Luísa Nathália Bolda Mariano

The study aimed to investigate the potential antiurolithic effects of extracts, fractions, and betulinic acid (BA) from Citharexylum mirianthum. In vitro analysis involved precipitating calcium oxalate (CaOx) crystals in urine. For in vivo studies, rats were divided into four groups: naive; vehicle; potassium citrate (KC); and BA. Urolithiasis was induced using ethylene glycol and ammonium chloride. After seven days, urine, blood, and kidney tissues were evaluated. The results showed that methanolic extract, hexane, dichloromethane, and ethyl acetate fractions, as well as BA, reduced CaOx crystal formation. In vivo, the vehicle-treated group exhibited reduced urinary volume and Na⁺ excretion, while the BA-treated group showed restored urinary volume and Na⁺ excretion similar to the naive group. BA also significantly reduced urinary monohydrate and dihydrate crystal formation, comparable to the KC group. Other urinary parameters remained unchanged, but plasma analysis revealed decreased Na⁺, K⁺, and Ca²⁺ in the KC group. Renal tissue analysis indicated reduced lipid hydroperoxides and increased reduced glutathione in all urolithiasis groups, with unchanged nitrite levels. BA treatment also improved renal corpuscle morphology. Overall, our findings demonstrate that treatment with BA effectively prevented kidney damage induced by EG+AC ingestion, thereby improving renal function in the urolithiasis model.

This study aimed to assess the ability of rosmarinic acid (RA) to prevent kidney stone formation in an ethylene glycol and ammonium chloride (EG/AC) model. There was an increase in diuresis in the normotensive (NTRs) and hypertensive rats (SHRs) treated with hydrochlorothiazide (HCTZ) and exposed to EG/AC, while RA restored urine volume in NTRs. The EG/AC groups exhibited lower urine pH and electrolyte imbalance; these parameters were not affected by any of the treatments. Both HCTZ+EG/AC and RA+EG/AC reduced calcium oxalate crystal formation in NTR and SHR urine. Kidney tissue analysis revealed alterations in oxidative stress and inflammation parameters in all EG/AC-receiving groups, with RA enhancing antioxidant defenses in SHRs. Additionally, crystals were found in the kidney histology of all EG/AC-exposed groups, with reduced Bowman’s capsule areas in NTRs and SHRs. The NTR VEH+EG/AC group showed intense renal damage, while the others maintained their structures, where treatments with HCTZ and RA were fundamental for kidney protection in the NTRs. Docking analysis showed that RA exhibited good binding affinity with matrix metalloproteinase-9, phosphoethanolamine cytidylyltransferase, and human glycolate oxidase enzymes. The data disclosed herein underscore the importance of further research to understand the underlying mechanisms better and validate the potential of RA for clinical use.

3-demethyl-2-geranyl-4-prenylbellidifoline (DGP), a natural xanthone isolated from Garcinia achachairu, has previously demonstrated remarkable diuretic and renal protective actions. The present study expands its actions on the cardiovascular system by evaluating its vasorelaxant and blood pressure-lowering effects in spontaneously hypertensive rats (SHRs). Aortic endothelium-intact (E+) preparations of SHRs pre-contracted by phenylephrine and exposed to cumulative concentrations of G. achachairu extract, fractions, and DGP exhibited a significant relaxation compared to vehicle-only exposed rings. The non-selective muscarinic receptor antagonist (atropine), the non-selective inhibitor of nitric oxide synthase (L-NAME), as well as the inhibitor of soluble guanylate cyclase (ODQ) altogether avoided DGP-induced relaxation. Tetraethylammonium (small conductance Ca²⁺-activated K⁺ channel blocker), 4-aminopyridine (a voltage-dependent K⁺ channel blocker), and barium chloride (an influx-rectifying K⁺ channel blocker) significantly reduced DGP capacity to induce relaxation without the interference of glibenclamide (an ATP-sensitive inward rectifier 6.1 and 6.2 K⁺ channel blocker). Additionally, administration of DGP, 1 mg/kg i.v., decreased the mean, systolic, and diastolic arterial pressures, and the heart rate of SHRs. The natural xanthone DGP showed promising potential as an endothelium-dependent vasorelaxant, operating through the nitric oxide pathway and potassium channels, ultimately significantly reducing blood pressure in hypertensive rats.