Antiplatelet aggregation activity of diterpene alkaloids from Spiraea japonica

Overview of the chemistry and biological activities of natural atisine-type diterpenoid alkaloids

Atisine-type C20-diterpenoid alkaloids (DAs) are a very important class of diterpenoid alkaloids, which play an important role in the biosynthesis of DAs. To date, 87 atisine-type DAs and 11 bis-DAs containing an atisine unit have been reported from five genera in two families. The genus Spiraea in Rosaceae family could be regarded as the richest resource for atisine-type DAs, followed by the genera Delphinium and Aconitum in the Ranunculaceae family. Among the reported atisine-type DAs, several possess unprecedented skeletons. Natural atisine-type DAs have a wide range of biological activities, including antitumor, antiplatelet aggregation, biological control, and anti-inflammatory, analgesic, antiarrhythmic, and cholinesterase inhibitory effects, which are closely related to their structures. In particular, the antiparasitic effect of atisine-type DAs is more prominent than that of other types of DAs, which highlights their potential in antiparasite drug discovery. In summary, the high chemical and biological diversity of atisine-type DAs indicates their great potential as a vast resource for drug discovery.

Analyses of phytochemical compounds in the flowers and leaves of Spiraea japonica var. fortunei using UV-VIS, FTIR, and LC-MS techniques

Spiraea japonica var. fortunei has been extensively used in traditional Chinese medicine and is well-known for its alkaloids. However, there is no adequate study concerning the phenolic compounds. Therefore, this study aimed to investigate phenolic compounds found in the leaves and the flowers of the plant both qualitatively and quantitatively. Extractions were performed either with ethanol or methanol, and methanol has shown better performance than ethanol. The leaves were a better source of phenolic compounds than the flowers. The total phenolic content of the methanol extract of the leaves was 25.64 ± 0.32 mg GAE/g dry matter, and antioxidant activity, as determined with the DPPH method, was 69.76 ± 0.34 %. UV-VIS spectrum and FTIR analyses confirmed the presence of phenolic compounds. The phenolic profile was investigated with LC-MS using both negative and positive ionization, and a total of 55 phenolic compounds that are attractive for pharmaceutical and medical applications were observed.

Mechanism of platelet activation and potential therapeutic effects of natural drugs

BACKGROUND

Cardiovascular disease is one of the most concerning chronic diseases in the world. Many studies have shown that platelet overactivation is a very important factor in the occurrence and development of cardiovascular diseases. At present, the widely used antiplatelet drugs have some defects, such as drug resistance and adverse reactions.

PURPOSE

The purpose of this article is to summarize the main mechanisms and pathways of platelet activation, the main targets of antiplatelet aggregation, and the antiplatelet aggregation components of natural drugs and their mechanisms of action to provide new research ideas for the development and application of antiplatelet drugs.

STUDY DESIGN AND METHODS

In this review, we systematically searched the PubMed, Google Scholar, Web of Science, and CNKI databases and selected studies based on predefined eligibility criteria. We then assessed their quality and extracted data.

RESULTS

ADP, AA, THR, AF, collagen, SDF-1α, and Ca²⁺ can induce platelet aggregation and trigger thrombosis. Natural drugs have a good inhibitory effect on platelet activation. More than 50 kinds of natural drugs and over 120 kinds of chemical compounds, including flavonoids, alkaloids, saponins, terpenoids, coumarins, and organic acids, have significantly inhibited platelet activation activity. The MAPK pathway, cGMP-PKG pathway, cAMP-PKA pathway, PI3K-AKT pathway, PTK pathway, PLC pathway, and AA pathway are the main mechanisms and pathways of platelet activation.

CONCLUSION

Natural drugs and their active ingredients have shown good activity and application prospects in anti-platelet aggregation. We hope that this review provides new research ideas for the development and application of antiplatelet drugs.

Current update on herbal sources of antithrombotic activity—a comprehensive review

Background

Herbs are commonly used to treat cardiovascular diseases in various traditional medicine. On the other hand, herb-drug interactions are most commonly encountered with conventional antiplatelet and anticoagulant drug prescriptions. This review presents a compilation of plants investigated for antiplatelet and anticoagulation recently and enumerates their possible lead compounds responsible for its action for paving further drug discovery and knowledge update.

Main body of the abstract

Information about the herbs was withdrawn from the PubMed database of the previous 5 years. We also hand-searched the bibliography of relevant articles for the acquisition of additional information. About 72 herbal sources were identified with the effect of antiplatelet activity, antithrombotic activity, and anticoagulant activity. Bioactive compounds and various secondary metabolites responsible for it, such as alkaloids, saponins, flavonoids, coumarins, polyphenols, furan derivatives, iridoid glycosides, sesquiterpenes, aporphine compounds, were reported.

Conclusion

Newer pharmacological moieties are needed to prevent or reduce the adverse effects of current anti-thrombotic agents and to improve the safety of patients and cost-effectiveness.

Bioactive Compounds of Ganoderma boninense Inhibited Methicillin-Resistant Staphylococcus aureus Growth by Affecting Their Cell Membrane Permeability and Integrity

Some species of Ganoderma, such as G. lucidum, are well-known as traditional Chinese medicine (TCM), and their pharmacological value was scientifically proven in modern days. However, G. boninense is recognized as an oil palm pathogen, and its biological activity is scarcely reported. Hence, this study aimed to investigate the antibacterial properties of G. boninense fruiting bodies, which formed by condensed mycelial, produced numerous and complex profiles of natural compounds. Extract was cleaned up with normal-phase SPE and its metabolites were analyzed using liquid chromatography-mass spectrometry (LCMS). From the disc diffusion and broth microdilution assays, strong susceptibility was observed in methicillin-resistant Staphylococcus aureus (MRSA) in elute fraction with zone inhibition of 41.08 ± 0.04 mm and MIC value of 0.078 mg mL-1. A total of 23 peaks were detected using MS, which were putatively identified based on their mass-to-charge ratio (m/z), and eight compounds, which include aristolochic acid, aminoimidazole ribotide, lysine sulfonamide 11v, carbocyclic puromycin, fenbendazole, acetylcaranine, tigecycline, and tamoxifen, were reported in earlier literature for their antimicrobial activity. Morphological observation via scanning electron microscope (SEM), cell membrane permeability, and integrity assessment suggest G. boninense extract induces irreversible damage to the cell membrane of MRSA, thus causing cellular lysis and death.

The complete chloroplast genome sequence of Spiraea japonica var. acuminata Franch. (Rosaceae)

Spirea japonica var. acuminata Franch. (Rosaceae) is a Chinese herbal medicine distributed in southwest and east China. The first complete chloroplast genome of Spirea japonica var. acuminata Franch. was assembled and reported in this study. The genome is 153,822 bp in length and contained 125 encoded genes in total, including 80 protein-coding genes, eight ribosomal RNA genes, and 37 transfer RNA genes. The phylogenomic analysis showed that Spirea japonica var. acuminata Franch. was closely related to Spirea blumei, Spirea trilobata, Spirea mongolica and Spirea insularis according to the current sampling extent.

Mechanisms of Action of a Herbal Formula Huangqi Guizhi Wuwu Tang for the Management of Post-Stroke Related Numbness and Weakness: A Computational Molecular Docking Study

Stroke-related numbness and weakness (SRNW) are resultant symptoms of post-stroke sufferers. Existing research has supported the use of Huangqi Guizhi Wuwu Tang (HGWT) particularly for SRNW; however, their mechanisms of action have not been fully elucidated. Therefore, this study aimed to investigate the mechanisms of action of HGWT components targeting SRNW-related proteins through a computational molecular docking approach. Target proteins associated with SRNW were identified through DrugBank database and Open Targets database. Chemical compounds from each herb of HGWT were identified from the Traditional Chinese Medicine Systems Pharmacology and Analysis Platform (TCMSP). Autodock Vina was utilized and the cut-off criterion applied for protein-ligand complexes was a binding affinity score of ≤ -9.5 kcal/mol; selected protein-ligand complexes were identified using 3D and 2D structural analyses. The protein targets PDE5A and ESR1 have highlighted interactions with compounds (BS040, DZ006, DZ058, DZ118, and HQ066) which are the key molecules in the management of SRNW. PDE5A have bioactivity with the amino acid residues (Val230, Asn252, Gln133 and Thr166) throughout PDE5A-cGMP-PKG pathways which involved reduction in myofilament responsiveness. ESR1 were predicted to be critical active with site residue (Leu346, Glu419 and Leu387) and its proteoglycans pathway involving CD44v3/CD44 that activates rho-associated protein kinase 1 (ROCK1) and ankyrin increasing vascular smooth muscle. In conclusion, HGWT may provide therapeutic benefits through strong interactions between herbal compounds and target proteins of PDE5A and ESR1. Further experimental studies are needed to unequivocally support this result which can be valuable to increase the quality of life of post-stroke patients. Keywords Herbal medicine, Complementary and alternative medicine, Natural product, Post-stroke, Computational analysis.

Phytoconstituents and Bioactivity of Plants of the Genus Spiraea L. (Rosaceae): A Review

The genus Spiraea L. belongs to the Rosaceae Juss. family and includes more than 100 species distributed in the temperate zone and subtropical zone of the Northern Hemisphere at the center of species diversity in East Asia. Representatives of the genus are known as ornamental plants with many forms and varieties, are widely used in conventional medicine, and have a high resource potential. This review provides information on the diversity of phenolic compounds (flavonoids, phenolcarboxylic acids, and lignans), terpenoids, alkaloids, steroids, and other classes of secondary metabolites in the species of Spiraea worldwide. The article also presents little-known and hard-to-find data published in Russian concerning Spiraea phytochemistry. The biological activities of extracts and their fractions and of individual compounds having different types of biological activity (e.g., antioxidant, antibacterial, anti-inflammatory, and antifungal) are discussed. Data about biotechnological research on representatives of the genus Spiraea are presented too. The analysis of the literature showed that further chemical and pharmacological studies on Spiraea plants are quite promising.

Inhibitory effect on human platelet aggregation and coagulation and antioxidant activity of C. edulis Ker Gawl rhizome and its secondary metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

Although Canna edulis Ker Gawl rhizome has been used in Traditional Vietnamese Medicine to prevent and treat heart diseases without thorough scientific evidence, limited intensive search for the bioactivities and useful substances has been done.

AIM OF THE STUDY

This study aims to investigate the antiplatelet aggregation, anticoagulant and antioxidant activity of extracts from C. edulis rhizome, separate and purify its compounds from the most active fraction and evaluate the antiplatelet aggregation, anticoagulant and antioxidant activity of isolated compounds.

MATERIALS AND METHODS

C. edulis rhizome was extracted with ethanol, then fractionated with n-hexane, ethyl acetate and water. The inhibitory effect on adenosine diphosphate- and collagen-induced human platelet aggregation was evaluated. Prothrombin time, activated partial thromboplastine time and thrombine time were measured to examine the anticoagulant activity. The free radical scavenging ability was assessed with DPPH and ABTS assays. The fraction that showed the most active was used to separate and purify compounds. The structures of compounds were elucidated by NMR and MS spectroscopic methods. Isolated compounds were also tested for antiplatelet, anticoagulant and antioxidant activity.

RESULTS

The ethyl acetate fraction showed the most potent antiplatelet aggregation, anticoagulant and antioxidant activity. Subsequent fractionation of this active fraction resulted in the isolation of seven known compounds: 5-hydroxy-6-methyl-2H-pyran-2-one (1), epimedokoreanone A (2), nepetoidin B (3), ferulic acid (4), caffeic acid (5), hydroxytyrosol (6), and 1H-indole-3-carboxaldehyde (7). Previous studies reported the antiplatelet, anticoagulant and antioxidant activity of ferulic acid (4), caffeic acid (5) and hydroxytyrosol (6) and the antioxidant activity of nepetoidin B (3). This study demonstrated that both epimedokoreanone A (2) and nepetoidine B (3) also exhibited good antiplatelet effect and epimedokoreanone A (2) also had effective anticoagulant and antioxidant activity, while 5-hydroxy-6-methyl-2H-pyran-2-one (1) showed weaker antiplatelet and antioxidant activity but no anticoagulant effect.

CONCLUSIONS

This is the first experimental study to demonstrate the potent dose-dependent antiplatelet aggregation, anticoagulant and antioxidant activity of C. edulis rhizome and its pure compounds, supporting the traditional use of this plant for the treatment of heart diseases. The C. edulis rhizome is a potential source of bioactive compounds or functional food for treatment and/or prevention of heart- and oxidative stress-related diseases and its bioactive compounds are good candidates for drug development of anti-thrombosis and antioxidant agents.

Lead Compounds in the Context of Extracellular Vesicle Research

Studies of small extracellular vesicles (sEVs), known as exosomes, have been flourishing in the last decade with several achievements, from advancing biochemical knowledge to use in biomedical applications. Physiological changes of sEVs due to the variety of cargos they carry undoubtedly leave an impression that affects the understanding of the mechanism underlying disease and the development of sEV-based shuttles used for treatments and non-invasive diagnostic tools. Indeed, the remarkable properties of sEVs are based on their nature, which helps shield them from recognition by the immune system, protects their payload from biochemical degradation, and contributes to their ability to translocate and convey information between cells and their inherent ability to target disease sites such as tumors that is valid for sEVs derived from cancer cells. However, their transport, biogenesis, and secretion mechanisms are still not thoroughly clear, and many ongoing investigations seek to determine how these processes occur. On the other hand, lead compounds have been playing critical roles in the drug discovery process and have been recently employed in studies of the biogenesis and secretion of sEVs as external agents, affecting sEV release and serving as drug payloads in sEV drug delivery systems. This article gives readers an overview of the roles of lead compounds in these two research areas of sEVs, the rising star in studies of nanoscale medicine.

Fifteen new diterpenoid alkaloids from the roots of Aconitum kirinense Nakai

Extensive phytochemical investigation from the roots of Aconitum kirinense Nakai led to the identification of fifteen new compounds, including four ranaconitine type C₁₈-diterpenoid alkaloids (kirisines A-D, 1-4), one lappaconitine type C₁₈-diterpenoid alkaloid (kirisine E, 5), seven denudatine type C₂₀-diterpenoid alkaloids (kirisines F-L, 6-12), and three napelline type C₂₀-diterpenoid alkaloids (kirisines M-O, 13-15), together with 25 known ones. Their structures were elucidated by extensive spectroscopic analyses. Among them, compounds 1 and 2 are rare diterpenoid alkaloid with 9,14-methylenedioxy group, and the latter also has a rare chloro-substituent. The diterpenoid alkaloids isolated were C₁₈, C₁₉ and C₂₀-category, which might provide further clues for understanding the chemotaxonomic significance of this plant. The isolated compounds were tested for neuroprotective activity and acetylcholinesterase inhibitory activity. Compounds 7, 18, 30 and 40 which exhibited moderate activity at 80 μM against acetylcholinesterase.

Cardiotoxicity evaluation and comparison of diterpene alkaloids on zebrafish

Diterpene alkaloids (DAs) have a broad spectrum of pharmacological activities, but exhibiting extremely serious cardiotoxicity to induce arrhythmia, heart arrest, even death. This study aimed to evaluate the cardiotoxicity of three diester diterpene alkaloids (DDAs) including aconitine (AC), mesaconitine (MAC), hypaconitine (HAC) and three monoester diterpene alkaloids (MDAs) including 14-α-benzoylaconine (BAC), 14-α-benzoylmesaconine (BMAC), 14-α-benzoylhypaconine (BHAC) on zebrafish. Firstly, the zebrafish embryos after a 72-hour post fertilization were treated with different doses of AC, MAC, HAC, and BAC, BMAC and BHAC for 2, 10 and 24 h, respectively. The heart rates of the treated embryos were calculated and the morphological images of body, together with heart fluorescence were obtained. Results demonstrated that AC, MAC, and HAC at low doses (15.6 and 31.3 μM) decreased the heart rates and increased them at high doses (62.5, 125, and 250 μM), while BAC, BMAC, and BHAC decreased the heart rates in the dose range of 31.3-250 μM, but the highest dose (500 μM) of BAC and BMAC increased the heart rates. In addition, AC, MAC, and HAC exhibited serious organic and functional toxicities, while BAC, BMAC, and BHAC did not. It could be induced that DDAs expressed stronger cardiotoxicities than MDAs, which might be due to that they were known as the Na⁺ channel activators and K⁺ channel inhibitors, respectively. The β-acetate at C-8 position, along with the protonated nitrogen on ring A of their chemical structures contributed more for their different cardiotoxicities. This is the first study on cardiotoxicity comparison of DAs, providing references for the rational and safe application of these compounds and some plant species containing them to reduce side effects while retaining therapeutic efficacy.

Organocatalytic Asymmetric Synthesis of Bridged Acetals with Spirooxindole Skeleton

The first highly diastereo- and enantioselective synthesis of bridged O, O-acetals embedded with spirooxindoles has been developed. Dioxindoles and 2-hydroxy cinnamaldehydes were employed as the reaction partners in this method. The desired products were obtained via diaryl prolinol TBS ether catalyzed Michael reaction followed by acetal formation with TFA.

An Explorer of Chemical Biology of Plant Natural Products in Southwest China, Xiaojiang Hao

Xiaojiang Hao, who obtained Master Degree from Kunming Institute of Botany (KIB), Chinese Academy of Sciences (CAS) in 1985, and Doctor in Pharmacy degree in Pharmacy from Institute for Chemical Research, Kyoto University, in 1990, was born in Chongqing in July, 1951. In 1991, he returned to KIB, CAS, as an Associate professor and served as the chair of the Department of Phytochemistry. In 1994, he was promoted to a full professor at the current institute. He served as the Deputy Director of KIB and the Director of Open Laboratory of Phytochemistry from 1995 to 1997, and the Director of KIB from 1997 to 2005. Professor Hao has published more than 450 peer-reviewed SCI papers, which have been cited over 6000 times. He has obtained one PCT patent and 23 patents in China. Due to his tremendous efforts, one candidate drug, phenchlobenpyrrone, has entered the Phase II clinical trail for the treatment of Alzheimer's disease. Moreover, he won the First Prize of Natural Sciences in Yunnan Province for three times, and Ho Leung Ho Lee Fund Science and Technology Innovation Award in 2017.

Plant Alkaloids as Antiplatelet Agent: Drugs of the Future in the Light of Recent Developments

An alkaloid is a class of naturally occurring organic nitrogen-containing compounds that are frequently found in the plant kingdom. Many alkaloids are valuable medicinal agents that can be utilized to treat various diseases including malaria, diabetics, cancer, cardiac dysfunction etc. Similarly, platelet aggregation beyond the purpose of homeostasis is the underlying cause of blood clotting related diseases. This review presents a thorough understanding of alkaloids as antiplatelet agents with a possible mechanism of action based on the literature of the last decade. In addition, this review will address the antiplatelet activity of alkaloids and their medicinal usage as potent antiplatelet agents with a description of structural relationship activity and possible lead compounds for future drug discovery.

A bio-inspired synthetic route to the core ring systems of Spiraea atisine-type diterpenoid alkaloids and related diterpenes

A bio-inspired synthetic strategy for the construction of the complex substructures of biologically active atisine-type diterpenoid alkaloids and related diterpenes was successfully developed.

Diterpene alkaloids and diterpenes from Spiraea japonica and their anti-tobacco mosaic virus activity

Five new naturally occurring natural products, including two atisine-type diterpene alkaloids (1 and 2), two atisane-type diterpenes (3 and 4), and a new natural product spiramine C2 (5), along with nine known ones (6-14), were isolated from the ethanolic extracts of the whole plant of Spiraea japonica var. acuminata Franch. Their structures were elucidated by extensive spectroscopic analysis. The anti-tobacco mosaic virus (TMV) activities of all the compounds were evaluated by the conventional half-leaf method. Six compounds (2, 3, 6, 7, 11, and 12) exhibited moderate activities at 100 μg/mL with inhibition rates in the range of 69.4-92.9%, which were higher than that of the positive control, ningnanmycin. Their preliminary structure-activity relationships were also discussed.

Effect of traditional Uyghur medicine abnormal Savda Munziq extract on rabbit platelet aggregation in vitro and rat arteriovenous shunt thrombosis in vivo

OBJECTIVE

Abnormal Savda Munziq (ASMq) is a standard herbal preparation used in Uyghur traditional medicine to fight chronic diseases including cardiovascular, but its specific effects on thrombosis and platelet aggregation are unknown.

METHODS

Rabbit platelets were incubated with ASMq extract (10, 20, 40 µg/ml) for 15, 30, or 60 min, and aggregation was induced with ADP and collagen. In vivo, ASMq extract 2.97 g/kg, 5.94g/kg, 11.88 g/kg per os daily for 15 days were tested on thrombus wet weight in a rat model of arterio-venous bypass thrombosis. Plasma thromboxane B2 (TXB2) and 6-keto-PGF1a (6PG) were measured by radioimmunoassay. Aspirin (12 µg/ml and 5mg/kg) and saline were used as control in both experiments.

RESULTS

ASMq inhibited ADP and collagen-induced aggregation in vitro in a dose-dependent manner that increased over time, to a maximum of 6.4 ± 1.3% and 21.6 ± 4.0% for ADP and collagen, respectively, at one hour׳s incubation with the highest concentration, whereas the effects of aspirin (34.5 ± 2.2% and 41.9 ± 2.5%, respectively) were stable over time. In vivo, ASMq inhibited thrombus formation dose-dependently, by 70% at the highest dose, compared to 67% with aspirin. ASMq essentially did not change prostaglandin production, compared to the clear inhibition by aspirin.

CONCLUSION

Abnormal Savda Munziq extract inhibits dose-dependent platelet aggregation with ADP or collagen in vitro and thrombosis in vivo to values similar to those of aspirin, though unlike aspirin this effect does not seem mediated by an inhibition of cyclo-oxygenase.

A diterpenoid derivative 15-oxospiramilactone inhibits Wnt/β-catenin signaling and colon cancer cell tumorigenesis

The Wnt/β-catenin signaling pathway is a highly conserved pathway in organism evolution and regulates many biological processes. Aberrant activation of the Wnt/β-catenin signaling pathway is closely related to tumorigenesis. In order to identify potent small molecules to treat the over-activated Wnt signaling-mediated cancer, such as colon cancer, we established a mammalian cell line-based reporter gene screening system. The screen revealed a diterpenoid derivative, 15-oxospiramilactone (NC043) that inhibits Wnt3a or LiCl-stimulated Top-flash reporter activity in HEK293T cells and growth of colon cancer cells, SW480 and Caco-2. Treatment of SW480 cells with NC043 led to decreases in the mRNA and/or protein expression of Wnt target genes Axin2, Cyclin D1 and Survivin , as well as decreases in the protein levels of Cdc25c and Cdc2. NC043 did not affect the cytosol-nuclear distribution and protein level of soluble β-catenin, but decreased β-catenin/TCF4 association in SW480 cells. Moreover, NC043 inhibited anchorage-independent growth and xenograft tumorigenesis of SW480 cells. Collectively these results demonstrate that NC043 is a novel small molecule that inhibits canonical Wnt signaling downstream of β-catenin stability and may be a potential compound for treating colorectal cancer.

Hemiterpene glucosides and other constituents from Spiraea canescens

Five glycosides, 2-(trans-cinnamoyloxy-methyl)-1-butene-4-O-beta-D-glucopyranoside (1), 4-(6'-O-trans-cinnamoyl)-(2-hydroxymethyl-4-hydroxy-butenyl-beta-D-glucopyranoside (2), 6''-O-trans-p-coumaroyl-(4-hydroxybenzoyl)-beta-D-glucopyranoside (3), 6'-O-(4-methoxy-trans-cinnamoyl) alpha/beta-D-glucopyranose (4) 6'-O-(4''-methoxy-trans-cinnamoyl)-kaempferol-3-beta-D-glucopyranoside (7) along with six known compounds, (+)-isolariciresinol 3a-O-beta-D-glucopyranoside (8) (+)-lyoniresinol 3a-O-beta-D-glucopyranoside (9), apigenin 7-O-beta-D-glucopyranoside (10), quercetin 3-O-beta-D-glucopyranoside (11), 6'-O-cinnamoyl-alpha/beta-D-glucopyranose (6) 6'-O-p-coumaroyl-alpha/beta-D-glucopyranose (5) were isolated from the whole plant of Spiraea canescens. Some of these compounds showed potent radical scavenging activity in relevant non-physiological assays. Their structures were determined by NMR spectroscopic and CID mass spectrometric techniques.

A new fungitoxic metabolite from Spiraea alpina Pall

The fungitoxic metabolites of Spiraea alpina Pall. were identified using inhibition of Rhizoctonia solani, Gibberella zeae, Pyricularia oryzea and Exserohilum turcicum as an end-point. The major fungitoxic constituent of S. alpina was a new diacylated sugar, structurally elucidated as 6-O-(3',4'-dihydroxy-2'-methylenbutyryl)-1-O-trans-cinnamoyl-beta-D-glucopyranose. This compound could inhibit at 0.1 mg/ml Rhizoctonia solani and Exserohilum turcicum, 87.6% and 63.2%, respectively.

Strategies for antiplatelet targets and agents

Platelets play a key role in thrombosis and haemostasis, which can be either beneficial or deleterious depending on the circumstance. Antiplatelet therapy is the 'cornerstone' in the prevention and treatment of thrombotic diseases. Platelet activation is a complex process known as transmembrane signaling which then serves to activate the platelet via a cascade of biochemical interactions. Currently available strategies of antiplatelet therapy are generally based on the signaling pathway of platelet activation, which possess the characters that mono-agent, mono-target, and mainly irreversible inhibition. Therefore, both established and novel antiplatelet agents have their own pros and cons and such problems as resistance, drug-drug interaction, discontinuation and monitoring, etc. have been appeared. Due to the problems existing in current antiplatelet agents, future new strategies for antiplatelet targets, agent-developing and treatment might probably include three aspects: targeting the factors associated with platelet hyperactivity, developing novel antiplatelet agents with multiple targets, mild and reversible properties from natural products, and keeping healthy lifestyle and emphasizing prevention.

In vitro activity of C20-diterpenoid alkaloid derivatives in promastigotes and intracellular amastigotes of Leishmania infantum

The in vitro anti-proliferative effects are described of several atisine-type diterpenoid alkaloids against the protozoan parasite Leishmania infantum, which causes human visceral leishmaniasis and canine leishmaniasis in the Mediterranean basin, as well as human cutaneous leishmaniasis throughout the Mediterranean region. From a total of 43 compounds tested, including C19- and C20-diterpene alkaloids from several chemical classes, only 15,22-O-diacetyl-19-oxo-dihydroatisine, azitine and isoazitine were highly active against cultures of the parasite (promastigote form) with IC50 values within the range of the reference drug pentamidine-isothionate (7.39-12.80 mg/L for the test compounds, 11.32 mg/L for the positive control). These compounds were not toxic to the host cell. When treated with a dosage of 5 microg/mL of the active compounds (half of their IC50), the promastigote forms lost 80% of their infection capacity and the multiplication of extracellular forms of L. infantum was severely affected. The study showed that atisine-type C20-diterpenoid alkaloids exhibited promising anti-leishmanial properties with strong molecular selectivity. These might have implications for other intracellular pathogens- or phylogenetically related parasites, such as Trypanosoma spp.

Serofendic Acid, a Sulfur-Containing Diterpenoid Derived from Fetal Calf Serum, Attenuates Reactive Oxygen Species-Induced Oxidative Stress in Cultured Striatal Neurons

We previously identified a novel endogenous substance, serofendic acid, from a lipophilic extract of fetal calf serum. Serofendic acid protects cultured cortical neurons against the cytotoxicity of glutamate and nitric oxide. Here, we reported the protective effect of serofendic acid on reactive oxygen species-induced oxidative stress using primary rat striatal cultures. In addition, we compared the neuroprotective effect and the radical-scavenging activity of serofendic acid with those of dimethyl sulfoxide (DMSO), because serofendic acid possesses a DMSO structure. Paraquat caused neuronal death, which was inhibited by a cell-permeable superoxide dismutase (SOD) mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (Mn-TBAP); a cell-permeable SOD/catalase mimetic, EUK-134 [manganese 3-methoxy N,N'-bis(salicylidene)ethylenediamine chloride]; and a ferrous ion chelator, 2,2'-dipyridyl, in rat striatal cultures. Serofendic acid (10-100 microM) suppressed the neurotoxicity of paraquat, whereas DMSO (10-100 microM) did not. By contrast, higher concentrations (30-300 mM) of DMSO ameliorated the paraquat-induced cell death. Furthermore, H(2)O(2) induced neurotoxicity, which was prevented by EUK-134 and 2,2'-dipyridyl. Serofendic acid (10-100 microM) also protected striatal neurons against the H(2)O(2)-induced toxicity. Higher concentrations (30-300 mM) of DMSO ameliorated H(2)O(2)-induced neuronal death, whereas lower concentrations (10-100 microM) did not. Electron spin resonance spectrometry with a spin-trapping technique revealed that serofendic acid and DMSO had approximately the same ability to inhibit the formation of the hydroxyl radical (.OH). These results suggest that the.OH-scavenging activity of serofendic acid is attributable to its DMSO structure and that the remaining components such as the atisane structure play an important role in eliciting neuroprotection at a concentration range of 10 to 100 microM.