Cytotoxic sesquiterpene aryl esters from Armillaria gallica 012m

Objective: To study the chemical constituents from the EtOAc extract of Armillaria gallica 012m. Methods: The chemical constituents of the EtOAc extract of A. gallica 012m were isolated and purified by various column chromatography and their structures were elucidated on the basis of the 1D and 2D NMR spectroscopic and HRESIMS data. Cytotoxicity of all isolates against A549, HCT-116, M231 and W256 human tumor cells was determined by the MTT method. Results: A new sesquiterpene aryl ester, armimelleolide C (1), and eight known ones including armillarivin (2), melleolide F (3), 6''-chloromelleolide F (4), melleolide (5), melleolide K (6), melledonol (7), 13-hydroxydihydromelleolide (8), and armillane (9), were isolated from the EtOAc extract of A. gallica 012m. All isolates showed potential cytotoxic activities against at least one of the human cancer cell lines with IC50 values ranging from (3.17 ± 0.54) to (17.57 ± 0.47) μmol/L. Compound 1 showed significant inhibitory activity against M231 with an IC50 value of (7.54 ± 0.24) μmol/L compared with paclitaxel as the positive control. Compounds 2, 3, and 7, 9 showed obvious inhibitory activity against HCT-116 and were better than that of the positive control. Conclusion: The chemical constituents including a new sesquiterpene aryl ester armimelleolide C (1) from the EtOAc extract of A. gallica 012m have a variety of structures and potential antitumor activities.     

白芷中七个新的3,4-二氢呋喃香豆素衍生物

Objective: To study the chemical constituents of the roots of Angelica dahurica, a well-known Chinese herbal medicine named Baizhi in Chinese. Methods: Compounds were separated by various chromatographies, and the structures of the new compounds were elucidated based on the analysis of their spectroscopic and spectrometric data (1D, 2D NMR, HRESI MS, IR, and UV). The absolute configurations of the new compounds were determined by the calculated electronic circular dichroism and chemical derivatization. The inhibitory activities of all isolates against nitric oxide (NO) production were evaluated using lipopolysaccharide-activated RAW 264.7 macrophage cells. Results: Seven new 3,4-dihydro-furanocoumarin derivatives (1a/1b, 2a/2b, 3a/3b, 4) together with a known furanocoumarin (5) were isolated from the roots of A. dahurica. The new compounds included three pairs of enantiomers, (4S, 2′′R)-angelicadin A (1a)/(4R, 2′′S)-angelicadin A (1b), (4S, 2′′S)-angelicadin A (2a)/(4R, 2′′R)-angelicadin A (2b), and (4S, 2′′S)-secoangelicadin A (3a)/(4R, 2′′R)-secoangelicadin A (3b), together with (4R, 2′′R)-secoangelicadin A methyl ester (4). The known xanthotoxol (5) inhibited the NO production with the half-maximal inhibitory concentration (IC50) value of (32.8±0.8) μmol/L, but all the new compounds showed no inhibitory activities at the concentration of 100 μmol/L. Conclusion: This is the first report of the discovery of 3,4-dihydro-furanocoumarins from A. dahurica. The results are not only meaningful for the understanding of the chemical constituents of A. dahurica, but also enrich the reservoir of natural products.     

Chemical constituents from acid hydrolyzates of Panax quinquefolius total saponins and their inhibition activity to α-glycosidase and protein tyrosine phosphatase 1B

Objective: To investigate the hypoglycemic components from the acid hydrolyzates of Panax quinquefolius total saponins, and screen the active compounds by in vitro inhibitory activities to α-glycosidase enzymes and protein tyrosine phosphatase-1 B(PTP1 B).Methods: The hydrolyzates were chromatographed repeatedly over silica gel column, and the structures of the compounds were determined by means of NMR. The in vitro bioassay was performed through the inhibitory effects on α-glucosidase or/and PTP1 B.Results: Eight compounds were isolated, which identified as 20(S)-panaxadiol(1),(20 S,24 R)-dammarane-20,24-epoxy-3β,6α,12β,25-tetraol(2), 20(R)-dammarane-3β,12β,20,25-tetraol(3), 20(S)-dammarane-3β,6α,12β,20,25-pentol(4), 20(R)-dammarane-3β,12β,20,25-tetrahydroxy-3β-O-β-D-glucopyranoside(5),β-sitosterol(6), oleanolic acid(7) and 20(S)-protopanaxadiol(8). Compound 5 was ginseng triterpenoid isolated from the acid hydrolysates of total saponins from P. quinquefolius for the first time. In this paper,the possible in vitro inhibitory activities were investigated. Compound 5 exhibited significantly inhibitory activity against α-glucosidase, and the IC50 value [(0.22 ± 0.21) μmol/L] was about 43-fold lower than positive control. For the PTP1 B inhibition assay, compound 5 indicated the strongest inhibitory effect with IC50 of(5.91 ± 0.38) μmol/L, followed by compound 4 with IC50 of(6.21 ± 0.21) μmol/L, which were all showed competitive inhibitory pattern by using a Lineweaver-Burk plot.Conclusion: These results supported the potential application of dammaranes from acid hydrolyzates of P. quinquefolius total saponins can be used as ingredients of ancillary anti-diabetic agent or functional factor.     

Two new terpenoids from Reduning Injection

Objective: To study the antipyretic and anti-inflammatory constituents from the active fraction of Reduning(RDN) Injection.Methods: In this study, the active fraction of RDN Injection was screened by the LPS-induced mouse endotoxin shock model. The chemical constituents were isolated by chromatography on HP-20 macroporous adsorptive resins, silica gel, ODS columns and reverse phase MPLC and HPLC repeatedly, and their structures were elucidated based on spectroscopic analysis(HR-ESI-MS, NMR, ECD) and chemical methods.Meanwhile, we evaluated the anti-inflammatory activities of the isolates by measuring their inhibitory effects on TNF-α production in LPS stimulated RAW 264.7 macrophages.Results: The 95% ethanol eluate of RDN Injection by the macroporous adsorption resin column was proved to be the antipyretic and anti-inflammatory active fraction of this injection. A novel iridoid, named jasminoide A(1), and a new guaiane sesquiterpenoid, named(1 R,7 R,8 S,10 R)-7,8,11-trihydroxy-4-guaien-3-one(2), were isolated from Reduning injection, and compound 2 can inhibit TNF-α production with IC50 values of 72.24 μmol/L.Conclusion: In this study, two new terpenoids were isolated from Reduning Injection, and compound 2 showed inhibitory activity against LPS-activated TNF-α production in RAW 264.7 cells in vitro.     

New phenolic constituents obtained from Polygonum multiflorum

Objective: To isolate the phenolic compounds obtained from the dried roots of Polygonum multiflorum and investigate their pharmacological activities. Methods: The chemical constituents were isolated and purified by combining them with a macroporous resin (DM-8), MCI gel, and Sephadex LH-20 and by performing ODS column chromatography. Their structures were elucidated by 1D and 2D NMR analyses, as well as mass spectrometry. The isolated compounds were evaluated to determine their hepatoprotective and α-glucosidase inhibitory activities in vitro. Results: Two phenolic compounds, namely, polygonimitin E (1) and polygonimitin F (2), were isolated from the dried roots of P. multiflorum. Compound 2 (10 μmol/L) only showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage. Unfortunately, these two compounds exhibited no α-glucosidase inhibitory activity. Conclusion: Compounds 1 and 2 were new compounds. Compound 2 could be one of the potential hepatoprotective constituents of P. multiflorum.     

Chemical Constituents from Barks of Lannea coromandelica

Objective To study the chemical constituents from the barks of Lannea coromandelica.Methods The chemical constituents were isolated and purified by column chromatography on silica gel column.NMR spectra were used for structural identification.Results Thirteen compounds were isolated and identified as quercetin(1),(2S,3S,4R,10E)-2-[(2′R)-2′-hydroxytetracosanoyl amino]-10-octadecene-1,3,4-triol(2),aralia cerebroside(3),5,5′-dibuthoxy-2,2′-bifuran(4),β-sitosteryl-3β-glucopyranoside-6′-O-palmitate(5),β-sitosterol palmitate(6),myricadiol(7),protocatechuic acid(8),p-hydroxybenzoic acidethyl ester(9),isovanillin(10),transcinnamic acid(11),palmitic acid(12),and stearic acid(13).Conclusion Compounds2-13 are isolated from this plant for the first time.     

HPLC analysis of 16 compounds from Artemisia ordosica

Objective: To establish a high-performance liquid chromatographic method (HPLC) for the simultaneous determination of sixteen compounds from Artemisia ordosica. Methods: HPLC was used to analyze 16 quality indicators of A. ordosica. The HPLC conditions were as follows: Agilent Eclipse Plus C18 column (250 mm × 4.6 mm, 5 μm) with acetonitrile (A)-water (B) as mobile phase, gradient elution: 0?10 min, 75%?65% B; 10?30 min, 65%?35 % B; and finally 30?40 min, 35%?15% B. The flow rate was 1.0 mL/min, the column temperature was 40 °C, the injection volume was 10 μL, and monitored by absorbance at 285 nm for compounds 1?10, 12 and 225 nm for compounds 11, 13?16. Results: Under the selected experimental chromatographic conditions, compounds 1?16 showed good linearity (r > 0.9993) in a wide concentration range. Their average recoveries were 99.50%, 95.38%, 97.75%, 96.00%, 98.20%, 97.50%, 95.50%, 99.33%, 96.75%, 96.50%, 98.50%, 97.83%, 99.20%, 95.33%, 97.33% and 96.30%, respectively, and the RSD were 1.99%, 1.81%, 1.63%, 1.98%, 1.67%, 1.92%, 1.74%, 1.67%, 1.90%, 1.72%, 1.88%, 1.83%, 1.79%, 1.76%, 1.81% and 1.96%, respectively. Conclusion: Based on the results of the HPLC analysis, it was concluded that p-hydroxycinnamic acid (1), O-hydroxycinnamic acid (2), coniferyl alcohol (5), 5,4''-dihydroxy-7,3''-dimethoxyflavanone (8), 5,4''-dihydroxy-7-methoxyflavanone (9), 5-hydroxy-7,4''-dimethoxyflavanone (12), dehydrofalcarindiol (13), arteordoyn A (14), dehydrofalcarinol (15) and capillarin (16) are best suited for the role of quality indicators of A. ordosica grown in different ecological environments.     

Chemical constituents from leaves of Jatropha curcas

Objective: To investigate the chemical constituents from the leaves of Jatropha curcas and evaluate their inhibition on lipopolysaccharide (LPS)-activated BV-2 microglia cells. Methods: The n-BuOH extract of the leaves of J. curcas was isolated by macroporous adsorption resin, silica gel, ODS, column chromatography and semi-preparative HPLC. The structures of the compounds were identified by MS, NMR, ECD, and other spectroscopic methods. In addition, anti-neuroinflammatory effects of isolated compounds were evaluated by measuring the production of nitric oxide (NO) in over-activated BV-2 cells. Results: Seventeen compounds, including (7R,8S)-crataegifin A-4-O-β-D-glucopyranoside (1), (8R,8''R)-arctigenin (2), arctigenin-4''-O-β-D-glucopyranoside (3), (-)-syringaresinol (4), syringaresinol-4''-O-β-D-glucopyranoside (5), (-)-pinoresinol (6), pinoresinol-4''-O-β-D-glucopyranoside (7), buddlenol D (8), (2R,3R)-dihydroquercetin (9), (2S,3S)-epicatechin (10), (2R,3S)-catechin (11), isovitexin (12), naringenin-7-O-β-D-glucopyranoside (13), chamaejasmin (14), neochamaejasmin B (15), isoneochamaejasmin A (16), and tomentin-5-O-β-D-glucopyranoside (17) were isolated and identified. Compounds 2, 4 and 8 significantly inhibited the release of NO in BV-2 microglia activated by LPS, with IC50 values of 18.34, 29.33 and 26.30 μmol/L, respectively. Conclusion: Compound 1 is an undescribed compound, and compounds 2, 3, 8, 14–17 are isolated from Jatropha genus for the first time. In addition, lignans exhibited significantly inhibit NO release and the inhibitory activity was decreased after glycosylation.     

Chemical Constituents from Dried Aerial Parts of Eclipta prostrata

Objective To study the constituents in the dried aerial parts of Eclipta prostrata.Methods The constituents were isolated and purified by column chromatography and their structures were elucidated by spectroscopic methods(1D,2D NMR,UV,IR,and HRESI-TOF-MS)and chemical analyses.Results Eight compounds were isolated and identified as 7-O-methylorobol-4′-O-β-D-glucopyranoside(1),3′-hydroxybiochanin A(2),echinocystic acid28-O-β-D-glucopyranoside(3),ecliptasaponin A(4),eclalbasaponin I(5),eclalbasaponin IV(6),echinocystic acid(7),and 3-oxo-16α-hydroxy-olean-12-en-28-oic acid(8).Conclusion Compound 1 is a new compound and compound 3 is obtained from this genus for the first time.     

Chemical constituents of Lomatogonium carinthiacum and Halenia corniculata

Objective: To study the chemical constituents from traditional characteristic Lomatogonium carinthiacum and Halenia corniculate. Methods: The chemical constituents were isolated and purified by silicagel column, Sephadex LH-20, ODS and high performance liquid chromategramphy. The structures were identified by NMR and MS analysis technics. Results: Twelve compounds were isolated and identified as isovitexin (1), Luteolin-5-O-β-D-glucoside (2), Isosaponarin (3), Luteolin-7-O-β-D-glucoside (4,7), 1,4,8-Trimethoxy-xanthone-6-O-β-D-glucoronyl-(1→6)O-β-Dglucoside (5), friginosideD (6), 1-hydroxy-2,3,5-trimethoxyxanthone (8), 1-hydroxy-2,3,4,5-tetramethoxyxanthone (9), 1-hydroxy-2,3,4,7-tetramethoxyxanthone(10), 1-hydroxy-2,3,4,5,7-pentamethoxyxanthone (11) and usnic acid (12). Conclusion: Compounds 6 and 12 are obtained from this medicine for the first time.     

Antioxidation and active constituents analysis of flower residue of Rosa damascena

ObjectiveTo make full usage of resource and turn waste into treasure, the chemical constituents and bioactivity were firstly investigated on Damask rose (Rosa damascena) flower residue (DRFR).MethodsDPPH and ABTS experiments were applied to assess the antioxidant activity of DRFR. Then, column chromatography was used to purify compounds from an antioxidation extract (DRFR-A), and the chemical structure was identified using NMR. The total phenolic acid content was measured by Folin-Ciocalteu colorimetric method, and the content of gallic acid of the indicator ingredient was detected by HPLC.ResultsDRFR-A was found to show a high activity both on DPPH (IC₅₀: 2.760 µg/mL) and ABTS (IC₅₀: 2.258 µg/mL) compared to positive control V_C. Ten compounds were isolated and identified as quercetin (1), kaempferol (2), gallic acid (3), protocatechuic acid (4), pyrogallic acid (5), 2-phenylethyl 3,4,5-trihydroxybenzoate (6), methyl gallate (7), p-hydroxybenzoic acid (8), p-hydroxyphenethyl alcohol (9) and astragalin (10) from DRFR-A. Among them, pyrogallic acid, 2-phenylethyl-3, 4, 5-trihydroxybenzoate, p-hydroxybenzoic acid and p-hydroxyphenethyl alcohol are obtained from the plant for the first time. The content of total phenolic acids and gallic acid, main ingredient in DRFR-A was determined as 63.73% and 24.67%, respectively.ConclusionThis study provides a reliable data and lays the foundation for the development and utilization of rose residue, and hence for the full utilization of rose resources.     

Functional and binding studies of gallic acid showing platelet aggregation inhibitory effect as a thrombin inhibitor

Objective: This study was devoted to identifying natural thrombin inhibitors from traditional Chinese medicine (TCM) and evaluating its biological activity in vitro and binding characteristics. Methods: A combination strategy containing molecular docking, thrombin inhibition assay, surface plasmon resonance (SPR) and molecular dynamics simulation were applied to verify the study result. Results: Gallic acid was confirmed as a direct thrombin inhibitor with IC50 of 9.07 μmol/L and showed a significant inhibitory effect on thrombin induced platelet aggregation. SPR-based binding studies demonstrated that gallic acid interacted with thrombin with a KD value of 8.29 μmol/L. Molecular dynamics and binding free energy analysis revealed that thrombin-gallic acid system attained equilibrium rapidly with very low fluctuations, the calculated binding free energies was ?14.61 kcal/mol. Ala230, Glu232, Ser235, Gly258 and Gly260 were the main amino acid residues responsible for thrombin inhibition by gallic acid, providing a mechanistic basis for further optimization. Conclusion: This study proved that gallic acid is a direct thrombin inhibitor with platelet aggregation inhibitory effect, which could provide a basis for the follow-up research and development for novel thrombin inhibitors.     

Saponins from Roots of Panax notoginseng

Objective To study the chemical constituents in the dried roots of Panax notoginseng.Methods The constituents were isolated and purified with chromatographic methods.Their structures were elucidated by spectroscopic methods(1D,2D NMR,UV,IR,[α]D,and HRESI-TOF-MS)and chemical analyses.Results Twenty saponins including 20(S)-ginsenoside Rh1(1),6-O-β-D-(6′-acetyl)-glucopyranosyl-24-ene-dammar-3β,6α,12β,20S-tetraol(2),ginseno-side Rf(3),notoginsenoside R2(4),ginsenoside Rg2(5),ginsenoside Rg1(6),notoginsenoside Rt(7),koryoginsenoside R1(8),6-O-(β-D-glucopyranosyl)-20-O-(β-D-xylopyranosyl)-3β,6α,12β,20(S)-tetrahydroxy-dammar-24-ene(9),pseudoginsenoside Rt3(10),notoginsenoside R1(11),ginsenoside Re(12),notoginsenoside N(13),ginsenoside F1(14),ginsenoside U(15),ginsenoside Rk3(16),3β,12β-dihydroxydammar-(E)-20(22),24-diene-6-O-β-D-xylopyranosyl-(1→2)-β-D-glucopyranoside(17),ginsenoside Rh4(18),pseudoginsenoside Rt5(19),and vinaginsenoside R22(20)were obtained.Conclusion Compounds 2,19,and 20 are isolated from this species for the first time.The 1H-NMR data of compound 19 and1H-NMR and 13C-NMR data of compound 20 are first reported.Meanwhile,the NMR data ofβ-D-xylopyranosyl group in compound 9 is corrected.     

苏木种子的化学成分研究

目的研究苏木Caesalpinia sappan种子的化学成分。方法采用柱色谱方法对苏木种子95%甲醇提取物进行分离纯化,结合波谱技术与化学方法进行结构鉴定。结果从苏木种子95%甲醇提取物中分离得到了14个化合物,结构鉴定为phanginin F(1)、phanginin G(2)、phanginin H(3)、phanginin I(4)、phanginin J(5)、phanginin K(6)、phanginin L(7)、phanginin M(8)、柚皮素(9)、homoeriodictyol(10)、steraric acid(11)、1H-azirino[1,2-a]indole(12)、serlyticin A(13)、山柰酚(14)。结论化合物9~14为首次从云实属植物中分离得到。     

Chemical constituents from aerial parts of Scoparia dulcis

Objective: To study the chemical constituents from the aerial parts of Scoparia dulcis. Methods: Various chromatographic techniques were used to separate the constituents and their structures were elucidated using spectroscopic methods and by comparing their data to those reported in the literatures. The α-glucosidase inhibitory activity assay was used to identify potential α-glucosidase inhibitors. Results: Nine compounds were isolated from the aerial parts of S. dulcis. Their structures were identified as Scoparic zolone (1), (2S)-2,7-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (2), (2R)-7-hydroxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-D-glucopyranoside (3), (2R)-7-methoxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-D-glucopyranoside (4), (2S)-7-hydroxy-2H-1,4-benzoxazin-3(4H)-one-2-O-β-D-glucopyranoside (5), 6-methoxy-benzoxazolin-2(3H)-one (6), 4-acetonyl-3,5-dimethoxy-p-quinol (7), zizyvoside I (8), and 3,4-dihydroxy benzeneacetic acid (9). Compound 2 showed the potent α-glucosidase inhibitory activity with an IC50 value of (132.8 ± 11.5) μmol/L, which is 28-fold higher than the positive control acarbose. Conclusion: Compound 1 is a new natural product. Compounds 2 and 9 have not been reported in Scoparia before. Compounds 3, 5, 7, 8 are isolated from Scrophulariaceae for the first time.     

A New Phenylpropanol Glycoside and Its Five Known Analogues from Boschniakia rossica

Objective To study the constituents in the whole plant of Boschniakia rossica. Methods The constituents were separated and purified with chromatographic methods. Their structures were elucidated by spectroscopic methods (1D, 2D NMR, UV, IR, and HRESI-TOF-MS) and chemical analyses. Results One new phenylpropanol glycoside (1) and its five known analogues were obtained from B. rossica. They were identified as trans-p-coumaryl- (2′-O-β-D-glucopyranosyl)-β-D-glucopyranoside (1), salidroside I (2), rossicasin A (3), trans-p-coumaryl alcohol 1-O-β-glucopyranosyl(1→4)-α-rhamnopyranosyl(1→3)-β-glucopyranoside (4), salidroside (5), and acetoside (6). Conclusion Among the known compounds, compound 2 is firstly isolated from the plants in genus Boschniakia C. A. Mey. ex Bongard. Meanwhile, the 13 C-NMR data of 9 and 4′ positions in compound 4 are corrected.     

Chemical Constituents with Antihyperlipidemic Activities from Desmodium triquetrum

Objective To study the chemical constituents from Desmodium triquetrum and their antihyperlipidemic activities. Methods The constituents of D. triquetrum were isolated and purified using various column chromatographies. Their chemical structures were elucidated using extensive spectroscopic methods. The lipid-lowering effects of the isolates were evaluated in HepG2 cells. Results Nine compounds were obtained from the ethanol extract of D. triquetrum and determined to be 6′-O-cis-p-coumaroyl-3,5-dihydroxyphenyl-β-D-glucopyranoside(1), tadehaginoside(2), rutin(3), quercetin-3-O-β-D-glucopyranoside(4), quercetin-3-O-β-D-galactopyranoside(5), 6-O-(E)-p-hydroxy-cinnamoyl-β-glucose(6), 6-O-(E)-p-hydroxy-cinnamoyl-α-glucose(7), kaempferol-3-O-β-D-rutinoside(8), and 3-O-β-D-galacopyranosyl(6-1)-α-L-rhamnosyl quercetin(9). Compounds 1 and 2 significantly reduced the intracellular content of total cholesterols and triglycerides. Conclusion Compound 1 is a new phenolic compound and exhibits potent anti-hyperlipidemic activity. Additionally, compounds 6 and 7 are isolated from D. triquetrum for the first time.     

益母草香豆素类化学成分与抗血小板聚集活性

综合运用硅胶柱色谱、Sephadex LH-20、MCI色谱以及反相C18柱色谱等方法分离纯化益母草中的化学成分,运用有机波谱学方法鉴定各化合物的结构,并进一步测试各化合物的体外抗血小板聚集活性。从益母草的乙酸乙酯部位中分离鉴定了10个香豆素类化合物,依次为佛手柑内酯(1)、花椒毒素(2)、异茴芹内酯(3)、异栓翅芹醇(4)、异欧前胡素(5)、橙皮内酯水合物(6)、异橙皮内酯(7)、九里香酮(8)、橙皮油内酯烯(9)、欧芹酚甲醚(10)。除化合物9外,其他化合物均为首次从该属植物中分离得到,活性筛选结果表明化合物4和8对ADP诱导的血小板聚集有明显的抑制作用。     

桑白皮中α-葡萄糖苷酶抑制和抗氧化活性成分研究

目的：研究桑白皮（Morus alba）的化学成分及其α-葡萄糖苷酶抑制和DPPH自由基清除活性方法：采用硅胶、凝胶柱色谱和制备HPLC等方法进行分离纯化,通过高分辨质谱和核磁鉴定化合物结构结果：从桑白皮提取物中分离得到了13个化合物,其中化合物1,3和8表现出显著的α-葡萄糖苷酶抑制活性,IC50值分别为147.1 ± 1.1,314.1 ± 0.8和207.6 ± 0.1 µM,均低于阳性对照阿卡波糖（418.6 ± 0.1 µM）。化合物10和11均表现出良好的DPPH自由基清除活性,EC50值分别为2.9 ± 0.1和5.0 ± 0.1 µM,均低于阳性对照维生素C的EC50值（54.8 ± 0.1 µM)结论：化合物1、3和8的α-葡萄糖苷酶抑制活性为首次测定。     

Lung protective effects of dietary malate esters derivatives from Bletilla striata against SiO2 nanoparticles through activation of Nrf2 pathway

Objective: To study the protective activities of the dietary malate esters derivatives of Bletilla striata against SiO2 nanoparticles-induced A549 cell lines and its mechanism action. Methods: The components were isolated and elucidated by spectroscopic methods such as 1D NMR and 2D NMR. And MTT assays was used to tested these components on the A549 cell survival rates and ROS or proteins levels were detected by Western blotting. Results: A new glucosyloxybenzyl 2-isobutylmalate (a malate ester derivative), along with 31 known compounds were isolated and identified from n-BuOH extract of EtOH extract of B. striata. Among them, compounds 3, 4, 11, 12 and 13 possessed noteworthy proliferative effects for damaged cells, with ED50 of 14.0, 13.1, 3.7, 11.6 and 11.5 μmol/L, respectively, compared to positive control resveratrol (ED50, 14.7 μmol/L). Militarine (8) prominently inhibited the intracellular ROS level, and increased the expression of Nrf2 and its downstream genes (HO-1 and γ-GCSc). Furthermore, Nrf2 activation mediates the interventional effects of compound 8 against SiO2 nanoparticles (nm SiO2)-induced lung injury. Moreover, treatment with compound 8 significantly reduced lung inflammation and oxidative stress in nm SiO2-instilled mice. Molecular docking experiment suggested that 8 bound stably to the HO-1 protein by hydrogen bond interactions. Conclusion: The dietary malate esters derivatives of B. striata could significantly increase the viability of nm SiO2-induced A549 cells and decrease the finer particles-induced cell damages. Militarine is especially promising compound for chemoprevention of lung cancer induced by nm SiO2 through activation of Nrf2 pathway.