Antioxidants and carbohydrate content in infusions and microwave extracts from eight medicinal plants

Abstract

The aims of the current research were to evaluate and to compare the antioxidant activity and the content of total phenolic, flavonoids and fructan content in infusions and microwave-assisted extracts from eight herbs:and echinacea (Echinacea purpurea Moench.). The total phenolic contents, total flavonoids and antioxidant activity were evaluated by Folin-Ciocalteau, Al(NO3)3 methods and DPPH assays. The total fructans and sugars were determined by resorcinol and HPLC-RID methods. Infusion and microwave-assisted extraction (MAE) were evaluated as efficient methods for preparation of herbal drinks. The highest values of biologically active substances and antioxidant activity were found in MAE herbal extracts. Coltsfoot, thyme and great burdock extracts demonstrated the highest content of total phenolic and flavonoids. Coltsfoot and thyme extracts showed the highest antioxidant activity (334 mM TEg -1 and 287 mM TEg -1 dw, respectively). Fructans were found in coltsfoot (4.6%) and echinacea (3.9 %) leaves, in great burdock, dandelion and elecampane roots -14 %, 34% and 44% dw, respectively. Elecampane and dandelion roots were evaluated as sources of prebiotic inulin.

Ultrasound-assisted extraction of medicinal plants and evaluation of their biological activity

“…In comparison, Boukhira et al (2015) established TPC of 3.35±0.12 mg GA/g of extract in the ultrasound-assisted extract of S. vulgaris from Morocco and Kiselova et al (2006) established TPC for infusion of A. linearis of 437.90±1.11 µM QE. Compared to the report by Petkova et al (2017) TPC for E. purpurea microwave extract (24.1±1.1 mg GAE/g DW), our findings are lower -8.02±0.06 mg GAE/g DW. This could be due to the evaluation procedure differences and the plant sample variations.…”

The Influence of Microwave Treatments on Bioactive Compounds and Antioxidant Capacity of Mentha piperita L.

“…All the previous results can prescribe that the MW-treated samples perform with high levels of all analysed parameters and by this treatment for different time intervals, there are extracted different levels of active bio-compounds, chlorophyll, total carotenoids, and antioxidant capacity, but all are high above the untreated sample. Alternatively, Petkova et al [ 41 ] investigated the microwave-assisted extraction of phenolics from peppermint and obtained 37.7 ± 0.5 mg GAE/g while claiming that microwave processing provided slight advantages in total phenols yield when compared with conventional extraction.…”

Evaluation of Xanthine Oxidase Inhibitory and Antioxidant Activities of Three Organs of Idat (Cratoxylum glaucum Korth.) and Correlation with Phytochemical Cont

“…38 The antioxidant activity of flavonoids was influenced by the degree of hydroxylation and other substituents found in flavonoids. 34 Phenolic compounds are known to have antioxidant activity 39,40 and xanthine oxidase inhibitory activity. 41 Flavonoid compounds have antioxidants and an anti-inflammation.…”