Antileishmanial Activity of Ziziphus spina-christi Leaves Extract and Its Possible Cellular Mechanisms

Anti-leishmanial effects of Eryngium planum and Ecbilliun elaterum methanolic extract against Leishmania major

Leishmaniasis is a vector-borne disease, one of the most important neglected tropical diseases. Existing anti-leishmanial treatments are not effective for a long time and associated with toxic side effects so searching for a new, effective and safe alternative treatments against infectious diseases is greatly needed. This study is aimed to assess the leishmaniacidal effects of methanolic extracts of Eryngium planum (E. planum) and Ecbilliun elaterum (E. elaterum) on Leishmania major (L. major), In vitro. The selected plants were collected from northern areas of Iran. The methanolic extract from the aerial parts of plants were prepared using maceration methods. GC- Mass analysis was used to determine the compounds of the plants. Promastigotes of L. major was cultured in RPMI-1640 medium and the anti-leishmanial and cytotoxicity effects of extracts at concentrations of 100, 200, 400 and 800 µg/ml were assessed using MTT assay. The data obtained from gas chromatography revealed that α-Pinene, Caryophyllene oxide, β-Caryophyllene, Bicyclogermacrene and α-Bisabolol are the main compounds extracted from E. planum and α-Pinene, Germacrene D, Caryophyllene oxide, γ-Eudesmol and α-Bisabolol are the main components of E. elaterum. The results of MTT Assay revealed that E. planum at concentrations of 800 µg/ml after 24 h at 400 µg/ml after 48 h and the E. elaterium at concentrations of 800 µg/ml after 48 h at 400 µg/ml after 72 h had similar anti-leishmanial effects to the positive control. These results indicated that E. planum and E. elaterum are the potential sources for the discovery of novel anti-leishmanial treatments.

GC-MS Analysis, Antibacterial, and Anticancer Activities of Hibiscus sabdariffa L. Methanolic Extract: In Vitro and In Silico Studies

The emergence of bacteria that are resistant to several antibiotics has represented a serious hazard to human health globally. Bioactive metabolites from medicinal plants have a wide spectrum of therapeutic possibilities against resistant bacteria. Therefore, this study was performed to investigate the antibacterial efficacy of various extracts of three medicinal plants as Salvia officinalis L., Ziziphus spina-christi L., and Hibiscus sabdariffa L. against pathogenic Gram-negative Enterobacter cloacae (ATCC13047), Pseudomonas aeruginosa (RCMB008001), Escherichia coli (RCMB004001), and Gram-positive Staphylococcus aureus (ATCC 25923), bacteria using the agar-well diffusion method. Results revealed that, out of the three examined plant extracts, the methanol extract of H. sabdariffa L. was the most effective against all tested bacteria. The highest growth inhibition (39.6 ± 0.20 mm) was recorded against E. coli. Additionally, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the methanol extract of H. sabdariffa were detected in the case of all tested bacteria. Moreover, an antibiotic susceptibility test revealed that all tested bacteria showed multidrug resistance (MDR). While 50% of tested bacteria were sensitive and 50% were intermediately sensitive to piperacillin/tazobactam (TZP) based on the inhibition zone but still less than the extract. Synergistic assay demonstrated the promising role of using a combination of H. sabdariffa L. and (TZP) against tested bacteria. A surface investigation using a scanning electron microscope of the E. coli treated with TZP, extract, or a combination of the two revealed extremely considerable bacterial cell death. In addition, H. sabdariffa L. has a promising anticancer role versus Caco-2 cells with IC₅₀ of 17.51 ± 0.07 µg/mL and minimal cytotoxicity upon testing versus Vero cells with CC₅₀ of 165.24 ± 0.89 µg/mL. Flow cytometric analysis confirmed that H. sabdariffa extract significantly increased the apoptotic rate of Caco-2-treated cells compared to the untreated group. Furthermore, GC-MS analysis confirmed the existence of various bioactive components in the methanol hibiscus extract. Utilizing molecular docking with the MOE-Dock tool, binding interactions between n-Hexadecanoic acid, hexadecanoic acid-methyl ester, and oleic acid, 3-hydroxypropyl ester were evaluated against the target crystal structures of E. coli (MenB) (PDB ID:3T88) and the structure of cyclophilin of a colon cancer cell line (PDB ID: 2HQ6). The observed results provide insight into how molecular modeling methods might inhibit the tested substances, which may have applications in the treatment of E. coli and colon cancer. Thus, H. sabdariffa methanol extract is a promising candidate to be further investigated for developing alternative natural therapies for infection treatment.

Antileishmanial Activities of Medicinal Herbs and Phytochemicals In Vitro and In Vivo: An Update for the Years 2015 to 2021

Leishmaniasis is one of the most neglected tropical diseases that present areal public health problems worldwide. Chemotherapy has several limitations such as toxic side effects, high costs, frequent relapses, the development of resistance, and the requirement for long-term treatment. Effective vaccines or drugs to prevent or cure the disease are not available yet. Therefore, it is important to dissect antileishmanial molecules that present selective efficacy and tolerable safety. Several studies revealed the antileishmanial activity of medicinal plants. Several organic extracts/essential oils and isolated natural compounds have been tested for their antileishmanial activities. Therefore, the aim of this review is to update and summarize the investigations that have been undertaken on the antileishmanial activity of medicinal plants and natural compounds derived, rom plants from January 2015 to December 2021. In this review, 94 plant species distributed in 39 families have been identified with antileishmanial activities. The leaves were the most commonly used plant part (49.5%) followed by stem bark, root, and whole plant (21.9%, 6.6%, and 5.4%, respectively). Other plant parts contributed less (<5%). The activity was reported against amastigotes and/or promastigotes of different species (L. infantum, L. tropica, L. major, L. amazonensis, L. aethiopica, L. donovani, L. braziliensis, L. panamensis, L. guyanensis, and L. mexicana). Most studies (84.2%) were carried out in vitro, and the others (15.8%) were performed in vivo. The IC50 values of 103 plant extracts determined in vitro were in a range of 0.88 µg/mL (polar fraction of dichloromethane extract of Boswellia serrata) to 98 µg/mL (petroleum ether extract of Murraya koenigii). Among the 15 plant extracts studied in vivo, the hydroalcoholic leaf extract of Solanum havanense reduced parasites by 93.6% in cutaneous leishmaniasis. Voacamine extracted from Tabernaemontana divaricata reduced hepatic parasitism by ≈30 times and splenic parasitism by ≈15 times in visceral leishmaniasis. Regarding cytotoxicity, 32.4% of the tested plant extracts against various Leishmania species have a selectivity index higher than 10. For isolated compounds, 49 natural compounds have been reported with anti-Leishmania activities against amastigotes and/or promastigotes of different species (L. infantum, L. major, L. amazonensis, L. donovani and L. braziliensis). The IC50 values were in a range of 0.2 µg/mL (colchicoside against promastigotes of L. major) to 42.4 µg/mL (dehydrodieuginol against promastigotes of L. amazonensis). In conclusion, there are numerous medicinal plants and natural compounds with strong effects (IC50 < 100 µg/mL) against different Leishmania species under in vitro and in vivo conditions with good selectivity indices (SI > 10). These plants and compounds may be promising sources for the development of new drugs against leishmaniasis and should be investigated in randomized clinical trials.

Therapeutic Potential and Safety of the Cinnamomum zeylanicum Methanolic Extract Against Chronic Toxoplasma gondii Infection in Mice

Background

This experimental study determined the in vitro, in vivo, and toxicity effects of Cinnamomum zeylanicum methanolic extract (CZME) against Toxoplasma gondii infection.

Methods

The in vitro activity of CZME T. gondii tachyzoites was studied by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Infected mice were treated with CZME for two weeks at doses of 20, 40, and 60 mg/kg/day. Then, the therapeutic effects of CZME were evaluated by assessing the mean number and mean size of T. gondii tissue cysts, oxidant-antioxidant enzymes, pro-inflammatory cytokines, and mRNA expression levels of bradyzoite surface antigen 1 (BAG1) by real-time PCR.

Results

CZME significantly (p <0.001) increased the mortality rate of parasites in a dose- and time-dependent response. The mean number of intracellular tachyzoites was significantly reduced after CZME therapy. The treatment of infected mice with CZME resulted in a significant (p <0.001) downregulation of BAG1 and the level of lipid peroxidation (LPO) and nitric oxide (NO) as oxidative stress markers. However, a considerable rise (p <0.05) was found in the levels of antioxidant markers such as glutathione peroxidase (GPx), catalase enzyme (CAT), and superoxide dismutase enzyme activity (SOD). In a dose-dependent response, after treatment of infected mice with CZME, the level of pro-inflammatory cytokines of IFN-γ, IL-1β, and IL-12 was considerably elevated. CZME had no significant cytotoxicity on Vero cells, with a 50% cytotoxic concentration of 169.5 ± 5.66 μg/ml.

Conclusion

The findings confirmed the promising therapeutic effects of CZME on chronic toxoplasmosis in mice. Nevertheless, further investigations must confirm these results, elucidate its precise mechanisms, and examine its effectiveness in human volunteers.

Ethnopharmacology, Biological Evaluation, and Chemical Composition of Ziziphus spina-christi (L.) Desf.: A Review

Medicinal plants are the primary raw materials used in the production of medicinal products all over the world. As a result, more study on plants with therapeutic potential is required. The tropical tree Ziziphus spina belongs to the Rhamnaceae family. Biological reports and traditional applications including management of diabetes and treatment of malaria, digestive issues, typhoid, liver complaints, weakness, skin infections, urinary disorders, obesity, diarrhoea, and sleeplessness have all been treated with different parts of Z. spina all over the globe. The plant is identified as a rich source of diverse chemical compounds. This study is a comprehensive yet detailed review of Z. spina based on major findings from around the world regarding ethnopharmacology, biological evaluation, and chemical composition. Scopus, Web of Science, BioMed Central, ScienceDirect, PubMed, Springer Link, and Google Scholar were searched to find published articles. From the 186 research articles reviewed, we revealed the leaf extract to be significant against free radicals, microbes, parasites, inflammation-related cases, obesity, and cancer. Chemically, polyphenols/flavonoids were the most reported compounds with a composition of 66 compounds out of the total 193 compounds reported from different parts of the plant. However, the safety and efficacy of Z. spina have not been wholly assessed in humans, and further well-designed clinical trials are needed to corroborate preclinical findings. The mechanism of action of the leaf extract should be examined. The standard dose and safety of the leaf should be established.

Chemical Composition and Insecticidal, Antiplasmodial, and Anti-Leishmanial Activity of Capparis spinosa Essential Oil and Its Main Constituents

Background

This investigation was designed to evaluate the insecticidal, antiplasmodial, anti-leishmanial, and cytotoxic effects of Capparis spinosa essential oil (CSEO) and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene.

Methods

Insecticidal activity of CSEO and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene, was determined against Aedes aegypti 4th-instar larvae at 25 ± 2°C. Antiplasmodial and anti-leishmanial effects of CSEO and its main components were carried out against chloroquine-resistant Plasmodium falciparum K1 strain and Leishmania major amastigotes based on the Malstat method and the macrophage model, respectively. We also performed the cytotoxic activity of CZEO and its main components against J774A1 macrophage cells using the colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In addition, the plasma membrane permeability and caspase-3-like activity CSEO and its main components were evaluated against L. major.

Results

CSEO and its main components showed considerable (p < 0.001) larvicidal activity against Ae. aegypti larva. The 50% lethal concentration values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 21.6, 30.9, 41.6, and 35.3 μg/mL, respectively. By antiplasmodial effects, the 50% inhibitory concentration (IC₅₀) values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 7.4, 14.5, 19.6, and 21.3 μg/mL, respectively, while these values for their anti-leishmanial effects were 9.1, 20.7, 23.3, and 18.6 μg/mL, respectively. The 50% cytotoxic concentration values for CSEO, methyl isothiocyanate, hexadecanoic acid, and limonene were 93.7, 216.2, 199.4, and 221.3 μg/mL, respectively. Different concentrations of CSEO and its main components significantly (p < 0.05) increased the plasma membrane permeability and caspase-3-like activity against L. major promastigote level as dose-dependent response.

Conclusion

Based on the obtained results, C. spinosa essential oil and its main components, methyl isothiocyanate, hexadecanoic acid, and limonene, displayed insecticidal, antiplasmodial, and anti-leishmanial activity against healthy 4th-instar larvae of A. aegypti, chloroquine-resistant P. falciparum K1 strain, and L. major amastigotes, respectively. However, further surveys are required to display the mechanisms of action mode of tested drugs and their efficacy in animal model and clinical settings.