Tribulus terrestris (protodioscin) in the treatment of male infertility with idiopathic
oligoasthenoterato-zoospermia
A Adimoelja, L Setiawan, and T Djojotananjo
Academic Hospital Dr. Soetomo and Airlangga University, Surabaya, Indonesia
in First International Conference of Medical Plants for Reproductive Medicine in Taipei, Taiwan
(1995)
SUMMARY
Tribulus terrestris L (TTL) extract is a natural remedy that has been successfully tested clinically
for its use in the treatment of idiopathic oligoasthenoteratozoospermia (OTA). Here, we conducted
a double blind study of 45 infertile, married men with OTA. 36 men were treated with 500 mg
purified TTL (Libilov) 3 times daily for 3 months. Composing the controlled group, 9 men were
given placebo (sugar pills) for the same period of time. Spouses of 8 of the men in the treated group
successfully achieved pregnancies after treatment of their husbands, whereas no pregnancies
occurred in the spouses of the men in the control group. An improvement in the sperm morphology,
including that observed under conventional phase contrast microscopy as well as improvements in
acrosome morphology and reaction, seemed to account for the increased fertility after treatment. In
addition, TTL was also shown to increase the level of dehydroepiandrosterone (DHEA) and might
also contributed to the activation of cell membrane receptors and the production of weak androgens.
These, in turn, might additionally improve fertility by increasing the level of spermatogenesis.
ABSTRACT
Recently, herbal remedies have became popular in many Eastern as well as Western countries.
Many of the active ingredients of these remedies have been successfully purified and standardized,
resulting in a diversity of various extracts known as pythochemicals. Tribulus terrestris L (TTL) is
one of such herbal remedies that have been successfully tested clinically for its use in the treatment
of idiopathic oligoasthenoteratozoospermia (OTA) in male subjects. In this double blind study, 45
infertile married men with OTA were recruited. Thirty six men were treated with 500 mg purified
TTL (Libilov) 3 times daily for 3 months. 9 men were given sugar pills (placebo) to compose the
control group for the same period of treatment. Spouses of 8 men in the treated group achieved
pregnancies after treatment, whereas no spouse of the males in the control group did. No significant
differences (p > 0.05) in liver and kidney function tests, as well as serum sex hormone levels (FSH,
LH, PRL, T) were reported before and after treatment. The results of the semen analyses done
before and after treatment of both the control and the treated groups, however, showed a significant
increase in sperm concentration. Hence, the increased sperm concentration did not seem to
contribute to the successful pregnancies. No improvement of sperm motility were observed between
the two groups. There was, however, improvement in sperm morphology in the treated group (p >
0.05), which could explain the successful pregnancies in this group. Better sperm morphology was
observed microscopically by the conventional phase contrast procedure. TTL seemed to improve
the acrosome morphology of the sperm cells and enhanced the acrosome reaction, thus contributing
to increased fertility. The active component of TTL, termed protodioscin, was shown to increase the
level of dehydroepiandrosterone (DHEA), and might also have contributed to the activation of cell
membrane receptors and the activation of weak androgens, thus contributing to increased
spermatogenesis and fertility.
INTRODUCTION
In the late 20th century, herbal medicines became more popular, especially after scientific and
pharmacological efforts to identify active components were able to introduce standardization to this
field. This contributed very much to our understanding of the role of the natural bioactive
phytochemical components in traditional herbal medicines in benefiting human health and in
understanding its possible side-effects as well.
Tribulus terrestris L (TTL) is one such herbal remedy that has recently been scientifically studied,
purified, standardized and clinically tested for its usefulness or benefits in treating male infertility
due to oligoasthenozoospermia (Protich et al. 1984). The Tribulus plant has long been used as
herbal remedies in Eastern European and Asian countries to treat sexual disorders, such as
impotence or to treat infertility. Recent scientific research identified the active ingredient of TTL
extracts as a non-steroidal furostanol saponin, which constituted 45% or more of the purified extract
(Zarkova 1984).
Recently, the purified dry powder of TTL, in form of a tablet preparation, has been studied in a
multi-center study in Indonesia for treatment of infertile males diagnosed with idiopathic
oligoasthenoteratozoospermia (OTA) (Moeloek et al. 1994). The active ingredient of TTL extracts
has received approval by the Indonesian Food and Drugs Administration (POM), and is marketed
under the name of Libilov™. A total of 45 subjects were involved in this study: 36 of which were
treated and 9 of which were given placebo for the entire duration of the study. After 3 months, eight
(22%) of the infertile male subjects in the treated group succeeded in impregnating their spouses,
whereas no subjects in the control group did.
Semen analyses were conducted to determine the factor or factors responsible for the increased
fertility of the treated group, as compared to the control group. There was no significant difference
in conventional laboratory sperm analyses in both groups before and after treatment. Significant
improvements in sperm concentration, however, were observed for both the treated and the control
groups. Although this was a significant benefit, as sperm concentration also increased in the control
group, we concluded that this could not be the reason for the successful conception of the spouses
of the male subjects in the treated group. Preliminary data suggested that improved sperm
morphology, specifically improved acrosome reaction, might be the responsible factor. We are
currently conducting further research efforts to identify factors responsible for the increased fertility
of the treated group.
SUBJECTS AND METHODS
Six subjects from the Libilov treated group who had successfully impregnated their spouses, six
other subjects taken randomly from the treated group, and six subjects from the control group were
subjected to laboratory semen analyses. In vitro sperm-cervical mucus interaction test and in vivo
post-coital test were conducted (WHO 1987). Preliminary study on sperm acrosome morphology
was performed by the acrosin staining method (Pedersen, 1976; Schill 1976).
RESULT
Better penetration was observed in sperms from the treated group, which consisted of subjects that
successfully or unsuccessfully impregnated their spouses, as compared to that of the control group.
However, no significant differences were observed in sperm samples from within the treated
groups, i.e. between those who were successful in impregnating their spouses as compared to those
who were not.
Post-coital tests performed also suggested improvements in the treated group as compared to the
control group. There was, however, no significant difference between those who successfully
impregnated their spouses and those who did not.
Acrosin staining revealed a significant increase in the percentage of normal acrosomes in sperms
from the treated subjects who succeeded in impregnating their spouses. In contrast, no increase was
observed in sperms from both the control group subjects or from the treated subjects who were not
successful in achieving pregnancy in their spouses.
DISCUSSION AND CONCLUSION
The clinical study described in this paper resulted in successful fertilization in 22% of subjects that
took part as the treated group. Detailed analyses of the sperm from the treated and control groups
revealed that there were significant improvements in sperm morphology, especially the acrosome
reaction, but no significant differences in sperm concentration or motility. The improved spermcervical mucus interaction and improvements measured by the post-coital test suggested that the
increased acrosome reaction led to the improved sperm functions, thus resulting in successful
conception. A further study on the effect of TTL treatment on acrosome reaction is currently being
conducted.
The chemical structure of protodioscin is very similar to that of dehydroepiandrosterone (DHEA),
one of the most important hormones in the body. We speculate that protodioscin can stimulate the
production of DHEA, or can serve as a non-hormonal precursor to DHEA. Protodioscin-stimulation
of DHEA levels can also contribute to increased fertility, as DHEA has been reported in several
studies to be important in the process of sperm maturation in the epididymis. Furthermore, the
conversion of DHEA to testosterone or dihydrotestosterone, both potent androgens or sex hormones
important for spermatogenesis in the seminiferous tubules, can also contribute to increased fertility.
A better understanding of the function of DHEA in general health, and specifically in the male
reproduction and sexual functions, is therefore also important to our understanding of infertility and
its treatment.
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