Ginseng is the root of some Araliaceae plants, which grows in northeast China. Ginseng is the number one herb in TCM that is used to maintain the balance of the body and enhance the vital Qi energy. ED is said to be caused by Qi deficiencies in the Kidney and Liver and Ginseng helps to improve Qi flow to these organs, especially when used with acupuncture. It has been confirmed clinically to enhance erectile function. The ginsenosides are the main active components in ginseng that give it anti-inflammation, anti-tumor, antioxidant, as well as apoptosis inhibition and preventing the degeneration of neurons in dorsal penile nerves while reducing the oxidative stress in the corpus cavernosum. 1
Yohimbe A number of clinical trials have shown that the primary component of this bark from an African tree can improve sexual dysfunction associated with selective-serotonin reuptake inhibitors (SSRIs) used to treat depression. This herb has been linked to a number of side effects, including increased blood pressure, fast or irregular heartbeat, and anxiety. Yohimbe shouldn't be used without a doctor's supervision.
Currently, there are four orally active drugs are available to treat ED. These include: sildenafil citrate (Viagra [Pfizer, USA]), vardenafil hydrochloride (Levitra [Bayer, Germany]), tadalafil (Cialis [Eli Lilly, USA]) and avanafil (Stendra, Spedra [Vivus Inc, USA]). These drugs inhibit the enzyme phosphodiesterase type 5 (PDE-5), which is responsible for the hydrolysis of cGMP. PDE-5 inhibitors and cGMP act as effectors of dilation of smooth muscle of cavernosal bodies. PDE-5 inhibitors are contraindicated in patients taking any kind of nitrate therapy for angina, and may not be appropriate for men with certain health conditions, such as severe heart disease, heart failure, history of stroke or heart attack, uncontrolled high blood pressure or diabetes, and patients with pigmental retinopathy. PDE-5 inhibitors are less effective in men with diabetes and men who have been treated for prostate cancer. PDE-5 inhibitors are also not effective in men with retinitis pigmentosa, a genetic disease involving PDE-5 deficiency. The common side effects of PDE-5 inhibitors include gastrointestinal upset, headache, nasal congestion, back pain and dizziness. The PDE-5 inhibitors may interact with other medications including antihypertension drugs. Nonetheless, the PDE-5 inhibitors are generally safe and effective for most men. The primary mechanism of action of these drugs is through the mediation of NO. NO is one of the key molecules involved in ED. It is a short-lived, highly permeable, pleiotropic, gaseous molecule, secreted from the postganglionic cavernosal parasympathetic nerves, endothelium of the cavernosal blood vessels, platelets in the cavernosal sinuses and phagocytic cells (monocytes, macrophages and neutrophils). NO acts on platelets to inhibit platelets adhesion and aggregation. NO causes relaxation of the smooth muscle of the cavernosal blood vessels of the penis, leading to vasodilation, tumescence and stimulation. Release of NO in the corpus cavernosum of the penis during stimulation activates the enzyme guanylate cyclase, which results in increased levels of cGMP, producing smooth muscle relaxation in the corpus cavernosum and resulting in increased blood flow (5). NO is mainly produced from cavernosal nerves, which are nonadrenergic, noncholinergic nerves within the penis, and acting via its second messenger cGMP. It has been suggested that maintaining normal body weight and mild exercise, as well as dietary supplementation of folic acid, zinc, calcium, vitamin C, vitamin E and L-arginine, a precursor of NO, can support the biochemical pathway leading to NO release . NO is an effector molecule that is involved in a number of intracellular functions such as vasorelaxation, endothelial regeneration, inhibition of leukocyte chemotaxis and platelet adhesion . A small proportion of autonomic nerves do not release either Ach or norepinephrine . For example, the cavernous nerves predominantly release NO in the penis. The exact mechanism is not known, but it is believed to be through increased intracellular calcium. Another gaseous molecule produced in the corpora cavernosa is hydrogen sulphide (H2S), which is also known to be involved in erectile function . H2S activates ATP-sensitive potassium channels in smooth muscle cells. Some reports indicate that NO acts in large vessels and H2S in small vessels. A high level of tumour necrosis factor-alpha has been shown in ED patients . Although current ED therapies using PDE-5 inhibitors are safe and effective, approximately 40% of ED patients do not respond to currently available treatment [11,12]. For these patients, herbal therapy may be useful.
Maca root (Lepedium meyenii W): this native Peruvian root has been cultivated for thousands of years. Considered an integral part of the diet, the Incans found maca root so potent (14), it was restricted to royal use only. Known for its energy enhancing abilities, maca root enjoys a special place amongst herbalists and health seekers. Like ginseng, this plant is employed to increase strength, libido and sexual function (14). Clinically its effects have been proved with experimental animals (5,15).
A number of nonprescription products claim to be herbal forms of Viagra. Some of these products contain unknown amounts of ingredients similar to those in prescription medications, which can cause dangerous side effects. Some actually contain the real drug, which should be given by prescription only. Although the Food and Drug Administration has banned many of these products, some potentially dangerous erectile dysfunction remedies remain on the market.