Natural Agents Modulating ACE-2: A Review of Compounds with Potential against SARS-CoV-2 Infections.

One of the biggest challenges of public health worldwide is reducing the number of events and deaths related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. The angiotensinconverting enzyme 2 (ACE-2), a carboxypeptidase that degrades angiotensin II into angiotensin 1-7, has been identified as a potent receptor for SARS-CoV-2. In the last decades, ACE inhibition has assumed a central role in reducing cardiovascular and renal events. However, with the advent of COVID-19, attention has been turned to ACE-2 as a possible target to reduce virus binding to different human cells. This review aims to discuss recent developments related to the medicinal properties of natural compounds as ACE/ACE-2 inhibitors, which should be highlighted in the future development of studies looking for modulators in SARS-CoV-2 infection. Data show that bioactive compounds isolated from several natural products act by inhibiting ACE/ACE-2, which changes the entire axis of this system. Of the compounds addressed in this review, 7 phenolic compounds, including quercetin, curcumin, naringenin, luteolin, hesperidin, mangiferin, and gallic acid showed binding affinity with molecular ACE-2 target in silico, and 1, esculetin, decreased ACE-2 expression in vivo. Regarding terpenoids and alkaloids, nimbin, withaferin A, andrographolide, zingiberene and, berberine, piperine and thebaine, respectively, showed a binding affinity with molecular ACE-2 target in silico. These findings reinforce the need for future preclinical and clinical studies on these compounds and specific inhibitory effects on ACE-2 of all the other compounds described herein only as nonspecific ACE inhibitors. It is important to mention that some natural compounds such as magnolol, resveratrol, rosmarinic acid, tanshinone IIA, and nicotine have also demonstrated the potential to increase the activity or expression of ACE-2, and could therefore aggravate SARS-CoV-2 infection.

Repurposing Drugs for the Management of Patients with Confirmed Coronavirus Disease 2019 (COVID-19).

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), termed coronavirus disease 2019 (COVID-19) by the World Health Organization, is a newly emerging zoonotic agent that emerged in China in December 2019. No specific treatment for COVID-19 is currently available. Usual palliative treatment includes maintaining hydration and nutrition and controlling fever and cough. The clinical severity and extent of transmission need to be determined, and therapeutic options need to be developed and optimized. METHODS: The present review discusses the recent repurposing of drugs for COVID-19 treatment. RESULTS: Several compounds, including remdesivir, lopinavir, ritonavir, interferon-ß, ribavirin, chloroquine/ hydroxychloroquine, azithromycin, tocilizumab, and ivermectin, have emerged as promising alternatives. They block the virus from entering host cells, prevent viral replication, and attenuate exacerbation of the host's immune response. CONCLUSION: Although some evidence indicates the positive actions of different classes of compounds for the treatment of COVID-19, few clinical assays have been established to definitively demonstrate their therapeutic value in humans. Multicenter clinical studies are urgently needed to validate and standardize therapeutic regimens that involve these agents. Although science has not yet presented us with a specific drug against COVID-19, the repurposing of drugs appears to be promising in our fight against this devastating disease.

Antimicrobial activity of Asteraceae species against bacterial pathogens isolated from postmenopausal women.

PURPOSE: Investigation of the antibacterial action of aqueous extracts of Bidens sulphurea, Bidens pilosa, and Tanacetum vulgare, species of Asteraceae family that are popularly used for the treatment of genito-urinary infection. METHODS: The minimum inhibitory concentration (MIC) and minimal bacterial concentration (MBC) of the extracts against standard strains of Staphylococcus aureus (ATCC25923), Enterococcus faecalis (ATCC29212), Escherichia coli (ATCC25922), and Pseudomonas aeruginosa (ATCC27853) and against bacteria that were isolated from cultures of vaginal secretions and urine from menopausal women with a diagnosis of recurrent urinary tract infections (rUTI) were determined by broth microdilution. RESULTS: The MIC values of the three extracts against Gram-positive and Gram-negative standard bacterial strains ranged from 7.81 to 125.00 mg ml-1, and the MBC values ranged from 7.81 to 500.00 mg ml-1. However, B. sulphurea was more efficient. In the urine samples, the three extracts inhibited the growth of coagulase-negative Staphylococcus spp., and the B. pilosa was the most active extract against E. coli compared with the other ones. For the vaginal secretion samples, no significant differences in the inhibition of coagulase-positive Staphylococcus spp. and P. mirabilis were found among the extracts. T. vulgare and B. sulphurea were more effective in inhibiting coagulase-negative Staphylococcus spp. compared with B. pilosa. E. coli was more susceptible to the B. sulphurea extract compared with the B. pilosa and T. vulgare extracts. CONCLUSION: The present results suggested the potential medicinal use of Asteraceae species, especially B. sulphurea, as therapeutic agents against rUTI-related bacteria.

Cellular and Molecular Mechanisms of Antithrombogenic Plants: A Narrative Review.

Heart attack, stroke, and deep vein thrombosis are among the conditions that alter blood coagulation and are modulated by antithrombogenic drugs. Natural products are an important source of antithrombogenic agents and have been considered remarkable alternatives with greater efficacy and usually with fewer side effects. However, the efficacy and toxicity of many of these plants that are used in traditional medicine must be scientifically tested. Despite a large number of published articles that report that plants or plant-derived components may act as antithrombogenic agents, few studies have investigated the mechanism of action of medicinal plants. This review presents the current knowledge about the major cellular and molecular mechanisms of antithrombogenic plants and their main components. Many well-established mechanisms (e.g., platelet aggregation, coagulation factors, and thrombolysis) are related to the antithrombogenic activity of many natural products. However, the central pathways that are responsible for their activity remain unclear. Further studies are needed to clarify the central role of each of these pathways in the pleiotropic response to these agents.

Cell-based Therapy for Hypertension: Challenges and Perspectives.

Hypertension is a non-transmissible chronic disease with a high prevalence, morbidity, and mortality. Different strategies for the treatment of hypertension are employed worldwide, but the control of hypertension remains a major challenge for global health. Many unsuccessful unconventional therapies have been proposed in recent years, including herbal medicines and the development of small molecules or antibodies that seek to disrupt the disease's pathogenesis. Cell-based therapies may be used as replacement or complementary treatment strategies. The results of recent preclinical studies of cell-based therapies are promising. However, human clinical trials are scarce, the data are insipid, and many issues have been raised about the safety and efficacy of cell-based therapies. The present review summarizes research on cell-based therapy for hypertension. We also briefly summarize relevant clinical trials and discuss future perspectives and possible clinical applications.

Herbal Medicine as an Alternative Treatment in Autism Spectrum Disorder: A Systematic Review.

BACKGROUND: This review focuses on the efficacy and safety of herbal medicines in the management of autism spectrum disorder (ASD) in humans and animals. METHOD: PubMed, Scopus, Google Scholar, Web of Science, and Science Direct databases were searched up to October 30, 2016. The key terms used were "ASD", "Asperger", "autism", "healing plants", "herbal medicine", and "medicinal plants". In each database, the searches consisted of each of three key terms describing the disorder and subtypes plus each of the terms describing the therapy. All human and animal studies on the effects of herbs with the key outcome of change in autism symptoms were included. In vitro studies were excluded. RESULTS: From the publications perused in the initial database, 3157 results were identified, reviewed and a total of 23 studies were included. Preclinical studies using critically validated models were conducted, with some promising preliminary results. Data availability on controlled clinical studies is currently very limited. The use of different methodologies and the very small number of patients raise doubts about the effects of these preparations. CONCLUSION: Available data do not yet allow us to suggest the effectiveness of herbal medicines as an add-on in the treatment of ASD symptoms.

Safety Assessment and Botanical Standardization of an Edible Species from South America.

Tropaeolum majus L. (Tropaeolaceae), commonly known as nasturtium, is an important edible plant native to the Andean States and widely disseminated throughout South America. Despite the use of this species is quite widespread, there are no minimum quality control standards or data on its genotoxicity. So, the aim of this study was to present a detailed anatomical and histochemical study for Tropaeolum majus and provide genotoxicity parameters of a preparation routinely used in South American countries. First, three different Tropaeolum majus aqueous extracts (TMAEs) at concentrations of 1.5%, 7%, and 15% were prepared according to the popular use. Then, genetic toxicity of TMAE was evaluated on bacterial reverse mutation, genomic lesions, and micronucleus formation in male rats. Furthermore, a detailed anatomical and histochemical study of the leaves and stems of Tropaeolum majus were performed. No revertant colonies were found in any bacterial cultures examined. In the comet assay, TMAE showed no significant DNA damage in all tested doses. Micronucleus assay showed no significant increases in the frequency of inducing micronuclei in any dose examined. Light and electron microscope images of cross-section of leaves and stems from Tropaeolum majus revealed useful diagnostic features. The presented data showed significant safety parameters for the use of TMAE and provided important data for the quality control of this plant species.

Inulin-type fructan and infusion of Artemisia vulgaris protect the liver against carbon tetrachloride-induced liver injury.

BACKGROUND: Infusions of aerial parts of Artemisia vulgaris L. (Asteraceae) are used in herbal medicine to treat several disorders, including hepatosis. PURPOSE: Evaluation of in vivo hepatoprotective effects of A. vulgaris infusion (VI) and inulin (VPI; i.e., the major polysaccharide of VI). STUDY DESIGN: The hepatoprotective effect of A. vulgaris extracts on carbon tetrachloride (CCl4)-induced hepatotoxicity and the probable mechanism involved in this protection were investigated in mice. METHODS: A. vulgaris infusion (VI) was prepared according to folk medicine using the aerial parts of the plant. Carbohydrate, protein, and total phenolic content was determined in VI, and its phenolic profile was determined by high-performance liquid chromatography (HPLC). Male Swiss mice were orally pretreated for 7 days with VI or VPI (once per day). On days 6 and 7 of treatment, the mice were intraperitoneally challenged with CCl4. Liver and blood were collected and markers of hepatic damage in plasma and oxidative stress in the liver were analyzed. Hepatic histology and inflammatory parameters were also studied in the liver. The scavenging activity of VI and VPI were evaluated in vitro using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. RESULTS: VI contained 40% carbohydrates, 2.9% proteins and 9.8% phenolic compounds. The HPLC fingerprint analysis of VI revealed chlorogenic, caffeic and dicaffeoylquinic acids as major low-molar-mass constituents. Oral pretreatment with VI and VPI significantly attenuated CCl4-induced liver damage, reduced the activity of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) in plasma, and prevented reactive oxygen species accumulation and lipid peroxidation in the liver. Comparisons with the CCl4-treated group showed that VI and VPI completely prevented necrosis, increased the levels of reduced glutathione (GSH), and reduced tumor necrosis factor alpha (TNF-α) level in the liver. VI and VPI also exhibited high radical scavenging activity in vitro. CONCLUSION: VI and VPI had remarkable hepatoprotective effects in vivo, which were likely attributable to antioxidant and immunomodulatory properties. The present findings support the traditional use of A. vulgaris infusion for the treatment of hepatic disorders.

Hydroethanolic extract of Baccharis trimera promotes gastroprotection and healing of acute and chronic gastric ulcers induced by ethanol and acetic acid.

Ethanol is a psychoactive substance highly consumed around the world whose health problems include gastric lesions. Baccharis trimera is used in folk medicine for the treatment of gastrointestinal disorders. However, few studies have evaluated its biological and toxic effects. To validate the popular use of B. trimera and elucidate its possible antiulcerogenic and cytotoxic mechanisms, a hydroethanolic extract of B. trimera (HEBT) was evaluated in models of gastric lesions. Rats and mice were used to evaluate the protective and antiulcerogenic effects of HEBT on gastric lesions induced by ethanol, acetic acid, and chronic ethanol consumption. The effects of HEBT were also evaluated in a pylorus ligature model and on gastrointestinal motility. The LD50 of HEBT in mice was additionally estimated. HEBT was analyzed by nuclear magnetic resonance, and a high-performance liquid chromatography fingerprint analysis was performed. Oral HEBT administration significantly reduced the lesion area and the oxidative stress induced by acute and chronic ethanol consumption. However, HEBT did not protect against gastric wall mucus depletion and did not alter gastric secretory volume, pH, or total acidity in the pylorus ligature model. Histologically, HEBT accelerated the healing of chronic gastric ulcers in rats, reflected by contractions of the ulcer base. Flavonoids and caffeoylquinic acids were detected in HEBT, which likely contributed to the therapeutic efficacy of HEBT, preventing or reversing ethanol- and acetic acid-induced ulcers, respectively. HEBT antiulcerogenic activity may be partially attributable to the inhibition of free radical generation and subsequent prevention of lipid peroxidation. Our results indicate that HEBT has both gastroprotective and curative activity in animal models, with no toxicity.

Sydnone 1: A Mesoionic Compound with Antitumoral and Haematological Effects In Vivo.

This study evaluated the antitumour activity of the mesoionic compound sydnone 1 (Syd-1) against Walker-256 carcinosarcoma. Tumour cells were subcutaneously inoculated in the hind limb in male Wistar rats. The animals were orally treated for 12 days with Syd-1 (75 mg/kg) or vehicle. At the end of treatment, considerable decreases in tumour volume and tumour weight were observed in treated animals. Samples of these tumours presented increases in apoptotic bodies and pro-apoptotic protein expression (Bax and p53), while the expression of the anti-apoptotic protein Bcl-2 was reduced. A decrease in reduced glutathione levels and an increase in glutathione peroxidase activity were observed in tumour after Syd-1 treatment. However, significant splenomegaly was evident in animals that received Syd-1, most likely attributable to the induction of haemolysis. This study demonstrated the antitumour activity of Syd-1 against Walker-256 carcinosarcoma. Its mechanism of action is linked to the activation of apoptotic pathways that lead to tumour cell death.