Protodioscin is a steroidal

Steroid

A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

 saponin

Saponin

Saponins are a class of chemical compounds, one of many secondary metabolites found in natural sources, with saponins found in particular abundance in various plant species...

 compound found in a number of plant species, most notably in the Tribulus

Tribulus

Tribulus is a genus of plants found in many warm regions. The best-known member is T. terrestris , a widespread weed and also the source of a dietary supplement....

, Trigonella

Trigonella

Trigonella is a genus from the family Fabaceae. The best known member is the herb Fenugreek.-Species:The genus Trigonella currently has 37 recognized species:* Trigonella anguina Delile* Trigonella arabica Delile...

and Dioscorea

Dioscorea

Dioscorea is a genus of over 600 species of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates...

families. It is best known as the putative active component of the herbal aphrodisiac

Aphrodisiac

An aphrodisiac is a substance that increases sexual desire. The name comes from Aphrodite, the Greek goddess of sexuality and love. Throughout history, many foods, drinks, and behaviors have had a reputation for making sex more attainable and/or pleasurable...

 plant Tribulus terrestris

Tribulus terrestris

Tribulus terrestris is a flowering plant in the family Zygophyllaceae, native to warm temperate and tropical regions of the Old World in southern Europe, southern Asia, throughout Africa, and Australia. It can thrive even in desert climates and poor soil...

.

Extracts from T. terrestris standardised for protodioscin content have been demonstrated to produce proerectile effects in isolated tissues and aphrodisiac action in several animal species. The mechanism for these effects has not been clearly established, and while protodioscin has been demonstrated to trigger release of nitric oxide

Nitric oxide

Nitric oxide, also known as nitrogen monoxide, is a diatomic molecule with chemical formula NO. It is a free radical and is an important intermediate in the chemical industry...

 in corpus cavernosum

Corpus cavernosum penis

The corpus cavernosum penis is one of a pair of sponge-like regions of erectile tissue which contain most of the blood in the penis during penile erection...

 tissue, and also to produce statistically significant increases in the levels of the hormones testosterone

Testosterone

Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

, dihydrotestosterone

Dihydrotestosterone

Dihydrotestosterone is an androgen or male sex hormone. The enzyme 5α-reductase synthesises DHT in the prostate, testes, hair follicles, and adrenal glands...

 and dehydroepiandrosterone

Dehydroepiandrosterone

5-Dehydroepiandrosterone is a 19-carbon endogenous steroid hormone. It is the major secretory steroidal product of the adrenal glands and is also produced by the gonads and the brain. DHEA is the most abundant circulating steroid in humans....

in animal studies, evidence for efficacy in humans is limited and remains controversial.