Antithrombotic potential of Lippia alba: A mechanistic approach.

ETHNOPHARMACOLOGICAL RELEVANCE: Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson is traditionally used in Brazil as an adjunct in the relief of mild anxiety, as an antispasmodic, and as an antidyspeptic. This medicinal species was included in the Phytotherapeutic Form of the Brazilian Pharmacopeia 2nd edition (2021) and has already been described as the most used medicinal plant in a study with patients from an Anticoagulation Clinic in Brazil. Meanwhile, no studies were found that support the safety of the use of L. alba in patients using anticoagulants, a drug with several safety limitations. AIM OF THE STUDY: Provide scientific evidence to ensure the safety of the concomitant use of L. alba and warfarin and support the management of these patients by evaluating its in vitro anticoagulant effect and chemical composition. And, as a timely complementation, evaluate the potential of this medicinal species in the development of new antithrombotics. METHODS: The chemical profile of L. alba derivatives was analyzed by chromatographic methods such as Ultra-Performance Liquid Chromatography (UPLC) coupled with electrospray ionization mass spectrometry (ESI-MS), qualitative UPLC using Diode-Array Detection, and Thin Layer Chromatography. The anticoagulant activity was evaluated by the innovative Thrombin Generation Assay by Calibrated Automated Thrombogram method and using traditional coagulometric tests: prothrombin time, activated partial thromboplastin time, and plasma fibrinogen measurement. RESULTS: Extracts and fractions prolonged the coagulation time in all the tests and reduced thrombin formation in thrombin generation assay. Coagulation times with the addition of ethanloic extract (2.26 mg/mL) was 17.78s, 46.43s and 14.25s respectively in prothrombin time, activated partial thromboplastin time and fibrinogren plasma measurement. In thrombin generation test, this same extract showed ETP as 323 nM/min compared to control (815 nM/min) with high tissue factor and 582 nM/min compared to control (1147 nM/min) using low tissue factor. Presence of flavonoids, phenylpropanoids, and triterpenes were confirmed by chromatographic methods and 13 compounds were identified by UPLC-ESI-MS. Based on these results and on the scientific literature, it is possible to propose that phenylpropanoids and flavonoids are related to the anticoagulant activity observed. CONCLUSION: The results demonstrate the in vitro anticoagulant activity of L. alba, probably due to the activation of intrinsic and extrinsic pathways. It is concluded, then, that there is a potential for interaction, which needs to be further studied, between L. alba and warfarin. Also, this medicinal species shows a great potential for use in the development of new antithrombotics.

Effects of Swimming Goggles Wearing on Intraocular Pressure, Ocular Perfusion Pressure, and Ocular Pulse Amplitude.

PURPOSE: To evaluate changes in the ocular pulse amplitude (OPA) and ocular perfusion pressure (OPP), and investigate factors associated with intraocular pressure (IOP) elevation due to periorbital compression during swimming goggles (SG) use. METHODS: This cross-sectional study evaluated 35 eyes of 35 healthy volunteers during the wearing of a drilled SG. OPP calculation, Goldman applanation tonometry, and OPA measurements (using Pascal dynamic contour tonometer) were performed before, during, and after SG use. Scleral rigidity (calculated with Schiotz tonometry readings), orbital rim area, exophthalmometry, spherical equivalent, axial length, corneal thickness, and the goggles' rubber elastic force were considered in the multivariable analysis as potentially related to IOP changes. RESULTS: SG significantly increased IOP after 2 minutes of use (13.34±2.67 vs. 23.46±7.20 mm Hg, P<0.0001). After removal, IOP decreased significantly (10.20±5.85 mm Hg, P<0.0001). A inverse correlation between IOP and OPP differences was observed with the SG wearing (r=-0.57; P=0.0003). Mean OPA was significantly higher during compared with before SG wear (2.57±1.34 vs. 1.82±0.55 mm Hg for the timepoints 2 and 1, respectively; P=0.0064). Only orbital rim area (P=0.0052) and elastic force (P=0.0019) were significantly associated with IOP elevation. CONCLUSIONS: SG provoked acute IOP elevation and disturbance in the ocular hemodynamics, which was associated with larger orbital rim area and greater SG elastic force. These findings could have implications for subjects at high risk for glaucoma onset or progression.

The effect of levodopa on postural stability evaluated by wearable inertial measurement units for idiopathic and vascular Parkinson's disease.

BACKGROUND: Postural stability analysis has shown that postural control is impaired in untreated idiopathic Parkinson's disease (IPD), even in the early stages of the disease. Vascular Parkinson's disease (VPD) lacks consensus clinical criteria or diagnostic tests. Moreover, the levodopa effect on postural balance remains undefined for IPD and even less so for VPD. OBJECTIVE: To characterize postural stability, using kinematic analysis with wearable inertial measurement units, in IPD and VPD patients without clinical PI, and to subsequently analyze the response to levodopa. METHODS: Ten patients with akinetic-rigid IPD and five patients with VPD were included. Clinical and postural stability kinematic analysis was performed before and after levodopa challenge, on different standing tasks: normal stance (NS), Romberg eyes open (REO) and Romberg eyes closed. RESULTS: In the "off state", VPD patients had higher mean distances and higher maximal distance of p ostural sway on NS and REO tasks, respectively. VPD patients maintained a higher range of anterior-posterior (AP) postural sway after levodopa. In the absence of PI and non-significant differences in UPDRS-III, a higher mPIGD score in the VPD patients was mainly due to gait disturbance. Gait disturbance, and not UPDRS-III, influenced the degree of postural sway response to levodopa for VPD patients. CONCLUSION: Quantitative postural sway evaluation is useful in the investigation of Parkinsonian syndromes. VPD patients have higher AP postural sway that is correlated with their gait disturbance burden and also not responsive to levodopa. These observations corroborate the interconnection of postural control and locomotor networks.

[Natural helminth infection in Sicalis flaveola (Linnaeus, 1766), by Acuaria mayori Lent, Freitas and Proença, 1945 (Nematoda: Acuarioidea) in Brazil]. / Infecção natural em Sicalis flaveola (Linaeus, 1766) por Acuaria mayori lent, freitas e proença, 1945 (nematoda: acuarioidea) no Brasil.

This is the first report of a natural infection in the saffron finch Sicalis flaveola (Linnaeus, 1766) captured in Brazil, with the establishment of a new host record for the acuarioid nematode Acuaria mayori Lent, Freitas and Proença, 1945, previously referred in Cyanocorax chrysops (Vieillot, 1818) from Paraguay and Sporophila caerulescens caerulescens (Vieillot, 1823) and C. cyanomelas (Wied, 1821) from Brazil and Myarchus nuttingi (Ridgway, 1883) from Costa Rica.

Kinetics and crystal structure of catechol-o-methyltransferase complex with co-substrate and a novel inhibitor with potential therapeutic application.

Catechol-O-methyltransferase (COMT; E.C. 2.1.1.6) is a ubiquitous enzyme in nature that plays an important role in the metabolism of catechol neurotransmitters and xenobiotics. In particular, inactivation of drugs such as L-3,4-dihydroxyphenylalanine (L-DOPA) via O-methylation is of relevant pharmacological importance, because L-DOPA is currently the most effective drug used in the treatment of Parkinson's disease. This justified the interest in developing COMT inhibitors as potential adjuncts to L-DOPA therapy. The kinetics of inhibition by BIA 3-335 (1-[3,4-dihydroxy-5-nitrophenyl]-3-(N-3'-trifluormethylphenyl)-piperazine-1-propanone dihydrochloride) were characterized using recombinant rat soluble COMT. BIA 3-335 was found to act as a potent, reversible, tight-binding inhibitor of COMT with a K(i) of 6.0 +/- 1.6 nM and displaying a competitive inhibition toward the substrate binding site and uncompetitive inhibition toward the S-adenosyl-L-methionine (SAM) binding site. The 2.0-A resolution crystal structure of COMT in complex with its cosubstrate SAM and a novel inhibitor BIA 3-335 shows the atomic interactions between the important residues at the active site and the inhibitor. This is the first report of a three-dimensional structure determination of COMT complexed with a potent, reversible, and tight-binding inhibitor that is expected to have therapeutic applications.

Structure of beta-cinnamomin, a protein toxic to some plant species.

Phytophthora and Pythium species are among the most aggressive plant pathogens, as they invade many economically important crops and forest trees. They secrete large amounts of 10 kDa proteins called elicitins that can act as elicitors of plant defence mechanisms. These proteins may also induce a hypersensitive response (HR) including plant cell necrosis, with different levels of toxicity depending on their pI. Recent studies showed that elicitins function as sterol carrier proteins. The crystallographic structure of the highly necrotic recombinant beta-cinnamomin (beta-CIN) from Phytophthora cinnamomi has been determined at 1.8 A resolution using the molecular-replacement method. beta-CIN has the same overall structure as beta-cryptogein (beta-CRY), an elicitin secreted by Phytophthora cryptogea, although it shows a different surface electrostatic potential distribution. The protein was expressed in Pichia pastoris and crystallized in the triclinic space group with two monomers in the asymmetric unit. The interface formed by these two monomers resembles that from beta-CRY dimer, although with fewer interactions.