Pharmacognostical investigation of Acori rhizomes (2) histological and chemical studies of Acori rhizomes in Asian markets

Anatomical and chemical (essential oils) investigations of Acori rhizomes from various Asian markets showed that rhizomes commercially obtained from south-east Asia under the name 'shyobu-kon' or corresponding names were of Acorns calamus of chemotype A, and that some samples in Chinese markets were A. calamus mixed with rhizomes of A. gramineus. Rhizomes called 'shi chang pu' in Chongqing market (China) were those of A. calamus. A. gramineus samples in Chinese markets were classified into three chemotypes, A-1, A-2, and A-3, whose major essential oil constituents were asarone (Z and/or E), elemicine, and metkylisoeugenol (Z and/or E), respectively. The histological characteristics of samples of chemotype A-3 were quite different from those of chemotypes A-1 and A-2, suggesting that A. gramineus of chemotype A-3 might be a variant or sub-species of A. gramineus.