In vitro biological action of aqueous extract from roots of Physalis angulata against Leishmania (Leishmania) amazonensis

Medicinal plants with promising antileishmanial activity in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Toxicity and resistance to chemotherapy used to treat leishmaniasis are increasing. Research on natural plant compounds has revealed their antileishmanial effects on certain Leishmania organisms. This review aimed to estimate the pooled IC50 values of medicinal plants with promising antileishmanial activity in Ethiopia.

METHODS

A systematic literature search was conducted using Science Direct, PubMed, Cochrane Library, and Google Scholar to locate potential studies. Studies published in peer-reviewed journals and gray literature in university repositories before April 1, 2022, which included a full-length study reporting the half-maximal inhibitory concentration (IC50) of Ethiopian medicinal plants that were written in English were included. Conference proceedings, review articles, letters to the editor, and correspondence were excluded. The quality of the included studies was assessed using the GIVIMP critical appraisal tools. Heterogeneity between studies was verified using Cochrane Q test statistics and I2 test statistics, and the effects were checked using Egger statistical test at a level of significance. A random-effects model was used to estimate the pooled IC50 of the medicinal plants.

RESULTS

Six articles that were conducted in Ethiopia that fulfilled the inclusion criteria, with a total of 62 in vitro experiments, were reviewed. The aggregated mean IC50 for medicinal plants in Ethiopia was 16.80 (95% CI: 12.44, 21.16) and 13.81 (95% CI: 13.12, 14.50) µg/mL for antipromastigote and antiamastigote activity, respectively. Aqueous was the significant preparation with IC50 of 0.53 (0.34, 0.73) µg/mL against promastigote and 0.98 (0.20, 1.76) µg/mL against the amastigote stage.

DISCUSSION

This review indicated that the pooled mean of IC50 for Ethiopian medicinal plants against promastigotes and amastigotes was relatively low and showed better efficacy. This strongly suggests the need to focus on antipromastigote and antiamastigote medicinal plants in Ethiopia for the development of antileishmanial drugs. It is necessary to identify their active components, and their potential toxic effects can lead to the production of well-tolerated and safe drugs for leishmaniasis. The high heterogeneity is the limitation of this study.

REGISTRATION

The review has been registered at Prospero with identification number CRD42022343543.

S. Marinho V, H. Holanda F, M. Ferreira I, Oliveira da Silva E. Polymeric nanoparticles containing kojic acid induce structural alterations and apoptosis-like death in Leishmania (Leishmania) amazonensis

Leishmaniasis encompasses a cluster of neglected tropical diseases triggered by kinetoplastid phatogens belonging to the genus Leishmania. Current therapeutic approaches are toxic, expensive, and require long-term treatment. Nanoparticles are emerging as a new alternative for the treatment of neglected tropical diseases. Silk Fibroin is a biocompatible and amphiphilic protein that can be used for formulating nanoemulsions, while kojic acid is a secondary metabolite with antileishmanial actions. Thus, this study evaluated the efficacy of a nanoemulsion, formulated with silk fibroin as the surfactant and containing kojic acid (NanoFKA), against promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. The NanoFKA had an average particle size of 176 nm, Polydispersity Index (PDI) of 0.370, and a Zeta Potential of -32.3 mV. It presented inhibitory concentration (IC50) values of >56 μg/mL and >7 μg/mL for the promastigote and amastigote forms, respectively. Ultrastructural analysis, cell cycle distribution and phosphatidylserine exposure showed that NanoFKA treatment induces apoptosis-like cell death and cell cycle arrest in L. (L.) amazonensis. In addition, NanoFKA exhibited no cytotoxicity against macrophages. Given these results, NanoFKA present leishmanicidal activity against L. (L.) amazonensis.

Exploration of Antileishmanial Compounds Derived from Natural Sources

AIMS

Leishmaniasis is a deadly tropical disease that is neglected in many countries. World Health Organization, along with a few other countries, has been working together to protect against these parasites. Many novel drugs from the past few years have been discovered and subjected against leishmaniasis, which have been effective but they are quite expensive for lower-class people. Some drugs showed no effect on the patients, and the longer use of these medicines has made resistance against these deadly parasites. Researchers have been working for better medication by using natural products from medicinal plants (oils, secondary metabolites, plant extracts) and other alternatives to find active compounds as an alternative to the current synthetic drugs.

MATERIALS AND METHODS

To find more potential natural products to treat Leishmania spp, a study has been conducted and reported many plant metabolites and other natural alternatives from plants and their extracts. Selected research papers with few term words such as natural products, plant metabolites, Leishmaniasis, in vivo, in vitro, and treatment against leishmaniasis; in the Google Scholar, PubMed, and Science Direct databases with selected research papers published between 2015 and 2021 have been chosen for further analysis has been included in this report which has examined either in vivo or in vitro analysis.

RESULTS

This paper reported more than 20 novel natural compounds in 20 research papers that have been identified which report a leishmanicidal activity and shows an action against promastigote, axenic, and intracellular amastigote forms.

CONCLUSION

Medicinal plants, along with a few plant parts and extracts, have been reported as a possible novel anti-leishmanial medication. These medicinal plants are considered nontoxic to Host cells. Leishmaniasis treatments will draw on the isolated compounds as a source further and these compounds compete with those already offered in clinics.

In Vitro Leishmanicidal Activity of Copaiba Oil and Kojic Acid Combination on the Protozoan Leishmania (Leishmania) amazonensis and Host Cell

(1) Background: Leishmaniasis refers to a group of anthropozoonotic diseases caused by Leishmania. The major chemotherapeutic agent used for its treatment is Glucantime®®, but the search continues for new compounds that are economically viable and act on the protozoan without causing damage to the host cell. As an alternative approach, this study used a combination of copaiba oil (CO) and kojic acid (KA) to determine their in vitro action on host cells, on the Leishmania (Leishmania) amazonensis protozoan and its interaction with macrophages. (2) Methods: In vitro culture, analysis of cytokine release and microscopy assays were performed. Statistical analysis was performed with ANOVA (GraphPad Prism). (3) Results: The combination did not induce cytotoxic effects on macrophages after treatment but promoted morphological changes in the protozoan, such as nuclear alterations (apoptotic characteristics), alterations in the cellular body and an increase in the number of electrodense structures and acidocalcisomes, observed mainly at the concentrations of CO20KA50 and CO30KA50 μg/mL. We observed reductions in the intracellular amastigote number and in the production of proinflammatory cytokines, such as IL-6 and TNF-α, after treatment with CO30KA at 50 µg/mL. (4) Conclusions: We report here, for the first time, that the combination of CO and KA may be a promising approach against Leishmania (Leishmania) amazonensis.

GC-MS screening and antiparasitic action of Putranjiva roxburghii leaves against sensitive and resistant strains of Leishmania donovani

Looming drug resistance cases of leishmaniasis infection are an undeniably serious danger to worldwide public health, also jeopardize the efficacy of available drugs. Besides this, no successful vaccine is available till date. Since the ancient era, many plants and their parts have been used as medicines against various ailments. Hence, the importance of drug development for new molecules against Leishmania infection is significant that is a cost-effective and safer drug preferably from the natural herbal resources. We evaluated the GC-MS screening and efficacy of Putranjiva roxburghii (PR) against the sensitive and resistant promastigotes of L. donovani. GC-MS profiling revealed that the extract was rich in myo-inositol-4-C-methyl, azulene and desulphosinigrin. Quantitative investigation of phytoconstituents confirmed that PR was rich in phenols, flavonoids and terpenoids. We found an IC50 25.61 ± 0.57 µg/mL and 29.02 ± 1.21 µg/mL of PR against sodium stibogluconate sensitive and resistant strain respectively. It was found to be safer in cytotoxicity assay and generated ROS mediated oxidative stress in the parasitic cells which was evidenced by the increased and decreased levels of superoxide radicals, lipid peroxidation products, lipid bodies and levels of thiol, plasma membrane integrity respectively. Therefore, our results support the importance of P. roxburghii as a medicinal plant against L. donovani and showed potential for exploration as an antileishmanial agent.

Anti-inflammatory effects of three withanolides isolated from Physalis angulata L. in LPS-activated RAW 264.7 cells through blocking NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis angulata L. is commonly used in many countries as popular medicine for the treatment of a variety of diseases such as malaria, hepatitis, dermatitis and rheumatism. But the anti-inflammatory active constituents of this medicinal plant and their molecular mechanism are still not elucidated clearly.

AIM OF THE STUDY

The aim of the study is to isolate and identify a series of compounds from the ethanolic extract of Physalis angulata L., and to investigate the anti-inflammatory activities in vitro and the molecular mechanism of physagulin A, physagulin C, and physagulin H.

MATERIALS AND METHODS

In order to further understand the anti-inflammatory mechanism of the three compounds, their potential anti-inflammatory activities were investigated in vitro in LPS-activated RAW 264.7 macrophage cells by Griess assay, ELISA, Western blot and immunofluorescence methods in the present study.

RESULTS

Physagulin A, physagulin C, and physagulin H could not only inhibit the release of NO, PGE₂, IL-6 and TNF-α, but also could down-regulate the expression of iNOS and COX-2 proteins. Furthermore, physagulin A, physagulin C, and physagulin H could remarkably block the degradation of IκB-α and the nuclear translocation of NF-κB/p65 in LPS-activated RAW 264.7 cells. However, none of them could inhibit the phosphorylation of MAPKs family proteins ERK, JNK and p38. Thus, the anti-inflammatory actions of physagulin A, physagulin C, and physagulin H were mainly due to the significant inhibition of NF-κB signaling pathway rather than MAPKs signaling pathway.

CONCLUSIONS

All the results clearly showed that physagulin A, physagulin C, and physagulin H demonstrated potent anti-inflammatory activity and can be used as novel NF-κB inhibitors. They are potential to be developed as an alternative or complementary agents for inflammatory diseases.

Secure and Sustainable Sourcing of Plant Tissues for the Exhaustive Exploration of Their Chemodiversity

The main challenge of plant chemical diversity exploration is how to develop tools to study exhaustively plant tissues. Their sustainable sourcing is a limitation as bioguided strategies and dereplication need quite large amounts of plant material. We examine if alternative solutions could overcome these difficulties by obtaining a secure, sustainable, and scalable source of tissues able to biosynthesize an array of metabolites. As this approach would be as independent of the botanical origin as possible, we chose eight plant species from different families. We applied a four steps culture establishment procedure, monitoring targeted compounds through mass spectrometry-based analytical methods. We also characterized the capacities of leaf explants in culture to produce diverse secondary metabolites. In vitro cultures were successfully established for six species with leaf explants still producing a diversity of compounds after the culture establishment procedure. Furthermore, explants from leaves of axenic plantlets were also analyzed. The detection of marker compounds was confirmed after six days in culture for all tested species. Our results show that the first stage of this approach aiming at easing exploration of plant chemodiversity was completed, and leaf tissues could offer an interesting alternative providing a constant source of natural compounds.

Ethanolic extract of Croton blanchetianus Ball induces mitochondrial defects in Leishmania amazonensis promastigotes

Leishmaniasis is a neglected disease caused by Leishmania. Chemotherapy remains the mainstay for leishmaniasis control; however, available drugs fail to provide a parasitological cure, and are associated with high toxicity. Natural products are promising leads for the development of novel chemotherapeutics against leishmaniasis. This work investigated the leishmanicidal properties of ethanolic extract of Croton blanchetianus (EECb) on Leishmania infantum and Leishmania amazonensis, and found that EECb, rich in terpenic compounds, was active against promastigote and amastigote forms of both Leishmania species. Leishmania infantum promastigotes and amastigotes presented IC50 values of 208.6 and 8.8 μg/mL, respectively, whereas Leishmania amazonensis promastigotes and amastigotes presented IC50 values of 73.6 and 3.1 μg/mL, respectively. Promastigotes exposed to EECb (100 µg/mL) had their body cellular volume reduced and altered to a round shape, and the flagellum was duplicated, suggesting that EECb may interfere with the process of cytokinesis, which could be the cause of the decline in the parasite multiplication rate. Regarding possible EECb targets, a marked depolarization of the mitochondrial membrane potential was observed. No cytotoxic effects of EECb were observed in murine macrophages at concentrations below 60 µg/mL, and the CC50 obtained was 83.8 µg/mL. Thus, the present results indicated that EECb had effective and selective effects against Leishmania infantum and Leishmania amazonensis, and that these effects appeared to be mediated by mitochondrial dysfunction.

Antileishmanial activity of Urtica dioica extract against zoonotic cutaneous leishmaniasis

BACKGROUND

Neglected parasitic diseases (NTDs) like cutaneous leishmaniasis (CL) have caused high mortality and morbidity rate in developing countries. This disease is considered as one of the six major tropical diseases, and has a great importance in HIV infected individuals as an opportunistic infection in those areas that both infections are endemic. This study evaluated the therapeutic effects of the Urtica dioica L (U. dioica) aqueous extract as an anti-leishmanial herbal drug in-vitro and in-vivo, and in addition to that, evaluated two vital immune system cytokines including gamma interferon (IFN-γ) and interleukin-4 (IL-4) plus nitric oxide (NO) and arginase activity against Leishmania major (L. major) infected mice.

METHODOLOGY/PRINCIPAL FINDINGS

In-vitro anti-leishmanial activity of U. dioica aqueous extract was determined using MTT method and also Parasite Rescue Transformation Assay. Also, the footpad lesion size and parasite load in BALB/c mice infected with L. major were quantified for in-vivo assessment. Furthermore, for evaluating the immune responses, the levels of IFN-γ, IL-4, NO and arginase were measured in the BALB/c mice. These results indicated that U. dioica extract significantly reduced the L. major promastigotes viability. According to the in-vitro cytotoxicity assay of the extract on Leishmania parasites (CC50) and infected macrophages (EC50), the extract had no toxicity to the macrophages, however it efficiently killed the L. major amastigotes. In addition, the lesion size, parasite load, IL-4, and ARG were decreased in the treated infected mice, however IFN-γ and NO were significantly increased.

CONCLUSIONS/SIGNIFICANCE

This study established satisfactory results in Leishmania parasite clearing both in-vivo and in-vitro. Therefore, U. dioica extract can be considered as an effective and harmless herbal compound for killing the parasite without toxicity to the host macrophages. Furthermore, it also can treat the CL by switching the mouse immune response towards a cell-mediated response (Th1); hence, it may be identified as a perfect therapeutic herbal drug for CL treatment.

Withanolides from the genus Physalis: a review on their phytochemical and pharmacological aspects

Objectives

Withanolides are a group of modified C28 ergostane-type steroids with a C-22, C-26 δ-lactone side chain or a C-23, C-26 γ-lactone side chain. They enjoy a limited distribution in the plant kingdom and predominantly occur in several genera of Solanaceae. Of which, the genus Physalis is an important resource for this type of natural molecules. The present review aims to comprehensively illustrate the structural characteristics and classification of withanolides, and particularly focus on the progression on phytochemical and pharmacological aspects of withanolides from Physalis ranging from January 2015 to June 2019.

Key findings

Approximately 351 natural withanolides with novel and unique structures have so far been identified from genus Physalis, mainly isolated from the species of P. angulata and P. peruviana. Withanolides demonstrated diverse biological activity, such as anticancer, anti-inflammatory, antimicrobial, immunoregulatory, trypanocidal and leishmanicidal activity. Their observed pharmacological functions supported the uses of Physalis species in traditional or folk medicines.

Summary

Due to their unique structure skeleton and potent bioactivities, withanolides are regarded to be promising drug candidates, particularly for developing anticancer and anti-inflammatory agents. Further investigations for discovering novel withanolides of genus Physalis, exploiting their pharmacological values and evaluating their potency as therapeutic agents are significant work.

Transcriptome-wide identification of microRNAs and functional insights inferred from microRNA-target pairs in Physalis angulata L

Physalis angulata L., a member of the family Solanaceae, is widely used as the folk medicine in various countries. Continuous research efforts are devoted to the discovery of the effective medicinal ingredients from Physalis angulata. However, due to the limited resources of genome and transcriptome sequencing data, only a few studies have been performed at the gene regulatory level. In this study, the transcriptomes of five organs (roots, stems, leaves, flowers and fruits) of Physalis angulata were reported. Based on the transcriptome assembly containing 196,117 unique transcripts, a total of 17,556 SSRs (simple sequence repeats) were identified, which could be useful RNA-based barcoding for discrimination of the plants closely relative to Physalis angulata. Additionally, 24 transcripts were discovered to be the potential microRNA (miRNA) precursors which encode a total of 31 distinct mature miRNAs. Some of these precursors showed organ-specific expression patterns. Target prediction revealed 116 miRNA-target pairs, involving 31 miRNAs and 83 target transcripts in Physalis angulata. Taken together, our results could serve as the data resource for in-depth studies on the molecular regulatory mechanisms related to the production of medicinal ingredients in Physalis angulata.

In vitro antileishmanial effects of Physalis angulata root extract on Leishmania infantum

OBJECTIVE

In the present study, we evaluated the effects of the aqueous extract of Physalis angulata root (AEPa) on Leishmania infantum proliferation, morphology, and the driving mechanism in leishmanicidal activity and modulatory action on macrophages.

METHODS

L. infantum promastigotes were treated with 50 and 100 µg/mL AEPa for 72 h and then antipromastigote assay was performed by counts in a Newbauer chamber, morphological changes were analyzed by transmission electron microscopy and the mechanism of the leishmanicidal activity was detected. In addition, macrophages were infected with L. infantum and were used to evaluate anti-amastigote activity of AEPa and effects of AEPa on cytokine secretion after 72-hour treatment.

RESULTS

Treatment with AEPa reduced the numbers of L. infantum promastigotes (50% inhibitory concentration (IC₅₀) = 65.9 μg/mL; selectivity index (SI) = 22.1) and amastigotes (IC₅₀ = 37.9 μg/mL; SI = 38.5) compared with the untreated control. Amphotericin B reduced 100% of the promastigote numbers after 72 h of treatment (IC₅₀ = 0.2 μg/mL). AEPa induced several morphological changes and increased the production of reactive oxygen species and apoptotic death in promastigotes after treating for 72 h. AEPa (100 μg/mL) promoted tumor necrosis factor-α secretion in macrophages infected with L. infantum after 72 h of treatment, but did not induce an increase in this cytokine in noninfected macrophages. In addition, AEPa showed no cytotoxic effect on J774-A1 cells (50% cytotoxic concentration >1000 μg/mL).

CONCLUSION

AEPa presented antileishmanial activity against the promastigotes and amastigotes of L. infantum without macrophage cytotoxicity; these results show that natural products such as P. angulata have leishmanicidal potential and in the future may be an alternative treatment for leishmaniasis.

Leishmanicidal and cytotoxic activity from plants used in Tacana traditional medicine (Bolivia)

ETNOPHARMACOLOGICAL RELEVANCE

Thirty-eight Tacana medicinal plant species used to treat skin problems, including leishmania ulcers, skin infections, inflammation and wound healing, were collected in the community of Buena Vista, Bolivia, with the Tacana people. Twenty two species are documented for the first time as medicinal plants for this ethnic group living in the northern area of the Department of La Paz.

AIM OF THE STUDY

To evaluate the leishmanicidal effect (IC₅₀) and cytotoxicity (LD₅₀) of the selected plants. To carry out bioguided studies on the active extracts. To assess the potential of Bolivian plant biodiversity associated with traditional knowledge in the discovery of alternative sources to fight leishmaniasis.

MATERIALS AND METHODS

Seventy three ethanol extracts were prepared from 38 species by maceration and were evaluated in vitro against promastigotes of Leishmania amazonensis and L. braziliensis. Active extracts (IC₅₀ ≤ 50 μg/mL) were fractionated by chromatography on Silica gel column and the fractions were assessed against the two Leishmania strains. The most active fractions and the crude extracts were evaluated against reference strains of L. amazonensis, L. braziliensis, L. aethiopica, two native strains (L. Lainsoni and L. braziliensis) and for cytotoxicity against HeLa cells. The chromatographic profile of the active fractions was obtained by reverse phase chromatography using HPLC.

RESULTS

From the 73 extracts, 39 extracts (53.4%) were inactive and 34 showed activity. Thirteen species were sselected for bioguided studies. The crude extracts and their 36 fractions were evaluated against two Leishmania strains. The most active fraction were tested in a panel of five leishmania strains and for cytotoxicity. The Selective Index (SI = LD₅₀/IC₅₀) was calculated, and were generally low. Retention time and UV spectra were recorded for the active fractions by HPLC-DAD using a reverse phase column. Profiles were very different from each other, showing the presence of different compounds.

CONCLUSION

Bolivian traditional knowledge from the Tacanba was useful to identify plants with effect on Leishmania promastigotes. Chromatographic bioguided studies showed stronger leishmanicidal and cytotoxic activity for the medium polar fraction. HPLC analysis showed different chromatographic profiles of the active fractions.

Phloroglucinol derivatives from Hypericum species trigger mitochondrial dysfunction in Leishmania amazonensis

Bioactive molecules isolated from plants are promising sources for the development of new therapies against leishmaniasis. We investigated the leishmanicidal activity of cariphenone A (1), isouliginosin B (2) and uliginosin B (3) isolated from Hypericum species. Promastigotes and amastigotes of Leishmania amazonensis were incubated with compounds 1-3 at concentrations 1-100 µm for 48 h. The anti-promastigote effect of compounds was also tested in combinations. The cytotoxicity against macrophages and human erythrocytes were determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method and hemolysis assay, respectively. The compounds 1-3 showed high leishmanicidal activity against promastigotes, IC50 values of 10.5, 17.5 and 11.3 µm, respectively. Synergistic interactions were found to the associations of compounds 1 and 2 [Σ fractional inhibitory concentration (FIC) = 0.41], and 2 and 3 (ΣFIC = 0.28) on promastigotes. All Hypericum compounds induced mitochondrial hyperpolarization and reactive oxygen species production in promastigotes. The compounds showed low cytotoxicity toward mammalian cells, high selectivity index and killed intracellular amastigotes probably mediated by oxidative stress. These results indicate that these compounds are promising candidates for the development of drugs against leishmaniasis.

Leishmanicidal Activity of (+)-Phyllanthidine and the Phytochemical Profile of Margaritaria nobilis (Phyllanthaceae)

The effects of the Securinega alkaloid (+)-phyllanthidine on Leishmania (L.) amazonensis and the first chemical investigation of Margaritaria nobilis L.f. (Phyllanthaceae) are described. Treating the parasites with this alkaloid caused a dose-dependent reduction in promastigote growth of 67.68% (IC₅₀ 82.37 μg/mL or 353 µM) and in amastigote growth of 83.96% (IC₅₀ 49.11 μg/mL or 210 µM), together with ultrastructural alterations in the promastigotes. No cytotoxic effect was detected in mammalian cells (CC₅₀ 1727.48 µg/mL or CC₅₀ 5268 µM). Classical chromatographic techniques and spectral methods led to the isolation and identification of betulinic acid, kaempferol, corilagin, gallic acid and its methyl ester, besides (+)-phyllanthidine from M. nobilis leaves and stems. Margaritaria nobilis is another source of the small group of Securinega alkaloids, together with other Phyllanthaceae (Euphorbiaceae s.l.) species. The low toxicity to macrophages and the effects against promastigotes and amastigotes are suggestive that (+)-phyllanthidine could be a promising antileishmanial agent for treating cutaneous leishmaniasis.