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

Antiprotozoal activity of auranofin on Trypanosoma cruzi, Leishmania tropica and Toxoplasma gondii: in vitro and ex vivo study

BACKGROUND

Three obligate intracellular protozoan parasite species, which are responsible for significant morbidity and mortality and settle in macrophage cells, affect more than one-half of the world's population, namely, Trypanosoma cruzi, Leishmania tropica and Toxoplasma gondii, which are causative agents of Chagas disease, leishmaniasis and toxoplasmosis, respectively. In the current study, it was aimed to investigate the in vitro and ex vivo antiprotozoal activity of auranofin on T. cruzi, L. tropica and T. gondii.

METHODS

The in vitro drug efficacy (IC50) of auranofin was investigated by haemocytometry and the CellTiter-Glo assay methods and the ex vivo drug efficacy (IC50) by light microscopic examination of Giemsa-stained slides. Also, the cytotoxic activity (CC50) of auranofin was examined by the CellTiter-Glo assay. The selectivity index (SI) was calculated for auranofin.

RESULTS

According to IC50, CC50 and SI data, auranofin did not exhibit cytotoxic activity on Vero cells, but exhibited antiprotozoal activity on epimastigotes and intracellular amastigotes of T. cruzi, promastigotes and intracellular amastigotes of L. tropica and intracellular tachyzoites of T. gondii (p<0.05).

CONCLUSIONS

The detection antiprotozoal activity of auranofin on T. cruzi, L. tropica and T. gondii according to the IC50, CC50 and SI values is considered an important and promising development. This is significant because auranofin may be an effective alternative treatment for Chagas disease, leishmaniasis and toxoplasmosis in the future.

In vitro effects of lapachol and β-lapachone against Leishmania amazonensis

Leishmaniasis is a neglected disease that affects millions of people worldwide, and special attention should be given to treatment because the available drugs have limitations, which can lead to low therapeutic adherence and parasitic resistance. This study evaluated the activity of the bioactive naphthoquinones, lapachol and β-lapachone, against Leishmania amazonensis. The cell alterations were evaluated in vitro on promastigote and amastigote forms. The lethal dose (LD50) at 24, 48, and 72 h on the promastigote's forms using lapachol was 75.60, 72.82, and 58.85 μg/mL and for β-lapachone was 0.65, 1.24, and 0.71 μg/mL, respectively. The naphthoquinones significantly inhibited the survival rate of L. amazonensis amastigotes at 83.11, 57.59, and 34.95% for lapachol (82.28, 41.14, and 20.57 µg/mL), and 78.49, 83.25, and 80.22% for β-lapachone (3.26, 1.63, and 0.815 µg/mL). The compounds on the promastigote's forms led to the loss of mitochondrial membrane potential, induced changes in the integrity of the membrane, caused damage to cells suggestive of the apoptotic process, and showed inhibition of tumor necrosis factor (TNF)-α and interleukin (IL)-6 production. The results showed that these naphthoquinones are promising candidates for research on new drugs with anti-Leishmania activity derived from natural products.

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.

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.

The anti-Leishmania potential of bioactive compounds derived from naphthoquinones and their possible applications. A systematic review of animal studies

Leishmaniasis affects millions of people worldwide, and available treatments have severe limitations. Natural and derivative products are significant sources of innovative therapeutic agents. Naphthoquinones are natural or synthetic chemical compounds with broad biological activity. This systematic review aimed to evaluate the potential anti-Leishmania activity of bioactive compounds derived from naphthoquinones in animal models. Conducted in accordance with PRISMA guidelines, two blocks of MeSH terms were assembled: group I, Leishmania OR Leishmaniasis; group II, Atovaquone OR Lapachol OR Beta lapachone OR Naphthoquinones. The search was performed on PubMed, Web of Science, SCOPUS, EMBASE, and Lilacs databases. Twenty-four articles were retrieved and submitted for quality assessment using the SYRCLE critical appraisal tool. The in vivo anti-Leishmania potential of naphthoquinones was evaluated in visceral and cutaneous leishmaniasis using several measurement parameters. Analyzed compounds varied in structure, association with reference drugs, and encapsulation using a drug delivery system. The study design, including treatment protocol, differed between studies. The findings of the studies in this systematic review indicate the anti-Leishmania potential of naphthoquinones in vivo, with different treatment regimens directed against different Leishmania species. The employed drug delivery systems improve the results concerning selectivity, distribution, and required therapeutic dose. The immunomodulatory action was shown to be beneficial to the host, favoring an adequate immune response against infection by Leishmania parasites since it favored Th₁ responses. All studies presented a moderate to high risk of bias. These findings suggest that more studies are needed to assess the overall effectiveness and safety of these treatments.

The Potential of Traditional Knowledge to Develop Effective Medicines for the Treatment of Leishmaniasis

Leishmaniasis is a neglected tropical disease that affects people living in tropical and subtropical areas of the world. There are few therapeutic options for treating this infectious disease, and available drugs induce severe side effects in patients. Different communities have limited access to hospital facilities, as well as classical treatment of leishmaniasis; therefore, they use local natural products as alternative medicines to treat this infectious disease. The present work performed a bibliographic survey worldwide to record plants used by traditional communities to treat leishmaniasis, as well as the uses and peculiarities associated with each plant, which can guide future studies regarding the characterization of new drugs to treat leishmaniasis. A bibliographic survey performed in the PubMed and Scopus databases retrieved 294 articles related to traditional knowledge, medicinal plants and leishmaniasis; however, only 20 were selected based on the traditional use of plants to treat leishmaniasis. Considering such studies, 378 quotes referring to 292 plants (216 species and 76 genera) that have been used to treat leishmaniasis were recorded, which could be grouped into 89 different families. A broad discussion has been presented regarding the most frequent families, including Fabaceae (27 quotes), Araceae (23), Solanaceae and Asteraceae (22 each). Among the available data in the 378 quotes, it was observed that the parts of the plants most frequently used in local medicine were leaves (42.3% of recipes), applied topically (74.6%) and fresh poultices (17.2%). The contribution of Latin America to studies enrolling ethnopharmacological indications to treat leishmaniasis was evident. Of the 292 plants registered, 79 were tested against Leishmania sp. Future studies on leishmanicidal activity could be guided by the 292 plants presented in this study, mainly the five species Carica papaya L. (Caricaceae), Cedrela odorata L. (Meliaceae), Copaifera paupera (Herzog) Dwyer (Fabaceae), Musa × paradisiaca L. (Musaceae), and Nicotiana tabacum L. (Solanaceae), since they are the most frequently cited in articles and by traditional communities.

Trichilianones A-D, Novel Cyclopropane-Type Limonoids from Trichilia adolfi

The fractionation of an ethanol extract of the bark of Trichilia adolfi yielded four novel limonoids (trichilinones A-D, 1-4), with five fused rings and related to the hortiolide-type limonoids. Starting with an ε-lactone, which is α,β-unsaturated in trichilinones A and D (1 and 4), attached to a tetrahydrofuran ring that is connected to an unusual bicyclo [5.1.0] hexane system, joined with a cyclopentanone with a 3-furanyl substituent [(2-oxo)-furan-(5H)-3-yl in trichilinone D (4)], the four compounds isolated display a new 7/5/3/5/5 limonoid ring system. Their structures were established based on extensive analysis of NMR spectroscopic data. As the crude extract possessed anti-leishmanial properties, the compounds were assayed for cytotoxic and anti-parasitic activities in vitro in murine macrophages cells (Raw 264.7) and leishmania promastigotes (L. amazoniensis and L. braziliensis), respectively. The compounds showed moderate cytotoxicity (approximately 70 μg/mL), but are not responsible for the leishmanicidal effect of the extract.

Subtribe Hyptidinae (Lamiaceae): A promising source of bioactive metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

The subtribe Hyptidinae contains approximately 400 accepted species distributed in 19 genera (Hyptis, Eriope, Condea, Cantinoa, Mesosphaerum, Cyanocephalus, Hypenia, Hyptidendron, Oocephalus, Medusantha, Gymneia, Marsypianthes, Leptohyptis, Martianthus, Asterohyptis, Eplingiella, Physominthe, Eriopidion and Rhaphiodon). This is the Lamiaceae clade with the largest number of species in Brazil and high rates of endemism. Some species have been used in different parts of the world mainly as insecticides/pest repellents, wound healing and pain-relief agents, as well as for the treatment of respiratory and gastrointestinal disorders.

AIM OF THE REVIEW

This review aims to discuss the current status concerning the taxonomy, ethnobotanical uses, phytochemistry and biological properties of species which compose the subtribe Hyptidinae.

MATERIALS AND METHODS

The available information was collected from scientific databases (ScienceDirect, Pubmed, Web of Science, Scopus, Google Scholar, ChemSpider, SciFinder ACS Publications, Wiley Online Library), as well as other literature sources (e.g. books, theses).

RESULTS

The phytochemical investigations of plants of this subtribe have led to the identification of almost 300 chemical constituents of different classes such as diterpenes, triterpenes, lignans, α-pyrones, flavonoids, phenolic acids and monoterpenes and sesquiterpenes, as components of essential oils. Extracts, essential oils and isolated compounds showed a series of biological activities such as insecticide/repellent, antimicrobial and antinociceptive, justifying some of the popular uses of the plants. In addition, a very relevant fact is that several species produce podophyllotoxin and related lignans.

CONCLUSION

Several species of Hyptidinae are used in folk medicine for treating many diseases but only a small fraction of the species has been explored and most of the traditional uses have not been validated by current investigations. In addition, the species of the subtribe appear to be very promising as alternative sources of podophyllotoxin-like lignans which are the lead compounds for the semi-synthesis of teniposide and etoposide, important antineoplastic agents. Thus, there is a wide-open door for future studies, both to support the popular uses of the plants and to find new biologically active compounds in this large number of species not yet explored.

Antiparasitic activity of two Brazilian plants: Eugenia mattosii and Marlierea eugeniopsoides

Parasitoses are very common throughout the world, generating serious consequences for public health. Leishmaniosis and giardiasis are examples of fairly recurrent, but neglected diseases. Several higher plants have demonstrated promising activity against the parasites. The aim of this study was to evaluate the biological activity of extracts, fractions and isolated compounds from the leaves and stems of two Brazilian plants: Eugenia mattosii and Marlierea eugeniopsoides (Myrtaceae) against Leishmania and Giardia. XTT and the fluorimetric method were used to for this evaluation, respectively. Cytotoxicity was evaluated against HeLa cells. The results demonstrated that chloroform fractions of E. matosii and pinostrobin presented the most pronounced antiparasitic activity, with the CLF-stems being the most effective against Leishmania amazonensis and Leishmania braziliensis. Pinostrobin also presented activity against G. lamblia. Therefore, E. mattosii stems and pinostrobin may be considered possible targets for the continuity of studies against other parasites.

Ethnopharmacology, phytochemistry, biological activities, and therapeutic applications of Cedrela serrata Royle: A mini review

ETHNOPHARMACOLOGICAL RELEVANCE

Cedrela serrata Royle (C. serrata) is a medicinal plant not only used for constructions but also an important conventional medicine for the treatment of various diseases such as; diabetes, jaundice, liver diseases, diarrhea, fever, chronic infantile dysentery, intestinal worms, hypertension, skin and blood diseases.

AIMS

This review article documents and critically assesses, for the first time; up to date categorized information about C. serrata including its reported pharmacological activities, cultural uses, active compounds, and botanical description.

MATERIALS AND METHOD

s: All provided information about C. serrata was collected using the electronic databases (e.g. Google Scholar, Web of Science, Scopus, PubMed, Science Direct and Springer Link), books (e.g. Trees of Pakistan and Herbalism, Phytochemistry, and Ethnopharmacology) and thesis.

RESULTS

Qualitative and quantitative phytochemical studies on C. serrata revealed the presence of important chemical constituents such as; flavonoids, phenolic acids, alkaloids, saponins, tannins, and cardiac glycosides. The phytochemicals showed various in vitro activities like antioxidant, anti-infective, antiglycation, cytotoxic activities. Major areas of research conducted on C. serrata are its antioxidant and anti-infective activities. Few historical uses of C. serrata are supported by modern in vitro pharmacological studies such as; antidiarrheal, antidiabetic, and leishmanicidal activity.

CONCLUSION

There were convincing evidence in in vitro studies supporting C. serrata antioxidant, anti-infective, anti-diabetic, anti-glycating, and cytotoxic activities. Nevertheless, all reported pharmacological activities were carried out in vitro and a gap in research i.e. preclinical and clinical investigation still exists. The authors emphasize the need for future in-depth research and clinical trials to investigate C. serrata pharmacological activity, clinical efficacy and safety. The potential chemical compounds with suggestive classes may need to be isolated and pharmacological activities must be established for these compounds. The plant has very limited information about pharmacological activities and the data available for supportive cultural uses needs proper validation.

Mosquito Larvicidal Activity of the Essential Oils of Erechtites Species Growing Wild in Vietnam

Mosquito-borne infections are a constant problem in Vietnam, and mosquito vector control is a primary approach to control these infections. Essential oils represent environmentally friendly alternatives to synthetic pesticides for mosquito control. The essential oils of two weedy species in Vietnam, Erechtites hieraciifolius and E. valerianifolius, have been obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. The essential oils have been screened for mosquito larvicidal activity against Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus. The essential oil from the aerial parts of E. hieraciifolius was rich in α-pinene (14.5%), limonene (21.4%), and caryophyllene oxide (15.1%), while E. valerianifolius essential oil was dominated by myrcene (47.8%) and α-pinene (30.2%). Both essential oils showed good larvicidal activity against Ae. albopictus (24-h LC₅₀ 10.5 and 5.8 μg/mL, respectively) and Ae. aegypti (24-h LC₅₀ 10.6 and 12.5 μg/mL, respectively). The essential oil of E. valerianifolius also showed good activity against Cx. quinquefasciatus larvae (24-h LC₅₀ = 40.7 μg/mL). Thus, Erechtites essential oils may serve as low-cost vector control agents for mosquito-borne infections.

Antiparasitic Metabolites from Hyptis brevipes, a Tacana Medicinal Plant

A bioassay screening against protozoa parasites of several Tacana medicinal plants gave Hyptis brevipes (Id'ene eidhue), traditionally used as decoction for intestinal parasites, as the most active extract. In this work we did a bioguided isolation of active constituents found in leaves. Structure elucidation was carried out by NMR spectroscopy and MS spectrometry analyses. Active constituents showed differentiated activity towards Giardia lamblia, Trypanosoma cruzi, several Leishmania strains, Plasmodium falciparum and cytotoxicity against HeLa cells. Brevipolide H (1) was the less cytotoxic and best antiparasitic, while the catechol derivative (2) the most active and cytotoxic.