Analysis of phenolic compounds in Bidens tripartita, L. during different vegetation phases

Abstract

Currently special attention is paid to the quality of food, pharmacological preparations, products of cosmetics and hygiene, so the scientists are in search of new natural sources of biologically active materials. Although three-lobe beggarticks (Bidens tripartita, L.) is known in Lithuania as weed it is used in medicine since it contains biologically active substances, such as polyphenols, flavonoids, carotenoids, vitamin C, essential oils, microelements. The aim of this study was to carry out analysis of phenolic compounds in Bidens tripartita, L. extracts using spectrophotometric methods. Additionally, the quantity of vitamin C, chlorophyll a and b as well as the total quantity of carotenoids was determined. All the analyses were carried out using the extracts of plants of different vegetation phase. Aqueous methanolic extracts were prepared using raw material of Bidens tripartita, L. collected at different vegetation phase. During spectrophotometric analysis of extracts the total amount of phenolic compounds and flavonoids was determined. The data were expressed in rutin equivalents using calibration curves of this compound. The repetitive extraction and analysis were carried out to asses the reproducibility of results. The quantity of vitamin C was determined by titrimetric analysis using iodine solution. After the extraction the absorbance of the extract was measured and the quantity of chlorophyll a and b as well as the total quantity of carotenoids were determined. The quantity of phenolic compounds was evaluated by HPLC with reaction detector. The compounds were identified according the retention time of external standards. Their radical scavenging activity was determined using free radical of 2,2-diphenyl -1- picrylhydrazyl (DPPH). The highest quantity of phenolic compounds was determined at the end of flowering stage 92.17 mg/g. [...]