Menthol and Menthone Associated with Acetylsalicylic Acid and Their Relation to the Hepatic Fibrosis in Schistosoma mansoni Infected Mice

Inhibition of carbonic anhydrase using aspirin is a novel method to block schistosomiasis infection of the parasitic trematode, Schistosoma mansoni, in the intermediate snail host, Biomphalaria glabrata

Schistosomiasis is a major public health concern worldwide. Although praziquantel is currently available as the only treatment option for schistosomiasis, the absence of reliable diagnostic and prognostic tools highlights the need for the identification and characterization of new drug targets. Recently, we identified the B. glabrata homolog (accession number XP_013075832.1) of human CAXIV, showing 37% amino acid sequence identity, from a BLAST search in NCBI (National Center for Biotechnology Information). Carbonic Anhydrases (CAs) are metalloenzymes that catalyze the reversible hydration/dehydration of CO2/HCO3. These enzymes are associated with many physiological processes, and their role in tumorigenesis has been widely implicated. CAs create an acidic extracellular environment that facilitates the survival, metastasis, and growth of cancer cells. In this study, we investigated the role of CA inhibition in B. glabrata snails exposed to S. mansoni miracidia. We analyzed the expression of the B. glabrata CA encoding transcript in juvenile susceptible and resistant snails, with and without exposure to S. mansoni. Our results showed that the expression of the CA mRNA encoding transcript was upregulated during early and prolonged infection in susceptible snails (BBO2), but not in the resistant BS-90 stock. Notably, sodium salicylate, a form of aspirin, inhibited the expression of CA, post-exposure, to the parasite. Increasing research between parasites and cancer has shown that schistosomes and cancer cells share similarities in their capacity to proliferate, survive, and evade host immune mechanisms. Here, we show that this model system is a potential new avenue for understanding the role of CA in the metastasis and proliferation of cancer cells. Further studies are needed to explore the potential of CA as a biomarker for infection in other schistosomiasis-causing parasites, including S. japonicum and S. haematobium.

Menthol carbonates as potent antiparasitic agents: synthesis and in vitro studies along with computer-aided approaches

Introduction

Despite the number of deaths and the significant economic and social costs associated with Chagas, Leishmaniasis and Malaria diseases worldwide, available drugs are limited and have serious side effects and high toxicity for the patient. Therefore, there is an urgent need for safe, low-cost, and effective treatments. Natural products are an important source of bioactive compounds and there is current interest in finding natural bioactive molecules that can be used for treating these parasitic diseases. In the present study we proposed to evaluate the in vitro antiparasitic activity of new menthol derivatives against Trypanosoma cruzi, Leishmania braziliensis and Plasmodium falciparum; moreover, we propose to explore their mode of action through in silico approaches.

Material and methods

A series of carbonate prodrugs (1–9) were synthesized from menthol with different aliphatic alcohols. Spectroscopic techniques were used to confirm the structures of the synthesized compounds. The cytotoxicity of the compounds was assessed using U-937 cells. In vitro trypanocidal, leishmanicidal and antiplasmodial activity were evaluated using a T. cruzi, L. braziliensis and P. falciparum organism, respectively. In addition, in silico studies were also performed through molecular dynamics simulations and MM-PBSA analysis.

Results

The assay revealed that most of the compounds were highly active against intracellular amastigotes of T. cruzi and L. braziliensis, and had moderate activity against the total forms of P. falciparum. Compound 2 was one of the drugs that showed a high selectivity index (SI) for the three organisms evaluated. The prediction of the ADME properties suggests that all the compounds have drug-like molecular properties and the probability to be lead candidates. Finally, molecular dynamics simulations, and MM-PBSA studies indicate that menthol at the substrate binding site of TcDHODH, LbDHODH and PfDHODH is structurally stable in the same order as the natural substrate; also, interactions of menthol with residues involved in the inhibition of TcDHODH and PfDHODH proteins were predicted.

Conclusions

The present study demonstrates that menthol prodrugs are promising antiparasitic agents; however, the mechanisms of action proposed in this study need to be experimentally verified by future enzymatic assays.

Menthone inhibits type-I interferon signaling by promoting Tyk2 ubiquitination to relieve local inflammation of rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease. RA development is mediated by the abnormal activation of multiple signaling pathways. Recent studies have revealed that type-I interferon (IFN-I) signaling plays an essential role in the occurrence and development of RA. However, how to target IFN-I signaling to develop anti-rheumatoid arthritis drugs remains largely unexplored. Here, our study showed that IFN-I signaling was over-activated in articular synovial cells from collagen II-induced arthritis (CIA) mice. Interestingly, we found that a small molecule compound, menthone, strongly inhibited the activation of the IFN-I signaling pathway. Further studies revealed that menthone promoted K48-linked polyubiquitination of Tyk2, thus lowering the protein level and stability of Tyk2. Importantly, menthone administration in the local articulus of CIA mice significantly attenuated the local inflammation in CIA mice. This study could promote our understanding of rheumatoid arthritis, and also suggests a potential strategy to develop anti-RA drugs.

Peppermint essential oil: its phytochemistry, biological activity, pharmacological effect and application

Mentha (also known as peppermint), a genus of plants in the taxonomic family Lamiaceae (mint family), is widely distributed throughout temperate regions of the world. Mentha contains various constituents that are classified as peppermint essential oil (PEO) and non-essential components. PEO, consisting mainly of menthol, menthone, neomenthol and iso-menthone, is a mixture of volatile metabolites with anti-inflammatory, antibacterial, antiviral, scolicidal, immunomodulatory, antitumor, neuroprotective, antifatigue and antioxidant activities. Mounting evidence indicates that PEO may pharmacologically protect gastrointestinal, liver, kidney, skin, respiratory, brain and nervous systems, and exert hypoglycemic and hypolipidemic effects. Clinically, PEO is used for gastrointestinal and dermatological diseases, postoperative adjuvant therapy and other fields. This review aims to address the advances in the extraction and isolation of PEO, its biological activities, pharmacological effects, toxicity and applications, with an emphasis on the efficacy of PEO on burn wounds and psoriasis, providing a comprehensive foundation for research, development and application of PEO in future.

Activation of peripheral TRPM8 mitigates ischemic stroke by topically applied menthol

Background

No reports exist as to neuroprotective effects associated with topical activation of transient receptor potential melastatin 8 (TRPM8), a noted cold receptor. In the present study, we identified whether activating peripheral TRPM8 can be an adjuvant therapy for ischemic stroke.

Methods

Menthol, an agonist of TRPM8, was applied orally or topically to all paws or back of the mouse after middle cerebral artery occlusion (MCAO). We used Trpm8 gene knockout (Trpm8^−/−) mice or TRPM8 antagonist and lidocaine to validate the roles of TRPM8 and peripheral nerve conduction in menthol against ischemic stroke.

Results

Application of menthol 16% to paw derma attenuated infarct volumes and ameliorated sensorimotor deficits in stroke mice induced by MCAO. The benefits of topically applied menthol were associated with reductions in oxidative stress, neuroinflammation and infiltration of monocytes and macrophages in ischemic brains. Antagonizing TRPM8 or Trpm8 knockout dulls the neuroprotective effects of topically application of menthol against MCAO. Immunohistochemistry analyses revealed significantly higher TRPM8 expression in skin tissue samples obtained from the paws compared with skin from the backs, which was reflected by significantly smaller infarct lesion volumes and better sensorimotor function in mice treated with menthol on the paws compared with the back. Blocking conduction of peripheral nerve in the four paws reversed the neuroprotective effects of topical menthol administrated to paws. On the other hand, oral menthol dosing did not assist with recovery from MCAO in our study.

Conclusion

Our results suggested that activation of peripheral TRPM8 expressed in the derma tissue of limbs with sufficient concentration of menthol is beneficial to stroke recovery. Topical application of menthol on hands and feet could be a novel and simple-to-use therapeutic strategy for stroke patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02553-4.

Aspirin and Infection: A Narrative Review

Acetylsalicylic acid (ASA) is one of the most commonly used drugs in the world. It derives from the extract of white willow bark, whose therapeutic potential was known in Egypt since 1534 BC. ASA’s pharmacological effects are historically considered secondary to its anti-inflammatory, platelet-inhibiting properties; however, human studies demonstrating a pro-inflammatory effect of ASA exist. It is likely that we are aware of only part of ASA’s mechanisms of action; moreover, the clinical effect is largely dependent on dosages. During the past few decades, evidence of the anti-infective properties of ASA has emerged. We performed a review of such research in order to provide a comprehensive overview of ASA and viral, bacterial, fungal and parasitic infections, as well as ASA’s antibiofilm properties.

Investigating Immunization With Nucleotide Enzymes of Schistosoma mansoni: Nucleoside Diphosphate Kinase and Adenylosuccinate Lyase as New Antigenic Targets Against Schistosomiasis

Schistosomiasis, caused by Schistosoma mansoni trematode worm, affects more than 1.5 million people in Brazil. The current treatment consists in the administration of Praziquantel, the only medicine used for treatment for more than 40 years. Some of the limitations of this drug consist in its inactivity against schistosomula and parasite eggs, the appearance of resistant strains and non-prevention against reinfection. Thus, the objective of this study was to evaluate the effect of immunization with recombinant functional enzymes of the purine salvage pathway of S. mansoni, Nucleoside Diphosphate Kinase (NDPK) and Adenylosuccinate Lyase (ADSL), to evaluate the host immune response, as well as the parasite load after vaccination. For this, Balb/c mice were divided into 5 groups: control (uninfected and untreated), non-immunized/infected, NDPK infected, ADSL infected, and NDPK + ADSL infected. Immunized groups received three enzyme dosages, with a 15-day interval between each dose, and after 15 days of the last application the animals were infected with 80 cercariae of S. mansoni. On the 47th day after the infection, fecal eggs were counted and, on the 48th day after the infection, the evaluation of leukocyte response, parasite load, antibody production, cytokines quantification, and histopathological analysis were performed. The results showed that immunizations with NDPK, ADSL or NDPK + ADSL promoted a discreet reduction in eosinophil counts in lavage of peritoneal cavity. All immunized animals showed increased production and secretion of IgG1, IgG2a, and IgE antibodies. Increased production of IL-4 was observed in the group immunized with the combination of both enzymes (NDPK + ADSL). In addition, in all immunized groups there were reductions in egg counts in the liver and intestine, such as reductions in liver granulomas. Thus, we suggest that immunizations with these enzymes could contribute to the reduction of schistosomiasis transmission, besides being important in immunopathogenesis control of the disease.

Anti-echinococcal activity of menthol and a novel prodrug, menthol-pentanol, against Echinococcus multilocularis

Alveolar echinococcosis is one of the most dangerous parasitic zoonoses. This disease, widely distributed in the northern hemisphere, is caused by the metacestode stage of the tapeworm Echinococcus multilocularis. All surgical and non-surgical patients should perform chemotherapy with benzimidazoles, mainly with albendazole. However, the efficacy of albendazole is variable due to its deficient pharmacokinetic properties. Therefore, the need to find new therapeutic alternatives for the treatment of alveolar echinococcosis is evident. Menthol is a natural compound of low toxicity, used in industries such as cosmetics and gastronomy and generally recognized as safe by the Food and Drug Administration. In addition, menthol has important pharmacological effects and is effective against a wide variety of organisms. The development of prodrugs allows improving the pharmacokinetic properties of the parental drug. To improve lipophilicity and therefore the bioavailability of menthol, a novel prodrug called menthol-pentanol was developed by masking the functional polar group of menthol by linking n-pentanol by a carbonate bond. The aim of the current work was to evaluate the in vitro and in vivo efficacy of menthol and menthol-pentanol against E. multilocularis. Menthol-pentanol had a greater protoscolicidal effect than menthol. In addition, the prodrug demonstrated a similar clinical efficacy to albendazole. The increase in lipophilicity of the prodrug with respect to menthol was reflected in an increase in its antiparasitic activity against E. multilocularis. Thus, menthol-pentanol appears as a promising candidate for further evaluation as a potential alternative for the treatment of alveolar echinococcosis.

Dietary Menthol Attenuates Inflammation and Cardiac Remodeling After Myocardial Infarction via the Transient Receptor Potential Melastatin 8

BACKGROUND

Transient receptor potential melastatin subtype 8 (TRPM8) is a cold-sensing cation channel, mainly localized in the sensory neurons, which can be activated by menthol, a compound with a naturally cold sensation in mint. However, the effect of TRPM8 activation in inflammation and cardiac remodeling after myocardial infarction (MI) is not well defined.

METHODS

TRPM8 knockout (KO) mice (TRPM8-/-) and their wild-type littermates, aged 8 weeks, were randomly divided into sham and MI groups and were fed with chow or chow plus menthol.

RESULTS

Dietary menthol significantly attenuated MI injury, evidenced by decreased survival rates and plasma cardiac troponion I levels, reduced infarct size and cardiomyocytes, declined collagen deposition, and rescued cardiac function and hemodynamics. However, these effects of menthol disappeared when mice were lacking TRPM8. Furthermore, feeding of menthol ameliorated elevated expression of inflammatory cytokines and chemokines, and aggravated inflammation infiltration in the MI mice but not in TRPM8-/- mice. In addition, menthol treatment increased the release of calcitonin gene-related peptide (CGRP), which were absent in TRPM8-/- mice.

CONCLUSIONS

In conclusion, our results suggest that dietary menthol can protect against inflammation and cardiac remodeling after MI through activation of TRPM8.