As traditional Kampo medicine continues to garner global interest for its therapeutic benefits, rigorous quality control measures are essential for ensuring efficacy and safety. Daiokanzoto, a widely used Kampo formula combining Rhei rhizoma and Glycyrrhizae radix, is no exception. Ensuring the correct proportion and presence of glycyrrhizin (GLY) and sennoside A (SA) is crucial for the formula’s effectiveness. Now, a landmark study by a team of eminent scientists from Japan and Thailand, published on January 14, 2024, in Phytochemical Analysis (DOI: 10.1002/pca.3321), introduces a lateral flow immunoassay (LFA) that allows for the rapid and accurate detection of these vital compounds in Kampo medicine.
Keywords
1. Lateral Flow Immunoassay
2. Daiokanzoto Quality Control
3. Glycyrrhizin Detection
4. Sennoside A Detection
5. Kampo Medicine Safety
In the realm of traditional Japanese medicine, Daiokanzoto is a Kampo formula held in high esteem for its purgative and anti-inflammatory properties. The effectiveness of this age-old remedy largely hinges on two critical bioactive compounds: glycyrrhizin (GLY) and sennoside A (SA). The accurate quantification of these phytochemicals in Daiokanzoto samples is a cornerstone of quality control, directly influencing the therapeutic efficacy that practitioners and patients rely on. Adding to the complexities, Daiokanzoto formulations involve a blend ratio of Rhei rhizoma and Glycyrrhizae radix at 4:1 or 4:2—a balance that must be meticulously maintained.
The breakthrough lateral flow immunoassay (LFA), developed by a multi-disciplinary team led by researchers Akihiro Ochi, Poomraphie Nuntawong, Jiranan Chaingam, Tomoki Ota, Thaweesak Juengwatanatrakul, Waraporn Putalun, Yukihiro Shoyama, Hiroyuki Tanaka, Satoshi Morimoto, and Seiichi Sakamoto from Kyushu University, Japan, and collaborating institutions, is poised to revolutionize the field’s current analytical methods. The cross-institutional study represents a significant leap forward in affording manufacturers, healthcare providers, and researchers an efficient, sensitive, and straightforward means to evaluate Daiokanzoto’s quality.
The LFA utilizes monoclonal antibody (mAb) nanoparticles, which have proven to be highly specific in detecting GLY and SA. Working on the principle of competitive binding, the assay involves the mAb nanoparticles reacting against immobilized analyte conjugates on the LFA test strip and the free analytes in the sample. Significantly, this assay segregates itself from contemporary methods by enabling the simultaneous detection of both GLY and SA, rendering the process more expedient and cost-effective.
Visual detection of color change in the test zones is the crux of this novel assay. The presence of GLY and SA in a sample will engage in a bind with the mAb nanoparticles, effectively contending with the immobilized GLY-bovine serum albumin and SA-human serum albumin conjugates on the strip. This competitive process culminates in discernible color patterns on the test zone, which are then used to determine the presence and amount of these compounds. The study found the LFA’s limits of detection for both GLY and SA to be 3.13 μg/mL, showcasing its profound sensitivity.
Prior to this development, methods such as high-performance liquid chromatography (HPLC) and mass spectrometry (MS) platforms were the go-to resources for analyzing medicinal components in Kampo formulas. However, these procedures are not without drawbacks—time-consuming operations, the necessity for complex equipment, and the need for well-trained personnel are all barriers to efficiency. In stark contrast, the introduced LFA requires less technical expertise and can be administered rapidly with reliable accuracy, facilitating wider application in various settings from laboratories to field operations.
To validate the LFA, the research team conducted tests on plant samples and confirmed the assay’s performance against the established indirect competitive ELISA results. The findings indicate that the LFA, owing to its specificity and efficiency, holds great promise for becoming a standard testing procedure in Kampo medicine production, ensuring that the delicate balance of GLY and SA in Daiokanzoto remains unerring.
The scientific community has hailed this achievement as a landmark advancement for natural product testing. “Our results exemplify the continuous drive towards innovative approaches that reconcile traditional remedies with modern scientific scrutiny,” states Dr. Seiichi Sakamoto. “We are taking significant strides in bridging that divide, underpinning the reliability and credibility of traditional medicine in contemporary health systems.”
References
1. Watanabe K, et al. Evid Based Complement Alternat Med. 2011;2011:513842. doi:10.1093/ecam/neq067
2. Terasawa K. Evid Based Complement Alternat Med. 2004;1(3):219-222. doi:10.1093/ecam/neh046
3. Ministry of Health, Labour and Welfare of Japan. The Japanese Pharmacopoeia. 18th ed. 2021:2113-2114, 2013-2014.
4. Kon R, et al. J Ethnopharmacol. 2014;152(1):190-200. doi:10.1016/j.jep.2013.12.055
5. Nuntawong P, et al. J Nat Med. 2022;76(3):521-545. doi:10.1007/s11418-022-01605-6
The Daiokanzoto quality control field welcomes the LFA as a remarkable tool for phytochemical analysis, one that is bound to make significant contributions to the enhancement of Kampo medicine. Furthermore, this assay sets a precedent for future technologies and methodologies in the realm of traditional medicine, fostering its integration into modern healthcare practices while preserving its intrinsic values.