Anatabine is an alkaloid found in plants like Nicotiana tabacum, Solanum dulcamara, and other nightshade species. Anatabine impurities refer to other substances that are present in the anatabine extract that are not anatabine. These impurities are typically removed during the purification process to ensure the quality and purity of the anatabine extract. The presence of these impurities can affect the potency and effectiveness of the extract, and therefore it is essential to remove them.