3d image of roburin a skeletal formula

roburin tannin oak wood quercus robur petraea alba oak cork suber ellagitannin oligomer dimer hydrolyzable polyphenol galloyl 3d herbal medicine herbal phytochemical phytotherapy plant herb natural herbalism pharmacognosy pharmacopoeia parasympathomimetic flavonoid phytoalexin phytoestrogen bioactive cell biochemistry biomolecule biology molecule molecular formula skeletal structural structure geometry ball stick atom substance compound metabolite metabolism