*** Tribulus Terrestris: Bulgarian v The Rest of the World ***
By Dean Farley of Tierra Supplements

The theory behind Tribulus Terrestris' effects is its ability to trigger the body into releasing luteinizing hormone (LH), which in turn stimulates development of the interstitial cells of the testes that secrete the hormone testosterone.

The active constituents of tribulus are steroidal saponins of two types; furostanols and spirostanols. Studies suggest the furostanol steroidal saponins are not bio-active and must be first converted to spirostanols to become so. The saponin content will vary depending upon the identity of the plant, the source of saponin within the plant (e.g. seed, fruit, and leaves) and the conditions under which the plant is grown. The method of extraction will also affect the concentration of saponins. Using a special method of harvesting and pharmaceutical preparation, Bulgarian Tribulus Terrestris has a very high concentration of steroidal saponins, hence it's higher cost. The phytochemistry of Chinese and Indian Tribulus is considerably different from that of the Bulgarian, also Chinese and Indian Tribulus is made from a different part of the plant.

There are three groups of active phytochemicals in Bulgarian Tribulus Terrestris:

1. Dioscin, protodioscin, diosgenin, etc. These have an effect on sexual performance and may treat various sexual disorders, sexual energy level and strength by increasing the percentage of free testosterone level for men, and affects pregnenolone, progesterone, oestrogen, etc.

2. Sterols - betasitosterols, stigma, etc, which protect the prostate from swelling and in combination with the X steroidal saponins (third group listed below), protects the prostate from cancer.

3. Proprietary steroidal saponins currently referred to as X steroidal saponins. These affect the immune system and have been demonstrated to possess anti-bacterial and anti-viral (particularly anti-herpes) effects.

Chinese and Indian Tribulus Terrestris does not have the same pharmacological and physiological functions as Bulgarian Tribulus Terrestris. Theirs is used primarily as a diuretic and to treat kidney stones. At best, Indian and Chinese Tribulus Terrestris have but a trace of group 1, and contain virtually no X steroidal saponins. This could go some way to explaining the radical difference some people experience in the effects of Tribulus Terrestris from different sources, borne out by many posts on MuscleTalk with people disappointed with the results of non-Bulgarian Tribulus.

** Source of the following information: Townsend Letter for doctors and patients; Dec.2004 Kerry Bone

Quality Issues
Two studies have highlighted that most Tribulus products on the market are quite different from the Bulgarian extract (TLSE). The first study, conducted in the US, found that the level of protodioscin varied substantially with the plant part (leaf, stem or fruit) and origin (Bulgaria, India or China) of the Tribulus. Only leaf from Bulgaria was high in protodioscin. Analysis of products selected from the US market found deficiencies of protodioscin in the majority. The second study from Australia produced similar results. An Eastern European variety of Tribulus (from Slovakia) contained high levels of protodioscin in the leaf but none in the fruit. Leaf from Australia and India did not contain protodioscin. The principle of phytoequivalence dictates that, if the benefits demonstrated in a clinical trial are claimed for a herbal product, then that product must closely match the one used in the clinical trial. The Bulgarian clinical trials which have shown that Tribulus boosts libido and fertility and alleviates menopausal symptoms, all used Tribulus leaf rich in protodioscin collected from Bulgaria. Therefore only similar products might reasonably be expected to have the same effects. If a Tribulus product is made from the root or fruit of the plant, or is sourced from anywhere else other than Eastern Europe, it will probably contain low levels of protodioscin and so will be quite different from the Bulgarian standardized extract. The quality of Tribulus products is best assessed by high performance liquid chromatography as used in the two studies cited above.