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I Abstracts. PHYTOPHARM 2017
ISOMERIZATION STUDY OF THE PHENYLETHANOID ACTEOSIDE ISOLATED FROM ITS NEW AND RICH SOURCE: GALL OF FRAXINUS ANGUSTIFOLIA
© Moritz Zürn, Imre Boldizsar
Department of Plant Anatomy, Institute of Biology, Faculty of Sciences, Eötvös Loränd University;Budapest, Hungary
Acteoside is a valuable plant secondary metabolite belonging to phenylethanoid glycosides. It is an important anti-microbial, anti-fungal, anti-cancer, antioxidative and neuroprotective agent, which can mainly be found in the representatives of Lamiales and Asterales plants. Thus, also Fraxinus spp. were found to be acteoside containing. Plant galls are abnormal outgrowths of plant tissues which are caused by the influence of insects. They could be regarded as special tumors of plants. Based on this, our hypothesis was that the high cell division rate in the galls might result in an increased synthesis of secondary metabolites, characteristic to the host plant.
In order to characterize the conversion of acteoside into its closely related compounds, extracts were heated with methanol, water and 2 N trifluoroacetic acid (TFA) at 50 °C and 100 °C, applying different incubation periods.
As a result of our work, an extremely high amount of acteoside was determined in the gall of F. angustifolia (66,0 mg/g) for the first time, thus confirming the most abundant source of this compound in the plant kingdom. Following conversion characteristic of acteoside, its three related compounds (i.e., desrhamnosyl acteoside, isoacteoside and desrhamnosyl isoacteoside) were identified by HPLC-UV-MS. The optimum treatment conditions, resulting in the highest levels of the selected products, were determined as follows: TFA, 100 °C, 15 min. Applying these conditions, all conversion products were subsequently isolated by preparative HPLC for further structure identification and pharmacological tests.
In conclusion, in addition to acteoside, after an optimized acid treatment, three phenylethanoids occurring only in trace amounts in plants could also be isolated from the gall of F. angustifolia.
COMPARATIVE POLYPHENOLIC CONTENT AND ANTIOXIDANT ACTIVITIES OF WILD AND CULTIVATED BLACKBERRY RUBUS FRUTICOSUS L.
© Chiru T.12. Pompus I.2, Ciobanu N.12, Casian I.1
1 Faculty of Pharmacy, "Nicolae Testemitanu" State University of Medicine and Pharmacy of the Republic of Moldova; 2Scientific Center of Medicinal Plant Cultivation of"Nicolae Testemitanu" SUMPh of the Republic of Moldova
The wild and cultivated blackberry varieties ("Arapaho" and "Thornfree") from Moldova were analyzed comparatively in order to determine the total phenols, hydroxycinnamic acids, total flavonoids, total tannins, and total anthocyanins as well as the antioxidant activities of the leaves and fruits, using three different essays: Trolox equivalent antioxidant capacity (ABTS), 2,2- diphenylpicrylhydrazil radical scavenging capacity (DPPH) and metal chelating activity (ferrozina test).
Total polyphenols content ranged from 28.65 to 68.9 for fruits and ranged from 64.75 to 99.5 mg/g, expressed as (-) epicatechin equivalents, for R. fruticosus L. leaves. The sum of tannins, expressed in (-) epicatechin equivalents, marked out the highest values also for leaves: "Arapaho" 54.50, "Thornfree" 52.95, and wild blackberry 33.3 mg/g. Regarding the fruits, were obtained 24.0 - 37.5 for "Arapaho" and 28.2 - 57.8 mg/g for "Thornfree" cultivars. Also, the leaves had the highest content of flavonoids (0.68 - 2.74 mg/g expressed as luteolin 7-glucoside). The content of hydroxycinnamic acids in leaves varied between 6.25 (wild blackberry) and 6.69 ("Arapaho" cultivar)
mg/g, expressed as chlorogenic acid equivalent. Total anthocyanin content, expressed in cyaniding-3-glucoside equivalents, ranged from 0.594 in "Thornfree" to 0.921 %, in "Arapaho" fruits, respectively. The results showed statistical differences (p < 0.05) between antioxidant activity of the leaves and the fruits extracts. All antioxidant activity values obtained were highly correlated with total polyphenol contents (r2 > 0.95). Respectively, the values of IC50 DPPH were following: blackberry leaves (45.39 ig/ml) > blackberry fruits (215.44 ig/ml). The antioxidant activity determined by ABTS test was found to vary from 1.5 for fruits to 14.41 |M Trolox equivalent for leaves, respectively. The chelation of the iron ions was 33.58 for leaves and 3.32 % for fruit extracts, respectively.
The results show that composition is highly affected by differences in the plant genotypes. The leaves had higher total polyphenols content and also antioxidant activity compared with fruits. They could be taken in further consideration as a plant source for extraction of phenolic compounds with promising antioxidant activity.
Obzory po kliniceskoj farmacologii i lekarstvennoj terapii [Reviews of clinical pharmacology and drug therapy] vol. 15/2017/suppLement 1
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