Yohimbine also known as quebrachine, is an indole alkaloid derived from the bark of the african tree pausinystalia johimbe; also from the bark of the unrelated south american tree aspidosperma quebracho-blanco. Yohimbine is an α2-adrenergic receptor antagonist, and has been used in a variety of research projects. It is a veterinary drug used to reverse sedation in dogs and deer.

Berberine is a quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids found in such plants as berberis, such as berberis vulgaris (barberry), berberis aristata (tree turmeric), mahonia aquifolium (oregon grape), hydrastis canadensis (goldenseal), xanthorhiza simplicissima (yellowroot), phellodendron amurense (amur cork tree), coptis chinensis (chinese goldthread), tinospora cordifolia, argemone mexicana (prickly poppy), and eschscholzia californica (californian poppy). Berberine is usually found in the roots, rhizomes, stems, and bark.