Solvent effect on extraction amounts of polyphenolics in herbs growing Latvia

Aim of this research was to find optimal solvent and concentration to extract polyphenols from herbal drugs. Polyphenols are of great interest in search of alternative antibacterials and antihelmetics. This research is part of project “Development of herbal plant containing medical extracts with anti-parasitic effect” funded by the Latvia Ministry of Agriculture and Rural Support Service program LAD16.2 project: The support for pilot projects and for the development of new products, practices, processes and technologies. Wormwood herb (Artemisia absinthium), Mugwort herb (Artemisia vulgaris), Tansy flower and leaf (Tanacetum vulgaris), Heather herb (Calluna vulgaris) were collected in Latvia (Vidzeme) in July and August 2018, Oak bark (Quercus robur) was collected in March 2018, and dried in the shade, ambient temperature, grinded in mill (1-2mm). Extracts: 100ml ethanol and acetone (70%, 50%, 30%) and 10g of plant material. Extraction time 1h 20 min. Vacuum evaporation used to make semi solid extracts. Folin-Ciocalteu method was used to estimate the total phenolic content (TPC) in extracts. Results expressed as gallic acid equivalents (GAE). Statistical analysis: Microsoft Excel 2010. The highest amounts of TPC were found in 70% acetone extracts of Tansy leaf (6990mg/100g GAE; SD 271;CI 674), Heather herb (6126 mg/100g GAE; SD=757; CI=582), Mugwort herb (5876mg/100g GAE; SD=145; CI=361) and Oak bark (5511mg/100g GAE; SD=245; CI=609). Tansy flower 50% acetone (7737mg/100g GAE; SD=337; CI=837) and 30% acetone (7760mg/100g GAE; SD=295; CI=733) extracts showed the most TPC. However for Wormwood herb best extractants were 50% ethanol (3236mg/100g GAE; SD=411; CI=1021) and 30% acetone (3293mg/100g GAE; SD=520; CI=1292). Altogether acetone extracts had more TPC (7760-1136mg/100g GAE, median 5680mg/100g GAE), while ethanol extracts ranged form 6535 to 2867 mg/100g GAE, median 4349mg/100g GAE. Our research shows that optimal solvent varies on plant species and herb type. Our findings correspond with other polyphenol extraction optimization research results.