The Rosaceae family is a large and diverse family which includes over 3,000
economically important fruits and ornamental species. The genus Rubus counts about 750
species native to all continents. Members of this genus have been cultivated for centuries for
their fruits and are consumed fresh or processed to make food products such as jam, wine, tea,
ice cream, desserts, seedless jellies and bakery products. Extracted pigment from fruits is used
as a natural colorant in baked products, jellies, chewing gums, fruit-wines and beverages.
Fruits and other parts of Rubus plants have had a significant effect on human health and
nutrition in both ancient and modern times. Rubus species are widely used as antibacterial,
anti-inflammatory and pain relief drugs because they are rich in carbohydrates, proteins,
minerals, vitamins, superoxidase dismutase and phytochemicals. of Rubus plants are known
as a rich source of phenolic compounds, containing high level of Gallic acid which is a
markedly potent antioxidant are raspberries, black tea, and red wine which possesses 3-fold
higher antioxidant activity then either vitamin C or E which confers a significant potential
against cancerous cells and its preventative impacts on cell proliferation and cell death in
prostate cancer cell lines has been proven. The renewed interest in the benefits of wild fruits
and natural products has led to a substantial increase in the number of studies investigating
active compounds in Rubus species and their pharmacological effects.
The loganberry Rubus × loganobaccus is a hybrid of the North
American blackberry Rubus ursinus Cham&Schltdl., and the European raspberry Rubus
idaeus L., were accidentally created in the 1880’s in California by James Harvey Logan, for
whom they are named.
Tayberry is a hybrid obtained by the crossing of the blackberry – Rubus fruticosus and
the raspberry – Rubus idaeus. The original plant was selected from a family of seedlings
resulting from a cross made in 1969 at the Scottish Horticultural Research Institute, Dundee,
UK, between the octoploid blackberry Aurora and a tetraploid raspberry 626/67. This variety
resembles the Loganberry in some respects, but is superior to it with respect to fruit size,
yield, fruit color, mode of presentation of fruit.
The aim of this paper was to evaluate antioxidant actiyity of leaf extract from
Rubus loganobaccus grown under the conditions of the Republic of Moldova.
The Rubus loganobaccus that were cultivated in the experimental plot of the National
Botanical Garden (Institute) Chişinău, N 46°97′32.0″ latitude and E 28°88′77.4″ longitude,
served as subject of the research, Rubus fruticosus and Rubus idaeus- controls. The leaves
samples were collected after the harvest. The leaves of Rubus sp. (10-15 g) were grounded,
extract was extracted with 60 % aqueous ethanol, at room temperature, after 30 min of
permanent shaking, extract was filtered through Whatman no.2 filter paper by vacuum
suction, using Buchner funnel. The procedure was repeated 6 times. The combined extracts
were evaporated under reduced pressure to dryness at 40 ºC and stored at -4 ºC until analysis.
Total phenolic content of extracts was measured by employing the Folin-Ciocalteu
assay (Singleton et al., 1999). An aliquot of 50 μl of an extract was mixed with 250 μl of
Folin-Ciocalteu phenol reagent (10 x diluted), 500 μl water; and allowed to react for 1 min.
Then 800 μl of Na2CO3 solution 20 % was added and allowed to stand for 2 h (30 min at
40 ºC) before the absorbance of the reaction mixture was read at 760 nm against a blank
without extract. The total phenolic content of the extracts was expressed as mg gallic acid per
gram of plant material on dry basis.
The stable 1,1-diphenyl-2-picryl hydrazyl radical (DPPH) was used for the
determination of free radical-scavenging activity of the extracts. It is a free radical at room
temperature which produces violet color in methanol and it is reduced in the presence of an
antioxidant molecule, giving rise to uncolored solution. The use of DPPH provides an easy
and rapid way to evaluate antioxidants. Sample stock solutions (1mg/ ml) were diluted to final
concentration of 200, 100, 50, 25, 10, 5 and 1μg/ml in methanol. Different concentrations of
each extract were added, at an equal volume (0,75ml), to methanolic solution of DPPH
(1,5 ml, 20 mg/1). After 15 min at room temperature, the absorbance was recorded at 517 nm.
Methanol was used as the blank. DPPH solution (1,5 ml, 20mg/1) and methanol (0,75 ml) was
used as the negative control. The IC50 value was calculated graphically and it denotes the
concentration of sample, which is required to scavenge 50 % of DPPH free radicals (Brand-
Williams et al., 1995).
The method based on the capacity of a sample to inhibit the ABTS+ (2,2'-azino-bis(3-
ethylbenzothiazoline-6-sulphonic acid)) compared with antioxidant standard (Trolox) (Re et
al., 1999). The ABTS+ was generated by chemical reaction with potassium persulfate
(K2S2O8). For this purpose, 10 ml of ABTS 2mM was spiked with 0,1 ml of K2S2O8 (70 mM)
and allowed to stand in darkness at room temperature for 12-16 h (the time required for
formation of the radical). The working solution was prepared by taking a volume of the
previous solution (1 ml) and diluting it in 24 ml of ethanol until its absorbance at λ = 734 nm
was 0.70±0.02. The reaction took place directly in the measuring cuvette. For this purpose,
10 μl of sample or standard were added at 0.99 ml of ABTS+ radical, at which point the
antioxidants present in the sample began to inhibit the radical, producing a reduction in
absorbance, with a quantitative relationship between the reduction and the concentration of
antioxidants present in the sample. At the same time a Trolox calibration curve was prepared
for a concentration range of 2,5-30 μM and the inhibition percentage obtained for the sample
was interpolated to calculate the concentration in Trolox equivalents (μM TEAC).
The chelation of ferrous ions by extracts was estimated by method of Dinis et al.
(Dinis et al., 1994). Briefly. 50 μl of 2 mM FeCl was added to 60 μl of samples (10 mg/ml).
The reaction was initiated by the addition of 200 μl of 5 mM ferrozine solution. The mixture
was vigorously shaken and left to stand at room temperature for 10 min. The absorbance of
the solution was thereafter measured at 562 nm. The percentage inhibition of ferrozme-Fe2+
complex formation was calculated as [(A0- AS)/ AS] x 100: where A0 was the absorbance of
the control, and as was the absorbance of the extract standard. EDTA was used as a positive
control.
Data were expressed as mean of three replicates and standard error (SE). Statistical
significance (P<0.05) was evaluated by the Student's test. AII analyses were performed using
GraphPad Prism; version 6.01, 2012.
In leaf extracts the total phenolic content ranged from 57,90 to 99,50 mg/g dried
weight expressed as gallic acid equivalents. The antioxidant activity of studied Rubus sp. leaf
extracts are presented in Table. Analysing the results we found that leaf extracts of Rubus sp.
showed the highest values of antioxidant activity: DPPH – IC50= 45,39 – 68,11 μg/ml; ABTS
– 42,57 μM TE/g dried weight, Iron Chelating capacity – 53,06 %. A high correlation was
found between the values for the total phenolic content and antioxidant activity. Our results
confirmed that leaf extracts of Rubus sp. can prevent activity of free radicals by scavenging or
by inhibiting them.

Some authors mentioned various findings about phytochemical potentials of Rubus
species. Ekbatan Hamadani et al. remarked that total phenolic contents in R. loganobaccus
leaves cultured in the field were higher than those cultured in the greenhouse (66,63 ± 1,31
and 65,30 ± 2,56 mg GAE/g, respectively), in the field had a higher level of flavonoid (29,35
± 8,53 mg of QE/g) compared with greenhouse-cultured plants (22,44 ± 3,32 mg QE/g,
antioxidant capacity in terms of ascorbic acid equivalent showed that the EC50 of
R. loganobaccus leaves cultured in the field were higher than those cultured in the greenhouse
(2,82 ± 0,70 vs. 2,41 ± 0,75 μg/mL, respectively) (Ekbatan Hamadani et al., 2020). Veljkovic
et al. reported that total phenolic compounds of wild raspberry Rubus idaeus leaf methanolic
extracts ranged from 59,68 to 96,83 mg GA/g, the flavonoid concentration 7,02-
7,53 mg Ru/g, total tannins in the methanol extracts 0,73-1,27 mg/mL, anthocyanins 4,43 to
9.00 μg L, antioxidant activity 110,17-199,18 μg /mL, inhibitory activity between 2,5-
20,00 mg/ mL (Veljkovic B. et al., 2018).
Conclusion: This study suggests that Rubus sp. leaf extracts exhibit great potential for
antioxidant activity and may be useful for their nutritional and medicinal functions.
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