The effects of acute administration of lauric acid (LA), the most abundant medium-chain fatty acid of coconut oil, on blood pressure, heart rate and oxidative stress were investigated in spontaneously hypertensive rats (SHR). Intravenous doses of LA reduced blood pressure in a dose-dependent fashion (1, 3, 4, 8 and 10 mg/kg) in both SHR and Wistar Kyoto rats. LA (10 to 3 × 10 M) induced vasorelaxation in isolated superior mesenteric artery rings of SHR in the presence (n = 7) or absence (n = 8) of functional endothelium [maximum effect (ME) = 104 ± 3 versus 103 ± 4%]. After exposure to KCl (60 mM), LA also induced concentration-dependent vasorelaxation (n = 7) compared to that under Phe-induced contraction (ME = 113.5 + 5.1 versus 104.5 + 4.0%). Furthermore, LA-induced vasorelaxation in vessels contracted with S(-)-BayK8644 (200 nM), a L-type Ca channel agonist (ME = 91.4 + 4.3 versus 104.5 + 4.0%, n = 7). Lastly, LA (10 M) reduced NADPH-dependent superoxide accumulation in the heart (18 ± 1 versus 25 ± 1 MLU/min/μg protein, n = 4, p < 0.05) and kidney (82 ± 3 versus 99 ± 4 MLU/min/μg protein, n = 4, p < 0.05). Our data show that LA reduces blood pressure in normotensive and hypertensive rats. In SHR, this effect might involve Ca channels in the resistance vessels and by its capability of reducing oxidative stress in heart and kidneys.
BackgroundGaletin 3,6-dimethyl ether (FGAL) is a flavonoid isolated from aerial parts of Piptadenia stipulacea. Previously, FGAL was shown to inhibit both carbachol- and oxytocin-induced phasic contractions in the rat uterus, which was more potent with oxytocin. Thus, in this study, we aimed to investigate the tocolytic action mechanism of FGAL on the rat uterus.MethodsSegments of rat uterus ileum were suspended in organ bath containing modified Locke-Ringer solution at 32 °C, bubbled with carbogen mixture under a resting tension of 1 g. Isotonic contractions were registered using kymographs and isometric contractions using force transducer.ResultsFGAL was more potent in relaxing uterus pre-contracted with oxytocin than with KCl. Additionally, FGAL shifted oxytocin-induced cumulative contractions curves to the right in a non-parallel manner, with Emax reduction, indicating a pseudo-irreversible noncompetitive antagonism of oxytocin receptors (OTR) or a downstream pathway target. Moreover, FGAL shifted CaCl2-induced cumulative contraction curves to the right in a non-parallel manner in depolarizing medium, nominally without Ca2+, with Emax reduction, suggesting the inhibition of Ca2+ influx through CaV. The relaxant potency of FGAL was reduced by CsCl, a non-selective K+ channel blocker, suggesting positive modulation of these channels. Furthermore, in presence of apamin, 4-aminopyridine, glibenclamide or 1 mM TEA+, the relaxant potency of FGAL was attenuated, indicating the participation of SKCa, KV, KATP and highlighting BKCa. Aminophylline, a non-selective phosphodiesterase (PDE) blocker, did not affect the FGAL relaxant potency, excluding the modulation of cyclic nucleotide PDEs pathway by FGAL.ConclusionTocolytic effect of FGAL on rat uterus occurs by pseudo-irreversible noncompetitive antagonism of OTR and activation of K+ channels, primarily BKCa, leading to calcium influx reduction through CaV.
We aimed to investigate the possible spasmolytic activity of ent-7α-acetoxytrachyloban-18-oic acid (1) and ent-7α-hydroxytrachyloban-18-oic acid (2) on smooth muscle models. In male rat aorta and rat uterus, both diterpenes were unable to trigger spasmolytic action. However, 2 relaxed guinea-pig trachea: Compounds 1 and 2 antagonised, significantly and concentration-dependently, carbachol- and histamine-induced phasic contractions in guinea-pig ileum. Moreover, they induced a significant and concentration-dependent relaxation in pre-contracted (KCl, carbachol or histamine) guinea-pig ileum, with 2 being 15 times more potent than 1 in histamine-contracted ileum. These dissimilar results may be due to chemical differences between them. Thus, we demonstrated that 1 and 2 seem to be promising spasmolytic agents, although further studies are required to elucidate the spasmolytic action mechanism.
Molecules with antimicrobial properties, such as those found in non-antibiotic pharmaceuticals, may pressure bacteria to adapt to the environment. In this work, five of the most sold non-antibiotic pharmaceuticals in Brazil and in Egypt in 2020 (losartan 50 mg, acetylsalicylic acid 100 mg, diclofenac 50 mg, paracetamol 750 mg and metformin 500 mg and dipyrone 100 mg/mL), were tested against the wild strain Pseudomonas aeruginosa TGC04, previously isolated by our group and which has been characterized over the years. We evaluated inhibition of biofilm adhesion over 48 h using the crystal violet test. Exposure of P. aeruginosa TGC04 to the compounds promoted a similar moderate reduction in adherence for all the pharmaceuticals tested, amounting to about 60%. This indicated that the cells were also moderately adherent. However, although all non-antibiotic pharmaceuticals did not produce a biocidal effect on the wild strain, intense antibiofilm activity was observed, except for paracetamol.
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