Candimine-induced cell death of the amitochondriate parasite Trichomonas vaginalis

Candimine from Hippeastrum escoipense (Amaryllidaceae): Anti-Trypanosoma cruzi activity and synergistic effect with benznidazole

BACKGROUND

Chagas disease (CD), caused by Trypanosoma cruzi, represents a health threat to around 20 million people worldwide. Side effects of benznidazole (Bzn) cause 15-20% of patients to discontinue their treatment. Evidence has increased in favor of the use of drug combinations to improve the efficacy and tolerance of the treatment. Natural products are well known to provide structures that could serve as new drugs or scaffolds for CD treatment. Spp of the Amaryllidoideae sub family of Amaryllidaceae family are known by their bioactives alkaloids, which have been reported by their antiparasitic activities.

PURPOSE

To evaluate the anti-T. cruzi activity of the isolated alkaloid candimine (Cnd) from Hippeastrum escoipense Slanis & Huaylla; and to assess the combination effect between Cnd and Bzn against different life stages of T. cruzi parasites.

METHODS

The chemical profile of H. escoipense alkaloids extract (AE-H. escoipense), including quantitation of Cnd was performed through GC/MS and UPLC-MS/MS techniques. Subsequently, Cnd was isolated using Shephadex LH-20. Then, the AE-H. escoipense and Cnd were tested against T. cruzi, (epimastigotes, trypomastigotes, and amastigotes) by in vitro proliferation and viability assays. The cytotoxicity was evaluated against Vero and HepG2 mammalian cells. The ultrastructural analysis was perform by transmission electron microscopy (TEM) and mitochondrial activity was carried out by MTT assay. Drug combination assay between Cnd and Bzn was evaluated using the Chou-Talalay method.

RESULTS

The AE-H. escoipense and Cnd showed high and specific anti-T. cruzi activity, comparable to Bzn. Cnd induces ultrastructural changes in T. cruzi, such as vacuolization, membrane blebs, and increased mitochondrial activity. Regarding the interaction between Cnd and Bzn, it generates synergism in the combinations of 0.25×IC₅₀ in epimastigotes, 2×IC₅₀ in trypomastigotes+amastigotes, and 0.25, 2, and 4×IC₅₀ in amastigotes.

CONCLUSION

The synergism between Cnd and Bzn indicates that the combination at the concentration of 4×IC₅₀ could be useful as an effective new therapy against CD in the chronic stage. Thus, Cnd isolated from the leaves of H. escoipense emerges as potential candidate for the development of a new drug for the treatment of CD.

Oxidative damage by 1,10-phenanthroline-5,6-dione and its silver and copper complexes lead to apoptotic-like death in Trichomonas vaginalis

Trichomoniasis is a neglected, parasitic, sexually transmitted infection. Resistance to the only approved drugs is increasing worldwide, leaving millions of people without alternative medications. Thus, the search for new therapeutic options against this infection is necessary. Previously, our group reported that 1,10-phenanthroline-5,6-dione (phendione) and its silver(I) and copper(II) complexes (abbreviated as Ag-phendione and Cu-phendione, respectively) presented activity against the amitochondriate parasite Trichomonas vaginalis, with Cu-phendione being the most effective (IC₅₀ = 0.84 μM). Methods: qRT-PCR, SEM, flow cytometry. The current study on the effects of Cu-phendione on the antioxidant metabolism of T. vaginalis by qRT-PCR revealed that the complex causes a decrease in the relative expression of mRNA of NADH oxidase, flavin reductase, superoxide dismutase, peroxiredoxin, iron-sulfur flavoprotein, rubrerythrin and osmotically inducible proteins. In contrast, the mRNA expression of flavodiiron protein was increased. Detoxification-related enzymes were downregulated, impairing oxygen metabolism in trophozoites and triggering a subsequent accumulation of the superoxide anion. Although no DNA fragmentation was observed, the treatment of parasites with Cu-phendione led to a significant reduction in cell size and a concomitant increase in granularity. The complex promoted phosphatidylserine exposure at the plasma membrane (as judged by Annexin V binding) and propidium iodide was unable to passively permeate the parasites. All of these outcomes are classical hallmarks of cell death by apoptosis. In essence, the trichomonacidal effect of Cu-phendione operates through redox homeostasis imbalance, which is a mode of action that is quite distinct from that caused by metronidazole.

Mass Spectrometry Metabolomics Approach Reveals Anti-Trichomonas vaginalis Scaffolds from Marine Fungi

Trichomoniasis is the most common non-viral sexually transmitted infection (STI) in the world caused by Trichomonas vaginalis. Failures in the treatment with the 5-nitroimidazole class including parasite resistance to metronidazole elicit new alternatives. Marine natural products are sources of several relevant molecules, presenting a variety of metabolites with numerous biological activities. In this work, we evaluated the anti-T. vaginalis activity of fungi associated with marine invertebrates by mass spectrometry-based metabolomics approaches. After screening of six marine fungi, extract from Penicillium citrinum FMPV 15 has shown to be 100% active against T. vaginalis, and the gel permeation column on Sephadex LH-20® yielded twelve organic fractions which five showed to be active. Metabolomics and statistical analyses were performed with all the samples (extract and fractions), and several compounds were suggested to be related to the activity. These components include citrinin, dicitrinin C, citreoisocoumarin, dihydrocitrinone, decarboxycitrinin, penicitrinone C, and others. The minimum inhibitory concentration (MIC) value of anti-T. vaginalis activity of citrinin was 200 µM. The marine fungi metabolites show potential as new alternatives to overcome drug resistance in T. vaginalis infections.

Identification of the Constituents in Cnidii Fructus Active Against Trichomonas vaginalis Parasites

Ethanol extracts of Cnidii Fructus, the dried fruits of Cnidium monnieri (L.) Cusson, have been externally applied in the treatment of Trichomonas vaginalis. However, the precise identity of the major constituents responsible for activity against T. vaginalis is unknown, but there is probability they are coumarin derivatives. In this study, the anti-Trichomonas activity of 4 major coumarin derivative constituents of Cnidii Fructus, namely, osthole, xanthotoxin, isopimpinellin, and bergapten, was characterized in terms of the resulting kinetics of growth and morphology of T. vaginalis upon treatment. The results demonstrated that osthole and xanthotoxol had significant trichomonacidal ability, while isopimpinellin and bergapten displayed low or no inhibitory efficacy toward T. vaginalis parasites. Our study suggests that the coumarin derivatives osthole and xanthotoxol can be potentially used as a basis for the development and design of new drugs for application in alternative or synergistic therapy against T. vaginalis.

Alkaloid Profiling, Anti-Enzymatic and Antiproliferative Activity of The Endemic Chilean Amaryllidaceae Phycella cyrtanthoides

This research aims to identify the alkaloid profile and to evaluate the enzyme inhibitory potential and antiproliferative effects of the Amaryllidaceae plant Phycella cyrtanthoides. The alkaloid extracts from bulbs and leaves were analyzed using ultrahigh performance liquid chromatography orbitrap mass spectrometry (UHPLC-Orbitrap-MS) analysis. A total of 70 alkaloids were detected in the P. cyrtanthoides’ extracts. The enzyme inhibition potential against cholinesterases (AChE: acetylcholinesterase, and BChE butyrylcholinesterase) and tyrosinase were studied. Bulbs displayed the best IC₅₀ values against AChE (4.29 ± 0.03 µg/mL) and BChE (18.32 ± 0.03 µg/mL). These results were consistent with docking experiments with selected major compounds in the active sites of enzymes, while no activity was observed against tyrosinase enzyme. Antiproliferative effects were investigated against human cervical (HeLa), lung (A549, SW1573), colon (WiDr), and breast (HBL-100, T-47D) tumor cell lines. Bulbs and leaves were active in all cell lines (GI₅₀ < 2.5 µg/mL). These findings suggest that the endemic Chilean plant P. cyrtanthoides contains diverse types of bioactive alkaloids with antiproliferative activities and inhibitory effects with potential therapeutic applications for neurodegenerative diseases

Anti-parasitic activity of nano Citrullus colocynthis and nano Capparis spinose against Trichomonas vaginalis in vitro

The use of plant extracts and the benefit of their unique properties in treating various pathogens is the return to mother nature, and an attempt to overcome the problems of side effects resulting from the use of chemical drugs and the ability of some pathogens to resist these drugs. Nanotechnology has strengthened the ability of drugs to reach the target and reduced the size and amount of dose needed for treatment. Nano-extracts of Citrullus colocynthis and Capparis spinosa at concentrations of (100, 250 and 500) ppm prepared to the treatment Trichomonas vaginalis in vitro at the time (12, 24, 72) h. Results compared with the use of 0.1% of metronidazole (500 mg). The results showed that the concentrations (100, 250, 500) ppm of C. colocynthis had an inhibitory activity for the growth rate (43.77, 69.15, 89.89) at the time (12, 24 and 72) h, respectively. The inhibitory activity of C. spinosa was (43.18, 67.41, 87.04) at the same time and concentration, compared with metronidazole (43.47, 70.40, 87.04) at the same time. Neither plants showed severe effects in hemolysis. From the results, it can be concluded that either plant can be used as an alternative to metronidazole after completing human and animal tests.

A review study on the anti-trichomonas activities of medicinal plants

The parasitic diseases represent the most important health risk, especially in underdeveloped countries where they have a deep impact on public health. Trichomoniasis is a prevalent non-viral sexually transmitted disease, and a significant amount of new cases are identified each year globally. Furthermore, the infection is linked with serious concerns such as pregnancy outcomes, infertility, predisposition to cervical and prostate cancer, and increased transmission and acquisition of HIV. The therapy is restricted, adverse effects are often observed, and resistance to the drugs is emerging. Based on this, a new treatment for trichomoniasis is necessary. Natural products represent a rich source of bioactive compounds, and even today, they are used in the search for new drugs. Additionally, natural products provide a wide variety of leadership structures that can be used by the pharmaceutical industry as a template in the development of new drugs that are more effective and have fewer or no undesirable side effects compared to current treatments. This review focuses on the medicinal plants that possess anti-trichomonal activity in vitro or in vivo. An electronic database search was carried out covering the last three decades, i.e., 1990-2020. The literature search revealed that almost a dozen isolated phytoconstituents are being explored globally for their anti-trichomonal activity. Simultaneously, many countries have their own traditional or folk medicine for trichomoniasis that utilizes their native plants, as a whole, or even extracts. This review focuses mainly on the human parasite Trichomonas vaginalis. However, at some points mention is also made to Tritrichomonas foetus that causes trichomoniasis in animals of high veterinary and economical interest. We will focus on the plants and plant-based compounds and their anti-trichomonal activity. The literature search highlighted that there are abundant compounds that possess anti-trichomonal activity; however, in-depth in-vivo evaluation of compounds and their clinical evaluation has not been undertaken. There is a critical need for new anti-trichomonal compounds, and focused research on phytoconstituents can provide the way forward.

Antiprotozoal alkaloid principles of the plant family Amaryllidaceae

Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC₅₀ 0.15 μg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.

Trichomoniasis immunity and the involvement of the purinergic signaling

Innate and adaptive immunity play a significant role in trichomoniasis, the most common non-viral sexually transmitted disease worldwide. In the urogenital tract, innate immunity is accomplished by a defense physical barrier constituted by epithelial cells, mucus, and acidic pH. During infection, immune cells, antimicrobial peptides, cytokines, chemokines, and adaptive immunity evolve in the reproductive tract, and a proinflammatory response is generated to eliminate the invading extracellular pathogen Trichomonas vaginalis. However, the parasite has developed complex evolutionary mechanisms to evade the host immune response through cysteine proteases, phenotypic variation, and molecular mimicry. The purinergic system constitutes a signaling cellular net where nucleotides and nucleosides, enzymes, purinoceptors and transporters are involved in almost all cells and tissues signaling pathways, especially in central and autonomic nervous systems, endocrine, respiratory, cardiac, reproductive, and immune systems, during physiological as well as pathological processes. The involvement of the purinergic system in T. vaginalis biology and infection has been demonstrated and this review highlights the participation of this signaling pathway in the parasite immune evasion strategies.

Novel Benzo[a]quinolizidine Analogs Induce Cancer Cell Death through Paraptosis and Apoptosis

Paraptosis is nonapoptotic cell death characterized by massive endoplasmic reticulum (ER)- or mitochondria-derived vacuoles. Induction of paraptosis offers significant advantages for the treatment of chemotherapy-resistant tumors compared with anticancer drugs that rely on apoptosis. Because some natural alkaloids induce paraptotic cell death, a novel series of benzo[a]quinolizidine derivatives were synthesized, and their antiproliferative activity and ability to induce cytoplasmic vacuolation were analyzed. Structural optimization led to the identification of the potent compound 22b, which inhibited cancer cell proliferation in vitro and in vivo and profoundly facilitated paraptosis-like cell death and induced caspase-dependent apoptosis. Further investigation revealed that 22b-mediated vacuolation originated from persistent ER stress and upregulation of LC3B. Paraptosis induced by benzo[a]quinolizidine derivatives thus represents an alternative strategy for cancer chemotherapy.

Natural and synthetic compound anti-Trichomonas vaginalis: an update review

Trichomonas vaginalis is a flagellate protozoan that causes trichomonosis, a sexually transmitted disease of worldwide importance. However, the infection has long received much less attention than other parasitic and sexually transmitted diseases. This negligence leads to poor diagnosis and underestimated prevalence values, and consequently, it has been associated to increasing acquisition and transmission of HIV, pregnancy outcomes, infertility, pelvic inflammatory disease, and cervical and prostate cancer. In view of increased resistance to drugs belonging to the nitroimidazole class, new treatment alternatives are urgently needed. Natural products provide an immeasurable wealth of active molecules, and a great number of new drugs have been originated from these compounds. In addition, new synthetic products or derivatives from old drugs also provide an alternative to treat trichomonosis. Albeit many studies have been performed with natural products against T. vaginalis, none of them progressed to clinical trials. Overall, inadequate financial investments are made, and no alternative treatment for trichomonosis has been discovered; meanwhile, hundreds of thousands of people will remain infected and suffering the serious consequences of this nonviral STD. Thus, it is highlighted that clinical trials for better understanding the potential in vitro are necessary and urgent in order to furnish a new therapeutic alternative for trichomonosis treatment. The current review attempts to give an overview on the potential of natural and synthetic products as antitrichomonal.

Biological and pharmacological activities of amaryllidaceae alkaloids

This review discusses the recent developments on biological and pharmacological activities of amaryllidaceae alkaloids with IC₅₀or EC₅₀values since 2005, supporting the potential therapeutic possibilities for the use of these compounds.

Crinine-type alkaloids from Hippeastrum aulicum and H. calyptratum

An ongoing search for alkaloids in the Amaryllidaceae species using GC-MS resulted in the identification of two crinine-type alkaloids, aulicine (1) and 3-O-methyl-epimacowine, (2) from the indigenous Brazilian species Hippeastrum aulicum and Hippeastrum calyptratum, respectively. In addition, two alkaloids, 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, we provide here complete NMR spectroscopic data for the homolycorine analogues nerinine (5) and albomaculine (6). The absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was determined by circular dichroism and X-ray crystallographic analysis, thus presenting the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum.

Amaryllidaceae and Sceletium alkaloids

Covering: July 2010 to June 2012. Previous review: Nat. Prod. Rep., 2011, 28, 1126-1142. Recent progress on the isolation, identification, biological activity and synthetic studies of structurally diverse alkaloids from plants of the family Amaryllidaceae is summarized in this review. In addition, the structurally related alkaloids isolated from Sceletium species are discussed as well.

Remarkable anti-trichomonas vaginalis activity of plants traditionally used by the Mbyá-Guarani indigenous group in Brazil

Trichomonas vaginalis, a flagellate protozoan, is the causative agent of trichomonosis, the most common nonviral sexually transmitted disease worldwide. Taking into account the increased prevalence of metronidazole-resistant isolates, alternative drugs are essential for the successful treatment. Natural products are the source of most new drugs, and popular wisdom about the use of medicinal plants is a powerful tool in this search. In this study, the activity of 10 medicinal plants extensively used in daily life by Mbyá-Guarani indigenous group was evaluated against seven different T. vaginalis isolates. Among the aqueous extracts tested, Verbena sp. (Guachu ka'a in Mbyá-Guarani language) and Campomanesia xanthocarpa (Guavira in Mbyá-Guarani language) showed the highest activity against T. vaginalis with MIC value of 4.0 mg/mL reaching 100% of efficacy against the parasite. The kinetic growth assays showed that the extracts promoted complete growth abolishment after 4 h of incubation. In addition, the extracts tested did not promote a significant hemolytic activity against human erythrocytes. Our results show for the first time the potential activity of Verbena sp. and C. xanthocarpa against T. vaginalis. In addition, this study demonstrates that indigenous knowledge is an important source of new prototype antiprotozoal agents.

Lycorine derivatives against Trichomonas vaginalis

Six lycorine derivatives were prepared, characterized, and evaluated for their in vitro anti-Trichomonas vaginalis activity. Compounds bearing an acetyl (2), lauroyl (3), benzoyl (4 and 5), and p-nitrobenzoyl (6 and 7) groups were synthesized. The best activity was achieved with lycorine esterified at C-2 position with lauroyl group. Preliminary structure-activity relationship points that unprotected OH group at C-1 and C-2 is not necessary to the antiparasitic activity, and none of the derivative was less active than lycorine. The lycorine structural requisites required to kill this amitochondriate cell seem to be different in comparison with the derivatives most active against other parasites and tumor cell lines, both mitochondriated cells. This result is an important contribution with our ongoing studies regarding the mechanism of action of the Amaryllidaceae alkaloids on T. vaginalis cell death opening a new perspective to optimize this innovative pharmacological potential.

Alkaloids from Hippeastrum papilio

Galanthamine, an acetylcholinesterase inhibitor marketed as a hydrobromide salt (Razadyne®, Reminyl®) for the treatment of Alzheimer's disease (AD), is obtained from Amaryllidaceae plants, especially those belonging to the genera Leucojum, Narcissus, Lycoris and Ungernia. The growing demand for galanthamine has prompted searches for new sources of this compound, as well as other bioactive alkaloids for the treatment of AD. In this paper we report the isolation of the new alkaloid 11β-hydroxygalanthamine, an epimer of the previously isolated alkaloid habranthine, which was identified using NMR techniques. It has been shown that 11β-hydroxygalanthamine has an important in vitro acetylcholinesterase inhibitory activity. Additionally, Hippeastrum papilio yielded substantial quantities of galanthamine.