Leishmanicidal and cytotoxic activities of Nigella sativa and its active principle, thymoquinone

Thymoquinone Effect on Leishmania tropica/infantum and Leishmania-Infected Macrophages

INTRODUCTION

Leishmania is a parasitic protozoan that tries to enter and amplify within macrophages. Macrophage cells are also immune defense cells that phagocyte many microbes like bacteria, fungi, as well as parasites like Leishmania spp. However, they are unable to kill this parasite that resides in the phagosomes of contaminated macrophages and multiplies in these macrophages, leading to the destruction of contaminated macrophages and the emerging of Leishmania wounds. A large number of current therapies for Leishmania cure have adverse effects, or parasites have developed resistance to some of these therapies, so a better therapy for the cure of Leishmania is required. Thymoquinone is one of the Nigella Sativa ingredients with numerous biological effects, such as antioxidant as well as antimicrobial effects on a variety of microbes, namely fungi, bacteria, as well as parasites like Leishmania spp. The impacts of Thymoquinone on Leishmania tropica and Leishmania infantum, as well as Leishmania-infected macrophages, were examined in this study.

METHODS

The impact of various Thymoquinone dosages on L. tropica and L. infantum promastigotes and amastigotes was examined in vitro. Flow cytometry, as well as MTT, was also applied to examine the cytotoxic activity of Thymoquinone on promastigotes of L. tropica and L. infantum, as well as the incidence of apoptosis. The amastigote assay is also utilized to calculate the % of contaminated macrophages as well as the number of the present parasites in each macrophage.

RESULTS

The percentage of macrophages contaminated with L. tropica and L. infantum amastigotes after medicating with 20 μM of Thymoquinone was 23% and 19%, respectively. Also, after medicating with 10 μM of Thymoquinone, these percentages were 32% and 31%, respectively. Flow cytometry indicated that Thymoquinone caused 33.9% and 31.4% apoptosis in L. tropica and L. infantum, respectively. As determined by the promastigote assay, the inhibitory concentration (IC50) of Thymoquinone for L. tropica and L. infantum was 9.49 μM and 12.66 μM, respectively. The results of the promastigote and amastigote assay show that with an increase in Thymoquinone doses, its ability to kill Leishmania parasites increases, too.

CONCLUSION

According to the results of the study, Thymoquinone has a potentially lethal impact on L. tropica and L. infantum promastigotes as well as amastigotes (within leishmania contaminated macrophages).

The effect of Nigella sativa oil- and wheat germ oil-loaded metal organic frameworks on chronic murine toxoplasmosis

Treatment of chronic toxoplasmosis is challenging as the available drugs are effective only in the acute stage. Therefore, the current study aimed to investigate Nigella sativa oil (NSO) and wheat germ oil (WGO) loaded on copper-benzene tricarboxylic acid metal organic framework (Cu-BTC MOF) for treating chronic toxoplasmosis in a murine model. Eighty mice were divided into 8 groups (G); uninfected untreated negative control (GI), infected untreated positive control (GII), infected and treated with: Spiramycin (GIII), Spiramycin@Cu-BTC (GIV), Cu-BTC (GV), WGO@Cu-BTC (GVI), NSO@Cu-BTC (GVII) and combined WGO+NSO@Cu-BTC (GVIII). The infected groups were orally inoculated with 10 Toxoplasma gondii Me49 strain cysts/mouse. All drugs were orally administered for 14 consecutive days starting 8 weeks post-infection (wpi). The therapeutic efficacy was evaluated by parasitological (survival rate of mice and brain cyst burden) and histopathological (brain, liver, kidney, eye) parameters. At the end of 2-weeks therapy, the highest therapeutic outcome was achieved with GVII and GVIII exhibiting 100% survival, 64.3% and 51.4% reduction of brain cysts, and an apparent amendment of pathological insults. In the next place was GVI with 90% survival, 49.5% reduction of cysts and marked amelioration of pathological lesions. Meanwhile, GIII and GIV showed 80% survival, 42.4% and 41.8% reduction of cysts as well as minimal to moderate alleviation of tissue damage. The lowest effect was obtained with GV resulting in 70% survival and 24.4% reduction of cysts. The current results support the assertion that the new metal-based nanocomposites can be promising remedies of chronic toxoplasmosis particularly if conjugated with natural herbal extracts as NSO and WGO.

Antiprotozoal Activity of Thymoquinone (2-Isopropyl-5-methyl-1,4-benzoquinone) for the Treatment of Leishmania major-Induced Leishmaniasis: In Silico and In Vitro Studies

Leishmaniasis, a neglected tropical parasitic disease (NTPD), is caused by various Leishmania species. It transmits through the bites of the sandfly. The parasite is evolving resistance to commonly prescribed antileishmanial drugs; thus, there is an urgent need to discover novel antileishmanial drugs to combat drug-resistant leishmaniasis. Thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone; TQ), a primary pharmacologically active ingredient of Nigella sativa (black seed) essential oil, has been reported to possess significant antiparasitic activity. Therefore, the present study was designed to investigate the in vitro and in silico antileishmanial activity of TQ against various infectious stages of Leishmania major (L. major), i.e., promastigotes and amastigotes, and its cytotoxicity against mice macrophages. In silico molecular dockings of TQ were also performed with multiple selected target proteins of L. major, and the most preferred antileishmanial drug target protein was subjected to in silico molecular dynamics (MD) simulation. The in vitro antileishmanial activity of TQ revealed that the half-maximal effective concentration (EC₅₀), half-maximal cytotoxic concentration (CC₅₀), and selectivity index (SI) values for promastigotes are 2.62 ± 0.12 μM, 29.54 ± 0.07 μM, and 11.27, while for the amastigotes, they are 17.52 ± 0.15 μM, 29.54 ± 0.07 μM, and 1.69, respectively. The molecular docking studies revealed that squalene monooxygenase is the most preferred antileishmanial drug target protein for TQ, whereas triosephosphate isomerase is the least preferred. The MD simulation revealed that TQ remained stable in the binding pocket throughout the simulation. Additionally, the binding energy calculations using Molecular Mechanics Generalized-Born Surface Area (MMGBSA) indicated that TQ is a moderate binder. Thus, the current study shows that TQ is a promising antileishmanial drug candidate that could be used to treat existing drug-resistant leishmaniasis.

Mexican Oregano (Lippia berlandieri Schauer and Poliomintha longiflora Gray) Essential Oils Induce Cell Death by Apoptosis in Leishmania (Leishmania) mexicana Promastigotes

Leishmaniasis is a neglected vector-borne disease; there are different manifestations of the diseases and species involved, and cutaneous leishmaniasis caused by Leishmania (L.) mexicana is the most prevalent in Mexico. Currently, the drugs available for the treatment of leishmaniasis are toxic, expensive, and often ineffective; therefore, it is imperative to carry out research and development of new therapeutic alternatives, with natural products being an attractive option. In particular, oregano is a plant with worldwide distribution; in Mexico, two species: Lippia berlandieri Schauer and Poliomintha longiflora Gray are endemic. Both essential oils (EO’s) have been reported to have antimicrobial activity attributed to their main components, thymol and carvacrol. In this research, the leishmanicidal effect and mechanism of cell death induced by L. berlandieri EO, P. longiflora EO, thymol, and carvacrol in L. mexicana promastigotes were determined in vitro. Additionally, the cytotoxic activity in mammalian cells was evaluated. L. berlandieri EO presented higher leishmanicidal activity (IC₅₀ = 41.78 µg/mL) than P. longiflora EO (IC₅₀ = 77.90 µg/mL). Thymol and carvacrol were the major components of both Mexican oregano EO’s. Thymol presented higher leishmanial inhibitory activity (IC₅₀ = 22.39 µg/mL), above that of carvacrol (IC₅₀ = 61.52 µg/mL). All the EO’s and compounds evaluated presented lower cytotoxic activity than the reference drug; thymol was the compound with the best selectivity index (SI). In all cases, apoptosis was identified as the main mechanism of death induced in the parasites. The leishmanicidal capacity of the Mexican oregano EO is an accessible and affordable alternative that can be further explored.

Models for cytotoxicity screening of antileishmanial drugs: what has been done so far?

A growing number of studies have demonstrated the in vitro potential of an impressive number of antileishmanial candidates in the past years. However, the lack of uniformity regarding the choice of cell types for cytotoxicity assays may lead to uncomparable and inconclusive data. In vitro assays relying solely on non-phagocytic cell models may not represent a realistic result as the effect of an antileishmanial agent should ideally be presented based on its cytotoxicity profile against reticuloendothelial system cells. In the present review, we have assembled studies published in the scientific literature from 2015 to 2021 that explored leishmanicidal candidates, emphasising the main host cell models used for cytotoxicity assays. The pros and cons of different host cell types as well as primary cells and cell lines are discussed in order to draw attention to the need to establish standardised protocols for preclinical testing when assessing new antileishmanial candidates.

Antiproliferative properties of Turmerone on Leishmania major: Modes of action confirmed by antioxidative and immunomodulatory roles

Treatment of leishmaniasis by conventional synthetic compounds has faced a serious challenge worldwide. This study was performed to evaluate the effect and modes of action of aromatic Turmerone on the Leishmania major intra-macrophage amastigotes, the causative agent of zoonotic cutaneous leishmaniasis in the Old World. In the findings, the mean numbers of L. major amastigotes in macrophages were significantly decreased in exposure to Turmerone plus meglumine antimoniate (Glucantime®; MA) than MA alone, especially at 50 µg/mL. In addition, Turmerone demonstrated no cytotoxicity as the selectivity index (SI) was 21.1; while it induced significant apoptosis in a dose-dependent manner on L. major promastigotes. In silico molecular docking analyses indicated an affinity of Turmerone to IL-12, with the MolDock score of - 96.8 kcal/mol; which may explain the increased levels of Th1 cytokines and decreased level of IL-10. The main mechanism of action is more likely associated with stimulating a powerful antioxidant and promoting the immunomodulatory roles in the killing of the target organism.

Thymoquinone Induced Leishmanicidal Effect via Programmed Cell Death in Leishmania donovani

Visceral leishmaniasis (VL) or kala-azar is a vector-borne dreaded protozoal infection that is caused by the parasite Leishmania donovani. With increases in the dramatic infection rates, present drug toxicity, resistance, and the absence of an approved vaccine, the development of new antileishmanial compounds from plant sources remains the keystone for the control of visceral leishmaniasis. In this study, we evaluated the leishmanicidal effect of thymoquinone against L. donovani with an in vitro and ex vivo model. Thymoquinone exhibited potent antipromastigote activity with IC₅₀ and IC₉₀ concentrations achieved at 6.33 ± 1.21 and 20.71 ± 2.15 μM, respectively, whereas the IC₅₀ and IC₉₀ concentrations were found to be 7.83 ± 1.65 and 27.25 ± 2.20 μM against the intramacrophagic form of amastigotes, respectively. Morphological changes in promastigotes and growth reversibility study following treatment confirmed the leishmanicidal effect of thymoquinone. Further, thymoquinone exhibited leishmanicidal activities against L. donovani promastigote through cytoplasmic shrinkage, membrane blebbing, chromatin condensation, cellular and nuclear shrinkage, and DNA fragmentation, as observed under scanning and transmission electron microscopy analyses. The antileishmanial activity was exerted via programmed cell death as proved by exposure of phosphatidylserine, DNA nicking by TUNEL assay, and loss of mitochondrial membrane potential. Thymoquinone at a concentration of 200 μM was devoid of any cytotoxic effects against mammalian macrophage cells. Thymoquinone showed strong leishmanicidal activity against L. donovani, which is mediated via an apoptosis mode of parasitic cell death, and accordingly, thymoquinone may be the source of a new lead molecule for the cure of VL.

Metallic Nanoparticles: A New Frontier in the Fight Against Leishmaniasis

Abstract:

Leishmaniasis is a cutaneous, mucocutaneous, or visceral parasitic disease caused by protozoa of the Leishmania genus. According to the World Health Organization, Leishmaniasis causes approximately 20–40 thousand deaths annually, and Brazil, India, and some countries in Africa are the most affected by this neglected disease. In addition to parasite’s ability to evade the host’s immune system, the incidence of vectors, the genetics of different hosts, and the large number of deaths are mainly due to failures in conventional treatments that have high toxicity, low effectiveness, and prolonged therapeutic regimens. Thus, the development of new alternative therapeutics with more effective and safer actions has become one of the main challenges for researchers studying leishmaniasis. Among the many research and tested options, metallic nanoparticles, such as gold, silver, zinc oxide, and titanium dioxide, have been shown to be one of the most promising therapeutic tool because they are easily prepared and chemically modified, have a broad spectrum of action, low toxicity, and can generate reactive oxygen species and other immune responses that favor their use against different species of Leishmania. This review explores the progress of the use of metallic nanoparticles as a new tool in the treatment of leishmaniasis, as well as discusses the gaps in knowledge that need to be addressed to consolidate a safe, effective, and definitive therapeutic intervention against these infections.

A review of ethnobotany, phytochemistry, antimicrobial pharmacology and toxicology of Nigella sativa L

Nigella sativa L. is one of the most extensively used traditional medicinal plants. This widely studied plant is known to display diverse pharmacological actions, including antimicrobial activities. Current literature has documented its multi-target mode of antimicrobial actions. N. sativa or its bioactive compounds, such as thymoquinone, can induce oxidative stress, cell apoptosis (by producing reactive oxygen species), increase membrane permeability, inhibit efflux pumps, and impose strong biocidal actions. Despite its well-documented antimicrobial efficacy in the experimental model, to the best of our knowledge its antimicrobial mechanisms highlighting the multi-targeting properties have yet to be well discussed. Is N. sativa or thymoquinone a valuable lead compound for therapeutic development for infectious diseases? Are N. sativa's bioactive compounds potential antimicrobial agents or able to overcome antimicrobial resistance? This review aims to discuss the antimicrobial pharmacology of N. sativa-based treatments. Additionally, it provides a holistic overview of the ethnobotany, ethnopharmacology, and phytochemistry of N. sativa.

Anti-Leishmanial Activity of Artemisia persica, A. spicigera, and A. fragrance against Leishmania major

Background:

Neglected tropical diseases (NTDs) like zoonotic cutaneous leishmaniasis (ZCL), is a widespread infectious disease with high mortality and morbidity. Various medications are used for treating the disease, but several side effects and drug resistance have been reported. Herbal medicines are unlimited sources for discovering new medications to treat infectious diseases. We aimed to determine the leishmanicidal activity of three species of Iranian Artemisia herbal plant extracts in in-vitro.

Methods:

In-vitro anti-leishmanial activity of ethanolic extracts on both promastigotes and amastigotes was determined by using MTT method. IC50, CC50, EC50 and SI were calculated. The study was done in 2019-2020 in Iran University of Medical Sciences, Tehran, Iran.

Results:

All of the three Artemisia species significantly reduced the number of parasite promastigotes. Among them, A. persica had the highest leishmanicidal activity against parasite promastigotes. Cytotoxicity assay elucidated that the Artemisia had no toxicity to the host cells, and killed the L. major amastigotes very efficiently. By increasing the dose of extracts, the parasite number in both phases (promastigotes and amastigotes) was reduced significantly.

Conclusion:

These results indicated satisfactory anti-leishmanial activity of Artemisia extracts against ZCL in-vitro. Accordingly, Artemisia ethanolic extracts might be considered as a strong, effective and safe herbal compound for clearing the L. major with less toxicity to the host macrophages cells. Hence, it may be recognized as an excellent herbal therapy for treating the ZCL.

A Systematic Review of Curcumin and its Derivatives as Valuable Sources of Antileishmanial Agents

BACKGROUND

In recent years, antimonial agents and other synthetic antileishmanial drugs, such as amphotericin B, paromomycin, and many other drugs, have restrictions in use due to the toxicity risk, high cost, and emerging resistance to these drugs. The present study aimed to review the antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations on leishmaniasis.

METHODS

The present study was carried out according to the 06-preferred reporting items for systematic reviews and meta-analyses (PRISMA) guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Some English-language databases including PubMed, Google Scholar, Web of Science, EBSCO, Science Direct, and Scopus were searched for publications worldwide related to antileishmanial effects of curcumin, its derivatives, and other relevant pharmaceutical formulations, without date limitation, to identify all the published articles (in vitro, in vivo, and clinical studies). Keywords included "curcumin", "Curcuma longa", "antileishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo".

RESULTS

Out of 5492 papers, 29 papers including 20 in vitro (69.0%), 1 in vivo (3.4%), and 8 in vitro/in vivo (27.6%) studies conducted up to 2020, met the inclusion criteria for discussion in this systematic review. The most common species of the Leishmania parasite used in these studies were L. donovani (n = 13, 44.8%), L. major (n = 10, 34.5%), and L. amazonensis (n = 6, 20.7%), respectively. The most used derivatives in these studies were curcumin (n = 15, 33.3%) and curcuminoids (n = 5, 16.7%), respectively.

CONCLUSION

In the present review, according to the studies in the literature, various forms of drugs based on curcumin and their derivatives exhibited significant in vitro and in vivo antileishmanial activity against different Leishmania spp. The results revealed that curcumin and its derivatives could be considered as an alternative and complementary source of valuable antileishmanial components against leishmaniasis, which had no significant toxicity. However, further studies are required to elucidate this concluding remark, especially in clinical settings.

The Experimental Role of Medicinal Plants in Treatment of Toxoplasma gondii Infection: A Systematic Review

BACKGROUND

Toxoplasma gondii is the global protozoa that could cause contamination in warm-blooded animals and is considered among the opportunistic pathogens in immunocompromised patients. Among the people at risk, toxoplasmosis infection can lead to the incidence of severe clinical manifestations, encephalitis, chorioretinitis, and even death.

PURPOSE

The present research is focused on the new research for the treatment of toxoplasmosis parasitic disease using medicinal herbs.

METHODS

The search was performed in five English databases, including Scopus, PubMed, Web of Science, EMBASE, and Google Scholar up from 2010 to December 2019. Studies in any language were entered in the searching step if they had an English abstract. The words and terms were used as a syntax with specific tags of each database.

RESULTS

Out of 1832 studies, 36 were eligible to be reviewed. The findings showed that 17 studies (47%) were performed in vitro, 14 studies (39%) in vivo, and 5 studies (14%) both in vivo and in vitro.

CONCLUSION

The studies showed that the plant extracts can be a good alternative in reducing the toxoplasmosis effects in the host and the herbal extracts can be used to produce natural product-based drugs affecting toxoplasmosis with fewer side-effects than synthetic drugs.

Bioactive Levan-Type Exopolysaccharide Produced by Pantoea agglomerans ZMR7: Characterization and Optimization for Enhanced Production

Levan is an industrially important, functional biopolymer with considerable applications in the food and pharmaceutical fields owing to its safety and biocompatibility. Here, levan-type exopolysaccharide produced by Pantoea agglomerans ZMR7 was purified by cold ethanol precipitation and characterized using TLC, FTIR, ¹H, and ¹³C NMR spectroscopy. The maximum production of levan (28.4 g/l) was achieved when sucrose and ammonium chloride were used as carbon and nitrogen sources, respectively, at 35°C and an initial pH of 8.0. Some biomedical applications of levan like antitumor, antiparasitic, and antioxidant activities were investigated in vitro. The results revealed the ability of levan at different concentrations to decrease the viability of rhabdomyosarcoma and breast cancer cells compared with untreated cancer cells. Levan appeared also to have high antiparasitic activity against the promastigote of Leishmania tropica. Furthermore, levan had strong DPPH radical scavenging (antioxidant) activity. These findings suggest that levan produced by P. agglomerans ZMR7 can serve as a natural biopolymer candidate for the pharmaceutical and medical fields.

Current State and Promising Opportunities on Pharmaceutical Approaches in the Treatment of Polymicrobial Diseases

In recent years, the emergence of newly identified acute and chronic infectious disorders caused by diverse combinations of pathogens, termed polymicrobial diseases, has had catastrophic consequences for humans. Antimicrobial agents have been clinically proven to be effective in the pharmacological treatment of polymicrobial diseases. Unfortunately, an increasing trend in the emergence of multi-drug-resistant pathogens and limited options for delivery of antimicrobial drugs might seriously impact humans' efforts to combat polymicrobial diseases in the coming decades. New antimicrobial agents with novel mechanism(s) of action and new pharmaceutical formulations or delivery systems to target infected sites are urgently required. In this review, we discuss the prospective use of novel antimicrobial compounds isolated from natural products to treat polymicrobial infections, mainly via mechanisms related to inhibition of biofilm formation. Drug-delivery systems developed to deliver antimicrobial compounds to both intracellular and extracellular pathogens are discussed. We further discuss the effectiveness of several biofilm-targeted delivery strategies to eliminate polymicrobial biofilms. At the end, we review the applications and promising opportunities for various drug-delivery systems, when compared to conventional antimicrobial therapy, as a pharmacological means to treat polymicrobial diseases.

An Evidence-Based Research on Botanical Sources for Oral Mucositis Treatment in Traditional Persian Medicine

BACKGROUND

Cancer is one of the most prevalent diseases associated with heavy complications in treatment. Mucotoxic cancer therapies such as head and neck radiotherapy and some of the chemotherapy agents may lead to oral mucositis. In addition to its economic consequences, mucositis also affects patients' quality of life. In Traditional Persian Medicine (TPM) manuscripts, several medicaments have been suggested for the treatment of mucositis.

OBJECTIVE

Considering the public welcome for herbal medicine, the current evidence-based review study is conducted to investigate the herbal remedies which have been proposed for oral mucositis in TPM.

METHODS

At first, a comprehensive survey was done on Qanon fi al-Teb, which is the most important textbook of TPM; then the scientific name of the herbs was authenticated according to the botanical textbooks. At last, data banks including Scopus, Pubmed, Web of science and Science direct were investigated for possible relevant properties of each medicinal plant in the literature.

RESULTS

In total, 30 herbs are introduced in this study. According to the registered documents, 18 herbs are reported to have antioxidant, anti-inflammatory, antimicrobial, anti-nociceptive and wound healing properties of which the therapeutic effect of only a few herbs including Glycyrrhiza glabra, Malva sylvestris, Morus nigra, Punica granatum, and Solanum nigrum were directly evaluated against oral mucositis on the literature.

CONCLUSION

Despite the lack of human studies on mucositis for the other discussed herbs, their related pharmacological properties can be considered for new natural drug discovery supported by medieval and traditional experiments.

Effect of chitosan on Toxoplasma gondii infection: A systematic review

Background

The preferred treatment for management of toxoplasmosis is the combined use of pyrimethamine and sulfadiazine. However, there are a wide number of adverse side effects with these medications. Recent research has focused on the use of chitosan for the treatment of Toxoplasma gondii infections. This review was performed to obtain a better understanding of the in vivo and in vitro effects of chitosan on T. gondii strains.

Methods

The current study was carried out according to the PRISMA guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-analysis Facility (SyRF) database. The search was performed in five scientific databases, including Scopus, PubMed, Web of Science, EMBASE, and Google Scholar, with date limits of 1992 to December 2019. The search was restricted to articles published in the English language. The words and terms searched were "Toxoplasma gondii", "Chitosan", "nanoparticles" and "anti-toxoplasmosis" with AND or OR.

Results

Of 2500 manuscripts, 9 met the eligibility criteria for review. All studies used the RH strain of T. gondii, with Me49 and PRU each included in one study. Five studies (56%) were performed in vivo, one study in vitro and 3 studies included in vivo and in vitro tests.

Conclusion

Considering the low toxicity and the high inhibitory potency of chitosan against T. gondii, chitosan nanoparticles show potential as an alternative treatment for T. gondii infections.

Effects of a Plantago ovata-based herbal compound in prevention and treatment of oral mucositis in patients with breast cancer receiving chemotherapy: A double-blind, randomized, controlled crossover trial

BACKGROUND

Oral mucositis (OM) is one of the most common complications of mucotoxic cancer therapy. Mucositis induces clinically significant pain, increases the risk of infections and affects the patients' quality of life.

OBJECTIVE

This study investigated the effects of an herbal preparation from Plantago ovata hydrocolloid in the prevention and treatment of OM, in breast cancer patients undergoing chemotherapy with a regimen including adriamycin.

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS

This research was a double-blind, randomized, controlled crossover trial. The herbal compound consisted of a mixture of 500 mg of P. ovate husk in 30 mL water plus three drops of vinegar per dose, which was used as a mouthwash. Phytochemical and physicochemical tests of the compound were also performed. Twenty-eight patients who developed mucositis during the chemotherapy screening cycle were randomized to the herbal compound (n = 14) and placebo (n = 14) groups. They received herbal compound or placebo three times per day during their next chemotherapy cycle (cycle 1 of treatment). Patients were crossed over during cycle 2 of treatment and received the alternative therapy. An oral care protocol was prescribed to all patients in cycles 1 and 2 of the treatment.

MAIN OUTCOME MEASURES

The patients were visited at baseline, the end of the first and second weeks of the screening cycle, and the end of the first and second weeks of each of two treatment cycles. The degree of mucositis was used as the main treatment outcome. Other indexes, such as the severity of pain, xerostomia grade and the quality of life were also measured.

RESULTS

Compared with the placebo, the herbal compound significantly reduced the degree of mucositis, the severity of pain and the xerostomia grade; it also improved the patients' quality of life (P < 0.05). Comparison between the screening cycle and placebo treatment group showed that the oral care protocol had a significant effect in the reduction of OM (P < 0.05).

CONCLUSION

The oral care protocol and the herbal compound based on P. ovata are effective ways for preventing and treating OM in patients undergoing mucotoxic cancer therapy.

TRIAL REGISTRATION

Iranian registry of clinical trials IRCT20180923041093N1.

Thymoquinone (2-Isoprpyl-5-methyl-1, 4-benzoquinone) as a chemopreventive/anticancer agent: Chemistry and biological effects

Cancer remains the topmost disorders of the mankind and number of cases is unceasingly growing at unprecedented rates. Although the synthetic anti-cancer compounds still hold the largest market in the modern treatment of cancer, natural agents have always been tried and tested for potential anti-cancer properties. Thymoquinone (TQ), a monoterpene and main ingredient in the essential oil of Nigella sativa L. has got very eminent rankings in the traditional systems of medicine for its anti-cancer pharmacological properties. In this review we summarized the diverse aspects of TQ including its chemistry, biosynthesis, sources and pharmacological properties with a major concern being attributed to its anti-cancer efficacies. The role of TQ in different aspects involved in the pathogenesis of cancer like inflammation, angiogenesis, apoptosis, cell cycle regulation, proliferation, invasion and migration have been described. The mechanism of action of TQ in different cancer types has been briefly accounted. Other safety and toxicological aspects and some combination therapies involving TQ have also been touched. A detailed literature search was carried out using various online search engines like google scholar and pubmed regarding the available research and review accounts on thymoquinone upto may 2019. All the articles reporting significant addition to the activities of thymoquinone were selected. Additional information was acquired from ethno botanical literature focusing on thymoquinone. The compound has been the centre of attention for a long time period and researched regularly in quite considerable numbers for its various physicochemical, medicinal, biological and pharmacological perspectives. Thymoquinone is studied for various chemical and pharmacological activities and demonstrated promising anti-cancer potential. The reviewed reports confirmed the strong anti-cancer efficacy of thymoquinone. Further in-vitro and in-vivo research is strongly warranted regarding the complete exploration of thymoquinone in ethnopharmacological context.

Nigella sativa oil entrapped polycaprolactone nanoparticles for leishmaniasis treatment

This study is the first to investigate the antileishmanial activities of Nigella sativa oil (NSO) entrapped poly-ɛ-caprolactone (PCL) nanoparticles on Leishmania infantum promastigotes and amastigotes in vitro. NSO molecules with variable initial doses of 50, 100, 150, and 200 mg were successfully encapsulated into PCL nanoparticles identified as formulations NSO1, NSO2, NSO3, and NSO4, respectively. This process was characterised by scanning electron microscope, dynamic light scattering, Fourier transform infrared, encapsulation efficiency measurements, and release profile evaluations. The resulting synthetised nanoparticles had sizes ranging between 200 and 390 nm. PCL nanoparticles encapsulated 98% to 80% of initial doses of NSO and after incubation released approximately 85% of entrapped oil molecules after 288 h. All investigated formulations demonstrated strong antileishmanial effects on L. infantum promastigotes by inhibiting up to 90% of parasites after 192 h. The tested formulations decreased infection indexes of macrophages in a range between 2.4- and 4.1-fold in contrast to control, thus indicating the strong anti-amastigote activities of NSO encapsulated PCL nanoparticles. Furthermore, NSO-loaded PCL nanoparticles showed immunomodulatory effects by increasing produced nitric oxide amounts within macrophages by 2-3.5-fold in contrast to use of free oil. The obtained data showed significant antileishmanial effects of NSO encapsulated PCL nanoparticles on L. infantum promastigotes and amastigotes.

Emerging therapeutic targets for treatment of leishmaniasis

INTRODUCTION

Parasitic diseases that pose a threat to human life include leishmaniasis - caused by protozoan parasite Leishmania species. Existing drugs have limitations due to deleterious side effects like teratogenicity, high cost and drug resistance. This calls for the need to have an insight into therapeutic aspects of disease. Areas covered: We have identified different drug targets via. molecular, imuunological, metabolic as well as by system biology approaches. We bring these promising drug targets into light so that they can be explored to their maximum. In an effort to bridge the gaps between existing knowledge and prospects of drug discovery, we have compiled interesting studies on drug targets, thereby paving the way for establishment of better therapeutic aspects. Expert opinion: Advancements in technology shed light on many unexplored pathways. Further probing of well established pathways led to the discovery of new drug targets. This review is a comprehensive report on current and emerging drug targets, with emphasis on several metabolic targets, organellar biochemistry, salvage pathways, epigenetics, kinome and more. Identification of new targets can contribute significantly towards strengthening the pipeline for disease elimination.

Isopropyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives induce regulated necrosis-like cell death on Leishmania (Leishmania) mexicana

Leishmaniasis is a neglected tropical disease caused by the parasite of the genus Leishmania. About 13 million people are infected worldwide, and it is estimated that 350 million are at risk of infection. Clinical manifestations depend on the parasite species and factors related to the host such as the immune system, nutrition, housing, and financial resources. Available treatments have severe side effects; therefore, research currently focuses on finding more active and less toxic compounds. Quinoxalines have been described as promising alternatives. In this context, 17 isopropyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives were evaluated as potential leishmanicidal agents. Their effect on the cell metabolism of Leishmania mexicana promastigotes and their cytotoxic effects on the J774.A1 cell line and on erythrocytes were evaluated, and their selectivity index was calculated. Compounds T-069 (IC₅₀ = 1.49 μg/mL), T-070 (IC₅₀ = 1.71 μg/mL), T-072 (IC₅₀ = 6.62 μg/mL), T-073 (IC₅₀ = 1.25 μg/mL), T-085 (IC₅₀ = 0.74 μg/mL), and T-116 (IC₅₀ = 0.88 μg/mL) were the most active against L. mexicana promastigotes and their mechanism of action was characterized by flow cytometry and microscopy. Compound T-073, the most selective quinoxaline derivative, induced cell membrane damage, phosphatidylserine exposition, reactive oxygen species production, disruption of the mitochondrion membrane potential, and DNA fragmentation, all in a dose-dependent manner, indicating the induction of regulated necrosis. Light and transmission electron microscopy showed the drastic morphological changes induced and the mitochondrion as the most sensitive organelle in response to T-073. This study describes the mechanism by which active isopropyl quinoxaline-7-carboxylate 1,4-di-N-oxide quinoxalines affect the parasite.

Medicinal plants with promising antileishmanial activity in Iran: a systematic review and meta-analysis

BACKGROUND

Leishmaniasis is a major public health problem worldwide. The aim of the present study was to investigate medicinal plants with anti-Leishmania activity which used in Iran.

METHODS

Data were systematically gathered from five English databases including Ebsco, Science Direct, PubMed, Google Scholar and Scopus, four Persian databases including Magiran, Iran doc, Iran medex and the Scientific Information Database (SID) from 1999 to April 2015. Information obtained included plant family, extraction method, concentrations of extracts, animal models and parasite strains.

RESULTS

A total of 68 articles including 188 experiments (140 in vitro and 48 in vivo) between 1999 and 2015, met our eligibility criteria. Thoroughly, 98 types of plants were examined against three genera of Leishmania spp. For the heterogeneity study conducted, it was showed that there was a great deal of variation among studies. Based on random effect, meta-analysis pooled mean of IC50 was obtained 456.64 (95% CI: 396.15, 517.12).

CONCLUSION

The most Iranian plants used as anti-leishmanial activity were Artemisia species, Allium sativum, Achilleamille folium, Peganum harmala and Thymus vulgaris. The present systematic and meta-analysis review provide valuable information about natural products with anti-Leishmania activity, which would be examined in the future experimental and clinical trials and herbal combination therapy.

Trypanocidal Activity of Quinoxaline 1,4 Di-N-oxide Derivatives as Trypanothione Reductase Inhibitors

Chagas disease or American trypanosomiasis is a worldwide public health problem. In this work, we evaluated 26 new propyl and isopropyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives as potential trypanocidal agents. Additionally, molecular docking and enzymatic assays on trypanothione reductase (TR) were performed to provide a basis for their potential mechanism of action. Seven compounds showed better trypanocidal activity on epimastigotes than the reference drugs, and only four displayed activity on trypomastigotes; T-085 was the lead compound with an IC₅₀ = 59.9 and 73.02 µM on NINOA and INC-5 strain, respectively. An in silico analysis proposed compound T-085 as a potential TR inhibitor with better affinity than the natural substrate. Enzymatic analysis revealed that T-085 inhibits parasite TR non-competitively. Compound T-085 carries a carbonyl, a CF₃, and an isopropyl carboxylate group at 2-, 3- and 7-position, respectively. These results suggest the chemical structure of this compound as a good starting point for the design and synthesis of novel trypanocidal derivatives with higher TR inhibitory potency and lower toxicity.

A nanotechnology based new approach for chemotherapy of Cutaneous Leishmaniasis: TIO2@AG nanoparticles - Nigella sativa oil combinations

Since toxicity and resistance are the major drawbacks of current antileishmanial drugs, studies have been recently focused on combination therapy in fight against leishmaniasis. Combination therapy generally provides opportunity to decrease toxicity of applied agents and enhance their antimicrobial performance. Moreover, this method can be effective in preventing drug resistance. Highly antileishmanial effects of silver doped titanium dioxide nanoparticles (TiAgNps) and Nigella sativa oil were demonstrated in previous studies. However, toxicity is still an important factor preventing use of these molecules in clinic. By considering high antileishmanial potential of each agent and basic principles of combination therapy, we propose that use of combinations including non-toxic concentrations of TiAgNps and N. sativa oil may compose more effective and safer formulations against Leishmania parasites. Therefore, the main goal of the present study was to investigate antileishmanial effects of non-toxic concentrations of TiAgNps and Nigella sativa oil combinations on promastigote and amastigote-macrophage culture systems and also to develop nanotechnology based new antileishmanial strategies against Cutaneous Leishmaniasis. Numerous parameters such as proliferation, metabolic activity, apoptosis, amastigote-promastigote conversion, infection index analysis and nitric oxide production were used to detect antileishmanial efficacies of combinations. Investigated all parameters demonstrated that TiAgNps-N. sativa oil combinations had significant antileishmanial effect on each life forms of parasites. Tested combinations were found to decrease proliferation rates of Leishmania tropica promastigotes in a range between 1,5-25 folds and metabolic activity values between 2 and 4 folds indicating that combination applications lead to virtually inhibition of promastigotes and elimination of parasites were directly related to apoptosis manner. TiAgNps-N. sativa combinations also demonstrated killing effects on L. tropica amastigotes by decreasing infection index values of macrophages 5-20 folds, inhibiting their metabolic activities up to 5 fold, preventing amastigote-promastigote conversion and producing high amounts of nitric oxide. All these results emphasize high potential of TiAgNps-N. sativa oil combinations as new, safer and effective antileishmanial formulations against Cutaneous Leishmaniasis.

Chemical composition along with anti-leishmanial and cytotoxic activity of Zataria multiflora

CONTEXT

Natural products and their compounds are some of the most interesting sources of new drugs. Reviews have reported various pharmacological properties such as antimicrobial effects of Zataria multiflora Boiss (Lamiaceae).

OBJECTIVE

The present study investigates the chemical composition of Z. multiflora essential oil and evaluates its cytotoxic effects and anti-leishmanial activities against Leishmania tropica in an in vitro model.

MATERIALS AND METHODS

The components of Z. multiflora oil were identified by gas chromatography/mass spectroscopy (GC/MS) analysis. Anti-leishmanial effects of the essential oil (0-100 μL/mL) and methanol extract of Z. multiflora (0-100 μg/mL) on promastigote forms as well as their cytotoxic activities against J774 cells were evaluated using MTT assay for 72 h. The leishmanicidal activity against amastigote forms of L. tropica was evaluated at the concentrations of 0-50 μg/mL in a macrophage model for 48 h.

RESULTS

The chemical analyses demonstrated that the main components of essential oil were thymol (41.81%), carvacrol (28.85%), and p-cymene (8.36%). Regarding leishmanicidal activity, the IC50 values for the essential oil and methanol extract were 3.2 μL/mL and 9.8 μg/mL against promastigote forms and 8.3 μL/mL and 34.6 μg/mL against amastigote forms, respectively. Essential oil (CC50 89.3 μL/mL) indicated a higher cytotoxic effect than the methanol extract (CC50 591.6 μg/mL) of Z. multiflora.

CONCLUSION

The present study revealed the chemical composition of Z. multiflora that might be a natural source of new anti-leishmanial agents in terms of use against cutaneous leishmaniasis.

Zataria multiflora Bioss: lethal effects of methanolic extract against protoscoleces of Echinococcus granulosus

The present study was aimed to evaluate the lethal effects of Zataria multiflora Boiss (Lamiaceae) methanolic extract against Echinococcus granulosus protoscoleces. Protoscoleces were aseptically aspirated from sheep livers having hydatid cysts. Various concentrations of the essential oil (2.5-20 mg/mL) were used for 10-60 min. Viability of protoscoleces was confirmed using eosin exclusion test (0.1 % eosin staining). Obtained results showed that Z. multiflora extract at the concentration of 20 mg/mL after 10 min of exposure killed 100 % protoscoleces. The mean of mortality rate of protoscoleces after 20 min of exposure to the concentration of 10 mg/mL was also 100 %. Lower concentrations of Z. multiflora extract provoked a delayed protoscolicidal activity. The findings indicated potential of Z. multiflora methanolic extract as a natural source for the producing of new scolicidal agent for use in hydatid cyst surgery.

In Vitro and In Vivo Antileishmanial Effects of Pistacia khinjuk against Leishmania tropica and Leishmania major

The present study aims to evaluate the in vitro and in vivo antileishmanial activities of Pistacia khinjuk Stocks (Anacardiaceae) alcoholic extract and to compare its efficacy with a reference drug, meglumine antimoniate (MA, Glucantime), against Leishmania tropica and Leishmania major. This extract (0-100 µg/mL) was evaluated in vitro against promastigote and intracellular amastigote forms of L. tropica (MRHO/IR/75/ER) and then tested on cutaneous leishmaniasis (CL) in male BALB/c mice with L. major to reproduce the antileishmanial activity topically. In vitro, P. khinjuk extract significantly (P < 0.05) inhibited the growth rate of promastigote (IC50 58.6 ± 3.2 µg/mL) and intramacrophage amastigotes (37.3 ± 2.5 µg/mL) of L. tropica as a dose-dependent response. In the in vivo assay, after 30 days of treatment, 75% recovery was observed in the infected mice treated with 30% extract. After treatment of the subgroups with the concentration of 20 and 30% of P. khinjuk extract, mean diameter of lesions was significantly (P < 0.05) reduced. To conclude, the present investigation demonstrated that P. vera extract had in vitro and in vivo effectiveness against L. major. Obtained findings also provide the scientific evidences that natural plants could be used in the traditional medicine for the prevention and treatment of CL.

Antileishmanial and cytotoxic effects of essential oil and methanolic extract of Myrtus communis L

Plants used for traditional medicine contain a wide range of substances that can be used to treat various diseases such as infectious diseases. The present study was designed to evaluate the antileishmanial effects of the essential oil and methanolic extract of Myrtus communis against Leishmania tropica on an in vitro model. Antileishmanial effects of essential oil and methanolic extract of M. communis on promastigote forms and their cytotoxic activities against J774 cells were evaluated using MTT assay for 72 hr. In addition, their leishmanicidal activity against amastigote forms was determined in a macrophage model, for 72 hr. Findings showed that the main components of essential oil were α-pinene (24.7%), 1,8-cineole (19.6%), and linalool (12.6%). Findings demonstrated that M. communis, particularly its essential oil, significantly (P<0.05) inhibited the growth rate of promastigote and amastigote forms of L. tropica based on a dose-dependent response. The IC₅₀ values for essential oil and methanolic extract was 8.4 and 28.9 μg/ml against promastigotes, respectively. These values were 11.6 and 40.8 μg/ml against amastigote forms, respectively. Glucantime as control drug also revealed IC₅₀ values of 88.3 and 44.6 μg/ml for promastigotes and amastigotes of L. tropica, respectively. The in vitro assay demonstrated no significant cytotoxicity in J774 cells. However, essential oil indicated a more cytotoxic effect as compared with the methanolic extract of M. communis. The findings of the present study demonstrated that M. communis might be a natural source for production of a new leishmanicidal agent.

In Vitro Study of Leishmanicidal Activity of Biogenic Selenium Nanoparticles against Iranian Isolate of Sensitive and Glucantime-Resistant Leishmania tropica

BACKGROUND

Sensitive and glucantime (MA) resistance Leishmania tropica are referred to those isolates, which are responsive, or non-responsive to one or two full courses of treatment by MA systematically and/or intra-lesionally, respectively. In this study, we evaluated the antileishmanial activity of biogenic selenium nanoparticles (Se NPs) alone and in combination with MA against sensitive and glucantime-resistant L. tropica on in vitro model.

METHODS

The Se NPs were synthesized by employing the Bacillus sp. MSh-1. The antileishmanial effects of Se NPs alone and in combination with MA on promastigote and amastigote stages of sensitive and glucantime-resistant L. tropica strains have been investigated using a colorimetric MTT assay and in a macrophage model. In addition hemolytic activity in type O+ human red blood cells and infectivity rate of the promastigotes before and after treatment with the Se NPs was evaluated.

RESULTS

In the promastigote stage, various concentrations of Se NPs significantly inhibited (P<0.05) the growth of promastigotes of both strains in a dose-dependent manner. Similarly, Se NPs especially in combination with MA significantly reduced the mean number of amastigotes of both strains in each macrophage. Se NPs showed no hemolytic effect on human RBCs at low concentrations. Moreover, infection rate of macrophages by promastigotes significantly (P<0.05) was reduced when promastigotes pre-treated with Se NPs.

CONCLUSION

The findings of this study suggest a first step in the search of Se NPs as a new antileishmanial agent. Further experiments are needed to investigate antileishmanial effects of biogenic Se NPs on L. tropica using a clinical setting.