Strawberries (Health aspects)
Materia medica, Vegetable (Usage)
Materia medica, Vegetable (Health aspects)
Plant extracts (Usage)
Plant extracts (Health aspects)
Animal models in research (Usage)
Blood clot (Prevention)
|Publication:||Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 National Herbalists Association of Australia ISSN: 1033-8330|
|Issue:||Date: Spring, 2009 Source Volume: 21 Source Issue: 1|
|Topic:||Event Code: 310 Science & research|
|Product:||Product Code: 0171195 Strawberries NAICS Code: 111333 Strawberry Farming SIC Code: 0171 Berry crops|
|Geographic:||Geographic Scope: Australia Geographic Code: 8AUST Australia|
Mudnic I, Modun D, Brizic I, Vukovic J, Generalic I, Katalinic V et
al. 2009. Cardiovascular effects in vitro of aqueous extract of wild
strawberry (Fragaria vesca L) leaves. Phytomed article in press
While consumption of the strawberry fruit (Fragaria vesica) has been linked to many health benefits, including anticarcinogenic, and antithrombotic effects, there has not been much research into the pharmacological potential of the leaves, which are also a concentrated source of bioactive compounds. The fruit, particularly the wild strawberry, is high in phenolic compounds and substantially increases serum antioxidant levels in humans when eaten. As wild strawberry leaves are widely used by the general public as a herbal tea in Croatia, researchers became curious about their potential health benefits.
The study examined direct, dose dependent effects of aqueous extract of F. vesica leaves in two experimental models and animal species. Researchers examined the impacts upon heart contractility, electrophysiological function, coronary flow and oxygen extraction in isolated guinea pig hearts, and the direct vasodilatory activity of the extract on rat aortic rings. In order to have a reference standard they compared the vasodilatory potential with that of hawthorn (Crategus oxycantha) leaves and flowers. The extracts were also chemically analysed for their total phenolic content and related antioxidative capacity.
In the isolated hearts, strawberry extract was applied at concentrations of 0.06, 0.18, 0.6 and 1.8 mg/100 mL and perfused for 3.5 minutes with 15 minute washout periods. At the time scientists continually monitored heart contractility, electrophysiological activity, coronary flow and oxygen consumption. While there was no impact on heart rate or contractility, coronary flow increased by up to 45%, with a simultaneous 34% decrease in oxygen extraction. This disproportionate decrease indicates that the extract that acts as a direct vasodilator blunted autoregulation of coronary flow.
The isolated aortic rings of 24 rat hearts were then exposed to the extract at doses of 0.06, 0.6, 6 and 60 mg/100 mL in order to assess vasodilatory activity. This activity was compared to the standard vasodilatory potential of a hawthorn extract. Both extracts produced comparable, dose dependent vasodilation with maximal relaxation of 72.2+/-4.4% and 81.3+/-4.5% relatively. Finally in order to evaluate the role of endothelium, nitric oxide (NO) and cyclooxygenase products in producing this action, scientists formed three sub groups of rings, one of which was endothelium deprived. There was complete loss of vascular responsiveness in this aforementioned group, suggesting that the mechanism of action of F. vesica extract is endothelium dependant. Further testing of the subgroups indicated that nitric oxide and cyclooxygenase-products mediated this effect.
Phenolic fingerprinting identified various phenolic compounds, including procyanidin B1, procyanidin B2 and resveratrol as some of the active compounds. Researchers concluded that none of these individual compounds was solely responsible for vasodilatory activity, rather that it was likely to be an effect of a blend of polyphenols.
Overall the results of the study show F. vesica leaves, prepared as an aqueous extract, to be a potent endothelial dependant vasodilator acting via mediation of nitric oxide and cyclo-oxygenase products. Its potency is similar to hawthorn.
Tessa Finney-Brown MNHAA
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