Writing in the journal Food Research International, researchers from the Indian Institute of Technology Guwahati reviewed 24 plants said to have antioxidant properties, and report that many could find provide alternatives to synthetic preservatives like butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT) to slow down the oxidative deterioration of food.
According to a 2003 report by Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts, tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by easier consumer acceptance and legal requirements for market access.
Herbs like Amaranthus paniculatus, Aerva lanata, Coccinia indica and Coriandrum sativum are used as vegetables in India, stated the researchers, and this indicates a relative safe history of use.
"As plants produce significant amount of antioxidants to prevent the oxidative stress caused by photons and oxygen, they represent a potential source of new compounds with antioxidant activity," wrote lead author Shahin Sharif Ali.
The researchers state that, among the 24 plants studied, a wide-range of antioxidant compounds are present, including flavonoids, tannins, phenolics, ascorbic acid and alkaloids.
In terms of using the extracts as nutritional ingredients is concerned, the researchers state that, although in vitro tests have been carried out regarding their antioxidant potential, in vivo tests still need to be performed.
"The clinical efficacies of many plant preparations used are not yet validated," they added.
However, many reports are available in India of the use of the herbs for liver protection and for diabetes management.
Moreover, other health benefits linked to the herbs include neuro-protection, potential anti-cancer activity, boosting heart health and reducing cholesterol levels.
Despite significant further research being necessary, the researchers highlight the potential of these extracts for use as antioxidant and value-added ingredients.
"Interestingly a vast majority of these plats are also available in other parts of the world," stated Ali.
"Therefore if a systematic investigation is initiated the traditional medicinal systems practised in India can offer promising leads for the discovery of potent antioxidants that can have therapeutic and dietary use globally," he concluded.
Antioxidant revenues are predicted to grow from 46m ($55m) in 2004 to 58m ($70m) in 2008, according to Frost and Sullivan.
Source: Food Research International (Elsevier)
Published on-line 12 October 2007 ahead of print, doi: 10.1016/j.foodres.2007.10.001
"Indian medicinal herbs as sources of antioxidants"
Authors: S. S. Ali, N. Kasoju, A. Luthra, A. Singh, H. Sharanabasava, A. Sahu and U. Bora