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Health Sciences

Health Sciences

Chemical of the Week

Chemical of the Week: Theobromine

July 3, 2013

Theobromine is an alkaloid chemical produced by the cacao plant and thus is found in chocolate. Its molecular structure is very closely related to that of caffeine and it has some of the same properties – such as acting as a stimulant – albeit to a lesser extent.

The theobromine molecule.

The theobromine molecule.

Although one might expect to find bromine in this chemical, its name is actually derived from the Greek phrase “food of the gods” which is a pretty good description of chocolate!
In addition to being a weak stimulant, theobromine also has some other physiological effects. It can act as a diuretic and has been found to be better than codeine at stopping persistent coughs, due to its effect on the vagus nerve. Theobromine is also responsible for the fact that chocolate is toxic to dogs and some other animals.

Chemical of the Week: Tubocurarine (the “poison arrow” toxin)

June 24, 2013


The tubocurarine molecule.

Tubocurarine is an alkaloid found in the bark of a South American vine. It is one of a number of toxic compounds known under the general name of “curare.” Tubocurarine is capable of paralyzing muscle tissue by interfering with the transmission of the nerve impulses which normally control muscle movement. For this reason, it only affects voluntary muscles (not the heart muscle, for example). However, since the diaphragm is a voluntary muscle, it can be fatal by inducing asphyxiation.
Traditionally, curare poisons have been used by South American hunters to coat arrows and darts in order to kill prey. Interestingly, curare does not pass through the digestive tract and so poisoned prey can be eaten without harm! Tubocurarine has also been used as a muscle relaxant during surgery to prevent unwanted movement of the patient, although it has now largely been replaced by synthetic drugs which provide the same effect but more safely.

Chemical of the Week: Oxytocin (or “Cupid’s Secret”)

June 19, 2013

Oxytocin is a naturally occurring hormone common to many mammalian species, including humans. It is a peptide composed of nine amino acids which is synthesized in the hypothalamus and released from the pituitary. One of the main roles of oxytocin is to stimulate contractions during child birth, hence its name, which derives from the Greek phrase “quick birth.”

The oxytocin molecule.

The oxytocin molecule.

The interesting thing about oxytocin is that it is one of those amazing chemicals which affect mood and social behaviour. It is sometimes referred to as the “cuddle hormone” because elevated levels in the nervous system induce feelings of trust and affection between individuals. Release of oxytocin from the brain appears to be connected with the development of social groups, mother-child bonding and bonding between couples.