Tribulus terrestris is well-known in the US for its beneficial effects on testosterone levels and men’s health. However, it is also an excellent herb for the cardiovascular system. Ayurveda and Traditional Chinese Medicine have long used tribulus to benefit the heart and vasculature. It has many effects that make it an effective therapeutic agent for these tissues.
Several studies have shown that the antioxidant capacity of tribulus and its constituent tribulosin (a saponin) can be very protective against ischemia and reperfusion induced cardiac damage[1, 2]. In addition to its antioxidant activities tribulus increases the activity of the free-radical scavenging SOD (super oxide dismutase) and PKC epsilon (protein kinase C epsilon) which is an enzyme that protects against damage in cardiac cells due to hypoxia. It also decreases the expression of the apoptotic proteins Bax and caspace-3. A related study found that tribulus could relieve cases of angina with a total efficacy rate of 82.3%. It achieved these results by dilating coronary arteries and improving cardiac circulation. The researchers also found that tribulus did not harm the liver or kidneys and had no side-effects.
Tribulus can also be beneficial while recovering from a heart attack. It was found to improve overall cardiac function and ejection fraction while prevent left ventricular remodeling during the early post-MI recovery period. In addition, it improved the patients’ lipid profiles. This combination of effects makes it a tremendous herb for post-heart attack recovery.
However, tribulus can also be beneficial for the cardiovascular system before a serious cardiac event. A study out of Lodz University in Poland recently found that tribulus extract can inhibit platelet aggregation when platelets are exposed to collagen. This is considered one of the major factors that lead to the development of atherosclerotic lesions. Tribulus does so by inhibiting the peroxidation of arachidonic acid. It has also been shown to block the effects of angiotensin II and hydrogen peroxide in the vasculature. These molecules can create proatherosclerotic changes in the blood vessels. In rabbits fed a high cholesterol diet, treatment with tribulus resulted in a 65% reduction in total cholesterol and a 55% reduction in triglyceride levels. More importantly, it also reduced damage to the endothelial lining of the blood vessels. It has even been shown to prevent degenerative changes in the brain that are induced by a high cholesterol diet. These results are significant given the prevalence of heart disease and atherosclerosis in our culture.
Tribulus can also have beneficial effects on blood pressure. One study found that tribulus decreased ACE levels in the body resulting in lower blood pressure levels. It directly relaxes the smooth muscle of the vasculature by increasing nitric oxide synthesis. Tribulus has also been demonstrated to have a significant diuretic effect.
These studies illustrate the myriad cardiovascular benefits of tribulus. Whether before or after the development of heart disease tribulus can promote heart health. Given the high levels of heart disease in North America this is an herb that deserves consideration for wider use.
-  Phytotherapy Research. 2015 Jun;29(6):933-43. doi: 10.1002/ptr.5336. Epub 2015 Apr 8.Tribulus terrestris (Linn.) Attenuates Cellular Alterations Induced by Ischemia in H9c2 Cells Via Antioxidant Potential. Reshma PL1, Lekshmi VS1, Sankar V1, Raghu KG1.
-  Acta Pharmacologica Sinica. 2010 Jun;31(6):671-8. doi: 10.1038/aps.2010.45. Epub 2010 May 10.Tribulosin protects rat hearts from ischemia/reperfusion injury. Zhang S1, Li H, Yang SJ.
-  Yao Xue Xue Bao. 2010 Jan;45(1):31-6.[Effect of gross saponins of Tribulus terrestris on cardiocytes impaired by adriamycin].[Article in Chinese] Zhang S1, Li H, Xu H, Yang SJ.
-  Yao Xue Xue Bao. 2009 Feb;44(2):134-9. Mechanisms of gross saponins of Tribulus terrestris via activating PKCepsilon against myocardial apoptosis induced by oxidative stress. Wang SS1, Ji YS, Li H, Yang SJ.
-  Zhong Xi Yi Jie He Za Zhi. 1990 Feb;10(2):85-7, 68.[406 cases of angina pectoris in coronary heart disease treated with saponin of Tribulus terrestris].[Article in Chinese] Wang B1, Ma L, Liu T.
-  American Journal of Chinese Medicine. 2007;35(2):309-16. Effects of Tribuli saponins on ventricular remodeling after myocardial infarction in hyperlipidemic rats. Guo Y1, Shi DZ, Yin HJ, Chen KJ.
-  Platelets. 2015;26(1):87-92. doi: 10.3109/09537104.2013.867426. Epub 2014 Feb 10. Extracts from Tribulus species may modulate platelet adhesion by interfering with arachidonic acid metabolism. Olas B1, Hamed AI, Oleszek W, Stochmal A.
-  Cell Physiology and Biochemistry. 2013;32(5):1299-308. doi: 10.1159/000354528. Epub 2013 Nov 22.Cellular and molecular mechanisms in vascular smooth muscle cells by which total saponin extracted from Tribulus terrestris protects against artherosclerosis. Li M1, Guan Y, Liu J, Zhai F, Zhang X, Guan L.
-  Acta Histochemica. 2009;111(6):488-500. doi: 10.1016/j.acthis.2008.06.004. Epub 2009 Mar 9. Influence of Tribulus terrestris extract on lipid profile and endothelial structure in developing atherosclerotic lesions in the aorta of rabbits on a high-cholesterol diet. Tuncer MA1, Yaymaci B, Sati L, Cayli S, Acar G, Altug T, Demir R.
-  Histology and Histopathology. 2009 Jun;24(6):683-92. Changes in the brain cortex of rabbits on a cholesterol-rich diet following supplementation with a herbal extract of Tribulus terrestris. Berkman Z1, Tanriover G, Acar G, Sati L, Altug T, Demir R.
-  Life Sci. 2003 Oct 24;73(23):2963-71. Study of antihypertensive mechanism of Tribulus terrestris in 2K1C hypertensive rats: role of tissue ACE activity. Sharifi AM1, Darabi R, Akbarloo N.
-  Journal of Ethnopharmacology. 2006 Apr 6;104(3):351-5. Epub 2005 Nov 9. Antihypertensive and vasodilator effects of methanolic and aqueous extracts of Tribulus terrestris in rats. Phillips OA1, Mathew KT, Oriowo MA.
-  Journal of Ethnopharmacology. 2003 Apr;85(2-3):257-60. Tribulus terrestris: preliminary study of its diuretic and contractile effects and comparison with Zea mays. Al-Ali M1, Wahbi S, Twaij H, Al-Badr A.