Abstract Book - 3rd International Symposium on Medicinal Plants ...

3.11 Analysis of Crude and Chromatographic Fractions of Eucalyptus
globulus Leaves
Boulekbache-Makhlouf Lila, Slimani Sakina, and Khodir Madani
Faculty of Nature and Life Sciences, 3BS Laboratory, University of Bejaia 06000, Bejaia, Algeria.
<strong>Abstract</strong>: Leaves of E. globulus were taken from 25-year-old trees (ten trees) randomly
harvested from the arboretum of Derguinah; Bejaia in the north east of Algeria (36°31‟13.56‟‟N,
5°17‟18.43 E). The leaf samples were dried in an oven at 40°C, and ground to obtain a thin
powder (250 µm of diameter). 1g was extracted with l00 mL of aqueous acetone (70%) containing
0.5% acetic acid to prevent oxidation. The extract was filtered (Whatman paper no. 4) and the
acetone was evaporated under reduced pressure in rotary evaporation at 40° C. The remaining
aqueous phase was treated with hexane (25 mL x 3) to remove lipids, concentrated under reduced
pressure, and lyophilized. Acetonic extract was then fractionated by chromatography on a
Sephadex LH-20 column using consecutive elution with ethanol, methanol and aqueous acetone
(60%). The total phenolic concentration was determined using Folin-Ciocalteu reagent, flavonoids
content was evaluated by using 2% aluminium chloride method and tannin contents was
measured by protein precipitation method. The antioxidant activity of different extracts was
performed by using three methods: ferric reducing power, DPPH • radical scavenging activity and
scavenging of hydrogen peroxide (H 2 O 2 ). Fractionation of acetonic extract yielded three fractions:
FA, FB and FC. The total phenolic concentrations of different extracts varied from 53.79 to 432.63
mg/g dry weight, expressed as gallic acid equivalents (GAE). Flavonoids were detected only in
crude extract and their amount is about 3.65 mg quercetin equivalents (QE)/g dry weight. Tannin
contents varied from 27.54 to 105.39 mg/g dry weight, expressed as tannic acid equivalents
(TAE). Fraction C and B extracts exhibited high reducing power (CR 0.5 33.41 μg/ml and 43.17
μg/ml, respectively) than crude extract (43.1 μg/ml). It was observed that fraction B and C extracts
displayed the highest DPPH • scavenging ability (CI 50 87.77 and 87.12 μg/ml, respectively) followed
by crude extract (CI 50 114.25 μg/ml). These two fractions displayed also the highest ability to
neutralize hydrogen peroxide (53.58% and 43.20%, respectively). The results showed that
fractions B and fraction C exhibited considerably higher antioxidant activities for the three
antioxidant tests comparatively to that of crude extract and α-tocopherol. Fraction A exhibited the
lowest antioxidant.
Key words: Antioxidant test, chromatography, Eucalyptus globule, leaves, tannin.
3.12 Phytochemical Study and Antioxidant Activities of Leaves Extracts
from Rhamnus alaternus
Boussahel Soulef 1 , Dahamna S., 1 Giuseppe R., 2 Siracusa L 2 ., Harzallah D. 3
1 Laboratory of Phytotherapy Applied to Chronic Diseases, Department of ecology and vegetal
biology, Faculty of Natural and Life Sciences, University Ferhat Abbes, Setif 19000 Algeria,
2 Institute of biomolecular chemistry - C.N.R., Via Paolo Gaifami, 18 95126 Catania, Italy.
3 Laboratery of Applied Microbiology, Department of Microbiology, Faculty of Natural and Life
Sciences, University Ferhat Abbes, Setif 19000 Algeria.
<strong>Abstract</strong>: This study was designed to examine the chemical composition and in vitro antioxidant
activities of leaves extracts from Rhamnus alaternus L.; we submitted two extracts (methanolic
and aqueous) of different polarity to a deep compositional analysis through the use of an
advanced hyphenated technique like LC/Uv-vis-DAD/MS. to our knowledge no metabolic
fingerprint studies have been done on this species so far. So, we report for the fist time the
complete secondary metabolic fingerprint of R. alaternus polar extract, the chromatographic
pattern from aqueous extract has several similarities with the methanolic one; we note the
presence of Flavones (quercetin, kaempferol and rhamnetin derivatives). The samples were also
subjected to a screening for their possible antioxidant activities by using 2,2-diphenyl-1-
picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays, in the first case the IC 50 value was of
0,082±0,0006 mg/ml for the methanolic extract and 0,398±0,0074 mg/ml for the aqueous one, in
the β-carotene-linoleic acid system, the inhibition values of linoleic acid oxidation were estimated
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