TRIBULUS TERRESTRIS AND CARDIOVASCULAR HEALTH

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 ^[3](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^[4]. 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^[5].

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^[6]. 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^[7]. 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^[8]. 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^[9]. It has even been shown to prevent degenerative changes in the brain that are induced by a high cholesterol diet^[10]. 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^[11]. It directly relaxes the smooth muscle of the vasculature by increasing nitric oxide synthesis^[12]. Tribulus has also been demonstrated to have a significant diuretic effect^[13].

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.