New Insights into the Hypotensins from Tityus serrulatus Venom: Pro-Inflammatory and Vasopeptidases Modulation Activities

The Tityus serrulatus scorpion is considered the most dangerous of the Brazilian fauna due to the severe clinical manifestations in injured victims. Despite being abundant components of the venom, few linear peptides have been characterized so far, such as hypotensins. In vivo studies have demonstrated that hypotensin I (TsHpt-I) exerts hypotensive activity, with an angiotensin-converting enzyme (ACE)-independent mechanism of action. Since experiments have not yet been carried out to analyze the direct interaction of hypotensins with ACE, and to deepen the knowledge about these peptides, hypotensins I and II (TsHpt-II) were studied regarding their modulatory action over the activities of ACE and neprilysin (NEP), which are the peptidases involved in blood pressure control. Aiming to search for indications of possible pro-inflammatory action, hypotensins were also analyzed for their role in murine macrophage viability, the release of interleukins and phagocytic activity. TsHpt-I and -II were used in kinetic studies with the metallopeptidases ACE and NEP, and both hypotensins were able to increase the activity of ACE. TsHpt-I presented itself as an inhibitor of NEP, whereas TsHpt-II showed weak inhibition of the enzyme. The mechanism of inhibition of TsHpt-I in relation to NEP was defined as non-competitive, with an inhibition constant (Ki) of 4.35 μM. Concerning the analysis of cell viability and modulation of interleukin levels and phagocytic activity, BALB/c mice’s naïve macrophages were used, and an increase in TNF production in the presence of TsHpt-I and -II was observed, as well as an increase in IL-6 production in the presence of TsHpt-II only. Both hypotensins were able to increase the phagocytic activity of murine macrophages in vitro. The difference between TsHpt-I and -II is the residue at position 15, with a glutamine in TsHpt-I and a glutamic acid in TsHpt-II. Despite this, kinetic analyzes and cell assays indicated different actions of TsHpt-I and -II. Taken together, these results suggest a new mechanism for the hypotensive effects of TsHpt-I and -II. Furthermore, the release of some interleukins also suggests a role for these peptides in the venom inflammatory response. Even though these molecules have been well studied, the present results suggest a new mechanism for the hypotensive effects of TsHpt-I

Antihypertensive activity of ACE-Renin inhibitory peptide derived from Moringa oleifera protein

Moringa oleifera (MO) leaf is a potential plant protein resource with high nutritional and medicinal value. The study aims to investigate the hypotensive activity and stability of MO leaf peptide....

A Topical Formulation of Melatoninergic Compounds Exerts Strong Hypotensive and Neuroprotective Effects in a Rat Model of Hypertensive Glaucoma

Melatonin is of great importance for regulating several eye processes, including pressure homeostasis. Melatonin in combination with agomelatine has been recently reported to reduce intraocular pressure (IOP) with higher efficacy than each compound alone. Here, we used the methylcellulose (MCE) rat model of hypertensive glaucoma, an optic neuropathy characterized by the apoptotic death of retinal ganglion cells (RGCs), to evaluate the hypotensive and neuroprotective efficacy of an eye drop nanomicellar formulation containing melatonin/agomelatine. Eye tissue distribution of melatonin/agomelatine in healthy rats was evaluated by HPLC/MS/MS. In the MCE model, we assessed by tonometry the hypotensive efficacy of melatonin/agomelatine. Neuroprotection was revealed by electroretinography; by levels of inflammatory and apoptotic markers; and by RGC density. The effects of melatonin/agomelatine were compared with those of timolol (a beta blocker with prevalent hypotensive activity) or brimonidine (an alpha 2 adrenergic agonist with potential neuroprotective efficacy), two drugs commonly used to treat glaucoma. Both melatonin and agomelatine penetrate the posterior segment of the eye. In the MCE model, IOP elevation was drastically reduced by melatonin/agomelatine with higher efficacy than that of timolol or brimonidine. Concomitantly, gliosis-related inflammation and the Bax-associated apoptosis were partially prevented, thus leading to RGC survival and recovered retinal dysfunction. We suggest that topical melatoninergic compounds might be beneficial for ocular health.

THE STUDY OF THE EXTRACTION DYNAMICS OF BIOLOGICALLY ACTIVE SUBSTANCES FROM THE BIDENS TRIPARTITA L. HERB AND ANTIOXIDANT ACTIVITY OF THE OBTAINED EXTRACTS

The interest to study the genus Bidens and in particular Bidens tripartita L. (bur-marigold herb) is unmitigated due to its antioxidant, anti-allergic, antimicrobial, antifungal, hepatoprotective, immunostimulating and hypotensive activity. This pharmacological activities are determined by the presence of flavonoids, polyphenolic compounds, polysaccharides, components of essential oils, polyacetylenes, etc. The aim of the research was to study the process of extracting various biologically active substances (polysaccharides, flavonoids, polyphenols) from bur-marigold herb with water-alcohol mixtures of various concentrations, to study their component composition, as well as to evaluate their effect on the oxidative effect of free radicals. Materials and methods. The object of the research was the herb of Bidens tripartita L. Raw materials were collected and procured on the territory of Kharkiv, Zhytomyr and Poltava regions of Ukraine. All used methods for the quantitative determination of biologically active substances were pharmacopeial and described in various monographs in the European Pharmacopoeia and State Pharmacopoeia of Ukraine. Results. The extracts of the bur-marigold herb were analyzed for the content of the extractable matter, flavonoids, polysaccharides and it was found that they are maximally extracted (about 80 %) in the 1st percolate with a drug/solvent ratio of 1:10 for all the extractants. It was found that with an increase of ethanol concentration in the extraction mixture, the content of polyphenols and flavonoids, is expectedly increased, as well as the value of the antioxidant activity of the corresponding extracts, but the amount of extracted polysaccharides is significantly reduced. Conclusions. With the selected evaluation criteria, it was found that 40 % ethanol is optimal from the point of view of balanced extraction of flavonoids, polysaccharides and polyphenols. A strong positive and statistically significant correlation was found between the content of polyphenols in the obtained extracts and their antioxidant activity (Pearson correlation coefficient, r=0.9998), slightly weaker for flavonoids (r=0.9886), and an inverse correlation between polysaccharides content and TEAC- value.

The role of EP2 receptors in mediating the ultra-long-lasting intraocular pressure reduction by JV-GL1

BackgroundA single application of JV-GL1 substantially lowers non-human primate intraocular pressure (IOP) for about a week, independent of dose. This highly protracted effect does not correlate with its ocular biodisposition or correlate with the once-daily dosing regimen for other prostanoid EP2 receptor agonists such as trapenepag or omidenepag. The underlying pharmacological mechanism for the multiday extended activity of JV-GL1 is highly intriguing. The present studies were intended to determine EP2 receptor involvement in mediating the long-term ocular hypotensive activity of JV-GL1 by using mice genetically deficient in EP2 receptors.MethodsThe protracted IOP reduction produced by JV-GL1 was investigated in C57BL/6J and EP2 receptor knock-out mice (B6.129-Ptger2tm1Brey/J; EP2KO). Both ocular normotensive and steroid-induced ocular hypertensive (SI-OHT) mice were studied. IOP was measured tonometrically under general anaesthesia. Aqueous humour outflow facility was measured ex vivo using iPerfusion in normotensive C57BL/6J mouse eyes perfused with 100 nM de-esterified JV-GL1 and in SI-OHT C57BL/6J mouse eyes that had received topical JV-GL1 (0.01%) 3 days prior.ResultsBoth the initial 1-day and the protracted multiday effects of JV-GL1 in the SI-OHT model for glaucoma were abolished by deletion of the gene encoding the EP2 receptor. Thus, JV-GL1 did not lower IOP in SI-OHT EP2KO mice, but in littermate SI-OHT EP2WT control mice, JV-GL1 statistically significantly lowered IOP for 4–6 days.ConclusionsBoth the 1-day and the long-term effects of JV-GL1 on IOP are entirely EP2 receptor dependent.

Extra Virgin Olive Oil Phenols Dilate the Rat Mesenteric Artery by Activation of BKCa2+ Channels in Smooth Muscle Cells

Accumulating evidence has shown the beneficial health effects of extra virgin olive oil (EVOO) consumption in reducing blood pressure and preventing the risk of developing hypertension. Some studies associate the hypotensive activity of EVOO to a minor component—the phenols. This study was designed to investigate the effects of EVOO phenols on the rat resistance mesenteric artery (MA) and to find out the possible vascular pathways involved. The experiments were carried out using a pressurized myograph, which allowed the effects of phenols on isolated MA to be tested under different conditions: (a) with endothelium removed; (b) with inhibition of nitric oxide synthase by Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME, 10−4 M) + Nω-Nitro-l-arginine (l-NNA, 10−4 M); (c) with inhibition of cyclooxygenase by indomethacin (10−5 M); (d) with inhibition of guanylate cyclase by 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ,10−5 M) or adenylate cyclase by 9-(Tetrahydro-2′-furyl)adenine (SQ, 10−5 M); (e) with depolarization by high potassium chloride (40 mM); and (f) with inhibition of the large conductance Ca2+–potassium channels (BKCa2+) with paxilline (10−5 M). EVOO phenols induce vasodilation of the endothelium, mediated by a direct effect on smooth muscle cells (SMC) by activation of BKCa2+ channels, an action by which phenols can regulate the vascular tone of the resistance artery. Phenols can be regarded as bioactive molecules that may contribute to the antihypertensive effects of EVOO.

Botanical, agronomic, phytochemical and biological characteristics of Aspidosperma pyrifolium Mart.: A review

Known in popular medicine as “pereiro”, Aspidosperma pyrifolium has economic importance due to the use of its wood. However, there are no studies that provide relevant information related to botanical, agronomic, phytochemical and biological characteristics involving this plant species. Given the above, this study aimed to develop a study on different characteristics of A. pyrifolium. The present study is a narrative bibliographic review. Articles, monographs, dissertations and theses retrieved from the following databases were included: Lilacs, Scielo, PubMed, ScienceDirect and Banks of Theses and Dissertations from Public Universities. The studies highlight the use of A. pyrifolium by several populations, especially in the Northeast region of Brazil, more precisely in the Caatinga biome, where it has economic and ecological importance. Regarding metabolites, the presence of flavonoids and alkaloids is mainly observed. In addition, studies also report that this plant has analgesic, anti-inflammatory action, combats ectoparasites and infections, improves erectile dysfunction and has hypotensive activity. On the other hand, toxicity has been reported in different animal models. Thus, it is observed that “pereiro” has the potential to become a possible drug, phytodrug and/or phytotherapic.

Hypotensive, vaso-relaxant, cardio-depressant and diuretic effect of crude extract of Crotalaria burhia (Fabaceae)

Purpose: To examine 70 % aqueous-methanol crude extract of Crotalaria burhia (Cb.Cr) for its hypotensive and diuretic effects. Methods: The effect of intravenous administration of Cb.Cr on blood pressure (BP) of normotensive anesthetized rats was studied. In vitro experiments on rabbit isolated aortic and atrial preparations were performed to elucidate the mechanism of action. The diuretic effect was assessed following oral administration of Cb.Cr in rats. Results: Intravenous administration of Cb.Cr produced 14.70 ± 1.21, 22.00 ± 2.24 and 36.21 ± 2.65 % reduction in mean arterial blood pressure of the rats at doses of 1, 3 and 10 mg/kg, respectively. It was more potent in relaxing potassium (80 mM)- than phenylephrine (1 μM)-induced contractions in isolated aorta of rabbit with half-maximal effective concentration (EC50) values of 0.58 ± 0.03 and 1.58 ± 0.16 mg/mL, respectively, which are similar to verapamil. The extract showed depressant effects on spontaneously beating atrial preparations of rabbit in a dose-dependent manner. Moreover, Cb.Cr also increased urine volume and urinary electrolyte excretion in rats. Conclusion: Crotalaria burhia crude extract exhibits hypotensive and diuretic effects in rats. The hypotensive activity of the extract possibly involves vasodilator, cardio-depressant, calcium channel blocking and diuretic actions. Keywords: Khip, Crotalaria burhia, Calcium channel blocker, Antihypertensive, Diuretic

Anesthesia of laboratory animals in manufacturing of diagnostic and preventive biomedicines

Preparations such as XilaVet, Zoletil 100 as well as Aeranne (Isoflurane) are successfully applied for animal anesthesia in veterinary practice. We assessed a possibility of using parenteral narcosis with Zoletil 100 in combination with muscle relaxant Xila for producer-rabbits involved in manufacturing of natural rabbit serum subsequently deployed for production of diagnostic serum and immunoglobulin preparations. Administration of preparations into auricular vein is easy to do, while animals are sedated immediately allowing for safe fixation on restraining table and causing no additional stress for biomodels. This type of narcosis provides for expected depth of anesthesia and its maintenance until the end of blood-letting procedure. Parameters characterizing the state of cardiovascular system due to anesthetic products remained within the permitted limits. These preparations do not reduce heart beat rate allowing for collecting sufficient blood volumes. Application of inhalation anesthesia with Aeranne in laboratory animals provides for the specified depth of anesthesia and its maintenance until the end of the whole procedure. However, it requires specialized equipment and highly trained personnel with appropriate skills. Usage of Xila as a mono narcosis is not recommended as exhibits weak analgesic effects and strong hypotensive activity by decreasing quantity of collected blood volume. It was found that anesthetics such as Xila, Zoletil 100, Aeranne did not affect specific activity of immune sera in case of total dehematizing procedure. Moreover, antibody titers were not declined throughout entire observation (12 months) period and complied with the requirements of regulatory documentation. In addition, a feasibility of replacing old-fashioned anesthesia method with diethyl ether for a combination of safer contemporary preparations of Zoletil 100 and Xila was demonstrated while manufacturing tableted chemical cholera vaccine in experimental series with suckling rabbits used at diverse stages of raw material verification during surgical interventions. Xila, Zoletil 100, and Aeranne examined by us had no impact on the amount of blood obtained from donor-animals, immunological properties of the sera and ready-to-use diagnostic preparations. Such drugs were safe for all-age animals that comply with the requirements to anesthesia of animal biomodels and producer-animals in manufacturing of immunobiological preparations. Thus, our study allowed to conduct experiments with laboratory animals in a more humane manner.