New Hippolide Derivatives with Protein Tyrosine Phosphatase 1B Inhibitory Activity from the Marine Sponge Hippospongia lachne

Five new sesterterpenoids, compounds 1–5, have been isolated from the sponge Hippospongia lachne off Yongxing Island in the South China Sea. The structures of compounds 1–5 were elucidated through extensive spectroscopic analysis, including HRMS, 1D, and 2D NMR experiments. The stereochemistry, including absolute configurations of these compounds, was determined by spectroscopic, chemical, and computational methods. Compounds 1 and 5 showed moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activities with IC₅₀ values of 5.2 μM and 8.7 μM, respectively, more potent than previously reported hippolides.     

Characterization of ACE Inhibitory Peptides Prepared from Pyropia pseudolinearis Protein

More than 7000 red algae species have been classified. Although most of them are underused, they are a protein-rich marine resource. The hydrolysates of red algal proteins are good candidates for the inhibition of the angiotensin-I-converting enzyme (ACE). The ACE is one of the key factors for cardiovascular disease, and the inhibition of ACE activity is related to the prevention of high blood pressure. To better understand the relationship between the hydrolysates of red algal proteins and the inhibition of ACE activity, we attempted to identify novel ACE inhibitory peptides from Pyropia pseudolinearis. We prepared water soluble proteins (WSP) containing phycoerythrin, phycocyanin, allophycocyanin, and ribulose 1,5-bisphosphate carboxylase/oxygenase. In vitro analysis showed that the thermolysin hydrolysate of the WSP had high ACE inhibitory activity compared to that of WSP. We then identified 42 peptides in the hydrolysate by high-performance liquid chromatography and mass spectrometry. Among 42 peptides, 23 peptides were found in chloroplast proteins. We then synthesized the uncharacterized peptides ARY, YLR, and LRM and measured the ACE inhibitory activity. LRM showed a low IC₅₀ value (0.15 μmol) compared to ARY and YLR (1.3 and 5.8 μmol). In silico analysis revealed that the LRM sequence was conserved in cpcA from Bangiales and Florideophyceae, indicating that the novel ACE inhibitory peptide LRM was highly conserved in red algae.     

醋制对黑豆蛋白含量及多肽ACE抑制活性的影响

为考察醋制对黑豆蛋白含量及多肽ACE抑制活性的影响,为对黑豆醋浸过程中蛋白组分及含量变化进行分析,并对相应ACE抑制肽活性进行测定。黑豆经醋浸不同时间后,采用顺序抽提法提取清蛋白、球蛋白、醇溶蛋白和谷蛋白,并采用凯氏定氮法及SDS-PAGE电泳进行定量和定性分析;各蛋白组分经胃蛋白酶水解,经超滤(截留分子量3 k D)后收集滤液,获得多肽组分,RP-HPLC法进行ACE抑制活性评价。结果表明:经醋浸14 d后,黑豆总蛋白含量变化幅度小于±0.5%;清蛋白含量由55.13%(0 d)降低至9.61%(14 d);球蛋白由7.04%(0 d)增加到20.34%(14 d);醇溶蛋白由0.81%(0 d)增加到1.72(14 d);谷蛋白由21.11%(0 d)增加到59.45%(14 d),含量最高。醋浸处理降低了清蛋白源多肽的ACE抑制活性,但提高了球蛋白、醇溶蛋白及谷蛋白多肽的ACE抑制活性,其中,谷蛋白多肽抑制率由18.18%(0 d)增加至37.58%(14 d),抑制活性升高。醋浸可改变黑豆各蛋白组分的含量和对应多肽的ACE抑制活性,其中,谷蛋白含量及其多肽ACE抑制活性均有增加。研究结果表明可进一步采用分离纯化技术从谷蛋白多肽中获得高活性降压肽。     

Thioester-Containing Benzoate Derivatives with α-Glucosidase Inhibitory Activity from the Deep-Sea-Derived Fungus Talaromyces indigoticus FS688

Eurothiocins C–H (1–6), six unusual thioester-containing benzoate derivatives, were isolated from the deep-sea-derived fungus Talaromyces indigoticus FS688 together with a known analogue eurothiocin A (7). Their structures were elucidated through spectroscopic analysis and the absolute configurations were determined by X-ray diffraction and ECD calculations. In addition, compound 1 exhibited significant inhibitory activity against α-glucosidase with an IC₅₀ value of 5.4 μM, while compounds 4 and 5 showed moderate effects with IC₅₀ values of 33.6 and 72.1 μM, respectively. A preliminary structure–activity relationship is discussed and a docking analysis was performed.     

10种南药植物提取物乙酰胆碱酯酶抑制活性的筛选模型研究

采用筛选模型对10种南药样品乙酸乙酯提取物的乙酰胆碱酯酶抑制活性进行了评价。结果表明:10种南药(益智、鸡血藤、决明子、巴戟天、溪黄草、金樱子、化橘红、佛手、绞股蓝、五指毛桃)均具有不同程度的乙酰胆碱酯酶抑制活性。当提取物浓度为1.0 mg/mL时,溪黄草、益智、化橘红、绞股蓝、五指毛桃表现出较强的抑制活性,平均抑制率大于50%,分别为89.59%,77.10%,67.54%,52.62%,52.29%,其他5种南药的平均抑制率在20.81%~49.81%之间;提取物浓度为0.1 mg/mL时,溪黄草、益智、佛手仍表现出相对较强的抑制活性,平均抑制率大于25%,其他7种南药的平均抑制率在6.07%~24.78%之间。应该深入研究复方中药治疗老年痴呆的药效物质基础,加大对南药资源的开发利用。     

Preparation,Identification, Molecular Docking Study and Protective Function on HUVECs of Novel ACE Inhibitory Peptides from Protein Hydrolysate of Skipjack Tuna Muscle

To prepare bioactive peptides with high angiotensin-I-converting enzyme (ACE)-inhibitory (ACEi) activity, Alcalase was selected from five kinds of protease for hydrolyzing Skipjack tuna (Katsuwonus pelamis) muscle, and its best hydrolysis conditions were optimized using single factor and response surface experiments. Then, the high ACEi protein hydrolysate (TMPH) of skipjack tuna muscle was prepared using Alcalase under the optimum conditions of enzyme dose 2.3%, enzymolysis temperature 56.2 °C, and pH 9.4, and its ACEi activity reached 72.71% at 1.0 mg/mL. Subsequently, six novel ACEi peptides were prepared from TMPH using ultrafiltration and chromatography methods and were identified as Ser-Pro (SP), Val-Asp-Arg-Tyr-Phe (VDRYF), Val-His-Gly-Val-Val (VHGVV), Tyr-Glu (YE), Phe-Glu-Met (FEM), and Phe-Trp-Arg-Val (FWRV), with molecular weights of 202.3, 698.9, 509.7, 310.4, 425.6, and 606.8 Da, respectively. SP and VDRYF displayed noticeable ACEi activity, with IC₅₀ values of 0.06 ± 0.01 and 0.28 ± 0.03 mg/mL, respectively. Molecular docking analysis illustrated that the high ACEi activity of SP and VDRYF was attributed to effective interaction with the active sites/pockets of ACE by hydrogen bonding, electrostatic force, and hydrophobic interaction. Furthermore, SP and VDRYF could significantly up-regulate nitric oxide (NO) production and down-regulate endothelin-1 (ET-1) secretion in HUVECs after 24 h treatment, but also abolish the negative effect of 0.5 μM norepinephrine (NE) on the generation of NO and ET-1. Therefore, ACEi peptides derived from skipjack tuna (K. pelamis) muscle, especially SP and VDRYF, are beneficial components for functional food against hypertension and cardiovascular diseases.     

Preparation,COX-2 Inhibition and Anticancer Activity of Sclerotiorin Derivatives

The latest research has indicated that anti-tumor agents with COX-2 inhibitory activity may benefit their anti-tumor efficiency. A series of sclerotiorin derivatives have been synthesized and screened for their cytotoxic activity against human lung cancer cells A549, breast cancer cells MDA-MB-435 using the MTT method. Among them, compounds 3, 7, 12, 13, 15, 17 showed good cytotoxic activity with IC₅₀ values of 6.39, 9.20, 9.76, 7.75, 9.08, and 8.18 μM, respectively. In addition, all compounds were tested in vitro the COX-2 inhibitory activity. The results disclosed compounds 7, 13, 25 and sclerotiorin showed moderate to good COX-2 inhibition with the inhibitory ratios of 58.7%, 51.1%, 66.1% and 56.1%, respectively. Notably, compound 3 displayed a comparable inhibition ratio (70.6%) to the positive control indomethacin (78.9%). Furthermore, molecular docking was used to rationalize the potential of the sclerotiorin derivatives as COX2 inhibitory agents by predicting their binding energy, binding modes and optimal orientation at the active site of the COX-2. Additionally, the structure-activity relationships (SARS) have been addressed.     

Investigation of Marine-Derived Natural Products as Raf Kinase Inhibitory Protein (RKIP)-Binding Ligands

Raf kinase inhibitory protein (RKIP) is an essential regulator of the Ras/Raf-1/MEK/ERK signaling cascade and functions by directly interacting with the Raf-1 kinase. The abnormal expression of RKIP is linked with numerous diseases including cancers, Alzheimer’s and diabetic nephropathy. Interestingly, RKIP also plays an indispensable role as a tumor suppressor, thus making it an attractive therapeutic target. To date, only a few small molecules have been reported to modulate the activity of RKIP, and there is a need to explore additional scaffolds. In order to achieve this objective, a pharmacophore model was generated that explores the features of locostatin, the most potent RKIP modulator. Correspondingly, the developed model was subjected to screening, and the mapped compounds from Marine Natural Products (MNP) library were retrieved. The mapped MNPs after ensuing drug-likeness filtration were escalated for molecular docking, where locostatin was regarded as a reference. The MNPs exhibiting higher docking scores than locostatin were considered for molecular dynamics simulations, and their binding affinity towards RKIP was computed via MM/PBSA. A total of five molecules revealed significantly better binding free energy scores than compared to locostatin and, therefore, were reckoned as hits. The hits from the present in silico investigation could act as potent RKIP modulators and disrupt interactions of RKIP with its binding proteins. Furthermore, the identification of potent modulators from marine natural habitat can act as a future drug-discovery source.     

Purification and Identification of Novel Xanthine Oxidase Inhibitory Peptides Derived from Round Scad (Decapterus maruadsi) Protein Hydrolysates

The objective of the present study was to investigate the xanthine oxidase (XO) inhibitory effects of peptides purified and identified from round scad (Decapterus maruadsi) hydrolysates (RSHs). In this study, RSHs were obtained by using three proteases (neutrase, protamex and alcalase). Among them, the RSHs of 6-h hydrolysis by neutrase displayed the strongest XO inhibitory activity and had an abundance of small peptides (<500 Da). Four novel peptides were purified by immobilized metal affinity chromatography and identified by nano-high-performance liquid chromatography mass/mass spectrometry. Their amino acid sequences were KGFP (447.53 Da), FPSV (448.51 Da), FPFP (506.59 Da) and WPDGR (629.66 Da), respectively. Then the peptides were synthesized to evaluate their XO inhibitory activity. The results indicated that the peptides of both FPSV (5 mM) and FPFP (5 mM) exhibited higher XO inhibitory activity (22.61 ± 1.81% and 20.09 ± 2.41% respectively). Fluorescence spectra assay demonstrated that the fluorescence quenching mechanism of XO by these inhibitors (FPSV and FPFP) was a static quenching procedure. The study of inhibition kinetics suggested that the inhibition of both FPSV and FPFP was reversible, and the type of their inhibition was a mixed one. Molecular docking revealed the importance of π-π stacking between Phe residue (contained in peptides) and Phe⁹¹⁴ (contained in the XO) in the XO inhibitory activity of the peptides.     

Exophilone,a Tetrahydrocarbazol-1-one Analogue with Anti-Pulmonary Fibrosis Activity from the Deep-Sea Fungus Exophiala oligosperma MCCC 3A01264

A new compound, exophilone (1), together with nine known compounds (2–10), were isolated from a deep-sea-derived fungus, Exophiala oligosperma. Their chemical structures, including the absolute configuration of 1, were elucidated using nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectroscopy (HRESIMS), and electronic circular dichroism (ECD) calculation. Compounds were preliminarily screened for their ability to inhibit collagen accumulation. Compounds 1, 4, and 7 showed weaker inhibition of TGF-β1-induced total collagen accumulation in compared with pirfenidone (73.14% inhibition rate). However, pirfenidone exhibited cytotoxicity (77.57% survival rate), while compounds 1, 4, and 7 showed low cytotoxicity against the HFL1 cell line. Particularly, exophilone (1) showed moderate collagen deposition inhibition effect (60.44% inhibition rate) and low toxicity in HFL1 cells (98.14% survival rate) at a concentration of 10 μM. A molecular docking study suggests that exophilone (1) binds to both TGF-β1 and its receptor through hydrogen bonding interactions. Thus, exophilone (1) was identified as a promising anti-pulmonary fibrosis agent. It has the potential to be developed as a drug candidate for pulmonary fibrosis.     

Characterization of ACE Inhibitory Peptides from Mactra veneriformis Hydrolysate by Nano-Liquid Chromatography Electrospray Ionization Mass Spectrometry (Nano-LC-ESI-MS) and Molecular Docking

Food-derived bioactive compounds are gaining increasing significance in life sciences. In the present study, we identified angiotensin I-converting enzyme (ACE)-inhibitory peptides from Mactra veneriformis hydrolysate using a nano-LC-MS/MS method. Mactra veneriformis hydrolysate was first separated into four fractions (F1–F4) based on molecular weight by ultrafiltration. The fraction with molecular weight lower than 1 kDa (F1) showed the highest ACE inhibitory activity. F1 was then analyzed by a high throughput nano-LC-MS/MS method and sequences of peptides in F1 were calculated accordingly. The 27 peptides identified as above were chemically synthesized and tested for ACE-inhibitory activity. The hexapeptide VVCVPW showed the highest potency with an IC₅₀ value of 4.07 μM. We then investigated the interaction mechanism between the six most potent peptides and ACE by molecular docking. Our docking results suggested that the ACE inhibitory peptides bind to ACE via interactions with His383, His387, and Glu411 residues. Particularly, similar to the thiol group of captopril, the cysteine thiol group of the most potent peptide VVCVPW may play a key role in the binding of this peptide to the ACE active site.     

In Vitro Anti-Orthohantavirus Activity of the High-and Low-Molecular-Weight Fractions of Fucoidan from the Brown Alga Fucus evanescens

The Hantaan orthohantavirus (genovariant Amur–AMRV) is a rodent-borne zoonotic virus; it is the causative agent of haemorrhagic fever with renal syndrome in humans. The currently limited therapeutic options require the development of effective anti-orthohantavirus drugs. The ability of native fucoidan from Fucus evanescens (FeF) and its enzymatically prepared high-molecular-weight (FeHMP) and low-molecular-weight (FeLMP) fractions to inhibit different stages of AMRV infection in Vero cells was studied. The structures of derivatives obtained were determined using nuclear magnetic resonance (NMR) spectroscopy. We found that fucoidan and its derivatives exhibited significant antiviral activity by affecting the early stages of the AMRV lifecycle, notably virus attachment and penetration. The FeHMP and FeLMP fractions showed the highest anti-adsorption activity by inhibiting AMRV focus formation, with a selective index (SI) > 110; FeF had an SI of ~70. The FeLMP fraction showed a greater virucidal effect compared with FeF and the FeHMP fraction. It was shown by molecular docking that 2O-sulphated fucotetrasaccharide, a main component of the FeLMP fraction, is able to bind with the AMRV envelope glycoproteins Gn/Gc and with integrin β3 to prevent virus–cell interactions. The relatively small size of these sites of interactions explains the higher anti-AMRV activity of the FeLMP fraction.     

五指毛桃抗炎活性成分的分离及鉴定

以对5-LOX的抑制活性为抗炎活性评价指标,在活性跟踪下从五指毛桃中分离到6个化合物,经波谱数据分析后被鉴定为:羽扇豆醇棕榈酸酯(1)、β-香树脂醇乙酸酯(2)、补骨脂素(3)、芹菜素(4)、壬二酸(5)和胡萝卜苷(6),其中,化合物5、1对5-LOX表现出强的抑制活性,半数抑制浓度(IC50)分别为13.74μg/m L和13.96μg/m L;化合物1为首次从五指毛桃中分离得到。本研究结果可为五指毛桃的抗炎作用研究及其临床应用提供理论参考。     

Structure Activity Relationship of Brevenal Hydrazide Derivatives

Brevenal is a ladder frame polyether produced by the dinoflagellate Karenia brevis. This organism is also responsible for the production of the neurotoxic compounds known as brevetoxins. Ingestion or inhalation of the brevetoxins leads to adverse effects such as gastrointestinal maladies and bronchoconstriction. Brevenal shows antagonistic behavior to the brevetoxins and shows beneficial attributes when administered alone. For example, in an asthmatic sheep model, brevenal has been shown to increase tracheal mucosal velocity, an attribute which has led to its development as a potential treatment for Cystic Fibrosis. The mechanism of action of brevenal is poorly understood and the exact binding site has not been elucidated. In an attempt to further understand the mechanism of action of brevenal and potentially develop a second generation drug candidate, a series of brevenal derivatives were prepared through modification of the aldehyde moiety. These derivatives include aliphatic, aromatic and heteroaromatic hydrazide derivatives. The brevenal derivatives were tested using in vitro synaptosome binding assays to determine the ability of the compounds to displace brevetoxin and brevenal from their native receptors. A sheep inhalation model was used to determine if instillation of the brevenal derivatives resulted in bronchoconstriction. Only small modifications were tolerated, with larger moieties leading to loss of affinity for the brevenal receptor and bronchoconstriction in the sheep model.     

羧基化壳寡糖络合碘（CCOS-I）对水稻纹枯病菌的抑制作用及机理初讨

为明确羧基化壳寡糖络合碘（CCOS-I）对水稻纹枯病的防治作用,以 20%井冈霉素可湿性粉剂为对照药剂,测定 CCOS-I 对水稻纹枯病菌的室内抑菌效果和田间防效,以及对超氧化物歧化酶（superoxidedismutase,SOD）、叶片过氧化物酶（peroridase,POD）、多酚氧化酶（polyphenol oxidase,PPO）、苯丙氨酸解氨酶（phenylalanine ammonia-lyase,PAL）和 β-1,3-葡聚糖酶（β-1,3-glucanase）等相关防御酶活性的影响。结果表明：羧基化壳寡糖络合碘对该病菌抑制效果明显,经室内毒力测定,其 EC50 值 12.22 mg/L,明显高于对照药剂 20%井冈霉素粉剂。田间药效试验结果表明,在水稻第 3 次用药后 14 d,100 g/hm2 的羧基化壳寡糖络合碘防效达到 80.66%,与井冈霉素有效剂量 150 g/hm2 的效果相当,优于同剂量井冈霉素处理。CCOS-I 在试验剂量范围内对水稻纹枯病有很好的防治作用,且对水稻生长无任何药害现在发生,可以诱导水稻相关防御酶活性提高,适用于水稻纹枯病的防治,具有一定的开发推广价值。     

Predicting Antifouling Activity and Acetylcholinesterase Inhibition of Marine-Derived Compounds Using a Computer-Aided Drug Design Approach

Biofouling is the undesirable growth of micro- and macro-organisms on artificial water-immersed surfaces, which results in high costs for the prevention and maintenance of this process (billion €/year) for aquaculture, shipping and other industries that rely on coastal and off-shore infrastructure. To date, there are still no sustainable, economical and environmentally safe solutions to overcome this challenging phenomenon. A computer-aided drug design (CADD) approach comprising ligand- and structure-based methods was explored for predicting the antifouling activities of marine natural products (MNPs). In the CADD ligand-based method, 141 organic molecules extracted from the ChEMBL database and literature with antifouling screening data were used to build the quantitative structure–activity relationship (QSAR) classification model. An overall predictive accuracy score of up to 71% was achieved with the best QSAR model for external and internal validation using test and training sets. A virtual screening campaign of 14,492 MNPs from Encinar’s website and 14 MNPs that are currently in the clinical pipeline was also carried out using the best QSAR model developed. In the CADD structure-based approach, the 125 MNPs that were selected by the QSAR approach were used in molecular docking experiments against the acetylcholinesterase enzyme. Overall, 16 MNPs were proposed as the most promising marine drug-like leads as antifouling agents, e.g., macrocyclic lactam, macrocyclic alkaloids, indole and pyridine derivatives.     

青霉菌发酵液对大豆幼苗生长及生理特性的影响

采用室内生理检测及生物化学方法,研究了青霉菌发酵液对大豆幼苗生长及生理特性的影响。结果表明:用一定浓度的青霉菌发酵液对大豆浸种和茎叶处理,大豆幼苗的生长呈明显上升趋势,处理后大豆的株高、根长、株鲜重和根鲜重均明显得到了提高,且生长状态好于对照,不同浓度处理间具有明显差异,在发酵液浓度为5 g·L-1时,效果最佳。尤其是对根鲜重的影响,促进率最高可达56.21%,同时增强了幼苗根系活力,最大可以提高57.82%,浸种和茎叶处理后,分别提高了叶绿素含量41.25%和15.40%;超氧化物歧化酶活性12.20%和11.70%;过氧化物酶31.33%和29.95%;过氧化氢酶活性42.8%和20.0%,这为发酵液在大豆田推广应用、提高大豆产量提供了重要理论依据。     

EGCG纳米粒的制备及其抗肿瘤活性研究

采用热诱导法制备表没食子儿茶素没食子酸酯-抗坏血酸-β-乳球蛋白纳米粒（EGCG-Vc-β-Lg）,考察EGCG与Vc摩尔比对纳米粒粒径、Zeta电位、包埋率、装载量、颜色变化的影响;运用噻唑蓝（MTT）比色法和胞质分裂阻滞微核试验（CBMNT）研究纳米粒对人体黑色素瘤细胞（A-375）、食管癌细胞（TE-1）的增殖抑制作用和初步作用机制。结果表明：EGCG-Vc-β-Lg对A-375、TE-1的增殖抑制有增效作用,并且显著提高了其微核率、凋亡率和坏死率。     

磷水平对杂交水稻及其亲本根系酸性磷酸酶活性的影响

为了解优良亲本和杂交组合的磷营养遗传特性,以7份亲本及其4个组合为材料,采用水培试验研究了不同磷水平对水稻亲本及其杂交组合根系酸性磷酸酶(APase)活性的影响。在低磷条件下,磷低效型保持系材料Ⅱ-32B的APase活性较对照增加不显著,而磷高效型保持系材料D62B和D83B则通过显著提高根系APase活性增强了对磷胁迫环境的适应性。磷高效型恢复系材料R892和R527在分蘖期和孕穗期的APase活性均较对照显著提高,而磷低效型恢复系材料R549和R781除在分蘖期APase活性增加明显外,在孕穗期和灌浆期APase活性与对照差异不显著。不同亲本配制的杂交稻在低磷水平下,根系APase活性增加的幅度有所不同。磷低效型杂交组合Ⅱ优549分蘖期、孕穗期和灌浆期根系的APase活性在不同供磷水平下差异不显著;磷高效型杂交组合D83A/R527在低磷水平下3个时期APase活性均明显提高。由磷低效型保持系材料Ⅱ-32B与磷低效型恢复系材料R549配制的Ⅱ优549,根系APase活性受低磷胁迫增幅不大;磷高效型保持系材料D83B与磷高效型恢复系材料R527配制的D83A/R527,根系APase活性在低磷水平下上升显著;磷低效型保持系材料Ⅱ-32B与磷高效型恢复系材料R892配制的Ⅱ优892,以及磷高效型保持系材料D62B与磷低效型恢复系材料R781配制的D62A/R781,受低磷胁迫时根系APase活性上升幅度介于磷低效组合Ⅱ优549和磷高效组合D83A/R527之间。     

转基因马铃薯PPO、CAT活性变化及同工酶分析

采用生理生化方法对转基因马铃薯纯合四倍体甘单花9号(GD-9-qc)系列的试管苗进行了PPO活性检测、同工酶分析及CAT活性检测和POD同工酶分析。结果表明:反义PPO基因对大多数转基因马铃薯试管苗PPO的活性产生了明显的抑制效果,其中GD-9-qc-10与GD-9-qc-11的PPO活性比对照降低89.06%和83.98%,且相应转基因品系的PPO同工酶也被明显抑制。实验同时发现,转基因马铃薯不同品系中的过氧化氢酶和过氧化物酶的活性也受到不同程度的影响,表现为有的高于对照,有的低于对照;而POD同工酶所示结果与POD活性检测相一致。