Help for SARS Found in Red Onions?
by Bill Sardi
Hundreds of people die of infectious respiratory disease in China every day. But the fear is that SARS (severe acute respiratory syndrome), which has only killed a few hundred people since November of 2002, represents an unusual jump of a viral pathogen from animals to man. Coronaviruses generally mutate rapidly and cause upper respiratory disease, whereas the SARS coronavirus causes lower-lobe pneumonia and has not mutated over a 7-week monitoring period. This virus is not mutating into a weaker version as health authorities had hoped.
Corona viruses are a family of RNA viruses that often infect animals like cats, dogs, pigs and cows and cause 10—20 percent of cases of the common cold in humans. But the animal coronaviruses generally do not affect humans, until now.
Even though there are anti-viral drugs, there is no specific cure for SARS as yet, and researchers are urgently in search of an effective treatment. Reports in the news media describe the use of a synthetic protein inhibitor, called a peptide blocker, which may be able to control SARS. The protein or enzyme inhibitor drug, which already exists under the trade name bestatin (ubenimex), blocks the entry of RNA viruses like SARS coronavirus into cells. [The Lancet, volume 361: May 3, 2003; Clinical Experimental Metastasis, volume 10: 49—59, 1992] It does this by inhibiting the enzyme called aminopeptidase N.
A Medline search of the National Library of Medicine reveals a compound found naturally in red onions and the peel of red apples has the same biochemical action as bestatin (ubenimex) and may prove to be a natural remedy against SARS. The natural molecule, called quercetin, has the same or similar biochemical action as bestatin. A whole red onion provides about 30 milligrams of quercetin. Quercetin is widely sold as a dietary supplement in health food stores and is produced commercially by a number of pharmaceutical companies in China.
The February 1990 issue of the German medical journal Pharmazie, describes the ability of plant molecules, especially quercetin, in neutralizing aminopeptidase N, the specific enzyme that permits RNA coronaviruses to invade living cells. [Pharmazie, volume 55, 129—32, 2000]
Quercetin has other remarkable anti-viral properties, having been shown to be active against herpes simplex, adenoviruses, rotaviruses, paramyxoviruses, polio virus, parainfluenza and respiratory synctial virus. [Journal Medical Virology, volume 15: 71—79, 1985; Microbiologica, volume 13, 207—13, 1990]