At the beginning of July, Assoc. Prof. Dr. Stefka Valcheva - Kuzmanova, PhD, from the Department of Preclinical and Clinical Pharmacology made a public defense of her dissertation thesis, entitled "Psychopharmacological and Organoprotective Effects of Fruit Juice from Aronia Melanocarpa in Experimental Pharmacological Studies", for the award of the academic degree "Doctor of Science" in the academic field of Pharmacology.
Assoc. Prof. Kuzmanova, your interests in pharmacological studies of the plant are of a long duration. In 2005 you defended your first dissertation thesis on that topic. What are the aims and tasks of the study, recently presented by you?
My aim was to explore more specifically the psychopharmacological and organoprotective effects of the fruit juice from Aronia melanocarpa (Black chokeberry fruit) in experimental pharmacological studies. First of all, for this purpose, the content of polyphenol compounds had to be determined, which are the biologically active substances with the highest content in Aronia fruit juice. Also, it was important to examine in vitro the parameters, indicating the antioxidant activity of the fruit juice from the plant (its ability to prevent oxidative stress), since many of the beneficial effects are due precisely to it. The recent scientific data, proving the passing of polyphenols through the blood-brain barrier focused the research on searching for effects on the psychological state and behaviour. It was also interesting to examine the effects of the juice on damaged organs after the application of certain medications. We conducted the experiments on test rats.
How long did it take to conduct the research? How many test rats were used?
I began the first tests and experiments in 2006. Since then until the end of the study last year a total of 1226 laboratory rats were used. Most of the experiments were conducted in the laboratories of the Department of Preclinical and Clinical Pharmacology and at the Vivarium of MU-Varna, another part - at the Institute of Neurobiology, BAS, and one experiment was carried out at the Department of Pharmacology, MU-Pleven. We also had a very beneficial cooperation with the Department of Biochemistry, Molecular Medicine and Nutrigenomics at MU – Varna, with the Department of Pharmacology, Pharmacotherapy and Toxicology at the Faculty of Pharmacy at MU - Sofia, with the Department of Biochemistry at MU- Rijeka, Croatia, and a Laboratory in Plovdiv.
What did the results indicate?
As regards the composition of the juice we have found that the total content of polyphenols, which have been in the centre of attention recently, is about 2 times higher than that of the fruit juice from Rubus caesius (Blackberry) and about 1.5 times higher than that of the fruit juice from Punica granatum (Pomegranate), which are considered to be some of the richest in polyphenols fruits. The content of polyphenols is in direct relation to antioxidant activity, which precisely due to the higher content of polyphenols in aronia is higher than that of blackberry and pomegranate.
In what way does aronia juice affect the mind and mood of the test animals or in other words what are the so-called psychopharmacological effects?
A single dose of fruit juice from Aronia melanocarpa does not significantly affect the locomotor activity in rats. In sub-chronic administration (21 days and 30 days), depending on the dose, the locomotor activity and exploratory behaviour in rats is inhibited, without disturbing the habituation (adaptation) of the animals to the new environment. They become more relaxed, more sluggish, which indicates perhaps a sedative (relaxing) effect. This effect could be manifested in humans, as well. We have also found that the anxiety of test animals is reduced, both after a single dose and after sub-chronic administration of the juice. In single dose administration this effect is not accompanied with sedation and impairment of working memory. In sub-chronic administration the juice improves learning abilities and memory in young / healthy rats. Furthermore, it reduces the symptoms of depression in rats.
Would you tell us more about the organoprotective effects of aronia juice in rats? What kind of protection of organs is concerned?
This concerns the impairment of certain organs in use of a certain medicament, and respectively the protective effect of aronia juice administered before, during or after the toxic influence of the medicament. The research on the protective effects of fruit juice from Aronia melanocarpa in models of organ damages and oxidative stress indicate the important role of plant products in diabetes and drug toxicity. The rats used for the experiments, of course, were not sick to treat them with drugs and to monitor the adverse effects on organs. What we did was to deliberately damage a certain organ after administration of a medicament in a toxic dose.
For example, in inducing diabetes with streptozotocin in rats, we found that aronia fruit juice normalizes blood sugar and blood lipids, and prevents oxidative stress. In another model, we used the anti-arrhythmic drug amiodarone, which is capable of damaging the lung, causing irreversible damage - fibrosis (growth of connective tissue). In the experimental model of amiodarone-induced pulmonary toxicity, we found that the juice increases the resistance of alveolar-capillary membrane, reduces the signs of oxidative stress, inflammation and pulmonary fibrosis. In another model we used paracetamol, which is an exceptionally widely used drug with analgesic and temperature decreasing effect. At high doses, however, it is very toxic to the liver. In paracetamol -induced liver damage, aronia juice manifests hepatoprotective effect by preventing damage to the liver cells and prevents oxidative stress. In still another model, we used anti-cancer drug cisplatin, which is used for treatment of various tumors, but it has undesirable deleterious effects on kidney cells. In the model of cisplatin-induced toxicity on the cells of human embryonic kidney cell line HEK293T, the fruit juice from Aronia melanocarpa manifests a protective effect, as concentration dependent manner weakens the toxicity of cisplatin. In an experimental model of ethanol-induced oxidative stress, we found that the juice from Aronia melanocarpa prevents damage to cell membranes by free radicals, which are formed in the body during the metabolism of alcohol.
Of Mice, it has already become clear, and what can you say of men? Can we say what the psychopharmacological and organoprotective effects of aronia juice in humans are?
At this point we can assume that the established effects in animals will also be observed in humans. But in order to have a firm confirmation of this hypothesis, it is necessary to do clinical tests. Currently, we have the support of the University Management to plan such studies. Anyway, the studies made hitherto have contributed for the expansion of preclinical data on the effects of polyphenols on the functions of the central nervous system. So, I am positive that they will support the efforts to find natural products for the treatment of socially significant diseases such as depression, anxiety, and neurodegenerative diseases.
What about you, do you consume aronia juice?
Yes, we have a garden of aronia plants whose fruits we use for family consumption. On the Bulgarian market there are two production companies that offer high quality products from aronia - juice, nectar, syrup. Throughout all these years I have been working for the purposes of the study in cooperation with the agronomist Veselin Oreshkov from Troyan, who has been providing us with juice. What is valuable about aronia is that polyphenols, to a great extent, are preserved after heat treatment, and thus the products obtained after such treatment have pharmacological activity.
I've also heard that it is possible to make wine from aronia. And I wonder whether it contains the same features and benefits for the body.
Wine is usually made from a combination of aronia and grapes. Does it possess the same activities? Well, it needs to be investigated in order to come up with a definite answer.
Definitely, after this conversation we can't help craving for aronia juice!:-)
An interview of D. Velcheva