Cleopatra VII (69 BC - 30 BC)

 
According to some sources, Cleopatra committed suicide on this day in 30 BC [On this day: August 30]. Other sources say it was August 12th and still others claim that it was on the last day in August.

The situation was serious. The armies of Mark Antony and Cleopatra has just deserted to Octavian and Antony had committed suicide. Cleopatra was a prisoner in Alexandria. She had no hope of escaping Octavian.

Legend has it that she died after being bitten by an asp but it wasn't the modern asp, Vipera aspis, since that snake is only found in Europe. It's likely that the Romans used the word "asp" to describe all poisonous snakes. If it's true that Cleopatra used a snake to commit suicide then it was most likely the Egyptian cobra Naja haje that did the deed [Cleopatra’s Asp].

Corba venom contains a number of toxins and enzymes. For the biochemist, it's most famous for the presence of phospholipase A₂, an enzyme that cleaves glycerophospholipids, the main components of cell membranes. This leads to disruption and death of cells, especially red blood cells and lymphocytes in the blood stream. A picture of cobra venom phospholipase A₂ bound to a lipid molecule (left) can be found in most biochemistry textbooks.

Hyaluronidase is an enzyme found in many snake venoms. It degrades hyaluronic acid, a complex carbohydrate of the sort found in many glycoproteins. Hyaluronic acid is an important component of cartilage where it forms a central strand for attachment of proteoglycan molecules. The breakdown of cartilage lining the blood vessels leads to massive hemorhaging. The combination of phospholipase A₂ and hyaluronidase could eventually lead to death but it probably wasn't the immediate cause of death for Cleopatra. As it turns out, there are other things in the cobra venom that are even more lethal.

These other components of cobra venom include various cobra venom factors that interfere with the complement pathway leading to an extreme over-stimulation similar to that seen in septic shock. The venom also includes a number of neurotoxins that gain access to the central nervous system when blood vessels break down. The combination of all these proteins can cause death within minutes of receiving a cobra bite. However, many people survive cobra bites suggesting that the Cleopatra story may not be true.

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[The painting is The Death of Cleopatra by Reginald Arthur (d. 1896), 1892 [The Death of Cleopatra.]]