Potential low toxic alternative for Na-Cl cotransporter inhibition: A diuretic effect and mechanism study of Pyrrosia petiolosa

BACKGROUND

Hydrochlorothiazide, a diuretic commonly used for the treatment of hypertension, is often associated with serious metabolic side effects. Pyrrosia petiolosa (Christ) Ching is a traditional Chinese medicine that possesses diuretic properties, without any obvious side effects.

AIM

To evaluate the diuretic effect of P. petiolosa (Christ) Ching and to elucidate its underlying mechanism of action.

METHODS

Extracts obtained from different polar components of P. petiolosa (Christ) Ching were analyzed for toxicity in a Kunming mouse model. The diuretic effects of the extracts were compared to that of hydrochlorothiazide in rats. In addition, compound isolation procedures, cell assays of Na-Cl cotransporter inhibition and rat diuretic test of monomeric compounds were conducted to identify the active ingredients in the extract. Subsequently, homology modeling and molecular docking were performed to explain the reason behind the diuretic activity observed. Finally, LC-MS analysis was used to elucidate the underlying mechanism of action of P. petiolosa (Christ) Ching.

RESULTS

No toxicity was observed in mice administered P. petiolosa (Christ) Ching extracts. The ethyl acetate fraction showed the most significant diuretic effect. Similar results were obtained during the analysis for Na+ content in rat urine. Further separation of P. petiolosa (Christ) Ching components led to the isolation of methyl chlorogenate, 2',3'-dihydroxy propyl pentadecanoate, and β-carotene. Results from cell assays showed that the Na-Cl cotransporter inhibitory activity of methyl chlorogenate was greater than that of hydrochlorothiazide. This result was again confirmed by the diuresis tests of monomeric compounds in rats. The molecular simulations explain the stronger interactions between the methyl chlorogenate and Na-Cl cotransporter. Of the compounds determined using LC-MS analysis, 185 were identified to be mostly organic acids.

CONCLUSIONS

P. petiolosa possesses significant diuretic activities without any obvious toxicity, with least two possible mechanisms of action. Further study on this herb is warranted.

[Prescription of furosemide in general medicine in Aquitaine: Prospective practice survey among universities general practitioners]

OBJECTIVES

Furosemide is essential in the management of patients with congestive heart failure, and provides important iatrogenic complications. We described the prescription of this treatment in general medicine, and tried to identify areas for optimizing its use.

PATIENTS AND METHOD

We carried out a prospective inventory of the prescription of furosemide with the general practitioners of the universities of Bordeaux, between May 1, 2017 and July 30, 2017.

RESULTS

We obtained data from 119 prescriptions of furosemide. The indications seemed well known, largely dominated by heart failure (67%) and its associated signs (24%). Clinical and biological follow-up (52%) and therapeutic education (42%) seemed relatively infrequent.

CONCLUSIONS

Our study confirms the central role of the general practitioner in the prescription of furosemide, the predominant place of heart failure in its indications and the iatrogeny observed. We identified areas of optimization of the safety and effectiveness of the treatment. The reinforcement of training concerning heart failure and its treatments, a better communication between specialties, the implementation of reference systems dedicated to the prescription of furosemide and prescription support software seem promising.