The fruits of sea-buckthorn and black chokeberry present the rising interest, especially during the last decades, for medicine and healthy nutrition thanks to the content of natural constituents. The breeders try to create new varieties, forms, cultivars with valorous features (longer period of fruit maturity, fruit new quality – color, size, weight, value chemical composition) to satisfy the increasing needs of these fruits. That why in Dendrology Laboratory of the Botanical Garden of Academy of Science of Moldova has created new forms of sea-buckthorn and black chokeberry which would help ensure continued a longer period with fruits characterized by new chemistries.As biological material served the  fruits of new forms: 2 (1-13 and 3-13) of sea-buckthorn and 2 of black chokeberry (f and 2), created in Botanical Garden  In the fruits of these new forms of sea-buckthorn and black chokeberry the quantitative content of ascorbic acid (with 2.6-diclorfenolindofenolate solution by titrimetric method), fl avonoids (spectrophotometric method) and tannins (with KMnO4 solution by titrimetric method) [1]. Results and discussions Alimentary and therapeutic values of chokeberry and sea-buckthorn fruits are provided biologically active principles, represented by different classes of natural compounds such as fl avonoids, ascorbic acid and tannins. Biochemical study of these natural constituents in the fruits of new forms of sea-buckthorn revealed the form 3-13 with higher content of ascorbic acid and fl avonoids (exception constitutes the content of tannins) as compared to 1-13 form (Table 1), which correlates with the biological characteristics of the plant, especially of the fruit. In  case of new forms of chokeberry, the form 2 was evidenced with prevailing content of all analyzed constituents to form 1 (Table 1). Table 1.   The content of ascorbic acid, fl avonoids and tannins in new forms of sea-buckthorn and chokeberry fruits Nr. o/o Form Biological characteristics of fruits Conţent of ascorbic acid mg/100g Sum of fl avonoids (%) Total of tannins (%) I Hippophae rhamnoides L. I.1. 1-13 Colour – gold yellow; Length – 7,5 mm, width - 6,5 mm; Number of fruits on twig (10 cm) – 30; Weight of 100 fruits – 19,0 g. 93,2 0,862 2.07 I.2. 3-13 Colour – orange; Length – 8,5 mm, width – 7,0 mm; Number of fruits on twig (10 cm) – 72; Weight of 100 fruits – 20,2 g. 99,0 0,685 1,65 II Aronia melanocarpa (Michx) Elliot II.1. 1 Diameter – 8-12 mm; Number of fruits on twig (10 cm) – 1575; Weight of 100 fruits – 113 g. Number of fruits in 1 kg – 885. 64,4 2,228 3,326 II.2. 2 Diameter – 6-12 mm; Number of fruits on twig (10 cm) – 9-60; Weight of 100 fruits – 99 g; Number of fruits in 1 kg – 1010. 72,5 2,496 4,157  Conclusions The obtained results evaluated through bibliographic data to other forms and cultivars of sea buckthorn and black chokeberry shows that analyzed new forms present interest on chemical composition and biological qualities of the fruits.