A lupane-triterpene isolated from Combretum leprosum Mart. fruit extracts that interferes with the intracellular development of Leishmania (L.) amazonensis in vitro

Leishmanicidal and healing effects of 3β,6β,16β-trihydroxy lup-20 (29)-ene isolated from Combretum leprosum on Leishmania braziliensis infection in vitro and in vivo

Treatment of cutaneous leishmaniasis depends on drugs that potentially cause serious side effects and resistance. Thus, topical therapies are attractive alternatives to the drugs currently used. 3β, 6β, 16β-trihydroxylup-20 (29)-ene is a lupane triterpene isolated from Combretum leprosum Mart. leaves (CLF-1), with reports of in vitro antileishmanial effect against L. amazonensis and to promote lesion healing in animal model. Herein, we evaluated the in vitro and in vivo antileishmanial and healing effects of CLF-1 against L. braziliensis. CLF-1 treatment showed low toxicity in macrophages and significantly reduced parasite load in vitro. CLF-1 induced higher IL-12 and TNF-α production and more discrete IL-4 and IL-10 production. For in vivo evaluation, a CLF-1 cream formulation was prepared to treat hamsters infected with L. braziliensis. CLF-1 treatment was able to reduce parasite load of the infected skin and lymph node more efficiently than the conventional treatment. Histopathological analysis indicated a strong inflammatory response accompanied by an important healing response. Data from this study indicate that topical CLF-1 treatment was effective and non-toxic in L. braziliensis infected hamsters suggesting its potential for further development as a future therapeutic intervention.

Antimicrobial, Antibiofilm Activities and Synergic Effect of Triterpene 3β,6β,16β-trihydroxyilup-20(29)-ene Isolated from Combretum leprosum Leaves Against Staphylococcus Strains

Antimicrobial resistance is a natural phenomenon and is becoming a huge global public health problem, since some microorganisms not respond to the treatment of several classes of antibiotics. The objective of the present study was to evaluate the antibacterial, antibiofilm, and synergistic effect of triterpene 3β,6β,16β-trihydroxyilup-20(29)-ene (CLF1) against Staphylococcus aureus and Staphylococcus epidermidis strains. Bacterial susceptibility to CLF1 was evaluated by minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) assay. In addition, the effect combined with antibiotics (ampicillin and tetracycline) was verified by the checkerboard method. The biofilms susceptibility was assessed by enumeration of colony-forming units (CFUs) and quantification of total biomass by crystal violet staining. The compound showed bacteriostatic and bactericidal activity against all Staphylococcal strains tested. The synergistic effect with ampicillin was observed only for S. epidermidis strains. Moreover, CLF1 significantly inhibited the biofilm formation and disrupted preformed biofilm of the all strains. Scanning electron microscopy (SEM) images showed changes in the cell morphology and structure of S. aureus ATCC 700698 biofilms (a methicillin-resistant S. aureus strain). Molecular docking simulations showed that CLF1 has a more favorable interaction energy than the antibiotic ampicillin on penicillin-binding protein (PBP) 2a of MRSA, coupled in different regions of the protein. Based on the results obtained, CLF1 proved to be a promising antimicrobial compound against Staphylococcus biofilms.

Antileishmanial Effects of Bunium Persicum Crude Extract, Essential Oil, and Cuminaldehyde on Leishmania Major: In Silico and In Vitro Properties

PURPOSE

Cuminaldehyde (CA), an oxidized aldehyde monoterpene, is a major essential oil component in cumin seeds, which has shown different promising medical effects. In this study, we comprehensively evaluated the antileishmanial potential of Bunium persicum (Boiss) B. Fedtsch (Apiaceae) and one of its main essential oil constituents, CA, focus on the mechanisms of action.

METHODS

We used a molecular docking approach to examine the capability of CA for binding to IL-12P40 and TNF-α. The colorimetric assay was performed to assess the effect of B. persicum crude extract, essential oil, and CA, against Leishmania major promastigotes and intracellular amastigotes. The expression of IFN-γ, IL-12P40, TNF-α, and IL-10 genes was detected using quantitative real-time polymerase chain reaction qPCR.

RESULTS

Docking analyses in the current study indicated CA binds to IL-12P40 and TNF-α. These products were safe, extremely antileishmanial, and significantly promoted Th1-related cytokines (IFN-γ, IL-12P40, TNF-α), while downregulating the Th2 phenotype (IL-10).

CONCLUSION

Cumin essential oil and its major component, CA, possessed powerful antileishmanial activity. The primary mechanism of activity involves an immunomodulatory role toward Th1 cytokine response. Therefore, cumin essential oil and CA deserve further explorations as promising medications for treating leishmaniasis.

Demystifying the potential of inhibitors targeting DNA topoisomerases in unicellular protozoan parasites

DNA topoisomerases are a group of enzymes omnipresent in all organisms. They maintain the DNA topology during replication, repair, recombination, and transcription. However, the structure of topoisomerase in protozoan parasites differs significantly from that of human topoisomerases; thus, this enzyme acts as a crucial target in drug development against parasitic diseases. Although the therapeutic potential of drugs targeting the parasitic topoisomerase is well known, to manage the shortcomings of currently available therapeutics and the emergence of drug resistance, the discovery of novel antiparasitic molecules is an urgent need. In this review, we describe various investigational and repurposed topoisomerase inhibitors developed against protozoan parasites over the past few years. Teaser: Fatal parasitic diseases are an increasing cause for concern; here, we provide a compilation of different inhibitors targeting DNA topoisomerases, enzymes that are essential for, and unique to, protozoan parasites; therefore, inhibitors are efficient and have few adverse effects.

Bioactive Usual and Unusual Triterpenoids Derived from Natural Sources Used in Traditional Medicine

Triterpenoids are accessible in several terrestrial plants as well as marine organisms, including sponges, algae, fungi, and sea cucumbers are examples of marine creatures. So far, more than 20,000 natural triterpenoids have exhibited several varied bioactivities, including anticancer, antimalarial, anti-HIV, inhibit HIF-1 activation, antibacterial, chemopreventive, anti-inflammatory, antioxidant, cardioprotective, antiviral, neuroprotective, hepatoprotective, insecticidal, antidiabetic, cytotoxic. Several plants are used in folklore medicine to treat numerous ailments, and the preparation or uses of traditional practices have been scientifically validated. Although various structural diversity has been observed in the triterpenoids, this review presents the sources and uses of those triterpenoids that showed significant biological activities which could be accessible and promoted to familiar people in the form of traditional medicine or for industrial, or pharmaceutical applications.

Holanamine, a Steroidal Alkaloid from the Bark of Holarrhena pubescens Wall. ex G. Don Inhibits the Growth of Leishmania donovani by Targeting DNA Topoisomerase 1B

Leishmaniasis is a group of neglected tropical diseases (NTDs) caused by about 20 species of obligate intracellular protozoan parasites of the genus Leishmania, which occurs in cutaneous, mucocutaneous, and visceral forms. Many researchers have sought to utilize natural products for novel and effective treatments to combat many infectious diseases, including leishmaniasis. Holarrhena pubescens Wall. ex G. Don (Apocynaceae) bark is a rich source of bioactive steroidal alkaloids. The total alkaloidal extract (IC₅₀ 6.12 ± 0.117 μg/mL), and the isolated alkaloid, holanamine, showed significant antileishmanial activity (IC₅₀ 2.66 ± 0.112 μM against AG83 and 3.80 ± 0.126 μM against BHU-575) against the Leishmania donovani parasite, better than miltefosine (IC₅₀ 19.61 ± 0.093 μM against AG83 and 23.20 ± 0.094 μM against BHU-575). Holanamine inhibited the L. donovani topoisomerase 1B (LdToP1B) in a non-competitive manner (IC₅₀ 2.81 ± 0.105 μM), indicating that it interacts with the free enzyme and enzyme-DNA complex without inhibiting human topoisomerase. Hydrogen bonding and hydrophobic interactions of holanamine with the N-terminal and hinge region of the large subunit of LTop1B is responsible for its potent antileishmanial activity, as shown by docking studies. Treatment with holanamine causes apoptotic-like cell death by generating cellular and mitochondrial reactive oxygen species, disrupting the mitochondrial membrane potential and inducing ultrastructural alterations in the promastigotes. Holanamine effectively clears intracellular amastigotes but minimally affects host macrophages with no significant cytotoxicity in HEK 293 and L929 cell lines. Thus, our studies show that holanamine can further be used to develop effective antileishmanial agents against evolving drug-resistant parasites.

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.

Four new cycloartane-type triterpenoids from the leaves of Combretum mellifluum Eichler: assessment of their antioxidant and antileishmanial activities

The beneficial pharmacological actions including antioxidant effects as an antileishmanial, antibacterial, antifungal, antidiabetic, anti-inflammatory, antitumor, antiviral, and analgesic of compounds isolated from Combretum mellifluum Eichler (Combretaceae) are well established. The aim of the present study was to determine the phytochemistry as well as assess the antioxidant and antileishmanial activities of the leaves from Combretum mellifluum Eichler (Combretaceae). Analysis of ethanolic extract resulted in isolation and identification of two epimeric mixtures of four previously unknown cycloartane-type triterpenoids, methyl quadrangularate M and methyl 24-epiquadrangularate M, and 2α,3β,24β-trihydroxy-cycloart-25-ene and 2α, 3β, 24α-trihydroxy-cycloart-25-ene, and eight known compounds. Their structures were using one-dimensional nuclear magnetic resonance (1D NMR), 2D NMR and high-resolution electrospray ionization mass spectroscopy (HRESIMS) analysis. Further, the extract and fractions were tested for antioxidant potential. The ethyl acetate and aqueous fractions demonstrated the highest antioxidant activity against 2,2-dipheny-1-picrylhydrazl (DPPH) free radicals, which correlated directly with total flavonoid content. All extracts and fractions from C. mellifluum Eichler were assessed for antileishmanial activity. The supernatant fraction exhibited highest potential, inhibiting the growth of Leishmania amazonensis with IC₅₀ value 31.29 μg/ml. Our findings provide information on the chemical composition of C. mellifluum and the potential beneficial therapeutic usefulness as an antioxidant agent in various diseases.

Antiviral, Antibacterial, Antifungal, and Antiparasitic Properties of Propolis: A Review

Propolis is a complex phytocompound made from resinous and balsamic material harvested by bees from flowers, branches, pollen, and tree exudates. Humans have used propolis therapeutically for centuries. The aim of this article is to provide comprehensive review of the antiviral, antibacterial, antifungal, and antiparasitic properties of propolis. The mechanisms of action of propolis are discussed. There are two distinct impacts with regards to antimicrobial and anti-parasitic properties of propolis, on the pathogens and on the host. With regards to the pathogens, propolis acts by disrupting the ability of the pathogens to invade the host cells by forming a physical barrier and inhibiting enzymes and proteins needed for invasion into the host cells. Propolis also inhibits the replication process of the pathogens. Moreover, propolis inhibits the metabolic processes of the pathogens by disrupting cellular organelles and components responsible for energy production. With regard to the host, propolis functions as an immunomodulator. It upregulates the innate immunity and modulates the inflammatory signaling pathways. Propolis also helps maintain the host's cellular antioxidant status. More importantly, a small number of human clinical trials have demonstrated the efficacy and the safety of propolis as an adjuvant therapy for pathogenic infections.

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.

Annonaceae Family Alkaloids as Agents Against Leishmaniasis: A Review and Molecular Docking Evaluation

Leishmaniasis is a neglected disease that affects 15 million people worldwide. Existing treatments are associated with limitations, including high costs and toxicity. Several classes of natural substances have been reported to display leishmanicidal activity in the literature. Isoquinoline alkaloids, which are commonly found in the Annonaceae family, represent an important skeleton for the development of anti-leishmaniasis products. This study presents an overview of the potential use of Annonaceae alkaloids to treat leishmaniasis and describes a molecular docking study examining 215 isoquinoline alkaloids. All selected compounds contain a bisbenzyltetrahydroisoquinoline, suggesting the affinity of this skeleton for the target.

Docking with AutoDock4

AutoDock is one of the most popular receptor-ligand docking simulation programs. It was first released in the early 1990s and is in continuous development and adapted to specific protein targets. AutoDock has been applied to a wide range of biological systems. It has been used not only for protein-ligand docking simulation but also for the prediction of binding affinity with good correlation with experimental binding affinity for several protein systems. The latest version makes use of a semi-empirical force field to evaluate protein-ligand binding affinity and for selecting the lowest energy pose in docking simulation. AutoDock4.2.6 has an arsenal of four search algorithms to carry out docking simulation including simulated annealing, genetic algorithm, and Lamarckian algorithm. In this chapter, we describe a tutorial about how to perform docking with AutoDock4. We focus our simulations on the protein target cyclin-dependent kinase 2.

Structural Basis for Inhibition of Enoyl-[Acyl Carrier Protein] Reductase (InhA) from Mycobacterium tuberculosis

Background::

The enzyme trans-enoyl-[acyl carrier protein] reductase (InhA) is a central protein for the development of antitubercular drugs. This enzyme is the target for the pro-drug isoniazid, which is catalyzed by the enzyme catalase-peroxidase (KatG) to become active.

Objective::

Our goal here is to review the studies on InhA, starting with general aspects and focusing on the recent structural studies, with emphasis on the crystallographic structures of complexes involving InhA and inhibitors.

Method::

We start with a literature review, and then we describe recent studies on InhA crystallographic structures. We use this structural information to depict protein-ligand interactions. We also analyze the structural basis for inhibition of InhA. Furthermore, we describe the application of computational methods to predict binding affinity based on the crystallographic position of the ligands.

Results::

Analysis of the structures in complex with inhibitors revealed the critical residues responsible for the specificity against InhA. Most of the intermolecular interactions involve the hydrophobic residues with two exceptions, the residues Ser 94 and Tyr 158. Examination of the interactions has shown that many of the key residues for inhibitor binding were found in mutations of the InhA gene in the isoniazid-resistant Mycobacterium tuberculosis. Computational prediction of the binding affinity for InhA has indicated a moderate uphill relationship with experimental values.

Conclusion::

Analysis of the structures involving InhA inhibitors shows that small modifications on these molecules could modulate their inhibition, which may be used to design novel antitubercular drugs specific for multidrug-resistant strains.

Anti-inflammatory and phytochemical evaluation of Combretum aculeatum Vent growing in Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

Combretum aculeatum Vent was traditionally used in Sudan, Eretria and Ethiopia as anti-inflammatory in case of skin inflammation, catarrh, wounds, scorpion stings and snake bites. Nevertheless, there is no scientific information regarding this activity.

AIM OF STUDY

The present study aimed to evaluate the phytochemical constituents and the scientific basis for the traditional use of Combretum aculeatum Vent through studying its anti-inflammatory properties for the first time to illustrate the putative mechanisms behind this bioactivity.

MATERIALS AND METHODS

the ethanolic extract was partitioned by petroleum ether, methylene chloride, ethyl acetate, and n-butanol saturated with water. The petroleum ether fraction was saponified and the saponifiable and unsaponifiable fractions were analyzed on GC/MS. The different fractions were subjected to phytochemical investigation to isolate pure compounds. In-vivo anti-inflammatory activity of the ethanolic extract was evaluated using carrageenan induced rat paws edema method at doses of 200, 400 and 600 mg/kg and proved based on histopathological and biochemical parameters.

RESULTS

Five known compounds were isolated for the first time from the aerial parts of Combretum aculeatum Vent: quercetin, vitexin, isorhamnetin 3-O-β-glucoside, isovitexin and rutin, in addition to two previously isolated ones: β-sitosterol and its glucoside. The ethanolic extract evidenced in-vivo anti-inflammatory activity by oral intake of 400 mg/kg of the ethanolic extract significantly (P ≥ 0.05) decreased the paw edema (only 32±1.9% increase in paw weight after 4 h) compared to indomethacin (28.6±2.5%). Moreover, it significantly suppressed the serum malondialdehyde (MDA) and nitric oxide (NO) and increased the GSH to be 11.76±0.85, 5.13±0.62 μmol/mL and 5.66±0.28 μM/mL, respectively. It diminished the serum cytokines TNF-α, IL-6 and IL-1β levels to be 39.1±1.2, 32.6±1.1 and 37.5±1.2 pg/mL, respectively. Results are accompanied by histopathological examination.

CONCLUSION

Overall, the results herein presented significant anti-inflammatory properties traditionally ascribed to Combretum aculeatum Vent. Moreover, the biochemical mechanisms associated to this action were highlighted, introducing new prospects for the development of effective anti-inflammatory herbal medicinal products.

How Docking Programs Work

Protein-ligand docking simulations are of central interest for computer-aided drug design. Docking is also of pivotal importance to understand the structural basis for protein-ligand binding affinity. In the last decades, we have seen an explosion in the number of three-dimensional structures of protein-ligand complexes available at the Protein Data Bank. These structures gave further support for the development and validation of in silico approaches to address the binding of small molecules to proteins. As a result, we have now dozens of open source programs and web servers to carry out molecular docking simulations. The development of the docking programs and the success of such simulations called the attention of a broad spectrum of researchers not necessarily familiar with computer simulations. In this scenario, it is essential for those involved in experimental studies of protein-ligand interactions and biophysical techniques to have a glimpse of the basics of the protein-ligand docking simulations. Applications of protein-ligand docking simulations to drug development and discovery were able to identify hits, inhibitors, and even drugs. In the present chapter, we cover the fundamental ideas behind protein-ligand docking programs for non-specialists, which may benefit from such knowledge when studying molecular recognition mechanism.

Antimicrobial activity of the lupane triterpene 3β,6β,16β-trihydroxylup-20(29)-ene isolated from Combretum leprosum Mart

Introduction. Combretum leprosum (Combretaceae) is commonly found in the Northeast Region of Brazil and is known for several bioactivities, including antimicrobial ones. Because of increasing bacterial antibiotic resistance, natural products from several plants have been studied as putative adjuvants to antibiotic activity, including products from C. leprosum. Aims. This study was carried out to investigate the structural properties, bactericidal activity and antibiotic modifying action of the lupane triterpene 3β,6β,16β-trihydroxylup-20(29)-ene (CLF1) isolated from C. leprosum Mart. leaves.Methods. The CLF1 was evaluated by the Fourier transform infrared spectroscopy method and the antibacterial activity of this compound was assayed alone and in association with antibiotics by microdilution assay.Results. Spectroscopic studies confirmed the molecular structure of the CLF1 and permitted assignment of the main infrared bands of this natural product. Microbiological assays showed that this lupane triterpene possesses antibacterial action with clinical relevance against Staphylococcus aureus. The CLF1 triterpene increased antimicrobial activity against the multidrug-resistant Escherichia coli 06 strain when associated with the antibiotics gentamicin and amikacin. Synergistic effects were observed against the S. aureus 10 strain in the presence of the CLF1 triterpene with the antibiotic gentamicin.Conclusion. In conclusion, the CLF1 compound may be useful in the development of antibacterial drugs against the aforementioned bacteria.

SAnDReS: A Computational Tool for Docking

Since the early 1980s, we have witnessed considerable progress in the development and application of docking programs to assess protein-ligand interactions. Most of these applications had as a goal the identification of potential new binders to protein targets. Another remarkable progress is taking place in the determination of the structures of protein-ligand complexes, mostly using X-ray diffraction crystallography. Considering these developments, we have a favorable scenario for the creation of a computational tool that integrates into one workflow all steps involved in molecular docking simulations. We had these goals in mind when we developed the program SAnDReS. This program allows the integration of all computational features related to modern docking studies into one workflow. SAnDReS not only carries out docking simulations but also evaluates several docking protocols allowing the selection of the best approach for a given protein system. SAnDReS is a free and open-source (GNU General Public License) computational environment for running docking simulations. Here, we describe the combination of SAnDReS and AutoDock4 for protein-ligand docking simulations. AutoDock4 is a free program that has been applied to over a thousand receptor-ligand docking simulations. The dataset described in this chapter is available for downloading at https://github.com/azevedolab/sandres.

Molegro Virtual Docker for Docking

Molegro Virtual Docker is a protein-ligand docking simulation program that allows us to carry out docking simulations in a fully integrated computational package. MVD has been successfully applied to hundreds of different proteins, with docking performance similar to other docking programs such as AutoDock4 and AutoDock Vina. The program MVD has four search algorithms and four native scoring functions. Considering that we may have water molecules or not in the docking simulations, we have a total of 32 docking protocols. The integration of the programs SAnDReS ( https://github.com/azevedolab/sandres ) and MVD opens the possibility to carry out a detailed statistical analysis of docking results, which adds to the native capabilities of the program MVD. In this chapter, we describe a tutorial to carry out docking simulations with MVD and how to perform a statistical analysis of the docking results with the program SAnDReS. To illustrate the integration of both programs, we describe the redocking simulation focused the cyclin-dependent kinase 2 in complex with a competitive inhibitor.

Molecular Docking Simulations with ArgusLab

Molecular docking is the major computational technique employed in the early stages of computer-aided drug discovery. The availability of free software to carry out docking simulations of protein-ligand systems has allowed for an increasing number of studies using this technique. Among the available free docking programs, we discuss the use of ArgusLab ( http://www.arguslab.com/arguslab.com/ArgusLab.html ) for protein-ligand docking simulation. This easy-to-use computational tool makes use of a genetic algorithm as a search algorithm and a fast scoring function that allows users with minimal experience in the simulations of protein-ligand simulations to carry out docking simulations. In this chapter, we present a detailed tutorial to perform docking simulations using ArgusLab.

Homology Modeling of Protein Targets with MODELLER

Homology modeling is a computational approach to generate three-dimensional structures of protein targets when experimental data about similar proteins are available. Although experimental methods such as X-ray crystallography and nuclear magnetic resonance spectroscopy successfully solved the structures of nearly 150,000 macromolecules, there is still a gap in our structural knowledge. We can fulfill this gap with computational methodologies. Our goal in this chapter is to explain how to perform homology modeling of protein targets for drug development. We choose as a homology modeling tool the program MODELLER. To illustrate its use, we describe how to model the structure of human cyclin-dependent kinase 3 using MODELLER. We explain the modeling procedure of CDK3 apoenzyme and the structure of this enzyme in complex with roscovitine.

Anti-proliferative and anti-inflammatory effects of 3β,6β,16β-Trihydroxylup-20(29)-ene on cutaneous inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

3β,6β,16β-Trihydroxylup-20(29)-ene (TTHL) is a triterpene isolated from the flowers of Combretum leprosum, a plant used in folk medicine in the north of Brazil for the treatment of skin disorders.

AIM OF THE STUDY

In the present study, TTHL was evaluated as a potential topical anti-inflammatory and anti-proliferative agent through in vivo and in vitro models.

MATERIAL AND METHODS

Anti-inflammmatory and anti-proliferative effects of TTHL were assessed using Swiss mice in acute and chronic models of skin inflammation induced by 12-O-tetradecanoylphorbol-acetate (TPA) application. Anti-proliferative activity was proved through in vitro experiments with the HaCaT human keratinocyte cell line.

RESULTS

Treatment with TTHL inhibited inflammatory parameters such as oedema formation and cellular infiltration in acute and chronic models. In the chronic model, TTHL also inhibited epidermal hyperproliferation, as evidenced by reduction of epidermis thickness and proliferating cell nuclear antigen expression. The anti-proliferative effect was confirmed by the capability of TTHL in reducing the proliferation and inducing cell apoptosis of HaCaT cells. Suggesting a mechanism of action, TTHL showed activation of corticosteroid receptors, but without the induction of corticosteroid-related cutaneous side effects.

CONCLUSION

Our results demonstrate consistent anti-inflammatory and anti-proliferative activity and assign TTHL as a valuable tool in the development of a new treatment for skin inflammatory and proliferative diseases, such as psoriasis.

Setúbal S, Pontes AS, Nery NM, de Castro OB, Fernandes CFC, Honda ER, Zanchi FB, Calderon LA, Stábeli RG, Soares AM, Silva-Jardim I, Facundo VA, Zuliani JP. The effect of 3β, 6β, 16β-trihydroxylup-20(29)-ene lupane compound isolated from Combretum leprosum Mart. on peripheral blood mononuclear cells

BACKGROUND

The Combretum leprosum Mart. plant, popularly known as mofumbo, is used in folk medicine for inflammation, pain and treatment of wounds. From this species, it is possible to isolate three triterpenes: (3β, 6β, 16β-trihydroxylup-20(29)-ene) called lupane, arjunolic acid and molic acid. In this study, through preclinical tests, the effect of lupane was evaluated on the cytotoxicity and on the ability to activate cellular function by the production of TNF-α, an inflammatory cytokine, and IL-10, an immuno regulatory cytokine was assessed. The effect of lupane on the enzymes topoisomerase I and II was also evaluated.

METHODS

For this reason, peripheral blood mononuclear cells (PBMCs) were obtained and cytotoxicity was assessed by the MTT method at three different times (1, 15 and 24 h), and different concentrations of lupane (0.3, 0.7, 1.5, 6, 3 and 12 μg/mL). The cell function was assessed by the production of TNF-α and IL-10 by PBMCs quantified by specific enzyme immunoassay (ELISA). The activity of topoisomerases was assayed by in vitro biological assays and in silico molecular docking.

RESULTS

The results obtained showed that lupane at concentrations below 1.5 μg/mL was not toxic to the cells. Moreover, lupane was not able to activate cellular functions and did not alter the production of IL-10 and TNF-α. Furthermore, the data showed that lupane has neither interfered in the action of topoisomerase I nor in the action of topoisomerase II.

CONCLUSION

Based on preclinical results obtained in this study, we highlight that the compound studied (lupane) has moderate cytotoxicity, does not induce the production of TNF-α and IL-10, and does not act on human topoisomerases. Based on the results of this study and taking into consideration the reports about the anti-inflammatory and leishmanicidal activity of 3β, 6β, 16β-trihydroxylup-20(29)-ene, we suggest that this compound may serve as a biotechnological tool for the treatment of leishmaniasis in the future.