Anti-Leishmania effect of icetexanes from Salvia procurrens.

BACKGROUND AND PURPOSE: Leishmaniasis is a globally prevalent vector-borne disease caused by parasites of the genus Leishmania. The available chemotherapeutic drugs present problems related to efficacy, emergence of parasite resistance, toxicity and high cost, justifying the search for new drugs. Several classes of compounds have demonstrated activity against Leishmania, including icetexane-type diterpenes, previously isolated from Salvia and other Lamiaceae genera. Thus, in this study, compounds of Salvia procurrens were investigated for their leishmanicidal and immunomodulatory activities. METHODS: The exudate of S. procurrens was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by column and centrifugal planar chromatography over silica gel. The effects on L. amazonensis growth, survival, membrane integrity, reactive oxygen species (ROS) generation, mitochondrial membrane potential and cytotoxicity of the compounds towards human erythrocytes, peripheral blood mononuclear cells and macrophages were evaluated. The effects on intracellular amastigote forms, nitric oxide (NO) and TNF-α production were also investigated. RESULTS: The exudate from the leaves afforded the novel icetexane 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2), fruticulin A (3) and demethylfruticulin A (4). The compounds (1-4) were tested against promastigotes of L. amazonensis and showed an effective inhibition of the parasite survival (IC50 = 4.08-16.26 µM). In addition, they also induced mitochondrial ROS production, plasma membrane permeability and mitochondrial dysfunction in treated parasites, and presented low cytotoxicity against macrophages. Furthermore, all diterpenes tested reduced the number of parasites inside macrophages, by mechanisms involving TNF-α, NO and ROS. CONCLUSION: The results suggest the potential of 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2),fruticulin A (3) and demethylfruticulin A (4) as candidates for use in further studies on the design of anti-leishmanial drugs.

Topical Nanoemulsions as Delivery Systems for Green Extracts of Pterocaulon balansae Aiming at the Treatment of Sporotrichosis.

Coumarins are benzopyrones found in several plant genera, including Pterocaulon (Asteraceae). These compounds represent an important source of new treatments, especially as antimicrobial and antifungal agents. In this study, two coumarin-rich extracts from Pterocaulon balansae using green technologies were obtained through aqueous maceration (AE) and supercritical fluid extraction (SFE). Such extracts were incorporated into nanoemulsions (NAE and NSFE) composed of a medium-chain triglyceride oil core stabilized by phospholipids. The nanoemulsions exhibited droplet sizes between 127 and 162 nm, pH above 5.0, and viscosity of approximately 1.0 cP, properties compatible with the topical route. The coumarins permeation/retention from formulations through ear porcine skin using Franz-type diffusion cells were evaluated. Whatever the extract, coumarins were distributed in skin layers, especially in the dermis in both intact and impaired (tape stripping) skin. In addition, a significant increase in coumarins that reached up to the receptor fluid was observed for impaired skin, with increases of approximately threefold for NAE and fourfold for NSFE. Finally, antifungal activity of nanoemulsions was evaluated according to minimum inhibitory concentrations, and the values were 250 µg/mL for all strains tested. The overall results demonstrated the feasibility of incorporating P. balansae extracts into nanoemulsions and showed a potential alternative for the treatment of sporotrichosis.

Antiprotozoal potential of Vismia species (Hypericaceae), medicinal plants used to fight cutaneous leishmaniasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Species of Vismia (Hypericaceae), known in Brazil as "lacre", are commonly used in traditional Amazonian medicine for the treatment of skin lesions, including those caused by Leishmania infection. AIM OF THE STUDY: Hexane extracts from the leaves of Vismia cayennensis, V. gracilis, V. sandwithii and V. guianensis, as well as from the fruits of the latter, in addition to the anthraquinones vismiaquinone, physcion and chrysophanol isolated from these species were explored for their anti-promastigote and anti-amastigote activity on Leishmania amazonensis. MATERIALS AND METHODS: Extracts were prepared by static maceration with n-hexane. The compounds, isolated by chromatographic techniques, were identified by spectroscopic methods (1H and 13C NMR). Promastigotes of L.amazonensis were incubated with hexane extracts (1-50 µg/mL) or anthraquinones (1-50 µM) and the parasite survival analyzed. The action of compounds on reactive oxygen species (ROS) production, mitochondrial membrane potential, and membrane integrity of promastigotes were evaluated by flow cytometer, and the cytotoxicity on mammalian cells using MTT assay. Furthermore, the activity of compounds against amastigotes and nitric oxide production were also investigated. RESULTS: Vismiaquinone and physcion were obtained from the leaves of V. guianensis. Physcion, as well as chrysophanol, were isolated from V. sandwithii. Vismia cayennensis and V. gracilis also showed vismiaquinone, compound detected in lower quantity in the fruits of V. guianensis. All extracts were active against the parasite, corroborating the popular use. The greatest activity against promastigotes was achieved with V. guianensis extract (IC50 4.3 µg/mL), precisely the most used Vismia species for treating cutaneous leishmaniasis. Vismiaquinone and physcion exhibited relevant activity with IC50 12.6 and 2.6 µM, respectively. Moreover, all extracts and anthraquinones tested induced ROS production, mitochondrial dysfunction, membrane disruption and were able to kill intracellular amastigote forms, being worthy of further in vivo studies as potential antileishmanial drugs. CONCLUSIONS: The overall data achieved in the current investigation scientifically validate the traditional use of Vismia species, mainly V. guianensis, as an anti-Leishmania agent. Furthermore, the promising results presented here indicate species of Vismia as potentially useful resources of Brazilian flora for the discovery of therapeutic solutions for neglected diseases.

Iridoids as a Potential Hepatoprotective Class: A Review.

BACKGROUND: Liver disease rates are gradually increasing over the years, becoming a severe public health problem. The indiscriminate use of drugs associated with a rich fat diet, high consumption of alcoholic beverages, and exposure to viral infections and lipid peroxidative products are considered the chief factors for developing hepatic disorders. Owing to the absence of reliable hepatoprotective drugs in the therapeutic arsenal, since they present a high incidence of adverse reactions and/or lack of efficacy in some cases, liver diseases are widely treated with medicinal plants. Among them are the plants producing iridoids, which are believed to be good remedies for liver disease due to their bitter taste. The hepatoprotective effect of iridoids and extracts, rich in these compounds, has been demonstrated, both in vitro and in vivo. OBJECTIVE: This review aims to scrutinize the available literature related to the hepatoprotective activity of iridoids. METHODS: The information was obtained from scientific databases (Science Direct, PubMed, Web of Science, Scopus, ACS Publications, Wiley Online Library) until December, 2021. RESULTS AND CONCLUSION: A total of 63 hepatoprotective iridoids were found, including aucubin, catalpol and picroliv, a mixture of two iridoids. They are the target of a high number of studies, which revealed their protective action against different hepatotoxic agents and detailed action mechanisms.

Antimicrobial activity of dimeric acylphloroglucinols isolated from southern Brazilian Hypericum species against to resistant bacterial.

The hexanic extracts of Hypericum austrobrasiliense, H. caprifoliatum, H. denudatum, H. pedersenii and H. polyanthemum, and three isolated dimeric acylphloroglucinols (uliginosin B, japonicine A and hyperbrasilol B) were assayed for their antimicrobial activity against some Gram-positive and Gram-negative bacteria (including resistant strains). These extracts were assayed using the disc diffusion test, and the results indicated that the tested species did non exhibit activity on the Gram-negative strains. Subsequently, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were measured using the broth dilution technique adopted to macrodillution. The most susceptible strains were the MRSA and the S. aureus MLSb. Regarding these pathogens, the better MIC values were obtained with the extracts from H. austrobrasiliense, H. caprifoliatum and H. pedersenii. The acylphloroglucinols uliginosin B and hyperbrasilol B presented the lowest MIC values against Enterococcus faecalis, Staphylococcus aureus, MRSA and S. aureus MLSb resistance.

Revisiting nature: a review of iridoids as a potential antileishmanial class.

Leishmaniasis still stands as one of the most prevalent neglected tropical diseases in the least developed and emerging countries. The recommended therapeutic arsenal to treat leishmaniasis is characterized by several shortcomings, and resistance has already been reported. Hence, this dramatic background highlights the pressing need to develop novel, affordable, and safe antileishmanial drugs. Multiple classes of natural compounds have been reported to possess antileishmanial activity. Among these classes, iridoids stand out as a special type of monoterpenoids with diverse biological properties-including their antileishmanial potential. This review aims to discuss the available literature between 1991 and 2020 related to the antileishmanial activity of the iridoid class. Throughout the past decades, various investigations attributed antileishmanial action to assorted iridoid types, including inhibitory potential towards validated drug targets and immunomodulatory activity. The latter deserves special attention due to the ability of some iridoids to improve the host's immune response against parasites. It opens the possibility of iridoids become adjuncts in leishmaniasis treatments by improving the efficacy of currently employed drugs. Furthermore, the present study intends to provide a convenient visual representation of which iridoids and Leishmania spp. species have been most investigated as a guide for further researches.

The ethnobotanical relevance of the tribe Symphonieae (Clusiaceae) around the world.

ETHNOPHARMACOLOGICAL RELEVANCE: The tribe Symphonieae (Clusiaceae) encompasses 48 species accommodated in seven genera (Lorostemon, Montrouziera, Moronobea, Pentadesma, Platonia, Symphonia and Thysanostemon). Parts of these plants, mainly the exudates and the seeds oil are useful for different purposes, especially for treating dermatological conditions. In addition to the role in the folk medicine, some species are of great economic and cultural importance for native people from different continents. AIM OF THE REVIEW: The goal of this review is to critically summarize the current knowledge on systematics, ethnobotanical, chemical and pharmacological aspects of species from the tribe Symphonieae, as well as to provide support for future taxonomic and phylogenetic studies on the Clusiaceae family. MATERIALS AND METHODS: The available information was gathered from many different databases (Web of Science, ScienceDirect, Scopus, Pubmed, ChemSpider, SciFinder, ACS Publications, Wiley Online Library, Useful Tropical Plants Database, Google Scholar). Additional data from books, theses and dissertations were also included in this review. RESULTS: Chemical studies of Symphonieae have demonstrated that the genera are a source of benzophenones, xanthones and biflavonoids. Components as sesquiterpenoids, triterpenoids, flavonoids, free fatty acids, among others, have also been reported. Extracts and compounds isolated from a variety of species have been exhibiting antimicrobial, cytotoxic and antiprotozoal activities, corroborating part of their medicinal uses. In addition, certain species produce edible fruits and a kind of "butter" with economic importance. All species produce exudate, which often has great relevance in the daily lives of local people. CONCLUSION: Several species of Symphonieae have potential therapeutic applications and some of them have been investigated to scientifically validate their popular uses. In addition, a number of species have proved to be a rich source of promising pharmacologically active compounds. Finally, the value of fruits, exudate and butter, for instance, should serve as a stimulus for the sustainable development of products that aim to take advantage of these natural resources.

Optimization of Coumarins Extraction from Pterocaulon balansae by Box-Behnken Design and Anti-Trichomonas vaginalis Activity.

Trichomonas vaginalis causes trichomoniasis, a nonviral sexually transmitted infection with a high prevalence worldwide. Oral metronidazole is the drug of choice for the treatment of this disease, although high levels of T. vaginalis resistance to this agent are well documented in the literature. This study describes the anti-T. vaginalis activity of an optimized coumarin-rich extract from Pterocaulon balansae. Optimization was performed to maximize extraction of total coumarins by means of a 3-level Box-Behnken design, evaluating the effect of three factors: extraction time, plant : solvent ratio, and ethanol concentration. Optimum conditions were found to be 5 h extraction time and a plant : solvent ratio of 1% (w/v) and 60% (v/v) ethanol, which resulted in approximately 30 mg of total coumarins/g of dry plant. The coumarin-enriched extract exhibited a minimum inhibitory concentration of 30 µg/mL and an IC50 of 3.2 µg/mL against T. vaginalis, a low cytotoxicity, and a high selectivity index (18 for vaginal epithelial cells and 16 for erythrocytes). The coumarins permeation/retention profile through porcine vaginal mucosa was evaluated in Franz-type diffusion cells. After 8 h of kinetics, coumarins were detected in the tissue (4.93 µg/g) without detecting them in the receptor compartment. A significant increase of coumarins in the mucosa layers (8.18 µg/g) and receptor compartment (0.26 µg/g) was detected when a T. vaginalis suspension (2 × 105 trophozoites/mL) was previously added onto the mucosa. No alterations were visualized in the stratified squamous non-keratinized epithelium of the porcine vaginal mucosa after contact with the extract. Overall, these results suggest that the P. balansae coumarin-rich extract may have potential as a treatment for trichomoniasis.

Phloroglucinol derivatives from Hypericum species induce in vitro proliferation of cells involved in the wound healing process.

The genus Hypericum (Hypericaceae) is a recognized source of therapeutic agents, being some species widely used due to their wound healing properties. In a previous study, south Brazilian species H. caprifoliatum, H. carinatum, H. connatum, H. myrianthum and H. polyanthemum demonstrated potential to induce proliferation of keratinocytes. In the present study, the effect of phloroglucinol derivatives isolated from Hypericum on cell proliferation of human keratinocytes, fibroblasts and stem cells was investigated. The best results, determined by the MTT assay, were achieved with cariphenone B at concentrations of 0.01 and 0.1 µM (122.3% and 114%, respectively) on HaCaT cells. Uliginosin B was able to induce the proliferation of mesenchymal stem cells (129% at 10 µM) and MRC5 fibroblasts (152.5% at 5 µM). These findings confirm the capacity of phloroglucinol derivatives to induce the in vitro cellular proliferation and reinforce the importance of Hypericum species as potential sources of wound healing compounds.

In vitro protective effect of topical nanoemulgels containing Brazilian red propolis benzophenones against UV-induced skin damage.

The overexposure of the skin to ultraviolet (UV) radiation may lead to oxidative stress, resulting in severe damage. The prevention of skin injuries through the topical application of natural compounds rich in antioxidants, such as propolis extracts, has shown promising results. In Brazil, the "red propolis" extract has stood out due to its complex constitution, based mainly on polyprenylated benzophenones (BZP). However, although the use of red propolis extracts has been shown to be encouraging, their addition in topical formulations is limited by the low solubility of BZP. For this reason, this study aimed to develop topical nanoemulgels containing Brazilian red propolis (BRP) extract to increase the potential of topical application, and the evaluation of skin protection against UVA/UVB radiation damage by means of protein carbonylation, protein thiol content and TBARS assays. The nanoemulgels were obtained by adding gelling polymer to nanoemulsions that were previously prepared by spontaneous emulsification. In this sense, a nanoemulgel containing BRP extract-loaded nanoemulsions (H-NE) and a nanoemulgel containing BRP extract-loaded nanoemulsions with DOTAP (H-NE/DT) were prepared. The physicochemical characterization of nanoemulgels showed monodisperse populations of 200-300 nm. The H-NE zeta potential was -38 mV, while that of H-NE/DT was +36 mV. BZP content in the formulations was around 0.86 mg g-1. These parameters remained stable for 90 days under cold storage. H/NE and H-NE/DT presented a non-Newtonian pseudoplastic rheological behavior. Permeation/retention studies, through porcine ear skin, showed the highest BZP retention (18.11 µg cm-2 after 8 h) for H-NE/DT, which also demonstrated, in an in vitro study, the highest ability to protect skin against oxidative damage after UVA/UVB radiation exposure. The results concerning the antioxidant activity revealed that formulations containing the BRP n-hexane extract were the most promising in combating oxidative stress, probable due to the presence of polyprenylated BZP. Altogether, the outcomes of this study suggest that nanoemulgels have suitable characteristics for topical application, and may be an alternative for the prevention of oxidative skin damage caused by UVA/UVB radiation.

Hydrogels containing soybean isoflavone aglycones-rich fraction-loaded nanoemulsions for wound healing treatment - in vitro and in vivo studies.

Soybean isoflavone aglycones have been investigated as potential wound healing compounds for topical application. The aim of this study was to evaluate the wound healing properties of a soybean isoflavone aglycones-rich fraction (IAF) when incorporated into lipid nanoemulsions dispersed in acrylic-acid hydrogels. Formulations exhibited a mean droplet size in the sub 200 nm range, negative ζ-potential (-60 mV), and displayed non-Newtonian pseudoplastic behavior. The addition of a gelling agent decreased the IAF release from formulations and improved the retention of these compounds in intact porcine ear skin when compared with a control propylene glycol solution. No IAF were detected in receptor fluid of Franz-type diffusion cells. However, increasing amounts of IAF were noticed in both skin layers and the receptor fluid when the tissue was partially injured (tape stripping), or when the epidermis was completely removed. In vitro studies showed that IAF elicits an increased proliferation and migration of keratinocytes (HaCaT cell line). Subsequently, the healing effect of the formulations was evaluated in a model of dorsal wounds in rats, by assessing the size of the lesions, histology, inflammatory markers, and antioxidant activity. Overall findings demonstrated the potential of IAF-loaded formulations to promote wound healing by increasing angiogenesis by ∼200 %, reducing the lipid oxidation (TBARS) by ∼52 % and the inflammation (TNFα) by ∼35 %, while increasing re-epithelialization by ∼500 %, visualized by the epithelium thickness.

A Plumieridine-Rich Fraction From Allamanda polyantha Inhibits Chitinolytic Activity and Exhibits Antifungal Properties Against Cryptococcus neoformans.

Cryptococcosis is a fungal infection caused mainly by the pathogenic yeasts Cryptococcus neoformans and Cryptococcus gattii. The infection initiates with the inhalation of propagules that are then deposited in the lungs. If not properly treated, cryptococci cells can disseminate and reach the central nervous system. The current recommended treatment for cryptococcosis employs a three-stage regimen, with the administration of amphotericin B, flucytosine and fluconazole. Although effective, these drugs are often unavailable worldwide, can lead to resistance development, and may display toxic effects on the patients. Thus, new drugs for cryptococcosis treatment are needed. Recently, an iridoid named plumieridine was found in Allamanda polyantha seed extract; it exhibited antifungal activity against C. neoformans with a MIC of 250 µg/mL. To address the mode of action of plumieridine, several in silico and in vitro experiments were performed. Through a ligand-based a virtual screening approach, chitinases were identified as potential targets. Confirmatory in vitro assays showed that C. neoformans cell-free supernatant incubated with plumieridine displayed reduced chitinase activity, while chitinolytic activity was not inhibited in the insoluble cell fraction. Additionally, confocal microscopy revealed changes in the distribution of chitooligomers in the cryptococcal cell wall, from a polarized to a diffuse cell pattern state. Remarkably, further assays have shown that plumieridine can also inhibit the chitinolytic activity from the supernatant and cell-free extracts of bacteria, insect and mouse-derived macrophage cells (J774.A1). Together, our results suggest that plumieridine can be a broad-spectrum chitinase inhibitor.

Natural and synthetic coumarins as antileishmanial agents: A review.

The neglected tropical disease leishmaniasis is still a major public health problem that affects millions of people worldwide. Related to poor-living conditions, this vector-borne disease presents multiple clinical manifestations - from asymptomatic to systemic conditions. The protozoans of the genus Leishmania are the etiologic agents transmitted through the bite of sandflies, the main vectors. Current pharmacological interventions are outdated and present several drawbacks, thus the search for new antileishmanial compounds is imperative. Medicinal chemists have been continuously investigating for new alternatives to combat leishmaniasis, and coumarins play a pivotal role in this search. Various biological properties have been described owing to coumarin's structural versatility combined with its unique features, including antileishmanial activity. The aim of this review is to highlight the most relevant studies between 1997 and 2020 and provide a guide for the development of new antileishmanial coumarins. Naturally occurring and synthetically designed coumarins are comprised in this review, along with a structure-activity relationship to provide an insight for further development of coumarins with antileishmanial activity.

Hypericum species: An analysis on the patent technologies.

Hypericum (Hypericaceae) is a genus that comprises approximately 500 species around the world. The industrial relevance of these plants is based on the occurence of specialized metabolites that exhibit a range of pharmaceutical potential. Besides that, several species are relevant due to their ornamental value. Taking to account the vast market worth of products and processes involving Hypericum, the present study aims to provide a comprehensive overview of patents concerning this subject between 2007and 2017. For this purpose, a survey was performed in free databases (Espacenet®, PatentScope® and Google Patents®) using the keyword Hypericum in the patents title or title plus abstract. The documents were then organized by groups (medicinal and non-medicinal approaches), subgroups, type of applicants and countries. Espacenet® was chosen to data analysis, and a total of 174 patents were found. The majority of the applicants are from China and companies appear as the principal owners of patents. Several technologies are not intended for medicinal purposes, being mainly related to the development of new cultivars for ornamental uses. Concerning the medicinal approaches, the chief subject is related to extraction and incorporation into formulations. The main species cited in the documents is H. perforatum and the therapeutic use is for central nervous system diseases. In general, this study covers the patents published in recent years hoping to boost the scientists and companies that invest in Hypericum researches to visualize the state of art, opportunities and challenges for innovation in this area.

Leishmanicidal and antichemotactic activities of icetexanes from Salvia uliginosa Benth.

BACKGROUND: Several species of Salvia are used as medicinal plants around the world. Biological activities of isolated compounds have been described, being diterpenes frequently responsible for the effects. PURPOSE: Isolation of diterpenes from Salvia uliginosa Benth. and evaluation of the antichemotactic and leishmanicidal activities of the isolated compounds. STUDY DESIGN: To isolate diterpenes from S. uliginosa and evaluate their antichemotactic and leishmanicidal activities in vitro. METHODS: The exudate of S. uliginosa was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by repeated column chromatography over silica gel. The effects on L. amazonensis growth, survival, DNA degradation, ROS generation, as well as the antichemotactic activity and cytotoxicity of the compounds towards human erythrocytes and macrophages were evaluated. RESULTS: A novel icetexane diterpene, isoicetexone (IsoICT) along with the known diterpenes icetexone (ICT), and 7-acetoxy-6,7-dihydroicetexone were isolated from the dichloromethane surface exudate of S. uliginosa. The structures were elucidated using NMR and MS experiments, and by comparison with previously reported data. IsoICT and ICT at low concentrations caused completely inhibition of neutrophils migration in vitro. In addition, IsoICT and ICT showed high leishmanicidal activity against L. amazonensis, induced ROS production in parasites and presented low cytotoxicity against macrophages and human erythrocytes, and moderate to high selectivity index. CONCLUSION: These data indicated that IsoICT and ICT exhibit potent antichemotactic and leishmanicidal effects. Further studies are needed in order to evaluate the in vivo activities as well as the toxicity of the compounds.

Bioactive Dimeric Acylphloroglucinols from the Mexican Fern Elaphoglossum paleaceum.

Two new prenylated acylphloroglucinols, paleacenins A (1) and B (2), were isolated from the rhizome n-hexane and chloroform extracts of the fern Elaphoglossum paleaceum. Both compounds were found to possess the same geranylated filicinic acid moiety but have a different phloroglucinol ring substituent. Their structures were determined using 1H and 13C NMR spectroscopic, HRMS, and ECD analysis. The plant extracts and purified compounds were assayed for inhibition of monoamine oxidase (MAO) activity, and the n-hexane and chloroform extracts displayed 25.0% and 26.5% inhibition of MAO-A, respectively, as well as 42.5% and 23.7% inhibition of MAO-B, respectively. Compounds 1 and 2 exhibited IC50 values of 31.0 (1.3) µM for MAO-A and 4.7 (4.4) µM for MAO-B. Paleacenin A (1) showed a higher selective index (SI) toward MAO-B (SIMAO-B/MAO-A 0.1), and paleacenin B (2) exhibited selectivity to MAO-A (SIMAO-B/MAO-A, 3.5). The extracts showed cytotoxicity against a panel of prostate, cervix, breast, and colon cancer cell lines (IC50 values between 1.7 and 10.6 µg/mL); the pure compounds were more active against the prostate, cervix, and colon cancer cell lines. Paleacenins A (1) and B (2), with IC50 values of 46 and 41 µM, respectively, inhibited nitric oxide production by the RAW264.7 murine macrophage model.

In vitro and in silico Activity of Iridoids Against Leishmania amazonensis.

BACKGROUND: Leishmaniasis reaches millions of people around the world. The control of the disease is difficult due to the restricted access to the diagnosis and medication, and low adherence to the treatment. Thus, more efficient drugs are needed and natural products are good alternatives. Iridoids, natural products with reported leishmanicidal activity, can be exploited for the development of anti- Leishmania drugs. The aim of this study was to isolate and to investigate the in vitro activity of iridoids against Leishmania amazonensis and to compare the activity in silico of these compounds with those reported as active against this parasite. METHODS: Iridoids were isolated by chromatographic methods. The in vitro activity of asperuloside (1) and geniposide (2) from Escalonia bifida, galiridoside (3) from Angelonia integerrima and theveridoside (4) and ipolamiide (5) from Amphilophium crucigerum was investigated against promastigote forms of Leishmania amazonensis. Molecular modeling studies of 1-5 and iridoids cited as active against Leishmania spp. were performed. RESULTS: Compounds 1-5 (5-100 µM) did not inhibit the parasite survival. Physicochemical parameters predicted for 1-5 did not show differences compared to those described in literature. The SAR and the pharmacophoric model confirmed the importance of maintaining the cyclopentane[C]pyran ring of the iridoid, of oxygen-linked substituents at the C1 and C6 positions and of bulky substituents attached to the iridoid ring to present leishmanicidal activity. CONCLUSION: The results obtained in this study indicate that iridoids are a promising group of secondary metabolites and should be further investigated in the search for new anti-Leishmania drugs.

Oral Acute and Repeated-Doses Toxicity Study of Valepotriates from Valeriana glechomifolia (Meyer) in Mice.

BACKGROUND: Species of Valeriana show sedative, hypnotic, anxiolytic, antidepressant and anti-inflammatory properties, which are associated with valepotriates. However, data about toxicity and safety of these compounds are still limited. The aim of this study was to investigate the toxicity of a valepotriate-enriched fraction (VAL) from Valeriana glechomifolia Meyer based on the Organization for Economic Cooperation and Development (OECD) guidelines 423 and 407. METHODS: In the acute study, CF1 mice were treated with a single dose of VAL (2000 mg/kg, p.o.) and observed for 14 days. In the repeated dose study, CF1 mice received single daily doses of VAL (30, 150 or 300 mg/kg, p.o.) or vehicle for 28 days. These doses were chosen based on previous results by our group and according to Guideline 407- OECD. RESULTS: The acute study allowed to classify VAL in the hazard category 5. The repeat-dose study has shown that VAL 300 mg/kg delayed weight gain and reduced food consumption in the first week, probably due to transient sedative effects. The other doses had no effect on animals' ponderal evolution. At the end of the treatment, all groups had equal body weight and food consumption. None of the doses altered any behavioral, urinary, biochemical, hematological, anatomic or histological parameters. CONCLUSION: A valepotriate-enriched fraction from Valeriana glechomifolia presents relatively low oral acute toxicity and does not induce evident toxicity after oral repeated treatment (at least up to 300 mg/kg) in mice.

Hypericum polyanthemum cyclohexane extract potentiates behavioral effects and neurodegeneration induced by nigral infusions of 6-hydroxydopamine in rats.

INTRODUCTION: Parkinson's Disease (PD) is a progressive neurodegenerative disorder, hallmark of which is loss of nigral dopaminergic neurons. Since a Hypericum polyanthemum extract inhibits monoamine reuptake and some of its constituents present cytotoxic properties, the aim of this study was to evaluate the effect of this extract in an animal PD model. METHODS: Adult Wistar rats (110 days old) received 6-hydroxydopamine (6-OHDA) infusions into the right medial forebrain bundle. A cyclohexane extract from aerial parts of H. polyanthemum (POL; 90 mg/kg/administration; gavage) was administered in three different regimens. In Regimens 1 and 2, rats received 3 administrations of POL starting 4 or 24 h after 6-OHDA infusion, respectively. In Regimen 3, these administrations were carried out 1 day before any evaluation of ipsilateral rotational activity induced by methylphenidate (MP, 20 mg/kg, i.p.). MP was administered 10, 45, and 85 days after 6-OHDA infusion in all groups. Nigral tyrosine hydroxylase (TH) immunocontent was evaluated 120 days after 6-OHDA infusion in animals submitted to Regimen 2 only. The effect of POL on apomorphine-induced climbing behavior in non-lesioned adult CF1 mice (60 days old) treated with POL was also evaluated. RESULTS: Regimen 2 increased MP-induced rotational activity and decreased nigral TH levels in 6-OHDA-lesioned rats. Rotational activity was not altered in regimens 1 and 3. In addition, no change in climbing behavior was observed in non-lesioned mice. CONCLUSION: Together, these results indicate that, in 6-OHDA-lesioned rats, a cyclohexane H. polyanthemum extract potentiates neurotoxicity and MP-induced motor asymmetry depending on the time of administration. In the short term, it seems to not act directly on mice dopaminergic receptors.

Skin Permeation and Oxidative Protection Effect of Soybean Isoflavones from Topical Nanoemulsions-a Comparative Study of Extracts and Pure Compounds.

Soybean isoflavone-rich extracts have been considered as promising skin antiaging products due to their antioxidant activity. This study investigates the effect of soybean isoflavone forms on porcine ear skin permeation/retention from topical nanoemulsions and their potential in protecting skin against oxidative damage caused by UVA/UVB light. Soybean non-hydrolyzed (SNHE) and hydrolyzed (SHE) extracts, mainly composed of genistin and genistein, were produced. Nanoemulsions containing SNHE (NESNHE) and SHE (NESHE) were prepared by spontaneous emulsification procedure and yielded monodispersed nanoemulsions. A delay of isoflavone release was observed after extracts incorporation into nanoemulsions when compared to a propyleneglycol dispersion of pure compounds. An increase of isoflavone skin retention from nanoemulsions was also achieved. However, from extracts, a higher amount of genistin (NESNHE) and a lower amount of genistein (NESHE) were detected in the skin in comparison to pure isoflavones. Finally, the protection of porcine ear skin by formulations against UVA/UVB oxidative stress was evaluated. Extract-loaded nanoemulsions offered better skin protection than pure isoflavones. Skin lipids were similarly protected by NESHE and NESNHE, whereas skin proteins were more protected by NESNHE. Overall, nanoemulsions containing isoflavone-rich soybean extracts may be considered a better topical formulation aiming skin protection from UVA/UVB oxidative damage.