Phenolic compounds are widely distributed in plants. Over two dozen phenolic compounds have been isolated in maple syrup and evidence suggests that many more are present. In view of the well-established antioxidant activity these substances possess, it is suggested that it is the complexity of the mixture that makes maple syrup of particular interest rather than any one compound. These beneficial phenolic compounds make maple syrup a healthy choice as a sweetener.6
Additional information: This research isolated 24 phenolic compounds but evidence indicated the presence of many more. The total phenolic content of the maple syrup, however, is very small in proportion to the sugar content (about 20 ± 5 mg/10 mL of syrup, 0.2% by dry weight). However, it is suggested that the biological activity may aid in overcoming any negative effects of the high sugar content of the syrup on humans, thus, indulging a sweet tooth, and is most likely, as suggested by Theriault et al. (2006), not related so much to any particular compound as to the overall complexity of the mixture.
Over 20 antioxidant compounds have been discovered in pure maple syrup that have been linked to human health. Several of these antioxidant compounds are reported to have anti-cancer, anti-bacterial, and anti-diabetic properties. The amount of the effect is yet to be determined but the presence of these beneficial compounds in maple syrup is very interesting from a human health perspective. (Note: The number of antioxidant compounds discovered increased from 20 to 54 in 2011 from further research by these scientists.) 7
The results from research conducted by Legault, et al. in 2010 indicated that pure maple syrup possesses an interesting in vitro inhibition of cancer cell growth, with the strongest effect being found against prostate and lung cancer cells. Maple syrup extracts have also exhibited in vitro antioxidant and nitric oxide inhibition activities. The value of antioxidants in a protective role against cancer is well known. The ability of maple syrup to inhibit nitric oxide is also important as several works have shown that the overproduction of nitric oxide is a result of inflammation, a factor in the formation and development of cancer. Inhibiting nitric oxide results in inhibiting inflammation and thus may help to prevent diseases such as cancer.8
Phenolic compounds, widely distributed in plants, contribute to the colour and aroma of the food and may also have potential health benefits, including preventing or delaying the formation of cancer. The phenolic compounds present in maple syrup have antioxidant and antiradical activities as well as potential antimutagenic activities.9
Use of alternatives to refined sugar, such as pure maple syrup, can add to the cumulative antioxidant content of the diet by replacing refined sugar. This would increase antioxidant consumption similar to replacement of refined grains with whole grains.10
Maple syrup has been found to have antioxidant, antimutagenic, and human cancer cell antiproliferative properties (Ref: 8, 10).
Phenolic content was found to be higher at the beginning and at the end of the harvest season, for all three producers in the study conducted by Kermasha et. al. in 1995, the highest levels being at the end of the season. This differs from the study by Legault et. al. in 2010 where it was found that phenolic compounds were 29% lower and antioxidant activity 24% lower at the end of the season compared to the beginning. Phenolic compound concentrations were also found to differ among producers. These differences may be due to variations in harvest and processing as well as soil
and climatic conditions.11