Gromwell (Lithospermum erythrorhizon) is a herbal plant that holds a special importance within Japanese history and culture. Its roots contain the red pigment shikonin, which has been used in Asian countries for over 1,500 years as a crude drug and natural red-purple dye. Since the ancient Japanese Imperial Court of the Asuka Dynasty (A.D. 538 – 644), Buddhist monks of the highest rank, the Imperial Family, and the highest government officials were the only people officially allowed to wear the noble and sacred colour purple using fabrics dyed with gromwell-derived shikonin. From a scientific perspective, shikonin biosynthesis and secretion in gromwell is to this day actively studied worldwide, mostly due to its beneficial medicinal (e.g. anti-inflammatory) properties. Despite such importance, gromwell is currently listed as an endangered species. While there are non-profit organisations attempting to protect and restore this species, a potential risk is the loss of pure Japanese lineages through crossbreeding with foreign species like L. officinale. In this issue, Ito et al. (on pp. 567-570) raise awareness of the significance of gromwell in preserving Japanese history and culture, and the necessity to effectively combine both cultural and scientific forces to restore this important yet endangered plant species.
The cover shows cross and longitudinal sections of a one-year-old root from a gromwell plant; red shikonin pigments accumulate exclusively in the epidermal layer of the root. Photo credit: Hao Li (RISH, Kyoto University, Japan).