in Chinese Pharmacopoeia. Then, HPLC was adopted in the establishment of characteristic chromatogram and content determination. The results showed that the established method can achieve good separation for diosmin, linarin, and lobetyolin. Based on the results of detection for 18 batches of Lobeliae Chinensis Herba samples, the draft quality standard was established, which was expected to provide reference for the revision of this medicinal herb in Chinese Pharmacopoeia.

[Sesquiterpenoids from Aquilariae Lignum Resinatum].

Eight sesquiterpenoids were isolated from petroleum ether extract of Aquilariae Lignum Resinatum by various column chromatography techniques including silica gel, ODS, and semi-preparative HPLC. Their structures were identified on the basis of physicochemical properties, UV, IR, MS, and NMR spectroscopic data as(4S,5S,7R,10S)-5,7-dihydroxy-11-en-eudesmane(1),(7R,10S)-eudesma-4-en-11,15-diol(2),(2R,4S,5R,7R)-2-hydroxyeremophila-9,11-dien-8-one(3), 7α-H-9(10)-ene-11,12-epoxy-8-oxoeremophilane(4),(+)-9ß,10ß-epoxyeremophila-11(13)-en(5), 4(14)-eudesmene-8α,11-diol(6), 12,15-dioxo-selina-4,11-dien(7), and 2ß,8 aα-dihydroxy-11-en-eremophilane(8). Compounds 1 and 2 are new compounds, and their absolute configurations were determined by calculating ECD. Compounds 1, 4, and 6-8 could significantly improve taurocholic acid(TCA)-induced gastric mucosal GES-1 cell injury at a concentration of 20 µmol·L~(-1), and the cell protection rates were 23.51%±2.79%, 16.10%±1.25%, 24.45%±4.89%, 17.48%±2.93%, and 21.44%±2.39%, respectively.

Full Collision Energy Ramp-MS2 Spectrum in Structural Analysis Relying on MS/MS.

Albeit frequently being overlooked, MS2 spectrum variation against collision energy (CE) implies auxiliary structural clues for m/z values. Online energy-resolved MS (ER-MS) provides the opportunity to acquire the trajectory of ion intensity against CE for any fragment ion of interest, thus exactly offering the desired momentum to empower the conventional MS2 spectrum at a certain CE forward to a full-CE ramp MS2 spectrum (FCER-MS2). Efforts were made here to construct an FCER-MS2 spectrum and to evaluate its potential toward structural analysis. Flavonoids were employed as a proof of concept. MS2 spectra of 76 compounds were recorded by LC-Q-Exactive-MS, and online ER-MS was subsequently programmed using LC-Qtrap-MS to build a breakdown graph for each obvious fragment ion. After defining the greatest value amongst all regressive apices as 100%, the normalized breakdown graphs comprised an FCER-MS2 spectrum for each compound. The FCER-MS2 spectrum contained the MS2 spectrum at any CE as well as optimal CE (OCE) and maximal relative ion intensity (RIImax) of each fragment ion. Except the pronounced isomeric discrimination potential, either OCE or RIImax reflected certain structural properties, such as aglycone, glycosidic bond, and hydroxy, methoxy, and glycosyl substituents. These rules were subsequently applied for flavonoid-focused characterization of a famous herbal medicine, namely Scutellariae Radix, and high-level structural annotation was accomplished for 75 flavonoids. Above all, the FCER-MS2 spectrum includes m/z, OCEs, and RIImax features, thus facilitating confidence-advanced structural analysis.

[Research on in vivo metabolites of Longxue Tongluo Capsules by liquid chromatography coupled with hybrid ion trap/time-of-flight mass spectrometry].

Longxue Tongluo Capsules(LTC) has good efficacy against blood stasis syndrome during the recovery period of ischemic stroke. Its main active ingredient is the phenolic extract of Chinese dragon's blood. In our previous study, the primary mass fragmentation pathways of phenolic derivatives from LTC were clarified. Herein, the metabolites in rat plasma were characterized following the oral administration of loureirin A and loureirin C using liquid chromatography coupled with hybrid ion trap/time-of-flight mass spectro-metry(LC-IT-TOF-MS), with 18 and 55 metabolites identified, respectively. On this basis, with the help of the obtained accurate molecular weight, characteristic fragment ions, reference comparison, combined with LTC database and natural products database self-created in our group, 18 prototypes and 106 metabolites were tentatively identified in rat plasma after oral gavage of LTC at a dose of 500 mg·kg~(-1). Glucuronidation, sulfonation, and methylation were major biotransformation pathways of LTC. This study preliminarily clarified the LTC constituents absorbed into blood and laid the foundation for clarifying the effective substances of LTC.

[Condensed tannins from roots of Indigofera stachyodes].

Eleven condensed tannins were isolated from the roots of Indigofera stachyodes by various column chromatography techniques including silica gel, octadecyl silica(ODS), Sephadex LH-20, and semi-preparative high performance liquid chromatography(HPLC). These compounds were identified on the basis of physicochemical properties, nuclear magnetic resonance(NMR) and mass spectrometry(MS) data as stachyotannin A(1), epicatechin-(2ß→O→7,4ß→8)-epiafzelechin-(4ß→8)-catechin(2), cinnamtannin D1(3), cinnamtannin B1(4), epicatechin-(2ß→O→7,4ß→8)-epiafzelechin-(4α→8)-epicatechin(5), gambiriin C(6), proanthocyanidin A1(7), proanthocyanidin A2(8), aesculitannin B(9), proanthocyanidin A4(10), and procyanidin B5(11). Compound 1 is a new compound. Compounds 2-11 were isolated from Indigofera for the first time. Furthermore, compounds 1, 2, and 4-11 showed inhibitory effects on thrombin-induced ATP release in platelets.

[One new cembranoid diterpene from gum resin of Boswellia carterii].

This study aims to study the chemical components from the gum resin of Boswellia carterii. Five cembranoid diterpenes were isolated from the gum resin of B. carterii by various of column chromatographies including silica gel, Sephadex LH-20, and semi-preparative HPLC. Their structures were identified on the basis of physicochemical properties, mass spectrometry(MS), nuclear magnetic resonance(NMR), Ultraviolet(UV) and infrared(IR) spectroscopic data. These compounds were identified as(1S,2E,4R,5S,7E,11E)-4-methoxy-5-hydroxycembrane(1),(1R~*,4R~*,5E,8E,12E,15E)-4-hydroxycembra-5,8,12,15-tetraene(2), cembrene A(3),(3S,4S,7R)-4-hydroxycembrane(4), and pavidolide D(5). Compound 1 was a new compound. Compounds 2, 4, and 5 were obtained from the gum resin of B. carterii for the first time. Compound 2 showed weak inhibition on the human liver cancer cell line HepG2.

Retention Time and Optimal Collision Energy Advance Structural Annotation Relied on LC-MS/MS: An Application in Metabolite Identification of an Antidementia Agent Namely Echinacoside.

The structural annotation of metabolites now relies heavily on HR-MS/MS information, resulting in ambiguous identities in most cases. More auxiliary evidence is therefore desired to achieve confirmative identification. Herein, we made an attempt to involve retention time (tR) along with optimal collision energy (OCE) as the additionally structural clues, and the applicability validation was conducted via confidence-enhanced metabolite characterization of echinacoside, an antidementia drug candidate within clinical trials. Quantitative structure-retention relationships (QSRR) were modeled via assaying 184 authentic compounds on RPLC, HILIC, and serially coupled RPLC and HILIC (RPLC-HILIC). Online energy-resolved MS was developed to yield breakdown graphs for selected ion transitions, and OCE was demonstrated to be superior to CE50 toward pointedly denoting the bonds-of-interest. Nineteen metabolites (M1-M19) were confidently identified in biological samples from echinacoside-treated rats by analyzing m/z values first to yield empirical formulas and substructures, and tR and OCE subsequently contributed to sift the candidate structures. Structural identification was validated by oral administration of three relevant compounds in parallel and chromatographic purification as well. Above all, the integration of retention and dissociation behaviors enabled promoting one step forward for structural annotation confidences merely relied on HR-MS/MS.

Anti-inflammatory Dimeric 2-(2-Phenylethyl)chromones from the Resinous Wood of Aquilaria sinensis.

Sixteen new 2-(2-phenylethyl)chromone dimers, including four pairs of enantiomers (1a/1b, 3a/3b, 6a/6b, and 8a/8b), along with eight optically pure analogues (2, 4, 5, 7, and 9-12) were isolated from the resinous wood of Aquilaria sinensis. Their structures were determined by extensive spectroscopic analysis (1D and 2D NMR, UV, IR, and HRMS) and experimental and computed ECD data. Compounds 1-10 feature an unusual 3,4-dihydro-2 H-pyran ring linkage connecting two 2-(2-phenylethyl)chromone monomeric units, while compounds 11 and 12 possess an unprecedented 6,7-dihydro-5 H-1,4-dioxepine moiety in their structures. A putative biosynthetic pathway of the representative structures via a diepoxy derivative of a chromone with a nonoxygenated A-ring is also proposed. Compounds 1a/1b, 2, 3a/3b, 5, 7, 8a/8b, and 10-12 exhibited significant inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC50 values in the range 7.0-12.0 µM.

[Phenylpropanoid amides from whole plants of Corydalis edulis].

Ten phenylpropanoid amides were isolated from the whole plants of Corydalis edulis Maxim. by various of column chromatographies including silica gel, Sephadex LH-20, and ODS. Their structures were identified on the basis of physicochemical properties, MS, NMR, and IR spectroscopic data. These compounds were identified as N-trans-sinapoyl-3-methoxytyramine-4'-O-ß-glucoside(1), N-trans-sinapoyl-3-methoxytyramine(2), N-trans-sinapoyltyramine(3), N-trans-p-coumaroyltyramine(4), N-trans-sinapoyl-7-hydroxytyramine(5), N-cis-feruloyltyramine(6), N-cis-p-coumaroyltyramine(7), N-trans-feruloyltyramine(8), N-trans-feruloyl-3-methoxytyramine(9), and N-trans-feruloyl-7-hydroxytyramine(10). Compound 1 is a new compound. Compounds 2-7 are obtained from the plants of Papaveraceae for the first time, while compounds 8-10 are firstly isolated from C. edulis.

[Chemical constituents from the fruits of Vitex negundo var. cannabifolia and their biological activities in vitro].

Chemical constituents from the fruits of Vitex negundo var. cannabifolia and their nitric oxide (NO) inhibitory and cytotoxic activities were investigated. The compounds were isolated and purified by various column chromatography, and their structures were identified by physiochemical properties and spectroscopic data. Thirteen lignans and six phenolic compounds were isolated from the CH2Cl2 extract of the fruits of V. negundo var. cannabifolia, respectively. Their structures were elucidated as 6-hydroxy-4-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaldehyde (1), vitedoin A (2), vitexdoin F (3), detetrahydroconidendrin (4), vitexdoin E (5), 4-oxosesamin (6), L-sesamin (7), (+)-beechenol (8), ligballinol (9), 2-(4-hydroxyphenyl)-6-(3-methoxy-4-hydroxyphenyl)-3,7-dioxabicyclo[3.3.0]octane (10), (-)-pinoresinol (11), balanophonin (12), thero-guaiacylglycerol-ß-coniferyl aldehyde ether (13), trans-p-coumaryl aldehyde (14), coniferyl aldehyde (15), 5,7-dihydroxychromone (16), trans-3,5-dimethoxy-4-hydroxy-cinnamic aldehyde (17), frambinone (18), and alternariol 4-methyl ether (19). Compounds 8-10,14,18,19 were firstly isolated from Verbenaceae family, compound 13 was obtained from Vitex species, and 6,7,12,15-17 from V. negundo var. cannabifolia for the first time, respectively. The isolated compounds were evaluated for their anti-inflammatory and cytotoxic effects in vitro. Eight compounds (3,5,7,10,11,14,15,17) showed inhibition against NO production in LPS-stimulated RAW 267.4 cells (IC50 in the range of 7.8-81.1 µmol•L⁻¹) and four compounds (1-4) showed cytotoxicity on HepG-2 cells (IC50 in the range of 5.2-24.2 µmol•L⁻¹).

[Flavonoids from whole plants of Lagopsis supina].

The flavonoids were investigated from the whole plants of Lagopsis supina. The compounds were isolated and purified by various column chromatography, and their structures were identified by physiochemical properties and spectroscopic data. Two flavones were isolated from the CH2Cl2 layer of Lagopsis supina extract and identified as genkwanin (1) and 5-hydroxy-7,4'-dimethoxyflavone (2), respectively. Ten flavonoid glycosides were isolated from the water layer of Lagopsis supina and elucidated as kaempferol-3-O-6" (3-hydroxy-3-methylglutaryl) -ß-D-glucoside (3), quercetin-3-O-6"-(3-hydroxy-3-methylglutaryl) -ß-D-glucoside (4), quercetin-3-O-ß-D-glucoside(5), kaempferol-3-Of3-D-glucoside ( 6), isorhamnetin-3-O-/-D-glycopyranoside (7), apigenin-7-O-6-D-glucoside (8), luteolin-7-O-ß-D-glucoside (9), chrysoeriol-7-O-ß-D-glucoside (10), rutin (11 ), and kaempferol-3-ß-(6"-p-coumaroyl) -ß-D-glucoside (tiliroside, 12). Compounds 3 and 4 were firstly isolated from Lamiaceae family, and compounds 1-12 were isolated from the plants of Lagopsis genus for the first time.

QSAR Research of Novel Tetrandrine Derivatives against Human Hepatocellular Carcinoma.

BACKGROUND: The new tetrandrine derivative is an anti-human liver cancer cell inhibitor which can be used to design and develop anti-human-liver-cancer drugs. OBJECTIVE: A quantitative structure-activity relationship (QSAR) model was established to predict the physical properties of new tetrandrine derivatives using their chemical structures. METHODS: The best descriptors were selected through CODESSA software to build a multiple linear regression model. Then, gene expression programming (GEP) was used to establish a nonlinear quantitative QSAR model with descriptors to predict the activity of a series of novel tetrandrine chemotherapy drugs. The best active compound 31 was subjected to molecular docking experiments through SYBYL software with a small fragment of the protein receptor (PDB ID:2J6M). RESULTS: Four descriptors were selected to build a multiple linear regression model with correlation coefficients R2, R2CV and S2 with the values of 0.8352, 0.7806 and 0.0119, respectively. The training and test sets with a correlation coefficient of 0.85 and 0.83 were obtained via an automatic problem-solving program (APS) using the four selected operators as parameters, with a mean error of 1.49 and 1.08. Compound 31 had a good docking ability with an overall score of 5.8892, a collision rate of -2.8004 and an extreme value of 0.9836. CONCLUSION: The computer-constructed drug molecular model reveals the factors affecting the activity of human hepatocellular carcinoma cells, which provides directions and guidance for the development of highly effective anti-humanhepatocellular- carcinoma drugs in the future.

Formation Mechanism of Di-N-ethyl-2-pyrrolidinone-Substituted Epigallocatechin Gallate during High-Temperature Roasting of Tea.

Four di-N-ethyl-2-pyrrolidinone-substituted epigallocatechin gallate (EGCG) and two di-N-ethyl-2-pyrrolidinone-substituted gallocatechin gallate (GCG) flavan-3-ols (di-EPSFs) were prepared by the thermal simulation reaction. The effects of reaction temperature and time, initial reactant ratios, and pH values on the content of di-EPSFs were studied. The formation of six di-EPSFs was most favored when the initial reactant ratio of EGCG and theanine was 1:2 and heated under 130 °C at pH 10 for 120 min. The contents of di-EPSF1, di-EPSF2, and di-EPSF5 in large-leaf yellow tea (LYT) increased with the increase of roasting degree. Through quantitative analysis, it was found that EGCG would interact with the Strecker degradation products of theanine to form EPSFs, which further combined with the Strecker degradation products of theanine to form di-EPSFs. This study further improved the understanding of the transformation pathways of EGCG and theanine during tea processing and contributed to exploring the flavor characteristics and health benefits of di-EPSFs.

Neuroprotective effects of Longxue Tongluo Capsule on ischemic stroke rats revealed by LC-MS/MS-based metabolomics approach.

Objective: The present study aimed to evaluate the therapeutic effect and explore the underlying mechanisms of Longxue Tongluo Capsule (LTC) on ischemic stroke rats. Methods: Twenty-six rats were randomly divided into four groups, including sham group, sham + LTC group, MCAO group, and MCAO + LTC group. Ischemic stroke rats were simulated by middle cerebral artery occlusion (MCAO), and LTC treatment group were orally administrated with 300 mg/kg of LTC once daily for seven consecutive days. LTC therapy was validated in terms of neurobehavioral abnormality evaluation, cerebral infarct area, and histological assessments. The plasma metabolome comparisons amongst different groups were conducted by UHPLC-Q Exactive MS in combination with subsequent multivariate statistical analysis, aiming to finding the molecules in respond to the surgery or LTC treatment. Results: Intragastric administration of LTC significantly decreased not only the neurobehavioral abnormality scores but also the cerebral infarct area of MCAO rats. The interstitial edema, atrophy, and pyknosis of glial and neuronal cells occurred in the infarcted area, core area, and marginal area of cerebral cortex were improved after LTC treatment. A total of 13 potential biomarkers were observed, and Youden index of 11 biomarkers such as LysoPC, SM, and PE were more than 0.7, which were involved in neuroprotective process. The correlation and pathway analysis showed that LTC was beneficial to ischemic stroke rats via regulating glycerophospholipid and sphingolipid metabolism, together with nicotinate and nicotinamide metabolism. Heatmap and ternary analysis indicated the synergistic effect of carbohydrates and lipids may be induced by flavonoid intake from LTC. Conclusion: The present study could provide evidence that metabolomics, as systematic approach, revealed its capacity to evaluate the holistic efficacy of TCM, and investigate the molecular mechanism underlying the clinical treatment of LTC on ischemic stroke.

Novel Oxidation Oligomer of Chlorogenic Acid and (-)-Epigallocatechin and Its Quantitative Analysis during the Processing of Keemun Black Tea.

Not only do flavan-3-ols participate in the formation of chromogenic oxidation products such as theaflavins, but chlorogenic acid (3-caffeoylquinic acid, CQA) is also involved in the enzymatic oxidation during black tea processing. The critical oxidation product of CQA and (-)-epigallocatechin (EGC) were identified as an adduct containing benzobicyclo[3.2.2]nonenone structure, which was named as the dichlorogeniccatechin (DCGC) oligomer. It was composed of two molecules of CQA and one molecule of EGC. The effects of the initial reactant ratio and reaction time on the generation of DCGC were also analyzed. A high proportion of CQA promoted the production of DCGC, but a high proportion of EGC inhibited the DCGC formation. In addition, the content of DCGC in Keemun black tea during processing was determined. The content of DCGC highly increased after withering but decreased after drying. This study provides a new perspective for the investigation of other oxidation oligomers in black tea.

Anti-inflammatory flavonoid derivatives from the heartwood of Dalbergia odorifera T. Chen.

Two pairs of flavonoid enantiomers (1a/1b and 2a/2b) together with three known analogues (3-5) were isolated from the heartwood of Dalbergia odorifera T. Chen. Their structures were elucidated by extensive spectroscopic analysis (1 D and 2 D NMR, UV, IR, and HRMS) and experimental and calculated ECD data. Compound 2 features an unusual 2-methyl-3(2H)-furanone moiety forming the C-ring of flavonoid, and its putative biosynthetic pathway is also proposed. Compounds 3‒5 exhibited significant inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC50 values of 14.7 ± 0.3 µM, 40.2 ± 1.1 µM, and 3.2 ± 0.1 µM, respectively.

Isoquinoline alkaloids from Corydalis edulis Maxim. Exhibiting insulinotropic action.

Eleven undescribed isoquinoline analogues, namely edulisines A-K, along with sixteen known alkaloids, were isolated from the whole plants of Corydalis edulis. The structures of the isolated alkaloids were established on the basis of extensive spectroscopic data (1D and 2D NMR, UV, IR, and HRESIMS). Their absolute configurations were determined by single-crystal X-ray crystallographic analysis and ECD. Compounds (+)-1 and (-)-1 are a pair of undescribed isoquinoline alkaloids bearing a unique coupled pattern of coptisine and ferulic acid via Diels-Alder [4 + 2] cycloaddition, while compounds (+)-2 and (-)-2 feature benzo [1,2-d:3,4-d]bis [1,3]dioxole moiety. Compounds (+)-2, (-)-2, (-)-5, 10, 13, 15, 20, 22, and 23 significantly triggered the secretion of insulin in the HIT-T15 cells at a concentration of 40 µM.