Positive Health Online

Abstract

KIM and COLLEAGUES, Department of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07101-1709, USA.  kimda@umdnj.edu investigated how the Chinese herb Danshen acts in reducing hypertension.

Background

Danshen, a Chinese herb, reduces hypertension in Oriental medicine. The authors hypothesized that Danshen acts partially through endothelial nitric oxide synthase (eNOS) signaling mechanisms.

Methodology

The authors tested the hypothesis using tanshinone II(A), an active ingredient of Danshen, and the two-kidney, one-clip renovascular hypertension model in hamsters.

Results

Oral tanshinone (50 microg/100 g body wt) reduced mean arterial pressure (MAP) from 161.2 +/- 6.9 to 130.0 +/- 7.8 mmHg (mean +/- SE; P < 0.05) in hypertensive hamsters. MAP in sham-operated hamsters was 114.3 +/- 9.2 mmHg. Topical tanshinone at 1 microg/ml and 5 microg/ml increased normalized arteriolar diameter from 1.00 to 1.25 +/- 0.08 and 1.57 +/- 0.11, respectively, and increased periarteriolar nitric oxide concentration from 87.1 +/- 11.3 to 146.9 +/- 23.1 nM (P < 0.05) at 5 microg/ml in hamster cheek pouch. N(G)-monomethyl-L-arginine inhibited tanshinone-induced vasodilation. Hypertension reduced eNOS protein relative to sham-operated control. Tanshinone prevented the hypertension-induced reduction of eNOS and increased eNOS expression to levels higher than sham-operated control in hamster cheek pouch. Topical tanshinone increased normalized arteriolar diameter from 1.0 to 1.47 +/- 0.08 in the cremaster muscle of control mice and to 1.12 +/- 0.13 in cremasters of eNOS knockout mice. In ECV-304 cells transfected with eNOS-green fluorescent protein, tanshinone increased eNOS protein expression 1.35 +/- 0.05- and 1.85 +/- 0.07-fold above control after 5-min and 1-h application, respectively. Tanshinone also increased eNOS phosphorylation 1.19 +/- 0.07- and 1.72 +/- 0.20-fold relative to control after 5-min and 1-h application.

Conclusion

These data provide a basis to understand the action of a Chinese herb used in alternative medicine. The authors conclude that eNOS stimulation is one mechanism by which tanshinone induces vasodilation and reduces blood pressure.

References

Kim DD,  Sanchez FA, Duran RG,  Kanetaka T AND Duran WN. Endothelial nitric oxide synthase is a molecular vascular target for the Chinese herb Danshen in hypertension. American Journal of Physiology - Heart & Circulatory Physiology. 292(5): H2131-7. May 2007.