Autori: G.Stanciu, E. Chirila, T. Negreanu-Pirjol, S. Dobrinas

Editorial: The Journal of Biological and Chemical Luminiscence, 23, p.271, 2008.

Rezumat:

The use of natural antioxidants found in plants represents a worldwide trend for food, pharmaceutical and cosmetic
products (1–4). There are a variety of spectrometric and chemiluminometric analytical methods available, applied for antioxidant properties evaluation (3–6). This paper deals with recent original studies regarding the evolution of antioxidative properties for some alcoholic extracts of plant material used in cosmetics: poplar leaf-buds, sea buckthorn male buds,
snowdrop flowers and violet flowers using a method based on photochemiluminiscence. In principle, a photo sensitive compound provides free radicals by optical excitation, the antioxidants from the sample eliminate partially the free radicals
and the residual radicals react with luminol and produce luminescence. The calibration curve was plotted using Trolox as standard. Three individual measurements were performed and
the mean value is reported.
Alcoholic extracts of poplar (Populus nigra L.) leaf-buds
(sample 1), sea buckthorn (Hippopae rhamnoides L.) male buds
(sample 2), snowdrop (Galanthus nivalis L.) flowers (sample 3)
and violet (Viola odorata L.) flowers (sample 4), were investigated
for their antioxidative properties using photochemiluminiscence.
100 g plant fresh (sample 3) or dried in air (samples 1, 2, 4) have
been extracted in 300 mL (samples 1–3) or 500 mL (sample 4) of
ethanol 95% at dark, in brown recipients. The mixture was
strongly shaken three times every day. After 1, 7 and 15 days of
contact time with ethanol, samples of 5 mL alcoholic extract, previously filtered, were collected in glass recipients and stored at 4°C. Each extract was diluted with ethanol in various ratios and then 20 μL of sample was used for AC determinations. The analytical equipment was Photochem device provided by Analytic Jena Company.
The results show that the AC of the alcoholic extracts is high and increases continuously for the
samples 1 (from 183.85 to 391.48 nmol/mg dry weight) and 2 (from 30.71 to 246.70 nmol/mg dry weight). The other samples have a slightly increasing trend of AC: from 119.19 to 125.08 nmol/mg dry weight (sample 3) and from 104.37 to 135.73 nmol/mg dry weight (sample 4). Alcoholic extracts of buds (samples 1 and 2) show higher antioxidant properties than those
of the flowers. Leaf buds of poplar and male buds of sea buckthorn
are promising plant materials for more detailed investigation of
their antioxidant properties and application possibilities.
The antioxidative properties of all studied plant materials after 1, 7 and 15 days of contact time with ethanol showed different increasing trends of AC from 1 to 15 days.
The AC determination using
photochemiluminiscence, that combines the very fast photochemical radical generation with the highly sensitive
luminometric detection, represents a suitable technique to evaluate the antiradical properties of individual compounds as well as for any mixture.

Cuvinte cheie: photochemiluminiscence, antioxidative properties,