Browsing by Author "Yankova I."

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    Microscopic Analysis Of Japanese And Wax Paper Used For The Preservation Of Written Cultural Heritige
    (2021-01-01) Tsvetanska-Tsekova I.; Lasheva V.; Yankova I.; Peteva I.; Vasileva R.; Stancheva S.
    The paper is an integral part of our cultural development. Its’ properties are determined by the properties of the fibrous materials of which it is composed by and from the technological regime in its production. The good knowledge of the fibrous materials used, their chemical composition, morphological and anatomical structure in the restoration practice is essential for proper conduction of the recovery procedures. In world restoration practice, Japanese paper is the most often used material for the renovation of paper documents. The examination and microscopic analysis of Japanese paper contributes to its proper use in restoration practice.
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    POLYPHENOLS OF GRAPE POMACE FROM LOCAL BULGARIAN VARIETY MAVRUD. ANTIOXIDANT AND ANTITUMOR EFFECT AGAINST BREAST CANCER
    (2022-01-01) Radoeva R.; Yankova I.; Enchev B.; Karsheva M.; Ivanova E.; Iliev I.
    Grape pomace is the main by-product of winemaking, a valuable source of polyphenols with antimicrobial, antioxidant and anti-cancer effect. Grape seeds and marcs extracts are of strategic importance for the development of new therapeutic approaches against certain cancer diseases, including breast cancer. In this study the antioxidant and antitumor potential of the polyphenolic fraction of grape pomace obtained from the vinification of the local Bulgarian grape variety Mavrud is reported. After Soxhlet extraction with 50 % water solution of ethanol, the total polyphenol content of the extracts by the Folin-Ciocalteu colorimetric method was determined. The obtained extracts were characterized by HPLC-DAD and their antioxidant activity was studied with DPPH assay. The cytotoxic effect was tested on 3T3 cell line, while MCF-7 and MDA-MB-231 breast cancer cell lines were selected to determine antitumor activity. The results showed higher total polyphenol content in the marc compared to the seed extracts and prevalence of gallic acid, catechin and epigallocatechin. A correlation between antioxidant activity and total polyphenol content was established. The studied extracts had a low cytotoxic effect, as the seed extracts showed a stronger antitumor activity compared to the extracts of marcs and potential for treatment of luminal breast cancer.