Blood
About 98.5% of the oxygen in a sample of arterial blood in a healthy human breathing air at sea-level pressure is chemically combined with the hemoglobin. About 1.5% is physically dissolved in the other blood liquids and not connected to hemoglobin. The hemoglobin molecule is the primary transporter of oxygen in mammals and many other species (for exceptions, see below). Hemoglobin has an oxygen binding capacity between 1.36 and 1.40 ml O per gram hemoglobin, which increases the total blood oxygen capacity seventyfold, compared to if oxygen solely were carried by its solubility of 0.03 ml O per liter blood per mm Hg partial pressure of oxygen (about 100 mm Hg in arteries).
Umbellulone
Umbellulone induces rapid production of methemoglobine. Methemoglobine is a globin in the blood which mainly consists of ferric (Fe) haemoglobin instead of the usual ferrous (Fe) haemoglobin. Methemoglobin has a decreased ability to bind oxygen. But in combination with the 3 other ferrous irons on the hemoglobin unit, the oxygen release is also decreased. Red blood cells will be less able to nurture organs with oxygen. Therefore, the probability for a hypoxia increases. Methemoglobin lethality is possible at concentrations higher than 50% of the substance in red blood cells.