Tomatidine, a medicine against atherosclerosis from tomatoes
Tomatoes, and in particular other parts of tomato plants, contain a steroid-like substance called tomatidine. Results from Japanese in-vitro and animal studies suggest that the stuff prevents furring up of the arteries. Tomatidine lowers the concentration of the 'bad cholesterol' LDL in the blood, and inhibits the uptake of cholesterol by the immune cells that cause the arteries to harden.
The Japanese researchers' initial aim was to study the biological effects of the steroid-like esculeoside-A. One kilogram of ripe tomatoes contains half a gram of the substance.
Then they realised that the whole tomato plant – leaves, stems and roots – contain a compound that largely resembles it: tomatine. Tomatine is the precursor of esculeoside-A.
It should be possible to obtain the stuff from the waste products of tomato cultivation. Tomato leaves are a particularly good source: one kilogram of leaves contains one gram of tomatine.
In the end the researchers performed experiments with four substances: esculeoside-A and tomatine, and their bare analogues esculeogenin-A and tomatidine. The researchers made the 'bare' analogues by detaching the sugar groups from their mother compounds.
Tomatidine and esculeogenin-A sabotaged the uptake of cholesterol in human macrophages, the researchers discovered. Because the immune cells in the blood that soak up cholesterol play a crucial role in the clogging up of the blood vessels, tomatidine and esculeogenin-A may well work as medicines against atherosclerosis.
Tomatidine inhibits acyl-CoA:cholesterol acyl-transferase [ACAT], an enzyme that forms esters from cholesterol, which cells are able to store. There are two versions of this enzyme: ACAT1 and ACAT2, and tomatidine inhibits both.
The researchers then gave a group of lab mice that were genetically susceptible to atherosclerosis 50 mg tomatidine per kg bodyweight every day for 70 days. The human equivalent of this dose for someone weighing 80 kg would be about 400 mg per day.
"The total cholesterol levels significantly decreased by approximately 20% after the administration of 50 mg/kg/day tomatidine", the Japanese wrote. "Furthermore, administration of tomatidine significantly reduced the serum levels of LDL cholesterol by approximately 25%."
At the same time tomatidine inhibited the hardening of the arteries.
"The daily intake of tomatidine supplementation may also reduce the risk of cardiovascular diseases", the Japanese wrote. "The possibility that tomatidine may inhibit form cell formation and atherosclerosis by affecting targets other than ACAT activity will need to be examined in future projects."
You'll be seeing more posts on tomatidine in the near future. It's a substance with more interesting characteristics, some of which the readers of this blog - we know our onions - will find extreeeeemly interesting...
J Agric Food Chem. 2012 Mar 14;60(10):2472-9.
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