Planta Med 2020; 86(07): 496-504
DOI: 10.1055/a-1123-7852
Biological and Pharmacological Activity
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Vasorelaxant and Antihypertensive Effects of Neferine in Rats: An In Vitro and In Vivo Study

Piyawadee Wicha
1   Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
,
Amnart Onsa-ard
2   Division of Biochemistry, School of Medical Sciences, University of Phayao, Phayao, Thailand
,
Waraluck Chaichompoo
3   Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand
,
Apichart Suksamrarn
3   Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok, Thailand
,
Chainarong Tocharus
1   Department of Anatomy, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
› Author Affiliations

Supported by: The Thailand Research Fund DBG6180030
Further Information

Publication History

received 02 September 2019
revised 02 February 2020

accepted 14 February 2020

Publication Date:
27 March 2020 (online)

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Abstract

The present study was performed to examine the antihypertensive effect of neferine in hypertensive rats and its relaxant mechanisms in isolated rat thoracic aorta. The antihypertensive effect was evaluated by tail-cuff methods on NG-nitro-L-arginine methyl ester (L-NAME) (40 mg/kg BW) 4-week hypertensive-induced hypertensive rats. The vasorelaxant effect and its mechanisms were studied by the organ bath technique in the thoracic aorta isolated from normotensive rats. The results indicated that the treatment of neferine (1 mg/kg and 10 mg/kg) markedly decreased the systolic blood pressure (SBP) when compared with the hypertension group (137.75 ± 10.14 mmHg and 132.23 ± 9.5 mmHg, respectively, p < 0.001), without affecting the heart rate. Moreover, neferine (10−12 − 10−4 M) exhibited concentration-dependent vasorelaxation in endothelium-intact rings (Emax values = 98.95 ± 0.66% and pD2 = 7.93 ± 0.28) and endothelium-denuded rings (Emax values = 90.61 ± 1.91% and pD2 = 6.85 ± 0.36). The effects of neferine were reduced by pre-incubation with L-NAME and 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ) but not with pre-incubation with indomethacin and K+channel blockers. Neferine attenuated the contractions induced by phenylephrine and caffeine in a Ca2+-free solution and also inhibited in CaCl2- and phenylephrine-induced contracted rings. Our study suggests that neferine exhibited hypertensive potential, induced vasorelaxation through the endothelium nitric oxide synthase (eNOS)/nitric oxide (NO)/soluble guanylyl cyclase (sGC) pathway and involved the modulation of Ca2+ influx through Ca2+ channels and intracellular Ca2+ release from the sarcoplasmic reticulum.