Synephrine[meaning p-synephrine in most cases], is an alkaloid, occurring naturally in some plants and animals, and has been also supplemented in approved drugs products as its m-substituted analog known as neo-synephrine
[1].
Figure 1 Chemical structure of the synephrine. ;
Synephrine[Figure 1] is a key proto-alkaloid found in Citrus aurantium[bitter orange] and other Citrus species[C. reticulata, C. sinensis, C. deliciosa, C. limon, C.limonia, and C. unshiu] as well as in Evodia rutaecarpa[2-5]. It is widely used in weight management and sports performance products. Moreover, it is usually consumed in various foods and juices derived from Citrus species as Seville oranges, mandarin oranges and many other orange-related species containing p-synephrine[7,8]. However, p-synephrine may cause potential cardiovascular hazards as found in many previous studies
[9-11].
P-synephrine[P-s], often referred to as simply synephrine
[12], is an alpha-adrenergic agonist
[13] that also has some beta-adrenergic properties
[14]. P-s occurs naturally in the human body in small quantities and may act as a neurotransmitter
[15]. Since 1927, usually under the name oxedrine, it has been used as a pharmaceutical
[16], commonly in the form of eye drops. Oxedrine is thought to be the primary ingredient in C. aurantium that produces weight loss, but neither this nor whether C. aurantium produces weight loss in humans is firmly established. M-synephrine, often referred to as phenylephrine, is an isomer of p-s. It is also an alpha -adrenergic agonist that also has some beta-adrenergic agonist properties. It has been studied far more extensively than p-s and is one of the two most widely used OTC decongestants today
[12].
In Asian traditional medicine, synephrine was used in the treatment of digestive problems, to stimulate appetite and gastric secretion, in clear contrast with the aim of promoting weight-loss
[17]. In the Mediterranean region, it was used as a cardiac and vascular stimulant, with stomachic, sedative, and general tonic properties
[18]. Its most important and famous application is used for weight management, for the treatment of obesity.
