The researchers based at the Texas Agriculture Experiment Station have already shown that limonoids, of which eight different kinds have so far been characterised from extractions, reduce the ratio of LDL cholesterol to 'good' HDL cholesterol, improving the profile for a healthy heart.
The new research on neuroblastoma cells, submitted for publication in a scientific journal, adds to the potential benefits of the compound for future use by the food industry.
Neuroblastomas account for about 10 per cent of all cancers in children. Neuroblastoma cells died with relatively small amounts of concentrated limonoids, in 48 hours or less, said the researchers.
The citrus findings are important because limonoids induce no side affects, according to the researchers.
Limonoids, a major phytochemical class in citrus fruits, are not the only compounds to offer potential health benefits. A report commissioned by the Australian Citrus Growers Association suggested that the industry could promote the fruits for future mothers - due to their folate content - for blood pressure lowering - for the high potassium and low salt content - and for heart health, owing to the antioxidants, fibre, folate and phytochemicals present.
Dr Bhimu Patil, a plant physiologist at the Texas A&M University-Kingsville Citrus Center, noted that there is some work to go before the food industry can market purified limonoid extracts.
"It is very difficult to say whether these could be added to foods as we have not yet done any toxicity testing. However once such studies are completed, we may be able to start producing the isolated compounds in industrial scale with a partner," he told NutraIngredients.com.
He added that isolating the limonoid compounds is challenging "because some are present in very small concentrations".
The researchers are also hoping to learn how limonoids, not present in any other fruits or vegetables, work to fight cancer.
Structurally different from the flavonoids also found in citrus fruits, limonoids seem to work against cancer three ways: prevent it from forming, slow the growth of existing cancer and kill cancer cells.
Limonoids with a sugar unit attached, limonoid glucosides, are water soluble and tasteless and so could be a suitable food additive. These were also responsible for 'a dramatic effect' on cancer cell death.
Patil's lab is also examining whether the compounds vary among citrus species and at different times of the year.