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Preserving the living and the dead

You only have to think of Egyptian embalmers or ayurvedic medicine, to realise that the preservative and medicinal uses of spices form one of the oldest of sciences. Spices used in traditional medicineYet, it is only in recent years that 'modern science' has started paying much attention to the properties of spices, reflecting the greater open-mindedness that now exists towards alternative systems of medicine, regarded as 'cranky' by most people in the west only a few years ago.

Spice research typically involves identifying 'active ingredients', the chemicals that give spices their healing or preserving potency. Scientists are usually also keen to know whether these chemicals will continue to work in an isolated, pure form. This generally reflects commercial interests, since the companies who fund such research are not planning to enter the spice trade; their hope lies in putting the beneficial properties of spices into a marketable form, like a vitamin supplement. For this, they need to know exactly what is the active element and how much of it is required to be beneficial.

For many 'natural remedies' this information is already well known. Garlic is probably the best known medicinal plant in the west, commonly taken as a cure for viral infections like influenza. Less well known is the fact that even small quantities of garlic, taken daily, can work to inhibit cancers and reduce cholesterol, thereby lowering the risks of heart disease. Other research into the health benefits offered by spices includes work on curry leaves and ginger, at the CSIRO in Adelaide, where both plants are being investigated for their anti-oxidant properties.

Adult-onset diabetes might, in future, also have a spice-based treatment; scientists at the US Agricultural Research Service in Maryland have found that an extract from cinnamon can restore the ability of cells to respond to insulin, the hormone that the body uses to control blood sugar levels. The beneficial effect is caused by the chemical methyhydroxy chalcone polymer, and in their laboratory tests MCHP increased the rate of glucose processing by up to twenty times. While some scientists are recommending diabetics to add cinnamon to their diets, this has not yet become official medical advice.

Spice preservatives

Cinnamon is just one of a large number of spices that have long been known to preserve food. Recent research has tried to find out exactly how effective the spice can be, over what time period, and in suppressing which bacteria. At Kansas State University, microbiologists have been testing the effectiveness of cinnamon and other spices in eliminating one of the most virulent bacterial causes of food poisoning, E.coli type 0157. Complications arising from the bacteria can include anaemia and kidney problems, and a serious outbreak can lead to fatalities. The Kansas researchers found that cinnamon added to apple juice that had been contaminated with E.coli, was able to kill 99.5% of the bacteria within three days, at room temperature. They also did tests on meat and sausage, and found that cinnamon, cloves and garlic all had a powerful ability to stop the growth of the bacteria. Other microbiologists in Tennessee have found that oils extracted from oregano, coriander and basil, also have strong anti-microbial properties. In future we may see more natural preservatives supplementing the synthetic compounds currently in use.

Post-harvest crop protection is another area with potential for spicy solutions. While farmers in some developing countries commonly use plants to protect their grain stores from insect attack, in America and Europe the normal practice is to use chemical fumigants. However, some insects have developed resistance to the more widely used chemicals, and other fumigants have been withdrawn because of the threat they pose to the environment. Hence the research by entomologists at Albany in California, into the potential of menthone, a naturally-occurring 'active ingredient' found in Japanese Mint (Mentha arvensis). The plant was the most successful of sixteen spices and medicinal plants that were tested for their ability to protect grain from the rice weevil (Sitophilus oryzae). The weevil is one of the most damaging pests of stored cereals, boring into grains to eat the kernel - reducing their nutritional content and exposing them to further damage from mould and heat. A menthone-based fumigant could have many advantages over the chemicals currently used; it would leave no harmful residues, would be easy to store, being neither flammable nor corrosive, and could be easily removed from grain by aeration. The researchers also believe it would not affect the nutritional quality of the grain, but they have yet to discover whether it would modify taste and smell.

The natural talents of the spice world are also being recognised outside of food and agriculture. An extract of cloves (Eugenio caryophyllata), eugenol, may provide an answer to the hazards posed by asbestos. Asbestos was routinely used as a fireproof material in buildings, until it was discovered that the mineral's fibres, when inhaled, caused lung cancer. Up to now, removing asbestos or making it safe has been an expensive and lengthy process, and even when exhaustive precautions are taken, fibres can remain present in the air for years. However, Italian chemists have discovered that when this clove extract comes in contact with asbestos, it hardens into a polymer, trapping the fibres, and potentially making the asbestos 'safe'. Further testing will be needed to find out whether asbestos sealed by the process could safely be left in buildings, or would still need to be removed and buried. This will depend in part on how stable the polymer turns out to be. The amazing longevity of Egyptian embalming might suggest that a spice-based sealant could well outlast our modern synthetic alternatives. Good news for asbestos removers and, hopefully, for spice growers.

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