In vitro efficacy study of Cinnamomum zeylanicum essential oil and cinnamaldehyde against the larval stage of Echinococcus granulosus

Unraveling anthelmintic targets and mechanisms of action of trans-cinnamaldehyde from cinnamon essential oil

Parasitic nematodes pose a significant global socio-economic threat and contribute to neglected diseases. Current infection control relies on drug therapy, but increasing anthelmintic resistance highlights the urgent need for novel treatments. In this study, we investigate the molecular targets and mechanisms of action of trans-cinnamaldehyde (TCA), a principal component of Cinnamon Essential Oil (Cinnamomum verum EO), using Caenorhabditis elegans as a model organism. Our research offers new insights into the anthelmintic effects of TCA by identifying its specific interactions with key Cys-loop receptors and detailing its inhibitory mechanisms. The anthelmintic activity of C. verum EO and TCA manifests as rapid alterations in locomotor activity and inhibition of egg hatching. TCA screening of mutant worms lacking Cys-loop receptors reveal multiple receptor targets, including the levamisole-sensitive nicotinic ACh receptor (L-AChR), GABA-activated chloride channel (UNC-49) and glutamate-activated chloride channel. The mechanism behind the egg hatching inhibition by TCA remains unclear, as none of the mutants studied were found to be resistant to TCA. Furthermore, TCA increases the paralyzing effects of the anthelmintics levamisole and monepantel in a synergistic manner, offering a route for more effective polytherapy strategies. Electrophysiological studies on C. elegans Cys-loop receptors, in both native and heterologous systems, were used to elucidate the molecular mechanisms of TCA-induced paralysis. TCA reduces ACh- and GABA-elicited macroscopic currents and decreases single-channel activity and open durations of native muscle L-AChR channels, indicating an inhibitory action. Thus, by acting through a different mechanism to that of classical anthelmintics, TCA may be beneficial to counteract resistance in combined anthelmintic therapies. Our findings underscore the potential of the multitarget compound TCA as a valuable tool in integrated pharmacological strategies.

Anthelmintic Effect of Cannabidiol against Echinococcus granulosus sensu stricto

Cystic echinococcosis is a global parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus sensu lato. Cystic echinococcosis affects more than 1 million people worldwide, causing important economic costs in terms of management and livestock associated losses. Albendazole is the main drug used in treating human cystic echinococcosis. In spite of this, its low aqueous solubility, poor absorption, and consequently erratic bioavailability are the cause of its chemotherapeutic failures. Based on the described problem, new treatment alternatives urgently need to be developed. The aim of the present research was to study the in vitro and in vivo efficacy of cannabidiol (CBD), the second most abundant component of the Cannabis sativa plant, was demonstrated against E. granulosus sensu stricto. CBD (50 µg/mL) caused a decrease in protoscoleces viability of 80 % after 24 h of treatment which was consistent with the observed tegumental alterations. Detachment of the germinal layer was observed in 50 ± 10% of cysts treated with 50 µg/mL of CBD during 24 h. In the clinical efficacy study, all treatments reduced the weight of cysts recovered from mice compared with the control group. However, this reduction was only significant with ABZ suspension and the CBD + ABZ combination. As we could observe by the SEM study, the co-administration of CBD with ABZ suspension caused greater ultrastructural alteration of the germinal layer in comparison with that provoked with the monotherapy. Further in vivo research will be conducted by changing the dose and frequency of CBD and CBD + ABZ treatments and new available CBD delivery systems will also be assayed to improve bioavailability in vivo.

Essential oils and essential oil compounds in animal production as antimicrobials and anthelmintics: an updated review

Several countries have shown an increased prevalence of drug resistance in animal production due to the indiscriminate use of antibiotics and antiparasitics in human and veterinary medicine. This article aims to review existing methods using naturally occurring essential oils (EOs) and their isolated compounds (EOCs) as alternatives to antimicrobials and antiparasitic compounds in animal production and, consequently, to avoid resistance. The most-reported mechanism of action of EOs and EOCs was cell membrane damage, which leads to the leakage of cytoplasmic content, increased membrane permeability, inhibition of metabolic and genetic pathways, morphologic changes, antibiofilm effects, and damage to the genetic material of infections. In parasites, anticoccidial effects, reduced motility, growth inhibition, and morphologic changes have been reported. Although these compounds regularly show a similar effect to those promoted by traditional drugs, the elucidation of their mechanisms of action is still scarce. The use of EOs and EOCs can also positively influence crucial parameters in animal production, such as body weight gain, feed conversion rate, and cholesterol reduction, which also positively impact meat quality. The application of EOs and EOCs is enhanced by their association with other natural compounds or even by the association with synthetic chemicals, which has been found to cause synergism in their antimicrobial effect. By reducing the effective therapeutical/prophylactic dose, the chances of off-flavors – the most common issue in EO and EOC application – is greatly mitigated. However, there is very little work on the combination of EOs and EOCs in large in vivo studies. In addition, research must apply the correct methodology to properly understand the observed effects; for example, the use of only high concentrations may mask potential results obtained at lower dosages. Such corrections will also allow the elucidation of finer mechanisms and promote better biotechnologic use of EOs and EOCs. This manuscript presents several information gaps to be filled before the use of EOs and EOCs are fully applicable in animal production.

Antiparasitic Effects of Asteraceae Species Extracts on Echinococcus granulosus s.s

Cystic echinococcosis is a zoonotic disease caused by the parasite Echinococcus granulosus sensu lato (s.l.), which is worldwide distributed and causes long-lasting infections in animals and humans. The existing treatment is limited to the use of benzimidazoles, mainly albendazole (ABZ). However, it has unwanted side effects and its efficacy is about 50%. The Asteraceae family includes plants that have therapeutic applications (medicinal species) and has an important role in new drug development. The species belonging to a different genus of this family show a wide range of anti-inflammatory, antimicrobial, antioxidant, hepatoprotective, and antiparasitic activities, among others. The aim of the present study was to evaluate the in vitro efficacy of extracts of four Asteraceae species against protoscoleces of E. granulosus sensu stricto (s.s.). On the other hand, the Stevia aristata extract was assessed on the murine cyst of E. granulosus (s.s.) and the efficacy of S. aristata extract was investigated in a murine model of CE. Stevia satureiifolia, S. aristata, Grindelia pulchella, and G. chiloensis extracts at 100 μg/mL caused a decrease in protoscoleces viability; however, S. aristata extract produced the greatest in vitro protoscolicidal effect. After 20 days of treatment with the highest concentration (100 μg/mL) of S. aristata extract, protoscoleces viability decreased to 0%. The tegumental changes observed by scanning electron microscopy were consistent with the reduction in vitality. The collapse of the germinal layer was registered in 60 ± 5.8% and 83.3 ± 12.0% of cysts treated during 4 days with 50 and 100 μg/ml, respectively. The half maximal effective concentration (EC50) value of the S. aristata extract against E. granulosus (s.s.) cysts was 47.86 μg/mL (96 h). The dosage of infected animals with the 50 mg kg⁻¹ dose of S. aristata extract resulted in a significant reduction in cyst weight in comparison with the control group. In conclusion, S. aristata extract was demonstrated to exert a marked effect, both in vitro and in the murine model.

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

Background

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

Methods

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

Results

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

Conclusion

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

In vitro efficacy of Capparis spinosa extraction against larvae viability of Echinococcus granulosus sensu stricto

Cystic echinococcosis (CE) is a chronic zoonotic parasitic disease caused by infection with the larvae of the Echinococcus granulosus sensu lato (s.l.) cluster. Currently, new drugs are urgently required due to the poor therapeutic effect of the existing drugs albendazole and mebendazole. Capparis spinosa, a traditional medicinal plant, has potential therapeutic effects on various diseases based on extracts from its fruit and other parts. The results of this study demonstrated that the water-soluble and ethanolic extracts of C. spinosa fruit had in vitro killing effects on the larvae of E. granulosus sensu stricto (s.s.) and disrupted the ultrastructure of protoscoleces and metacestodes. In vitro cytotoxicity assays showed that the water-soluble and ethanolic extracts of C. spinosa fruit were not significantly toxic to primary mouse hepatocytes at an effective dose to CE. In conclusion, water-soluble and ethanolic extracts of C. spinosa fruit have great potential for the development of new drugs for the treatment of CE.

Status and prospect of novel treatment options toward alveolar and cystic echinococcosis

Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are the two most important global parasitic infectious diseases caused by species of Echinococcus granulosus and E. multilocularis, respectively. Although numerous trials have been performed in search of novel therapeutic options to curb the neglected zoonosis, no other nonsurgical options are currently available to replace the licensed anti echinococcal drugs albendazole (ABZ) and mebendazole (MBZ). A safer and more effective treatment plan for echinococcosis is therefore urgently needed to compensate for this therapeutic shortfall. Here, we present a review of the literature for state-of-the-art valuable anti-parasitic compounds and novel strategies that have proved effective against CE and AE, which includes details about the pharmaceutical type, practical approach, experimental plan, model application and protoscolecidal effects in vivo and in vitro. The content includes the current application of traditional clinical chemicals, the preparation of new compounds with various drug loadings, repurposing findings, combined programs, the prospects for Chinese herbal medicines, non-drug administrations and the exploration of target inhibitors based on open-source information for parasitic genes. Next the conventional experimental projects and pharmacodynamic evaluation methods are systematically summarized and evaluated. The demands to optimize the construction of the echinococcosis model and improve the dynamic monitoring method in vivo are also discussed given the shortcomings of in vivo models and monitoring methods.

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

Simple Summary

In the last years, targeted therapy and immunotherapy modified the landscape for metastatic melanoma treatment. These therapeutic approaches led to an impressive improvement in patients overall survival. Unfortunately, the emergence of drug resistance and side effects occurring during therapy strongly limit the long-term efficacy of such treatments. Several preclinical studies demonstrate the efficacy of essential oils as antitumoral agents, and clinical trials support their use to reduce side effects emerging during therapy. In this review we have summarized studies describing the molecular mechanism through which essential oils induce in vitro and in vivo cell death in melanoma models. We also pointed to clinical trials investigating the use of essential oils in reducing the side effects experienced by cancer patients or those undergoing anticancer therapy. From this review emerged that further studies are necessary to validate the effectiveness of essential oils for the management of melanoma.

Abstract

The last two decades have seen the development of effective therapies, which have saved the lives of a large number of melanoma patients. However, therapeutic options are still limited for patients without BRAF mutations or in relapse from current treatments, and severe side effects often occur during therapy. Thus, additional insights to improve treatment efficacy with the aim to decrease the likelihood of chemoresistance, as well as reducing side effects of current therapies, are required. Natural products offer great opportunities for the discovery of antineoplastic drugs, and still represent a useful source of novel molecules. Among them, essential oils, representing the volatile fraction of aromatic plants, are always being actively investigated by several research groups and show promising biological activities for their use as complementary or alternative medicine for several diseases, including cancer. In this review, we focused on studies reporting the mechanism through which essential oils exert antitumor action in preclinical wild type or mutant BRAF melanoma models. We also discussed the latest use of essential oils in improving cancer patients’ quality of life. As evidenced by the many studies listed in this review, through their effect on apoptosis and tumor progression-associated properties, essential oils can therefore be considered as potential natural pharmaceutical resources for cancer management.

Assessment of in vitro anthelmintic activity and bio-guided chemical analysis of BRS Boyrá pineapple leaf extracts

Species of the Bromeliaceae are known for their pharmacological actions, including anthelmintic effects. The aim of this study was to investigate the in vitro anthelmintic activity of extracts and fractions of BRS Boyrá pineapple leaf against the eggs and infective larvae of gastrointestinal nematodes (Trichostrongylidae) of goats and to identify the compounds involved in this activity. Crude methanol, hexane, dichloromethane, ethyl acetate and residual hydromethanol extracts were investigated by quantitative analysis of phenolic and flavonoid contents, antioxidant activity, anthelmintic activity against gastrointestinal nematodes of goats. The extracts were submitted to chromatographic methods for substance isolation and spectrometric techniques to identify their structures. The anthelmintic activity was performed by in vitro assays with eggs and larvae of nematodes obtained from naturally infected donor goats. All extracts contained phenolic (2.22-14.12 g of gallic acid equivalent per 100 g of dry extract) and flavonoid compounds (0.13-1.45 g of quercetin equivalent per 100 g of dry extract). Bio-guided fractionation of the BRS Boyrá pineapple leaves showed high antioxidant activity (EC₅₀ for DPPH of 2.16-21.38 mg mL^-1 and inhibition of co-oxidation of β-carotene of 36.40-74.86%) and anthelmintic activity (15.69-100% inhibition of egg hatching). The ethyl acetate extract exhibited greatest activity in all assays. Through chromatographic column analysis it was possible to isolate three substances: β-sitosterol and stigmasterol mixture in dichloromethane and hexane extracts, identified by NMR and p-coumaric acid in the ethyl acetate extract, identified by HPLC-DAD. The isolated p-coumaric acid exhibited high ovicidal effect against goat gastrointestinal nematodes (IC₅₀: 0.12 mg mL^-1) and can be considered the active substance of the ethyl acetate extract. This study revealed for the first time that the pineapple BRS Boyrá possesses inhibitory activity against gastrointestinal nematodes (Haemonchus spp., Oesophagostomum spp. and Trichostrongylus spp.), and that p-coumaric acid is an important bioactive.