Effects of (+)-usnic acid and (+)-usnic acid-liposome on Toxoplasma gondii

Bioactivities and Structure-Activity Relationships of Usnic Acid Derivatives: A Review

Usnic acid has a variety of biological activities, and has been widely studied in the fields of antibacterial, immune stimulation, antiviral, antifungal, anti-inflammatory and antiparasitic. Based on this, usnic acid is used as the lead compound for structural modification. In order to enhance the biological activity and solubility of usnic acid, scholars have carried out a large number of structural modifications, and found some usnic acid derivatives to be of more potential research value. In this paper, the structural modification, biological activity and structure-activity relationship of usnic acid were reviewed to provide reference for the development of usnic acid derivatives.

Anti-toxoplasma and Cytotoxic Activities of Holothuria leucospilota Extract and TiO2NPs In vitro and In vivo

BACKGROUND

An impressive treatment for toxoplasmosis is the combinatory use of sulfadiazine and pyrimethamine. However, both the drugs involve significant side effects and toxicity for the host. Therefore, the discovery of new anti-toxoplasma medications with high efficacy and less to no side effects is urgently needed.

OBJECTIVE

This study aimed to evaluate the anti-toxoplasmic effects of Holothuria leucospilota (H. leucospilota) extract and TiO₂NPs on the cell death of Toxoplasma gondii (T. gondii) tachyzoites in vitro and serum liver enzymes (AST, ALT, and ALP), and also to evaluate the immune response and production of IL-5, IFN-γ, and TNF-α in a mouse model.

MATERIALS AND METHODS

The cytotoxicity of TiO₂NPs and H. leucospilota extract against the tachyzoite of T. gondii was evaluated by the methyl thiazolyl tetrazolium (MTT) assay. The levels of serum TNF-α, IFN-γ, IL-5, and liver enzymes were measured, as well. All the groups were subjected to T. gondii, and the survival rate of experimental mice was evaluated.

RESULTS

Our findings suggested in vivo and in vitro anti-toxoplasmic activity of TiO₂NPs and H. leucospilota extract by inhibiting the proliferation and invasion of T. gondii tachyzoite. In addition, a significant increase in IFN-γ and TNF-α production was observed in mice treated with high doses of TiO₂NPs and H. leucospilota extract. However, IL-5 levels decreased in TiO₂NPs and H. leucospilota extract-treated mice. Our results also showed a highly significant increase (P < 0.05) in the levels of ALT, AST, and ALP in the groups injected with TiO₂NPs and H. leucospilota extract, but not the control group.

CONCLUSION

TiO₂NPs and H. leucospilota extract have greater anti-toxoplasma effects in vitro and in vivo. These two compounds could be considered as a candidate for use against toxoplasmosis, both therapeutically and prophylactically.

Insecticidal and Antiprotozoal Properties of Lichen Secondary Metabolites on Insect Vectors and Their Transmitted Protozoal Diseases to Humans

Since the long-term application of synthetic chemicals as insecticides and the chemotherapy of protozoal diseases have had various negative effects (non-target effects, resistance), research on less harmful biological products is underway. This review is focused on lichens with potential insecticidal and antiprotozoal activity. Literature sources (27) were surveyed from five bibliographic databases and analyzed according to the taxonomic group of the insect, the protozoal disease and the lichen, the type of bioactive compounds (including method of application and mount applied), and the potential bioactivity based on mortalities caused after 24 h of exposure on insects and on parasitic protozoa. Six species of protozoa and five species of mosquitoes, three kinds of larval stages of insects and three protozoa stages were tested. Insecticidal and antiprotozoal effects of crude extracts and seven lichen secondary metabolites (mostly usnic acid) of 32 lichen species were determined. Physiological and morphological changes on parasitic protozoa were observed. Mortality rates caused by LSMs on insect vectors closer to (or somewhat above) the WHO threshold were considered to be insecticides. The results are based on laboratory experiments; however, the efficacy of metabolites should be confirmed in the field and on non-human primates to control the insect vectors and human protozoal diseases transmitted by insects.

Beneficial Effects of Liposomal Formulations of Lichen Substances: A Review

Lichens are commonly used as essential traditional medicines to treat various conditions, including skin disorders, wounds, digestive, respiratory, obstetric, and gynecological problems in many cultures in Africa, Asia, Europe, Haitian, Oceania, and North and South America. Lichens have been deeply investigated for their phytochemical properties, and to date, numerous compounds (also known as substances) have been successfully isolated from the extracts. However, the low solubility and bioavailability of pure lichen substances have been widely recognized as the significant issues hindering their biological applications. Recently, several groups have investigated the properties and the potential applications of lichen metabolites-based liposomal formulations and revealed a substantial improvement in their solubility, bioactivity, and toxicity in the animal. Thus, in this topical review, we aimed to provide an overview of liposomal structures, the efficacy of liposomal formulations, as well as their beneficial effects as compared to the free compounds themselves.

Antimicrobial and antioxidant activity of Evernia prunastri extracts and their isolates

Lichens are symbiotic organisms formed by a fungus and one or more photosynthetic partners which are usually alga or cyanobacterium. Their diverse and scarcely studied metabolites facilitate adaptability to extreme living conditions. We investigated Evernia prunastri (L.) Ach., a widely distributed lichen, for its antimicrobial and antioxidant potential. E. prunastri was sequentially extracted by hexane (Hex), dichloromethane (DCM) and acetonitrile (ACN) that were screened for their antioxidant and antimicrobial (against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans) activities. The Hex extract possessed the highest antioxidant capacity (87 mg ascorbic acid/g extract) corresponding to the highest content of phenols (73 mg gallic acid/g extract). The DCM and Hex extracts were both active against S. aureus (MICs of 4 and 21 µg/ml, respectively) but were less active against Gram-negative bacteria and yeast. The ACN extract exhibited activity on both S. aureus (MIC 14 µg/ml) and C. albicans (MIC 38 µg/ml) and was therefore further fractionated by silica gel column chromatography. The active compound of the most potent fraction was subsequently characterized by 1H and 13C-NMR spectroscopy and identified as evernic acid. Structural similarity analyses were performed between compounds from E. prunastri and known antibiotics from different classes. The structural similarity was not present. Antioxidant and antimicrobial activities of E. prunastri extracts originate from multiple chemical compounds; besides usnic acid, most notably evernic acid and derivatives thereof. Evernic acid and its derivatives represent possible candidates for a new class of antibiotics.

Anti-Toxoplasma Activities of the Hydroalcoholic Extract of Some Brassicaceae Species

Background:

Toxoplasma gondii (T. gondii) is a protozoan parasite that infects a wide range of warm-blooded animals and humans. The conventional anti-Toxoplasma treatments cause significant toxicity. Brassicaceae family contains several medicinal plants with anti-inflammatory, chemopreventive, insecticide, antibacterial, antiviral, and antiparasitic effects. In this study, the hydroalcoholic extract of some Brassicaceae species was investigated against T. gondiiin vitro.

Materials and Methods:

Seeds of Alyssum homolocarpum, Lepidium perfoliatum, Lepidium sativum, and aerial parts of Nasturtium officinale and Capsellabursa-pastoris were extracted by maceration method using 80% ethanol. Vero cells were treated with different concentrations (5–600 μg/mL) of the extracts and pyrimethamine (as positive control), and the cellular viability was verified. Next, Vero cells were infected by T. gondii tachyzoites (RH strain), and the viability of the infected cells was measured by a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

Results:

The 50% inhibitory concentration values were 5.1, 14.67, 32.49, 37.31, 71.35, and 2.63 μg/mL, and the selectivity indices were 8.06, 2.59, 0.74, 0.78, 0.65 (P < 0.05 compared with positive control), and 3.03 for L. sativum, L. perfoliatum, N. officinale, A. homolocarpum, C. bursa-pastoris, and pyrimethamine, respectively.

Conclusion:

The results of this study demonstrated that the hydroalcoholic extracts of L. sativum and L. perfoliatum have the promising anti-Toxoplasma activity by growth inhibition of T. gondii tachyzoites in infected cells.

Recent progress on anti-Toxoplasma drugs discovery: Design, synthesis and screening

Toxoplasma gondii severely threaten the health of immunocompromised patients and pregnant women as this parasite can cause several disease, including brain and eye disease. Current treatment for toxoplasmosis commonly have high cytotoxic side effects on host and require long durations ranging from one week to more than one year. The regiments lack efficacy to eradicate T. gondii tissue cysts to cure chromic infection results in the needs for long treatment and relapsing disease. In addition, there has not been approved drugs for treating the pregnant women infected by T. gondii. Moreover, Toxoplasma vaccine researches face a wide variety of challenges. Developing high efficient and low toxic agents against T. gondii is urgent and important. Over the last decade, tremendous progress have been made in identifying and developing novel compounds for the treatment of toxoplasmosis. This review summarized and discussed recent advances between 2009 and 2019 in exploring effective agents against T. gondii from five aspects of drug discovery.

Licochalcone A: An effective and low-toxicity compound against Toxoplasma gondii in vitro and in vivo

Toxoplasma gondii, an obligate intracellular protozoan, is the causative agent of toxoplasmosis, which can cause serious public health problems. The current drugs used to treat toxoplasmosis have many limitations. This study evaluated the anti-T. gondii activity and potential mechanism of Licochalcone A (Lico A) in vitro and in vivo. The safe concentration of Lico A in HFF cells was determined by MTT cell viability assays. The presence of T. gondii was assessed by qPCR and Giemsa staining. Azithromycin and sulfadiazine, commonly used effective treatments, served as drug controls. T. gondii ultrastructural alterations were observed by electron microscopy. The anti-T. gondii activity of Lico A was evaluated using an in vivo mouse infection model. In vitro, Lico A had no negative effect on host cell viability at concentrations below 9 μg/mL; however, it did inhibit T. gondii proliferation in a dose-dependent manner, with a 50% inhibitory concentration (IC₅₀) of 0.848 μg/mL. Electron microscopy analyses indicated substantial structural and ultrastructural changes in tachyzoites after Lico A treatment. Nile Red staining assays demonstrated that Lico A caused lipid accumulation. Lico A treatment significantly increased the survival rate of BALB/c mice infected with T. gondii. Lico A achieved the same therapeutic effect as a commonly used clinical drugs (combination of sulfadiazine, pyrimethamine and folinic acid). In conclusion, Lico A has strong anti-T. gondii activity in vitro and in vivo and might be developed into a new anti-T. gondii drug. Moreover, Lico A may exert these effects by interfering with lipid metabolism in the parasite.

Nanomedicine advances in toxoplasmosis: diagnostic, treatment, and vaccine applications

Toxoplasmosis is an infectious disease caused by the intracellular parasite Toxoplasma gondii that affects about one third of the world's population. The diagnosis of this disease is carried out by parasite isolation and host antibodies detection. However, the diagnosis presents problems in regard to test sensitivity and specificity. Currently, the most effective T. gondii treatment is a combination of pyrimethamine and sulfadiazine, although both drugs are toxic to the host. In addition to the problems that compromise the effective diagnosis and treatment of toxoplasmosis, there are no reports or indications of any vaccine capable of fully protecting against this infection. Nanomaterials, smaller than 1000 nm, are currently being investigated as an alternative tool in the management of T. gondii infection. This article reviews how recent nanotechnology advances indicate the utility of nanomaterials in toxoplasmosis diagnosis, treatment, and vaccine development.

Identification and characterization of GRA6/GRA7 of Neospora caninum in MDBK cells

Neospora caninum, an apicomplexan parasite, is recognized as a major bovine abortifacient. Dense granule antigens (GRAs) play important roles in the formation and modification of parasitophorous vacuoles (PVs) in Toxoplasma gondii. However, a few studies investigating GRAs have been reported in N. caninum. The aim of the present study was to characterize the dense GRA6/GRA7 of N. caninum in PVs using MDBK cells as a host cell model. Neospora caninum was inoculated into MDBK cells, and changes were observed using a transmission electron microscope (TEM). Neospora caninum GRA6/GRA7 were identified and characterized using bioinformatics, cell fractionation, and immunofluorescence. The TEM results revealed that integrated PVs were present in MDBK cells after N. caninum infection. Bioinformatics analysis showed that NcGRA6/NcGRA7 shared 28.76% and 29.66% homology with T. gondii GRA6/GRA7 (TgGRA6/TgGRA7) but had similar signal peptides, transmembrane domains, and motifs. Cell fractionation and subcellular localization analyses both showed that NcGRA6 was distributed in the lumen and intravacuolar network in soluble and transmembrane forms. The transmembrane form of NcGRA7 was observed in the PV membrane. These data lay a foundation for further study on bovine neosporosis and NcGRA6/NcGRA7 function during PV formation.

Data on (+)-usnic acid: A new application to treat toxoplasmosis

Toxoplasma gondii pathogen is a threat to human health that results in economic burden. Unfortunately, there are very few high-efficiency and low-toxicity drugs for toxoplasmosis in the clinic. (+)-Usnic acid derived from lichen species has been reported to have anti-inflammatory, antibacterial, anti-parasitology, and even anti-cancer activities. In associated with the published article "Effects of (+)-Usnic Acid and (+)-Usnic Acid-Liposome on Toxoplasma gondii" [1], this dataset article provided the detailed information of experimental designing, methods, features as well as the raw data of (+)-usnic acid and (+)-usnic acid-liposome on toxoplasma in vivo and vitro. (+)-Usnic acid may be a potential agent for treating toxoplasmosis.