Research progress in strigolactones and application prospect in medicinal plants / 中国中药杂志

Strigolactones(SLs) are a class of sesquiterpenoids derived from the carotenoid biosynthesis pathway with the core carbon skeleton consisting of tricyclic lactone(ABC tricyclic ring) and α,β-unsaturated furan ring(D ring). SLs are widely distributed in higher plants and are symbiotic signals between plants and Arbuscular mycorrhiza(AM), which play key roles in the evolution of plant colonizing terrestrial habitats. As a new type of plant hormone, SLs possess such important biological functions as inhibiting shoot branching(tillers), regulating root architecture, promoting secondary growth, and improving plant stress resistance. Therefore, SLs have attracted wide attention. The biological functions of SLs are not only closely related to the formation of "excellent shape and quality" of Chinese medicinal materials but also have important practical significance for the production of high-quality medicinal materials. However, SLs have been currently widely studied in model plants and crops such as Oryza sativa and Arabidopsis thaliana, and few related studies have been reported on SLs in medicinal plants, which need to be strengthened. This review focused on the latest research progress in the isolation and identification, biological and artificial synthesis pathways, biosynthesis sites and transport modes, signal transduction pathways and mechanisms, and biological functions of SLs, and prospected the research on the regulation mechanism of SLs in the growth and development of medicinal plants and their related application on targeted regulation of Chinese herbal medicine production, which is expected to provide some references for the in-depth research on SLs in the field of Chinese medicinal resources.

Steroids and dihydroisocoumarin glycosides from Xylaria sp. by the one strain many compounds strategy and their bioactivities / 中国天然药物

The fungus Xylaria sp. KYJ-15 was isolated from Illigera celebica. Based on the one strain many compounds (OSMAC) strategy, the strain was fermented on potato and rice solid media, respectively. As a result, two novel steroids, xylarsteroids A (1) and B (2), which are the first examples of C28-steroid with an unusual β- and γ-lactone ring, respectively, along with two new dihydroisocoumarin glycosides, xylarglycosides A (3) and B (4), were identified. Their structures were elucidated by spectroscopic methods, X-ray diffraction and electronic circular dichroism (ECD) experiments. All isolated compounds were evaluated for cytotoxicity, DPPH radical scavenging activity, acetylcholinesterase inhibitory and antimicrobial effect. Compound 1 exhibited potent AChE inhibitory activity with an IC50 value of 2.61 ± 0.05 μmol·L-1. The β-lactone ring unit of 1 is critical for its AChE inhibitory activity. The finding was further confirmed through exploring the interaction of 1 with AChE by molecular docking. In addition, both compounds 1 and 2 exhibited obvious antibacterial activity against Bacillus subtilis with a minimum inhibitory concentration (MIC) of 2 μg·mL-1. Compounds 3 and 4 exhibited antibacterial activities against Staphylococcus aureus with MICs of 4 and 2 μg·mL-1, respectively, which also exhibited DPPH radical scavenging activity comparable to the positive control with IC50 values of 9.2 ± 0.03 and 13.3 ± 0.01 μmol·L-1, respectively.

Application of near infrared spectroscopy to predict contents of various lactones in chromatographic process of Ginkgo Folium / 中国中药杂志

This study established a method for rapid quantification of terpene lactone, bilobalide, ginkgolide C, ginkgolide A and ginkgolide B in the chromatographic process of Ginkgo Folium based on near infrared spectroscopy(NIRS). The effects of competitive adaptive reweighting sampling(CARS), random frog(RF), and synergy interval partial least squares(siPLS) on the performance of partial least squares regression(PLSR) model were compared to the reference values measured by HPLC. Among them, the correlation coefficients of prediction(Rp) of validation sets of terpene lactone, bilobalide, and ginkgolide C were all higher than 0.98, and the relative standard errors of prediction(RSEPs) were 5.87%, 6.90% and 6.63%, respectively. Aiming at ginkgolide A and ginkgolide B with relatively low content, the genetic algorithm joint extreme learning machine(GA-ELM) was used to establish the optimized quantitative analysis model. Compared with CARS-PLSR model, the CARS-GA-ELM models of ginkgolide A and ginkgolide B exhibited a reduction in RSEP from 15.65% to 8.52% and from 21.28% to 10.84%, respectively, which met the needs of quantitative ana-lysis. It has been proved that NIRS can be used for the rapid detection of various lactone components in the chromatographic process of Ginkgo Folium.

Atractylenolide Ⅰ improves acetaminophen-induced acute liver injury in mice by inhibiting MAPK/NF-κB signaling pathway / 中国中药杂志

This study explored the protective effect of atractylenolide Ⅰ(AO-Ⅰ) against acetaminophen(APAP)-induced acute liver injury(ALI) in mice and its underlying mechanism. C57 BL/6 J mice were randomly divided into a control group, an APAP group(500 mg·kg~(-1)), a low-dose combination group(500 mg·kg~(-1) APAP + 60 mg·kg~(-1) AO-Ⅰ), and a high-dose combination group(500 mg·kg~(-1) APAP + 120 mg·kg~(-1) AO-Ⅰ). ALI was induced by intraperitoneal injection of APAP(500 mg·kg~(-1)). AO-Ⅰ by intragastric administration was performed 2 hours before APAP treatment, and the control group received the same dose of solvent by intragastric administration or intraperitoneal injection. The protective effect of AO-Ⅰ against APAP-induced ALI was evaluated by detecting alanine aminotransferase(ALT) and aspartate aminotransferase(AST) levels in the plasma and H&E staining in liver tissues of mice. The malondialdehyde(MDA) and glutathione(GSH) content and catalase(CAT) activity in mouse liver tissues were detected to evaluate the effect of AO-Ⅰ on APAP-induced oxidative stress in the liver. The proteins in the liver p38 mitogen-activated protein kinase(p38 MAPK), c-jun N-terminal kinase(JNK), and nuclear factor kappa-B p65(NF-κB p65) signaling pathways were measured by Western blot, and the liver inflammatory cytokines interleukin-1β(IL-1β) and interleukin-6(IL-6) were detected by real-time PCR. Compared with the APAP group, the combination groups showed reduced APAP-induced ALT level and liver MDA content, potentiated liver CAT activity, and elevated GSH content. Mechanistically, AO-Ⅰ treatment significantly inhibited APAP-up-regulated MAPK phosphorylation and NF-κB p65, and significantly reduced the transcriptional activities of IL-1β and IL-6, downstream targets of NF-κB p65. AO-Ⅰ can improve APAP-induced ALI and the underlying mechanism is related to the inhibition of the MAPK/NF-κB p65 signaling pathway in APAP-challenged mice.

Atractylenolide III alleviates sepsis-mediated lung injury via inhibition of FoxO1 and VNN1 protein

ABSTRACT Purpose: To evaluate the influence of atractylenolide (Atr) III on sepsis-induced lung damage. Methods: We constructed a mouse sepsis model through cecal ligation and puncture. These mice were allocated to the normal, sepsis, sepsis + Atr III-L (2 mg/kg), as well as Atr III-H (8 mg/kg) group. Lung injury and pulmonary fibrosis were accessed via hematoxylin-eosin (HE) and Masson's staining. We used terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry for detecting sepsis-induced lung cell apoptosis. The contents of the inflammatory cytokines in lung tissue were measured via enzyme-linked immunosorbent assay (ELISA). Results: Atr III-H did not only reduce sepsis-induced lung injury and apoptosis level, but also curbed the secretion of inflammatory factors. Atr III-H substantially ameliorated lung function and raised Bcl-2 expression. Atr III-H eased the pulmonary fibrosis damage and Bax, caspase-3, Vanin-1 (VNN1), as well as Forkhead Box Protein O1 (FoxO1) expression. Conclusions: Atr III alleviates sepsis-mediated lung injury via inhibition of FoxO1 and VNN1 protein.

Advance in biosynthesis and metabolic regulation of ginkgolides / 中国中药杂志

Ginkgolides,the unique terpenoids in Ginkgo biloba,have a significant effect on the prevention and treatment of cardiovascular and cerebrovascular diseases. Metabolic regulation and synthetic biology strategies are efficient methods to obtain high-quality ginkgolides. The present study reviewed the cloning and functions of genes related to the biosynthetic pathway of ginkgolides,as well as relevant studies of omics,genetic transformation,and metabolic regulation in recent years,and predicted the research trends and prospects,aiming to provide a reference for discovering the key genes related to the biosynthetic pathway and the biosynthesis of ginkgolides.

A new seco-prezizaane-type sesquiterpene lactone from stems and branches of Illicium ternstroemioides / 中国中药杂志

Three seco-prezizaane-type sesquiterpene lactones, one phenylpropanoid, and two lignans were isolated from the 95% ethanol extract of stems and branches of Illicium ternstroemioides with silica gel column chromatography, ODS column chromatography, and preparative HPLC. Based on the spectral data, they were identified as burmanicumolide D(1), veranisatin A(2), veranisatin B(3), dihydroconiferylalcohol(4), pinoresinol(5),(-)-matairesinol(6), respectively. Among them, compound 1 was a new seco-prezizaane-type sesquiterpene lactone, and 2-6 were obtained from this plant for the first time. None of these compounds display antiviral or cytotoxic activities.

Germacrene-derived sesquiterpene lactones:opportunities and challenges for biosynthesis / 中国中药杂志

Sesquiterpene lactones are a kind of widely distributed natural organic compounds with anti-tumor, anti-malarial and other significant biological activities. Based on their carbocylic skeletons, sesquiterpene lactones are classified into germacranolide, guaia-nolide, xanthanolide, pseudo-guaianolide, elemonolide and eudesmanolide, etc. In recent years, with the development of various omics and synthetic biology technologies, the biosynthetic pathways of sesquiterpene lactone compounds of different structural types have gradually been resolved. Among them, the researches on germacrene-derived sesquiterpene lactones are relatively more than others. Therefore, this article focused on the germacrene-derived sesquiterpene lactone biosynthesis pathways and their key enzyme genes, which can lay the foundation for in-depth analysis of sesquiterpene lactone biosynthetic pathways, functional gene mining and heterologous synthesis of active ingredients.

Development and Characterization of Poly-ε -caprolactone Nanocapsules Containing β -carotene Using the Nanoprecipitation Method and Optimized by Response Surface Methodology

Abstract Nanoparticles demonstrate an important role in the protection of bioactive compounds from external factors such as temperature, oxygen and light. In this study, poly-ε-caprolactone (PCL) nanoparticles entrapped β-carotene was produced using the nanoprecipitation method. Firstly, was evaluated the lipophilic surfactant effect and carrier agent of the active compound in the nanocapsules formulation. After choosing the most stable formulation, the nanocapsules production was optimized using β-carotene, caprylic/capric triglycerides (CCT) and soybean lecithin. Response surface methodology (RSM) was adopted to evaluate the influence of soy lecithin concentration, volume of CCT and β-carotene concentration in the particle size, zeta potential, polydispersity index (PDI), encapsulation efficiency and recovery. Formulations containing soy lecithin and CCT demonstrated better stability comparing to the other formulations tested. The nanoparticle formulations presented an optimized particle size below 200 nm, PDI lower than 0.1 and encapsulation efficiency above 95%. Based on the results obtained, the optimum conditions to prepare PCL nanocapsules were 0.2160 mg/mL of β-carotene, 232.42 μL of CCT and 2.59 mg/mL of soy lecithin, suggesting an applicability to promote controlled released of β-carotene in food system.

Preparation and quality evaluation of orodispersible film containing ginkgolide B novel nanosuspension lyophilized powder / 中国中药杂志

To prepare a new dosage form that can improve the drug loading of the film--ginkgolide B nanosuspension lyophilized powder orodispersible film(GB-NS-LP-ODF) and to evaluate its quality. Firstly, ginkgolide B nanosuspension(GB-NS) was prepared by media milling method, and then ginkgolide B nanosuspension lyophilized powder(GB-NS-LP) was prepared with freeze-drying method. The mannitol was used as lyoprotectant and its dosage was also investigated. GB-NS-LP-ODF was prepared by solvent casting method and its formulation was screened by single factor test method and optimized by orthogonal test. The appearance, mechanical properties, content uniformity and in vitro dissolution of the optimized GB-NS-LP-ODF were investigated. The particle size of prepared GB-NS was about 201 nm, and the optimal dosage of mannitol was 8%. According to the optimal formula, the GB-NS-LP-ODF was prepared with GB-NS-LP 35.6%, PVA 0588 49.4%, PEG 400 10.7% and CMS-Na 4.3%, and completely disintegrated in about 30 s, and the particle size of reconstituted GB nanoparticles from ODF was about 210 nm. The film with smooth appearance and good mechanical properties was stable within 30 days and the content uniformity(A+2.2 S<15) conformed to the regulations. Scanning electron microscope(SEM) showed that GB-NS-LP-ODFs were evenly distributed and the particle size was about 200 nm. X-rays diffraction(XRD) showed that its crystallinity was significantly lower than that of GB raw drug and GB-ODF. The results of in vitro release test showed that the drug film was completely dissoluted within 10 minutes. These results indicated that nanosuspension lyophilized powder was prepared by freeze drying of nanosuspensions, and then loaded into the orodispersible film to effectively increase the drug loading of the ODF and have broad application prospects.

Relationship Between Parameters of Development and Functional Compounds of Yacon Leaves

Abstract Yacon is a tuberous root from the Andean region being increasingly grown across the world due to the low caloric values of their roots and the functional properties of extractions of its leaves. However, there is still a gap in the knowledge of how the plant develops, and if physical and chemical changes are noticed regarding maturity. The subject of this work was to investigate the dynamics of a group of parameters and to establish correlations across them. To achieve this goal, leaves collected from three different parts of the plant in three months were assessed regarding size (plant height and leaf area), color and the presence of sesquiterpene lactones. Different methods of extraction were also studied and the total phenolic content was analyzed. The analysis of the results revealed different patterns in the quantity, size and leaf distribution according to the age of the plant. From three different methods of extraction studied, decoction seems to be the most appropriate one to obtain phenolic compounds with greater yield and safety. Besides, the greenness of yacon leaves showed a linear correlation to the total phenolic content, being a simple and promising estimator of the corresponding bioactive group. Sesquiterpene lactones were identified in all extracts, indicating the ease of their extractability even in simple procedures of tea-making.

Correlation analysis of main agronomic traits and contents of diterpene lactones of Andrographis paniculata / 中国中药杂志

In order to study the correlation between the traits of Andrographis paniculata. The main agronomic traits and the content of four kinds of diterpene lactons were measured by the seedlings and the unmutagenized seeds carried by the spacecraft,and multiple comparisons,correlations and principal component analysis were carried out. The results showed that the agronomic traits of A. paniculata have different degrees of difference after being carried by space. The contents of diterpene lactones were quite different. The variation coefficients of deoxyandrographolide content,fresh weight,leaf dry weight,dehydrated andrographolide content,dry weight,neoandrographolide content and andrographolide content were all over 35%. There was a significant correlation between multiple traits,and the leaf weight ratio was significantly positively correlated with the number of primary tillers,leaf dry weight and dry weight,and was significantly negatively correlated with the content of deoxyandrographolide. Andrographolide content was a significantly negatively correlated with the number of leaves and the number of primary tillers,and positively correlated with the other three lactones. Five principal components were extracted from principal component analysis,and the cumulative contribution rate was 83. 127%,which were yield factor,plant type factor,leaf type factor,component factor and seed weight factor. Among the traits affecting the quality of A. paniculata,the yield factor for reliability of the selection of A. paniculata is higher than other factors. There are abundant variations among the traits of A. paniculata,carried in space which increase the genetic diversity. The principal component analysis method can be used to select the principal component factors according to the breeding requirements,which provides a theoretical basis for the breeding of high-yield and high-quality A. paniculata and the high-yield and stable cultivation of A. paniculata.

Effect of GR24 on accumulation of diterpenoids in Tripterygium wilfordii suspension cells / 中国中药杂志

Terpenoids are main bioactive components in Tripterygium wilfordii,but the contents of some terpenoids are relatively low. In order to provide scientific evidence for the regulation of terpenoids in T. wilfordii,this research explored the effect of GR24 on accumulations of four diterpenoids( triptolide,tripterifordin,triptophenolide,and triptinin B) in T. wilfordii suspension cells by biological technology and UPLC-QQQ-MS/MS. The results indicated that 100 μmol·L-1 GR24 inhibited the accumulations of triptolide,tripterifordin,triptophenolide,and triptinin B to different degrees. Compared with the control group,the contents of 4 diterpenoids( in the induced group) were down to 96.59%,63.80%,61.02% and 33.59% in 240 h,respectively. Among them,the accumulation of triptinin B iswas significantly inhibited. In addition,the key time point of inhibitory effect was 120 h after induction with GR24 in some diterpenoids. This is the first systematic study focusing on the effect of GR24 on the accumulations of diterpenoids in T. wilfordii suspension cells. The dynamic accumulation ruleregularity of four diterpenoids after induced by GR24 was summarized,which laid a foundation for further study on the chemical response mechanism of terpenoids to GR24.

Involvement of mitochondrial apoptotic pathway and MAPKs/NF-κ B inflammatory pathway in the neuroprotective effect of atractylenolide III in corticosterone-induced PC12 cells / 中国天然药物

Atractylenolide III (ATL-III), a sesquiterpene compound isolated from Rhizoma Atractylodis Macrocephalae, has revealed a number of pharmacological properties including anti-inflammatory, anti-cancer activity, and neuroprotective effect. This study aimed to evaluate the cytoprotective efficiency and potential mechanisms of ATL-III on corticosterone injured rat phaeochromocytoma (PC12) cells. Our results demonstrate that ATL-III increases cell viability and reduces the release of lactate dehydrogenase (LDH). The results suggest that ATL-III protects PC12 cells from corticosterone-induced injury by inhibiting the intracellular Ca overloading, inhibiting the mitochondrial apoptotic pathway and modulating the MAPK/NF-ΚB inflammatory pathways. These findings provide a novel insight into the molecular mechanism by which ATL-III protected the PC12 cells against corticosterone-induced injury for the first time. Our results provide the evidence that ATL-III may serve as a therapeutic agent in the treatment of depression.

Effect of Dehydrocostus Lactone on Proliferation of K562 Cells and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To explore the inhibitory effect of dehydrocostus lactone on the proliferation of human chronic myeloid leukemia K562 cells and the underlying mechanisms.@*METHODS@#Cell viability was evaluated by CCK-8 assay. Flow cytometry was used to assess the effect of dehydrocostus lactone on the cell cycle and apoptosis of K562 cells. The levels of BCR/ABL-STATs-related molecules were analyzed by using Western blot.@*RESULTS@#The CCK-8 assay showed that dehydrocostus lactone at graded concentration of 4, 6, 8, 10, 12 μmol/L could significantly inhibit the proliferation of K562 cells after exposure for 24 h. The proliferation inhibition rate was (24.32±3.05%), (42.91±3.89%), (46.35±4.93%), (77.06±5.42%) and (89.04±4.25%) respectively, showing statistically significantly different from (2.08±0.27%) in the control (P＜0.05). Also, the treatment with 5 and 10 μmol/L of dehydrocostus lactone induced K562 cell apoptosis, the apoptotic rate of K562 cells was significantly higher than that the control group (P＜0.05), and up-regulated the expression level of BAX and p21. Furthermore, dehydrocostus lactone (5 and 10 μmol/L) also increased the percentage of cells in G2/M [(8.53±1.71)% to (17.42±2.72) and (31.79±4.38%)](P＜0.05). The study results also revealed that dehydrocostus lactone significantly inhibited the expression of BCR/ABL STAT3, STAT5, CyclinB1, CDK1 and BCL-2, and up-regulated the expression level of BAX and p21.@*CONCLUSION@#Dehydrocostus lactone can suppress the proliferation of K562 cells and induce the apoptosis of K562 cells through BCR/ABL-STAT signaling pathways.

Anti-inflammatory Activity of Standardized Fraction from Inula helenium L. via Suppression of NF-κB Pathway in RAW 264.7 Cells

Inula helenium L. is rich source of eudesmane-type sesquiterpene lactones, mainly alantolactone and isoalantolactone, which have the various pharmacological functions. In this study, we examined the inhibitory effects of nitric oxide (NO) production of hexane, methylene chloride, ethyl acetate, butanol, and water fractions from I. helenium and investigated the anti-inflammatory effect of hexane fraction of I. helenium (HFIH) in LPS-induced RAW 264.7 cells. Quantification of alantolactone and isoalantolactone from HFIH was carried out for the standardization by multiple reaction monitoring using triple quadrupole mass spectrometer. HFIH significantly inhibited inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) protein as well as their downstream products NO and prostaglandin E₂ (PGE₂) in LPS-stimulated RAW 264.7 cells. Moreover, HFIH suppressed NF-κB transcriptional activity by decreasing the translocation of p65 to the nucleus. The in vivo study further confirmed that HFIH attenuated the paw edema induced by carrageenan in an acute inflammation model. These findings suggest that HFIH may be useful as a promising phytomedicine for inflammatory-associated diseases.

Cytotoxic Lactones from the Pericarps of Litsea japonica

From the pericarps of Litsea japonica (Thunb.) Jussieu, eighteen butanolide derivatives (1 – 18) were evaluated for their cytotoxic activity against HeLa, HL-60, and MCF-7 cells. Compounds 1 – 9 with 2-alkylidene-3-hydroxy-4-methylbutanolides structure exhibited cytotoxic activities against cancer-cell lines. Among them, compound 8 (litsenolide D₂) exhibited the most potent cytotoxicity against the tested cell lines, including HeLa, HL-60, and MCF-7, with IC₅₀ values of 17.6 ± 1.3, 4.2 ± 0.2, and 12.8 ± 0.0 µM, respectively. Compound 8 induced apoptosis in a dose-dependent manner. Annexin V/Propidium Iodide (PI) double staining confirmed that 8 effectively induced apoptosis in MCF-7 cells. To the best of our knowledge, we have reported cytotoxic activity of butanolides from L. japonica against these cancer-cell lines for the first time.

Cardioprotective effect of lipstatin derivative orlistat on normotensive rats submitted to cardiac ischemia and reperfusion

Abstract Purpose: To evaluate in vivo animal model of cardiac ischemia/reperfusion the cardioprotective activity of pancreatic lipase inhibitor of the orlistat. Methods: Adult male Wistar rats were anesthetized, placed on mechanical ventilation and underwent surgery to induce cardiac I/R by obstructing left descending coronary artery followed by reperfusion to evaluation of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) with pancreatic lipase inhibitor orlistat (ORL). At the end of reperfusion, blood samples were collected for determination of triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), lactate dehydrogenase (LDH), creatine kinase (CK), and creatine kinase-MB (CK-MB). Results: Treatment with ORL has been able to decrease the incidence of VA, AVB and LET. Besides that, treatment with ORL reduced serum concentrations of CK and LDL, but did not alter the levels of serum concentration of TG, VLDL and HDL. Conclusion: The reduction of ventricular arrhythmias, atrioventricular block, and lethality and serum levels of creatine kinase produced by treatment with orlistat in animal model of cardiac isquemia/reperfusion injury suggest that ORL could be used as an efficient cardioprotective therapeutic strategy to attenuate myocardial damage related to acute myocardial infarction.

Effect of γ-lactones and γ-lactams compounds on Streptococcus mutans biofilms

Abstract Considering oral diseases, antibiofilm compounds can decrease the accumulation of pathogenic species such as Streptococcus mutans at micro-areas of teeth, dental restorations or implant-supported prostheses. Objective To assess the effect of thirteen different novel lactam-based compounds on the inhibition of S. mutans biofilm formation. Material and methods We synthesized compounds based on γ-lactones analogues from rubrolides by a mucochloric acid process and converted them into their corresponding γ-hydroxy-γ-lactams by a reaction with isobutylamine and propylamine. Compounds concentrations ranging from 0.17 up to 87.5 μg mL-1 were tested against S. mutans. We diluted the exponential cultures in TSB and incubated them (37°C) in the presence of different γ-lactones or γ-lactams dilutions. Afterwards, we measured the planktonic growth by optical density at 630 nm and therefore assessed the biofilm density by the crystal violet staining method. Results Twelve compounds were active against biofilm formation, showing no effect on bacterial viability. Only one compound was inactive against both planktonic and biofilm growth. The highest biofilm inhibition (inhibition rate above 60%) was obtained for two compounds while three other compounds revealed an inhibition rate above 40%. Conclusions Twelve of the thirteen compounds revealed effective inhibition of S. mutans biofilm formation, with eight of them showing a specific antibiofilm effect.

Effect of phospholipase A2 inhibitors during infection caused by Leishmania (Leishmania) amazonensis

Lipid metabolites play an important role in parasite differentiation and virulence. Studies have revealed that Leishmania sp. uses prostaglandins to evade innate barriers, thus enabling the parasites to survive inside immune cells. Despite the role of the enzyme Phospholipase A2 (PLA2) in prostaglandins production, few studies have investigated the role of parasite PLA2 during the interaction between L. (L.) amazonensis and the host (in vitro and in vivo) immune cells. Methods: In the present work, the leishmanicidal effect of PLA2 inhibitors, methyl arachidonyl fluorophosphonate (MAFP), bromoenol lactone (BEL) and aristolochic acid (AA) were investigated in vitro (promastigote and intracellular amastigote forms of L. (L.) amazonensis) and during in vivo infection using BALB/c mice. Results: The aforementioned inhibitors were deleterious to promastigote and amastigote forms of the L. (L.) amazonensis and were non-toxic to peritoneal macrophages from BALB/c mice. L. (L.) amazonensis-infected BALB/c mice treated with the inhibitor BEL presented decreased lesion size and skin parasitism; however, BEL treatment induced hepatotoxicity in BALB/c mice. Conclusions: Results presented herein suggested that PLA2 inhibitors altered L. (L.) amazonensis viability. In spite of liver toxicity, treatment with BEL was the most selective compound in vitro, as well in vivo, resulting in lower skin parasitism in the infected mice. These findings corroborate the role of PLA2 in parasite virulence and maintenance in vertebrate hosts, and suggest that molecules structurally related to BEL should be considered when planning compounds against Leishmania sp.(AU)