High-resolution X-ray computed tomography for identifying herbal medicines was as effective as microscopic examination

Microscopic examination is one of the important identification methods for crude drug test described in the 18th Japanese Pharmacopoeia. This method is useful for identification because it can be used for small amounts of samples regardless of their storage conditions; however, this method requires a lot of technical skill in sectioning intricate and/or small samples and is time-consuming. High-resolution X-ray computed tomography (HRXCT) is a novel method for observing the internal morphology of materials. Previously, we used HRXCT to visualize the internal morphology of the Ephedra Herb, obtaining observations that closely match those obtained via microscopic examination. HRXCT employs a low-energy X-ray source and the permeation distance of the X-rays is very short. Therefore, HRXCT can be used for elucidating the morphology of small herbal medicines. In this study, Artemisia Capillaris Flower (capitulum with a diameter of approximately 2 mm) and Plantago Seed (seeds with a length of approximately 2 mm) were examined. The results showed that HRXCT examination was sufficient to illustrate the internal independent organs of Artemisia Capillaris Flower and that their inflorescences remained intact. When observing Plantago Seed, the internal morphology of more than one seed can be depicted simultaneously. Therefore, observation using HRXCT was easy, simple, and effective to illustrate the internal morphology of herbal medicines, which is typically time-consuming and requires advanced microscopy skills.