Quantitative analysis of tannins in some herbs of Latvian flora

Aim of this research was to analyse quantitative amounts of tannins in some Latvian flora herbs. We analysed plants commonly growing in Latvia: Wormwood (Artemisia absinthium), Common Wormwood or Mugwort (Artemisia vulgaris), Tansy (Tanacetum vulgaris), Heather (Calluna vulgaris). Tannins in these plants are less studied to our knowledge. Tannins have antibacterial effects, anthelmintic effects. 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. Plants were collected in Latvia cultural district of Vidzeme during blooming in July and August. Wormwood herb, Mugwort herb, Heather herb, Tansy flower and leaf were dried in the shade ambient temperature, then grinded in mill 1-2mm particles. Tannin amounts  were analysed as described in European Pharmacopoeia 9 using Hide powder at 760nm (METTLER TOLEDO UV7 spectrophotometer) protected from light. We used 1g of herbal material to make decoctions. Each experiment was done in triplets. Statistical analysis Microsoft Excel 2010. Mugwort herb contained the most tannins 3.02% (SD = 0.67; VR +/- 0.44). Heather herb and Tansy leaf contained approximately equal amounts of tannins of 2.45% (SD=0.17; VR +/- 0.03) and 2.43% (SD=0.37; VR +/- 0.14), respectively. Less tannin is found in Tansy flower 2.01% (SD=0.18; VR +/- 0.44) and Wormwood herb 1.10% (SD=0.07; VR +/- 0.17). Compared to the required minimum tannin content according to Eur Pharm 9 monographs for some commonly used tannin containing herbal drugs, such as Oak bark (Quercus cortex) and Witch-hazel leaf (Hamamelidis folium) min 3%, Pelargonium root (Pelargonii radix) min 2%, Common Lady's mantle (Alchemilla herba) min 6%; Bilberry fruit, dried (Myrtilli fructus siccus) min 1%, our analyzed plants have a medium amount of tannins. Experimental data show that analysed herbs have tannins, further research is necessary to identify types of tannins and to determine medicinal effects.