The main actives, accounting for many of the biological properties of Mirtoselect^®, are anthocyanins (anthocyanosides).

Nearly one thousand anthocyanins, and more than 15 anthocyanidins, exist in the vegetal kingdom, although the greater part of them occurs rarely^(1-2). The term anthocyanin was initially coined to indicate the substance responsible for the color of cornflower: it derives from the Greek term anthos=flower, and kuanos=blue, and refers to a group of water-soluble pigments responsible for red, pink, mauve, purple, blue, or violet color of most flower and fruits⁽³⁾.

Chemical structure of anthocyanins

The Vaccinium myrtillus L. (common name: bilberry or European blueberry) fruits are a well-known source of anthocyanins.
Prior et al.⁽⁴⁾ reported that Vaccinium myrtillus berries contain the highest amounts of anthocyanins in comparison with other berries, including those of Vaccinium angustifolium (also called "wild" (lowbush) blueberries) or V. corymbosum the most common cultivated specie in North America also called the Northern highbush blueberry. A linear relationship between ORAC and anthocyanins or total phenolics content has been shown thus not surprisingly Vaccinium myrtillus L. showed the highest ORAC result, followed by Vaccinium angustifolium L. samples.

The amount of anthocyanins in Vaccinium myrtillus L. berries ranges from 300 to 698 mg/100 g⁽¹⁾ and increases during the ripening process^(5-7).

Bilberry contains a balanced mixture (Table 1) of the five major anthocyanins aglycons (delphinidin-, petunidin-, cyanidin-, peonidin- and malvidin) bound to monosaccharides (glucose, galactose and arabinose).

	R	R1	R2	R3
Cyanidin 3-O-glycoside	OH	OH	H	arabinose or glucose or galactose
Delphinidin 3-O-glycoside	OH	OH	OH	arabinose or glucose or galactose
Malvidin 3-O-glycoside	OCH3	OH	OCH3	arabinose or glucose or galactose
Peonidin 3-O-glycoside	OCH3	OH	H	arabinose or glucose or galactose
Petunidin 3-O-glycoside	OH	OH	OCH3	arabinose or glucose or galactose

Table 1: Main anthocyanins of V. myrtillus L.

 

A HPLC profile of bilberry fruits shows a typical fingerprint characterized by the 15 major constituents of this fruit (Fig 1):

Fig 1: Fingerprint of V. myrtillus L. fruits

This profile is unique and is markedly different then the one of other fruits ^(8-9) including Highbush blueberry, Lowbush Blueberry, Cranberry...that are differing from the type of anthocyanins aglycones (Table 2) and/or the sugar moiety.

Fruit	Petunidin	Peonidin	Cyanidin	Delphinidin	Malvidin
Bilberry (Vaccinium myrtillus L.)	X	X	X	X	X
Blackcurrant	X		X	X
Cranberry		X	X
Blackberry			X
Lingonberry		X	X

Table 2: Concentration of anthocyanins grouped by aglycones

As an exemplification an HPLC chromatogram of black currant applying Indena's HPLC method  is hereunder reported. As clearly shown the major anthocyanins of blackcurrant contain rutinose, a sugar totally absent in bilberry anthocyanins. In fact, the two major peaks in the HPLC chromatogram of blackcurrant are totally absent in bilberry profile.

Fig 2: Fingerprint of Blackcurrant (Ribes nigrum L.) fresh fruit

Anthocyanidins present in low quantity in fresh bilberry fruits and in Mirtoselect^® (<1%), are anthocyanins without the sugar moiety and should be considered anthocyanin degradation products occurring when there has been incorrect extract production and/or storage. Anthocyanidins are rare in nature and the metabolism of the anthocyanins produces only trace amounts of bioavailable anthocyanidins.

 

 

1. Mazza G., Miniati E., “Anthocyanins in Fruits, Vegetables and Grains”, CRC Press (1993).
2. Andersen O.M. and M. Jordheim M., The anthocyanins. In: Anderson O.M., Markham K.R.: "Flavonoids, Chemistry, biochemistry and applications", CRC Press, Boca Raton, FL (2006), pp. 471–530.
3. Kumi Yoshida, Mihoko Mori and Tadao Kondo., "Blue flower color development by anthocyanins: from chemical structure to cell physiology", Nat. Prod. Rep., 2009, 26, 884-915, Review
4. Prior R.L., Cao G., Martin A., Sofic E., McEwen J., O’Brien C., Lischner N., Elhenfeldt M, Kalt W., Krewer G., Mainland C.M., "Antioxidant Capacity As Influenced by Total Phenolic and Anthocyanin Content, Maturity, and Variety of Vaccinium Species", J. Agric. Food Chem. 46, 2686 (1998).
5. Brenneisen R., Steinegger E., "Zur Analytik der Polyphenole der. Früchte von Vaccinium myrtillus L. (Ericaceae)", Pharm. Acta Helv. 56, 180 (1981).
6. Brenneisen R., Steinegger E., "Quantitativer vergleich del Polyphenole in Fruechten von Vaccinium myrtillus L. undersciedlichen Reifegrades", Pharm. Acta Helv. 56, 341 (1981).
7. L. Jaakola, K. Määttä, A.M. Pirttilä, R. Törrönen, S. Kärenlampi and A. Hohtola, "Expression of genes involved in anthocyanin biosynthesis in relation to anthocyanin, proanthocyanidin, and flavonol levels during bilberry fruit development", Plant Physiology 130 (2) (2002), pp. 729–739.
8. Kaisu R., Määttä-Riihinen KR, Kamal-Eldin A, Mattila PH, González-Paramás AM, Törrönen AR.,"Distribution and Contents of Phenolic Compounds in Eighteen
Scandinavian Berry Species", J. Agric. Food Chem. 2004, 52, 4477-4486
9. Internal Report: 01/08/LRA-00

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