They added that cholinergic neuronal loss in the brain was a major feature of Alzheimer’s disease, senile dementia, ataxia, neuromuscular disease myasthenia gravis and Parkinson’s disease.
However, pharmacological drugs used to inhibit cholinesterases – the latter are the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) which play a key role in cholinergic transmission – and treat these diseases had side effects: gastrointestinal disturbances, nausea, vomiting and diarrhea, as well as bioavailability problems, the scientists said.
“Because of this, researchers are seeking natural AChE and BuChE inhibitors with a better safety profile,” Gironés-Vilaplana et al. wrote, hence their novel research on lemon or black chokeberry compounds as cholinesterase inhibitors.
Rich phytochemical sources
Lemons were a rich nutrient and phytochemical source – flavonoids, citric acid, vitamin C and minerals – and provided an interesting design matrix for new beverages, the team explained.
They added that the fruit was also a suitable source of value-added products since overproduction and non-marketable fruits meant that the crop currently caused agrowaste problems.
Black chokeberry (an astringent berry derived from a shrub native to North America) is a rich source of phenolic antioxidants, quercetin derivatives and hydroxycinnamic acids and vitamin C.
Studies have linked the fruit to anti-proliferative effects against cancer cells (for instance, Lala et al. 2006), and other work has suggested anti-mutagenic, hepato-protective (ability to prevent liver damage) cardio-protective and anti-diabetic effects.
Gironés-Vilaplana et al. added black chokeberry concentrate to fresh lemon juice at 5% w/v (g/ml) and characterised its functional activity and phytochemical profile.
Using in vitro enzyme studies, the team screened the juice for substance bioactivity against the two cholinesterases, and found that the blend (5% black chokeberry concentrate in lemon juice blend measured against controls: lemon juice alone, and 5% chokeberry in citric acid) had the strongest effects against both.
Natural alternative to drugs?
Flavanols in both lemons and black chokeberries – and C-glycosol flavones (a class of flavonoids) in lemons (previously demonstrated to be cholinesterase inhibitors) may have led to the results, the team said.
“This effect was considerably lower than that of the pharmacological drugs used to treat neurological drugs used to treat neurological diseases, such as galantamine. However, this new blend represents a natural alternative, which can be taken every day, without side effects,” Gironés-Vilaplana et al. wrote.
The team added: “Our results are very promising, because until now cholinesterase inhibitory activity of lemon juice or black chokeberry has not been reported, as far we know.”
Further metabolic and biological studies were necessary, as well as the search for more sources of bioactive phytochemicals possessing these characteristics, Gironés-Vilaplana et al. said.
