Aristolone in Nardostachys jatamansi DC. induces mesenteric vasodilation and ameliorates hypertension via activation of the KATP channel and PDK1-Akt-eNOS pathway.

BACKGROUND: Nardostachys jatamansi DC. is a common medicinal herb used to treat cardiovascular diseases, particularly hypertension. Previously, our lab characterized the chemical compounds of N. jatamansi. However, the bioactive compounds of N. jatamansi and their mechanisms of action on blood pressure and blood vessels are unknown. PURPOSE: The vasorelaxant effects of the methanolic extract (MeOH ext.) of the roots and rhizomes of N. jatamansi, its main compounds, and their underlying mode of action, were investigated. METHODS: The main compounds of N. jatamansi were isolated and identified using UHPLC-TOF MS. The antihypertensive effect of N. jatamansi extracts and (-)-aristolone were determined using spontaneously hypertensive rats. The extracts, fractions, and compounds were also evaluated for their vasorelaxant effects on U46619 contractile responses in isolated thoracic aortic and mesenteric arterial rings. The endothelial-dependent relaxation, as well as the regulatory pathways and targets of (-)-aristolone, were studied in-vitro and ex-vivo. Molecular docking and biophysical characterization (Surface plasmon resonance) studies were utilized to investigate the molecular interaction between (-)-aristolone and the target protein. RESULTS: MeOH ext. (200 mg/kg) reduces the systolic and diastolic blood pressure in spontaneously hypertensive rats. MeOH ext. and its ethyl acetate fraction (EtOAc Fr.), but not the H2O fraction, had a significant relaxing effect on the thoracic aorta. (-)-aristolone and kanshone H from EtOAc Fr. induced vasorelaxation of the thoracic aorta and mesenteric artery. In human umbilical vein endothelial cells, (-)-aristolone treatment upregulated phosphorylation of Akt (T308) and eNOS. Molecular docking and surface plasmon resonance experiments revealed an interaction between (-)-aristolone and phosphoinositide-dependent protein kinase 1 (PDK1), an upstream protein kinase that phosphorylates Akt at T308. Treatment with PDK1 inhibitor PHT-427 and eNOS inhibitor L-NAME consistently inhibited (-)-aristolone-induced vasorelaxation. In addition, KATP channel inhibitor glibenclamide dramatically inhibited the vasorelaxant effects of (-)-aristolone and kanshone H in the endothelium-denuded thoracic aorta. Finally, (-)-aristolone lowers hypertensive rats' systolic and diastolic blood pressure. CONCLUSIONS: The extracts of N. jatamansi promote vasorelaxation and alleviate hypertension. The essential chemicals responsible for producing vasorelaxation effects are (-)-aristolone and kanshone H, which activate the PDK1-Akt-eNOS-NO relaxing pathway and stimulate the opening of the KATP channel. These findings point to N. jatamansi and aristolone as possible antihypertensive agents.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters.

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.