Cytotoxic, acute oral toxicity, genotoxic and mutagenic assessment of the essential oil from fresh leaves of Croton argyrophyllus (Kunth.).

ETHNOPHARMACOLOGICAL RELEVANCE: Croton argyrophyllus Kunth., commonly known as "marmeleiro" or "cassetinga," is widely distributed in the Brazilian Northeast region. Its leaves and flowers are used in traditional medicine as tranquilizers to treat flu and headaches. AIM OF THE STUDY: This study was conducted to determine the chemical composition and toxicological safety of essential oil from C. argyrophyllus leaves using in vitro and in vivo models. MATERIALS AND METHODS: The chemical composition of the essential oil was determined using a gas chromatograph coupled to a mass spectrometer. Cytotoxicity was tested in the HeLa, HT-29, and MCF-7 cell lines derived from human cells (Homo sapiens) and Vero cell lines derived from monkeys (Cercopithecus aethiops) using the MTT method. Acute toxicity, genotoxicity. Mutagenicity tests were performed in Swiss mice (Mus musculus), which were administered essential oil orally in a single dose of 2000 mg/kg by gavage. RESULTS: The main components of the essential oil were p-mentha-2-en-1-ol, α-terpineol, ß-caryophyllene, and ß-elemene. The essential oil exhibited more than 90% cytotoxicity in all cell lines tested. No deaths or behavioral, hematological, or biochemical changes were observed in mice, revealing no acute toxicity. In genotoxic and mutagenic analyses, there was no increase in micronuclei in polychromatic erythrocytes or in the damage and index in the comet assay. CONCLUSIONS: The essential oil was cytotoxic towards the tested cell lines but did not exert toxic effects or promote DNA damage when administered orally at a single dose of 2000 mg/kg in mice.

A novel insight on SARS-CoV-2 S-derived fragments in the control of the host immunity.

Despite all efforts to combat the pandemic of COVID-19, we are still living with high numbers of infected persons, an overburdened health care system, and the lack of an effective and definitive treatment. Understanding the pathophysiology of the disease is crucial for the development of new technologies and therapies for the best clinical management of patients. Since the manipulation of the whole virus requires a structure with an adequate level of biosafety, the development of alternative technologies, such as the synthesis of peptides from viral proteins, is a possible solution to circumvent this problem. In addition, the use and validation of animal models is of extreme importance to screen new drugs and to compress the organism's response to the disease. Peptides derived from recombinant S protein from SARS-CoV-2 were synthesized and validated by in silico, in vitro and in vivo methodologies. Macrophages and neutrophils were challenged with the peptides and the production of inflammatory mediators and activation profile were evaluated. These peptides were also inoculated into the swim bladder of transgenic zebrafish larvae at 6 days post fertilization (dpf) to mimic the inflammatory process triggered by the virus, which was evaluated by confocal microscopy. In addition, toxicity and oxidative stress assays were also developed. In silico and molecular dynamics assays revealed that the peptides bind to the ACE2 receptor stably and interact with receptors and adhesion molecules, such as MHC and TCR, from humans and zebrafish. Macrophages stimulated with one of the peptides showed increased production of NO, TNF-α and CXCL2. Inoculation of the peptides in zebrafish larvae triggered an inflammatory process marked by macrophage recruitment and increased mortality, as well as histopathological changes, similarly to what is observed in individuals with COVID-19. The use of peptides is a valuable alternative for the study of host immune response in the context of COVID-19. The use of zebrafish as an animal model also proved to be appropriate and effective in evaluating the inflammatory process, comparable to humans.

Experimental Bothropsatrox Envenomation: Blood Plasma Proteome Effects after Local Tissue Damage and Perspectives on Thromboinflammation.

The clinical manifestations of Bothrops atrox envenoming involve local and systemic changes, among which edema requires substantial attention due to its ability to progress to compartmental syndromes and sometimes cause tissue loss and amputations. However, the impact of edema on the poisoned body's system has not been explored. Thus, the present study aimed to explore the systemic pathological and inflammatory events that are altered by intraplantar injection of B. atrox venom in a mouse model through hematologic, lipidic, and shotgun proteomics analysis. Plasma samples collected showed a greater abundance of proteins related to complement, coagulation, lipid system, platelet and neutrophil degranulation, and pathways related to cell death and ischemic tolerance. Interestingly, some proteins, in particular, Prdx2 (peroxiredoxin 2), Hba (hemoglobin subunit alpha), and F9 (Factor IX), increased according to the amount of venom injected. Our findings support that B. atrox venom activates multiple blood systems that are involved in thromboinflammation, an observation that may have implications for the pathophysiological progression of envenomations. Furthermore, we report for the first time a potential role of Prdx2, Hba, and F9 as potential markers of the severity of edema/inflammation in mice caused by B. atrox.

Blood plasma proteome alteration after local tissue damage induced by Bothrops erythromelas snake venom in mice.

Snakes of the genus Bothrops are responsible the most snakebites in the Brazil, causing a diverse and complex pathophysiological condition. Bothrops erythromelas is the main specie of medical relevance found in the Caatinga from the Brazilian Northeast region. The pathophysiological effects involving B. erythromelas snakebite as well as the organism reaction in response to this envenomation are not so explored. Thus, edema was induced in mice paws using 2.5 µg or 5.0 µg of B. erythromelas venom, and the percentage of edema was measured. Plasma was collected 30  minutes after the envenomation-induced in mice and analyzed by mass spectrometry. It was identified a total of 112 common plasma proteins differentially abundant among experimental groups, which are involved with the complement system and coagulation cascades, oxidative stress, neutrophil degranulation, platelets degranulation and inflammatory response. Apolipoprotein A1 (Apoa), serum amyloid protein A-4 (Saa4), adiponectin (Adipoq) showed up-regulated in mice plasma after injection of venom, while fibulin (Fbln1), factor XII (F12) and vitamin K-dependent protein Z (Proz) showed down-regulated. The results indicate a protein pattern of thrombo-inflammation to the B. erythromelas snakebite, evidencing potential biomarkers for monitoring this snakebite, new therapeutic targets and its correlations with the degree of envenomation once showed modulations in the abundance among the different groups according to the amount of venom injected into the mice.

Biological and Molecular Docking Evaluation of a Benzylisothiocyanate Semisynthetic Derivative From Moringa oleifera in a Pre-clinical Study of Temporomandibular Joint Pain.

Objective: Moringa oleifera possesses multiple biological effects and the 4-[(4'-O-acetyl-α-L- rhamnosyloxy) benzyl] isothiocyanate accounts for them. Based on the original isothiocyanate molecule we obtained a semisynthetic derivative, named 4-[(2',3',4'-O-triacetyl-α-L-rhamnosyloxy) N-benzyl] hydrazine carbothioamide (MC-H) which was safe and effective in a temporomandibular joint (TMJ) inflammatory hypernociception in rats. Therefore, considering that there is still a gap in the knowledge concerning the mechanisms of action through which the MC-H effects are mediated, this study aimed to investigate the involvement of the adhesion molecules (ICAM-1, CD55), the pathways heme oxygenase-1 (HO-1) and NO/cGMP/PKG/K+ ATP, and the central opioid receptors in the efficacy of the MC-H in a pre-clinical study of TMJ pain. Methods: Molecular docking studies were performed to test the binding performance of MC-H against the ten targets of interest (ICAM-1, CD55, HO-1, iNOS, soluble cGMP, cGMP-dependent protein kinase (PKG), K+ ATP channel, mu (µ), kappa (κ), and delta (δ) opioid receptors). In in vivo studies, male Wistar rats were treated with MC-H 1 µg/kg before TMJ formalin injection and nociception was evaluated. Periarticular tissues were removed to assess ICAM-1 and CD55 protein levels by Western blotting. To investigate the role of HO-1 and NO/cGMP/PKG/K+ ATP pathways, the inhibitors ZnPP-IX, aminoguanidine, ODQ, KT5823, or glibenclamide were used. To study the involvement of opioid receptors, rats were pre-treated (15 min) with an intrathecal injection of non-selective inhibitor naloxone or with CTOP, naltrindole, or norbinaltorphimine. Results: All interactions presented acceptable binding energy values (below -6.0 kcal/mol) which suggest MC-H might strongly bind to its molecular targets. MC-H reduced the protein levels of ICAM-1 and CD55 in periarticular tissues. ZnPP-IX, naloxone, CTOP, and naltrindole reversed the antinociceptive effect of MC-H. Conclusion: MC-H demonstrated antinociceptive and anti-inflammatory effects peripherally by the activation of the HO-1 pathway, as well as through inhibition of the protein levels of adhesion molecules, and centrally by µ and δ opioid receptors.

Toxicological impact of SARS-CoV-2 on the health of the neotropical fish, Poecilia reticulata.

There have been significant impacts of the current COVID-19 pandemic on society including high health and economic costs. However, little is known about the potential ecological risks of this virus despite its presence in freshwater systems. In this study, we aimed to evaluate the exposure of Poecilia reticulata juveniles to two peptides derived from Spike protein of SARS-CoV-2, which was synthesized in the laboratory (named PSPD-2002 and PSPD-2003). For this, the animals were exposed for 35 days to the peptides at a concentration of 40 µg/L and different toxicity biomarkers were assessed. Our data indicated that the peptides were able to induce anxiety-like behavior in the open field test and increased acetylcholinesterase (AChE) activity. The biometric evaluation also revealed that the animals exposed to the peptides displayed alterations in the pattern of growth/development. Furthermore, the increased activity of superoxide dismutase (SOD) and catalase (CAT) enzymes were accompanied by increased levels of malondialdehyde (MDA), reactive oxygen species (ROS) and hydrogen peroxide (H2O2), which suggests a redox imbalance induced by SARS-CoV-2 spike protein peptides. Moreover, molecular docking analysis suggested a strong interaction of the peptides with the enzymes AChE, SOD and CAT, allowing us to infer that the observed effects are related to the direct action of the peptides on the functionality of these enzymes. Consequently, our study provided evidence that the presence of SARS-CoV-2 viral particles in the freshwater ecosystems offer a health risk to fish and other aquatic organisms.

A fingerprint of plasma proteome alteration after local tissue damage induced by Bothrops leucurus snake venom in mice.

Bothrops spp. is responsible for about 70% of snakebites in Brazil, causing a diverse and complex pathophysiological condition. Bothrops leucurus is the main species of medical relevance found in the Atlantic coast in the Brazilian Northeast region. The pathophysiological effects involved B. leucurus snakebite as well as the organism's reaction in response to this envenoming, it has not been explored yet. Thus, edema was induced in mice paw using 1.2, 2.5, and 5.0 µg of B. leucurus venom, the percentage of edema was measured 30 min after injection and the blood plasma was collected and analyzed by shotgun proteomic strategy. We identified 80 common plasma proteins with differential abundance among the experimental groups and we can understand the early aspects of this snake envenomation, regardless of the suggestive severity of an ophidian accident. The results showed B. leucurus venom triggers a thromboinflammation scenario where family's proteins of the Serpins, Apolipoproteins, Complement factors and Component subunits, Cathepsins, Kinases, Oxidoreductases, Proteases inhibitors, Proteases, Collagens, Growth factors are related to inflammation, complement and coagulation systems, modulators platelets and neutrophils, lipid and retinoid metabolism, oxidative stress and tissue repair. Our findings set precedents for future studies in the area of early diagnosis and/or treatment of snakebites. SIGNIFICANCE: The physiopathological effects that the snake venoms can cause have been investigated through classical and reductionist tools, which allowed, so far, the identification of action mechanisms of individual components associated with specific tissue damage. The currently incomplete limitations of this knowledge must be expanded through new approaches, such as proteomics, which may represent a big leap in understanding the venom-modulated pathological process. The exploration of the complete protein set that suffer modifications by the simultaneous action of multiple toxins, provides a map of the establishment of physiopathological phenotypes, which favors the identification of multiple toxin targets, that may or may not act in synergy, as well as favoring the discovery of biomarkers and therapeutic targets for manifestations that are not neutralized by the antivenom.

Synthesis and potential vasorelaxant effect of a novel ruthenium-based nitro complex.

This study aimed to investigate the synthesis and potential vasodilator effect of a novel ruthenium complex, cis-[Ru(bpy)2(2-MIM)(NO2)]PF6 (bpy = 2,2'-bipyridine and 2-MIM = 2-methylimidazole) (FOR711A), containing an imidazole derivative via an in silico molecular docking model using ß1 H-NOX (Heme-nitric oxide/oxygen binding) domain proteins of reduced and oxidized soluble guanylate cyclase (sGC). In addition, pharmacokinetic properties in the human organism were predicted through computational simulations and the potential for acute irritation of FOR711A was also investigated in vitro using the hen's egg chorioallantoic membrane (HET-CAM). FOR711A interacted with sites of the ß1 H-NOX domain of reduced and oxidized sGC, demonstrating shorter bond distances to several residues and negative values of total energy. The predictive study revealed molar refractivity (RM): 127.65; Log Po/w = 1.29; topological polar surface area (TPSA): 86.26 Å2; molar mass (MM) = 541.55 g/mol; low solubility, high unsaturation index, high gastrointestinal absorption; toxicity class 4; failure to cross the blood-brain barrier and to react with cytochrome P450 (CYP) enzymes CYP1A2, CYP2C19, CYP2C9, CYP2D6 and CYP3A4. After the HET-CAM assay, the FOR711A complex was classified as non-irritant (N.I.) and its vasodilator effect was confirmed through greater evidence of blood vessels after the administration and ending of the observation period of 5 min. These results suggest that FOR711A presented a potential stimulator/activator effect of sGC via NO/sGC/cGMP. However, results indicate it needs a vehicle for oral administration.

Phosphodiesterase-5 inhibitor sildenafil attenuates kidney injury induced by Bothrops alternatus snake venom.

Acute kidney injury pathogenesis in envenoming by snakes is multifactorial and involves immunologic reactions, hemodynamic disturbances, and direct nephrotoxicity. Sildenafil (SFC), a phosphodiesterase 5 inhibitor, has been reported to protect against pathological kidney changes. OBJECTIVE: This study aimed to investigate the protective effect of sildenafil against Bothrops alternatus snake venom (BaV)-induced nephrotoxicity. METHODS: Kidneys from Wistar rats (n = 6, weighing 260-300 g) were isolated and divided into four groups: (1) perfused with a modified Krebs-Henseleit solution (MKHS) containing 6 g% of bovine serum albumin; (2) administered 3 µg/mL SFC; (3) perfused with 3 µg/mL BaV; and (4) administered SFC + BaV, both at 3 µg/mL. Subsequently, the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR), and percentage of electrolyte tubular sodium and chloride transport (%TNa+, %TCl-, respectively) were evaluated. The cyclic guanosine monophosphate (cGMP) levels were analyzed in the perfusate, and the kidneys were removed to perform oxidative stress and histopathological analyses. RESULTS: All renal parameters evaluated were reduced with BaV. In the SFC + BaV group, SFC restored PP to normal values and promoted a significant increase in %TNa+ and %TCl-. cGMP levels were increased in the SFC + BaV group. The oxidative stress biomarkers, malondialdehyde (MDA) and glutathione (GSH), were reduced by BaV. In the SFC + BaV group, a decrease in MDA without an increase in GSH was observed. These findings were confirmed by histological analysis, which showed improvement mainly in tubulis. CONCLUSION: Our data suggest the involvement of phosphodiesterase-5 and cGMP in BaV-induced nephrotoxicity since its effects were attenuated by the administration of SFC.

Environmental impacts of COVID-19 treatment: Toxicological evaluation of azithromycin and hydroxychloroquine in adult zebrafish.

One of the most impact issues in recent years refers to the COVID-19 pandemic, the consequences of which thousands of deaths recorded worldwide, are still inferior understood. Its impacts on the environment and aquatic biota constitute a fertile field of investigation. Thus, to predict the impact of the indiscriminate use of azithromycin (AZT) and hydroxychloroquine (HCQ) in this pandemic context, we aim to assess their toxicological risks when isolated or in combination, using zebrafish (Danio rerio) as a model system. In summary, we observed that 72 h of exposure to AZT and HCQ (alone or in binary combination, both at 2.5 µg/L) induced the reduction of total protein levels, accompanied by increased levels of thiobarbituric acid reactive substances, hydrogen peroxide, reactive oxygen species and nitrite, suggesting a REDOX imbalance and possible oxidative stress. Molecular docking analysis further supported this data by demonstrating a strong affinity of AZT and HCQ with their potential antioxidant targets (catalase and superoxide dismutase). In the protein-protein interaction network analysis, AZT showed a putative interaction with different cytochrome P450 molecules, while HCQ demonstrated interaction with caspase-3. The functional enrichment analysis also demonstrated diverse biological processes and molecular mechanisms related to the maintenance of REDOX homeostasis. Moreover, we also demonstrated an increase in the AChE activity followed by a reduction in the neuromasts of the head when zebrafish were exposed to the mixture AZT + HCQ. These data suggest a neurotoxic effect of the drugs. Altogether, our study demonstrated that short exposure to AZT, HCQ or their mixture induced physiological alterations in adult zebrafish. These effects can compromise the health of these animals, suggesting that the increase of AZT and HCQ due to COVID-19 pandemic can negatively impact freshwater ecosystems.

Can use of hydroxychloroquine and azithromycin as a treatment of COVID-19 affect aquatic wildlife? A study conducted with neotropical tadpole.

The impacts on human health and the economic and social disruption caused by the pandemic COVID-19 have been devastating. However, its environmental consequences are poorly understood. Thus, to assess whether COVID-19 therapy based on the use of azithromycin (AZT) and hydroxychloroquine (HCQ) during the pandemic affects wild aquatic life, we exposed (for 72 h) neotropical tadpoles of the species Physalaemus cuvieri to the water containing these drugs to 12.5 µg/L. We observed that the increase in superoxide dismutase and catalase in tadpoles exposed to AZT (alone or in combination with HCQ) was predominant to keep the production of NO, ROS, TBARS and H2O2 equitable between the experimental groups. In addition, the uptake of AZT and the strong interaction of AZT with acetylcholinesterase (AChE), predicted by the molecular docking analysis, were associated with the anticholinesterase effect observed in the groups exposed to the antibiotic. However, the unexpected increase in butyrylcholinesterase (BChE) in these same groups suggests its constitutive role in maintaining cholinergic homeostasis. Therefore, taken together, our data provide a pioneering evidence that the exposure of P. cuvieri tadpoles to AZT (alone or in combination with HCQ) in a predictably increased environmental concentration (12.5 µg/L) elicits a compensatory adaptive response that can have, in the short period of exposure, guaranteed the survival of the animals. However, the high energy cost for maintaining physiological homeostasis, can compromise the growth and development of animals and, therefore, in the medium-long term, have a general negative effect on the health of animals. Thus, it is possible that COVID-19 therapy, based on the use of AZT, affects wild aquatic life, which requires greater attention to the impacts that this drug may represent.

Epidemiology of accidents involving venomous animals in the State of Ceará, Brazil (2007-2019).

INTRODUCTION: Envenomation remains a neglected public health problem in most tropical countries. Epidemiological studies on accidents caused by venomous animals are scarce in the Northeast region of Brazil, mainly in the state of Ceará. The present study aimed to describe the epidemiological features of envenomation cases involving venomous animals in the State of Ceará, Northeastern Brazil, from 2007 to 2019. METHODS: The online Notifiable Diseases Information System was consulted for data on all envenomation cases involving venomous terrestrial animals. Data collected were evaluated for the number of accidents/year, number of accidents/zoological group, antivenom therapy, zone of occurrence, sex, age-group distribution, and deaths. RESULTS: A total of 54,980 cases were recorded, with the highest incidence being that of scorpion stings (67.2%), predominantly in women (52.4%; odds ratio=3.6; 95% confidence interval=3.5-3.8), equally affecting people aged 10-19 years and 40-59 years (21.4%), in the urban areas (odds ratio=10.3; 95% confidence interval=9.9-10.8), especially in the rainy months. Snakebites (16.7%) had an incidence of 8.1/100,000 inhabitants, but the highest case-fatality rates were observed in bee stings (1.3%) and spider bites (0.5%). Regarding therapeutic variables, a small percentage of people had access to serotherapy (5.3%). CONCLUSIONS: This study highlights the accidents caused by terrestrial venomous animals as a public health problem that must be monitored in Ceará. Thus, our findings suggest that preventive actions against scorpion and bee stings should be intensified during the months of higher incidence to improve public policies for patient care.

Bothrops pauloensis snake venom-derived Asp-49 and Lys-49 phospholipases A2 mediates acute kidney injury by oxidative stress and release of inflammatory cytokines.

The envenomation caused by the Bothrops pauloensis snake leads to severe local and systemic effects including acute kidney injury. In this study, we investigated the renal effects by phospholipases A2 (PLA2s), divided into two main subgroups, Asp-49 and Lys-49, isolated from the Bothrops pauloensis snake venom (BpV) in isolated rat kidney system. Both PLA2s (3 µg/mL), added alone to the perfusion system and analyzed for 120 min, had significant effects on isolated rat kidney. Asp-49 reduced Glomerular Filtration Rate (GFR) at 60, 90 and 120 min, and the percentage of total tubular sodium transport (%TNa+) and potassium transport (%TK+) at 120 min. Lys-49 increased Perfusion Pressure (PP) at 120 min and reduced GFR, %TNa+ and the percentage of total tubular chloride transport (%TCl-) at 60, 90 and 120 min. Cytokine release in the kidney tissues were increased with Asp-49 PLA2 (IL-10) and Lys-49 PLA2 (TNF-α, IL-1ß, IL-10). Both increased MPO activity. Asp-49 PLA2 decreased Glutathione (GSH) and increased nitrite levels, while Lys-49 PLA2 increased Malondialdehyde (MDA), GSH and nitrite levels. Histological analysis of the perfused kidneys revealed the presence of glomerular degeneration and atrophy, deposit of proteinaceous material in Bowman's space and intratubular with both PLA2s. These findings indicated that both PLA2s modified the functional parameters in an isolated perfused kidney model with increased oxidative stress and cytokine release. PLA2s are one of the components at high concentration in BpV and our results provide important knowledge about their involvement with the nephrotoxic mechanism.

Epidemiology of accidents involving venomous animals in the State of Ceará, Brazil (2007-2019)

Abstract INTRODUCTION: Envenomation remains a neglected public health problem in most tropical countries. Epidemiological studies on accidents caused by venomous animals are scarce in the Northeast region of Brazil, mainly in the state of Ceará. The present study aimed to describe the epidemiological features of envenomation cases involving venomous animals in the State of Ceará, Northeastern Brazil, from 2007 to 2019. METHODS: The online Notifiable Diseases Information System was consulted for data on all envenomation cases involving venomous terrestrial animals. Data collected were evaluated for the number of accidents/year, number of accidents/zoological group, antivenom therapy, zone of occurrence, sex, age-group distribution, and deaths. RESULTS: A total of 54,980 cases were recorded, with the highest incidence being that of scorpion stings (67.2%), predominantly in women (52.4%; odds ratio=3.6; 95% confidence interval=3.5-3.8), equally affecting people aged 10-19 years and 40-59 years (21.4%), in the urban areas (odds ratio=10.3; 95% confidence interval=9.9-10.8), especially in the rainy months. Snakebites (16.7%) had an incidence of 8.1/100,000 inhabitants, but the highest case-fatality rates were observed in bee stings (1.3%) and spider bites (0.5%). Regarding therapeutic variables, a small percentage of people had access to serotherapy (5.3%). CONCLUSIONS This study highlights the accidents caused by terrestrial venomous animals as a public health problem that must be monitored in Ceará. Thus, our findings suggest that preventive actions against scorpion and bee stings should be intensified during the months of higher incidence to improve public policies for patient care.

In silico study of azithromycin, chloroquine and hydroxychloroquine and their potential mechanisms of action against SARS-CoV-2 infection.

Coronavirus disease 2019 (COVID-19) is a highly transmissible viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Clinical trials have reported improved outcomes resulting from an effective reduction or absence of viral load when patients were treated with chloroquine (CQ) or hydroxychloroquine (HCQ). In addition, the effects of these drugs were improved by simultaneous administration of azithromycin (AZM). The receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein binds to the cell surface angiotensin-converting enzyme 2 (ACE2) receptor, allowing virus entry and replication in host cells. The viral main protease (Mpro) and host cathepsin L (CTSL) are among the proteolytic systems involved in SARS-CoV-2 S protein activation. Hence, molecular docking studies were performed to test the binding performance of these three drugs against four targets. The findings showed AZM affinity scores (ΔG) with strong interactions with ACE2, CTSL, Mpro and RBD. CQ affinity scores showed three low-energy results (less negative) with ACE2, CTSL and RBD, and a firm bond score with Mpro. For HCQ, two results (ACE2 and Mpro) were firmly bound to the receptors, however CTSL and RBD showed low interaction energies. The differences in better interactions and affinity between HCQ and CQ with ACE2 and Mpro were probably due to structural differences between the drugs. On other hand, AZM not only showed more negative (better) values in affinity, but also in the number of interactions in all targets. Nevertheless, further studies are needed to investigate the antiviral properties of these drugs against SARS-CoV-2.

Renal effects of venoms of Mexican coral snakes Micrurus browni and Micrurus laticollaris.

The Micrurus snake venoms mainly cause systemic complications, essentially neurotoxicity. Previous studies, however, have described that they are involved in the occurrence of acute kidney injury (AKI) in animal models. AKI pathogenesis in snakebites is multifactorial and involves immunological reactions, hemodynamic disturbances, and direct nephrotoxicity. The aim of this study was to compare the nephrotoxic effects of coral snake venoms from M. browni (MbV) and M. laticollaris (MlV) on the proximal tubular epithelial cell line (LLC-MK2) and isolated perfused kidney. Using an MTT assay, both venoms significantly reduced cell viability at higher concentrations (25-100 µg/mL). MlV (10 µg/mL) increased the perfusion pressure (PP) at 60, 90 and 120 min, while the MbV did it only at 90 and 120 min. Renal vascular resistance (RVR) decreased at 60 min and increased at 120 min with MbV, but decreased at 60, 90 and 120 min with MlV. Urinary flow (UF) alterations were not observed with MlV, but MbV elevated them at 90 and 120 min. Both venoms significantly decreased the glomerular filtration rate (GFR), %TNa+, %TK+ and %TCl- levels as of 60 min of perfusion. Oxidative stress analysis revealed that both venoms behaved similarly, reducing glutathione and increasing malondialdehyde levels. Kidney injury is not usually described in clinical cases of Micrurus snakebites. However, the potential for nephrotoxicity should be considered in the overall picture of envenomation.

Plants and Phytocompounds Active Against Bothrops Venoms.

Snakebite envenomation is an important health problem in tropical countries, with severe human and social consequences. In Latin America, the Bothrops species constitute the main threat to humans, and the envenomation caused by these species quickly develops into severe local tissue damage, including swelling, hemorrhaging, myonecrosis, skin ulceration, and pain. The systemic effects of envenomation are usually neutralized by antivenom serum therapy, despite its intrinsic risks. However, neutralization of local tissue damage remains a challenge. To improve actual therapy, two major alternatives are proposed: the rational design of new specific antibodies for most of the tissue damaging/ poor immunogenic toxins, or the search for new synthetic or natural compounds which are able to inhibit these toxins and complement the serum therapy. Natural compounds isolated from plants, mainly from those used in folk medicine to treat snakebite, are a good choice for finding new lead compounds to improve snakebite treatment and minimize its consequences for the victims. In this article, we reviewed the most promising plants and phytocompounds active against bothropic venoms.

Renal effects of Bunodosoma caissarum crude extract: Prostaglandin and endothelin involvement.

Sea anemones contain a variety of interesting biologically active compounds, including some potent toxins. PLA2 from Bunodosoma caissarum, a sea anemone endemic in the Brazilian southern coast, has shown renal alterations on isolated kidney. The aim of this study was to evaluate the renal and vascular effects of B. caissarum crude extract (BcE) on isolated perfused kidney and arteriolar mesenteric bed, as well the involvement of prostaglandins and endothelin. BcE did not show any effect on arteriolar mesenteric bed, but increased perfusion pressure, renal vascular resistance, urinary flow, glomerular filtration rate and decreased the percentage of sodium tubular transport on isolated perfused kidney. Indomethacin blocked the renal effects induced by BcE and tezosentan only partially blocked these effects. These results demonstrate the effects of BcE on kidney in situ, suggesting the involvement of prostaglandins and endothelin.

Chemical composition, antioxidant and topical antiinflammatory activities of Croton cordiifolius Baill. (Euphorbiaceae)

Croton cordiifolius is widely used in Brazilian Caatinga folk medicine to treat general inflammation, pain, and gastrointestinal disturbances. Currently, its medicinal properties are not well understood, owing to the absence of chemical and pharmacological studies. The aims of this work were to analyze the chemical composition of C. cordiifolius stem bark and evaluate its in vitro antioxidant and in vivo anti-inflammatory activities. C. cordiifolius ethanolic extract (CcEE) was obtained by maceration, while essential oil (CcEO) was extracted by hydrodistillation in a Clevenger-type apparatus. The chemical composition was evaluated by thin-layer chromatography and GCMS. Total phenolics, flavonoids, and antioxidant activity were quantitated by spectrophotometry. Topical anti-inflammatory activity was evaluated by different ear edema models in mice. The major compounds in CcEO were α-pinene (51.76%) and ß-pinene (19.08%). CcEE analysis indicated the presence of alkaloids, mono- and sesquiterpenes, flavonoids, phenylpropanoids, triterpenes, steroids, and coumarins. CcEE showed antioxidant activity in vitro. In a topical anti-inflammatory assay, CcEO showed no activity. On the contrary, CcEE inhibited ear edema induced by phorbol 12-myristate 13-acetate (PMA), arachidonic acid (AA), ethyl phenylpropriolate (EPP), and phenol. Probable mechanisms include inhibition of AA metabolite biosynthesis, vasoactive amine activity, and cytokine release/activity. These results corroborate the popular reputation of C. cordiifolius as an anti-inflammatory remedy.(AU)