Preliminary survey of taxonomical problems, pharmacognostical characteristics, and chloroplast DNA polymorphisms of the folk medicinal herb Artemisia campestris from the Ryukyu Islands, Japan

Artemisia campestris L. (Compositae) occurs naturally along the coastline of the Ryukyu Islands and has been traditionally used as a folk medicine for the treatment of liver and kidney disorders. The authors obtained specimens from the Ishigaki and Kume Islands of the Ryukyu Islands, Japan, and from the USA. A survey of the literature revealed that the Japanese name for A. campestris is Niitaka-yomogi or Riukiu-yomogi. Two distinct overall plant-form phenotypes were identified: an erect phenotype with long, upright, and straight main axis and assurgent branches; and a prostrate phenotype, having branches that are longer than the main axis and which grow along the ground. Except for the number of ray flowers, most of the flower head characters in the erect phenotypes were significantly larger than those in the prostrate phenotypes. In this experiment, the flower heads contained only small amounts of either capillarisin (<0.01–0.11 of the dry weight, % DW) and 6,7-dimethylesculetin (<0.01–0.30% DW), or none at all. DNA polymorphisms at two sites of the rpl16–rpl14 spacer region (nucleotide position 181–189 and 291–300 from the 5′ end) revealed the existence of four different haplotypes. The number of adenines at nucleotide positions 291–300 appeared to be polymorphic within A. campestris from the Ryukyu Islands. Conversely, geographic differences between specimens from the Ryukyu Islands and USA manifested as a nine-base deletion at nucleotide positions 181–189. From a pharmacognostical context, the use of A. campestris flower heads as a substitute for Artemisiae capillaris Flos is not effective.