The basis of ED herbal therapies is that they are anti-inflammatory, antioxidant and immunomodulatory, and can stimulate testosterone production. On the other hand, the synthetic drugs act via NO. The principal mediator of the relaxation of corporal smooth muscle of the penis has been shown to be NO, which is released mainly from parasympathetic nerves and endothelium . NO is believed to relax the corporal smooth muscle by activating soluble guanylate cyclase to increase cGMP content [14,15]. Penile rigidity depends on maximizing inflow of blood while minimizing outflow . The increased blood flow in the cavernous sinuses puts pressure on the walls of the surrounding veins, causing the lumen of the veins narrow, temporarily interfering with the flow of blood but causing tumescence. Normally, the parasympathetic nerve produces Ach. Ach acts on muscarinic receptors and nicotinic cholinergic receptors. When the parasympathetic nerve is stimulated, preganglionic neurons release Ach at the ganglion, which acts on nicotinic receptors on postganglionic receptors. Postganglionic neurons then release Ach to stimulate muscarinic receptors of the target organs. The muscarinic receptor M3, present in the endothelial cells and smooth muscle, is activated, and the M2 receptor in the heart may also be activated. This may result in the production of Ach, which can cause endothelial cells to produce NO. Ach released from postganglionic parasympathetic nerves acting through G-protein-mediated muscarinic receptors and nicotinic cholinergic receptors helps to release NO. Normally, M1, M2 and M3 receptors are found in secretory glands, heart, smooth muscle and endothelial cells, respectively. M1, M2 and M3 receptors cause activation of phospholipase C and generate inositol trisphosphate and diacylglycerol, which increase calcium. Activation of M4 may inhibit adenylate cyclase, decreasing the messenger cyclic AMP. This mechanism may be involved in the relaxation and contraction of cavernosal smooth muscle cells.
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.
Gingko biloba: this is an example of a tonic herb that equilibrates our body systems. When tired it energizes and when stressed it relaxes the individual. It increases blood circulation which better prepares the male for the heart-racing excitement of sex. Early reference to its medicinal use was in 2900 BC Chinese Materia medica which believed it increased sexual energy. Gingko’s circulation enhancer called terpene lactone increases cerebral as well as genital blood flow and its significantly increased production of dopamine, adrenaline and other neurotransmitters in the brain improves pleasure arousal and alertness (5).