Enriching and Characterizing Triterpenoid Saponins from Platycodon grandiflorus Roots

In a recent study out of the Tiajin University of Commerce, the Tianjin University of Traditional Chinese Medicine, and Cleveland State University, scientists investigated how to efficiently enrich and characterize triterpenoid saponins, a type of chemical compound found in Platycodon grandiflorus roots. Their findings were published in the Journal of Chromatography A (1).

balloon flowers buds and blooming | Image Credit: © Sarah - stock.adobe.com

Platycodon grandiflorum, typically known as the balloon flower, is a perennial flowering plant that belongs to the Campanulaceae family. This traditional Chinese medicinal herb is rich in saponins, flavonoids, phenolic acids, and other compounds, which has led to its use in various applications. In Korea, its roots are added to various foods, and in traditional Chinese medicine, it can be used to help treat hypotension, lipid reduction, atherosclerosis, inflammation, relieving cough and phlegm, promoting cholic acid secretion, and as an antioxidant (2). For example, a 2022 study published in the Journal of Integrative and Complementary Medicine, scientists from various Japanese medical institutions monitored how kikyo-to, an herbal medicine that is partly made of Platycodon grandiflorum roots (PGR), is effective for treating symptoms related to acute upper respiratory tract infection (URTI) (3).

Among the chemical compounds present in PGR, triterpenoid saponins are garnering increased attention due to its various biological and pharmaceutical properties, including anti-inflammatory, antifungal, and antioxidant. Triterpenoid saponins especially stand out as one of the most potent types of bioactive components within PGR. Despite these qualities, there has been little explored regarding the purification and enrichment processes of triterpenoid saponins.

In this study, the scientists optimized the extraction and purification of triterpenoid saponins from PGR to enhance resource utilization while minimizing waste. This involved n-butanol extraction and microporous adsorption resin, yielding four extracts with varying saponins content. Using liquid chromatography–mass spectrometry (LC–MS), qualitative analysis was used to identify eight triterpenoid saponins across different extracts. Afterwards, fragmentation analysis was used to delineate characteristic ion patterns and cleavage pathways for the compounds. Quantitative analysis showed that separation and purification effectively increased triterpenoid saponin content, with the highest levels being obtained through 30% ethanol elution. Further, the 30% ethanol eluate had a notable absence of Platycodin D, one of the active substances in Platycodon grandiflorus. This likely stems from the origin, processing, and purification methods.

With these findings, there is strong theoretical support for developing and utilizing triterpenoid saponins from PGR. Creating efficient extraction and purification methods for this substance, in addition to maximizing the herbal resource’s utilization, enhances its industrial applicability. Further research must refine these methods to improve their efficiency and scalability, in addition to exploring the therapeutic potential of purified saponins in various applications. By ensuring PGR quality during all production stages, consistent and potent therapeutic outcomes can be more easily achieved.

References

(1) Li, W.; Zhang, Y.; Zhao, S.; Zhao, X.; Xie, J. Efficient Enrichment and Characterization of Triterpenoid Saponins from Platycodon grandiflorus Roots. J. Chromatogr. A 2024, 1735, 465332. DOI: 10.1016/j.chroma.2024.465332

(2) Ji, M-Y.; Bo, A.; Yang, M.; Xu, J-F.; et al. The Pharmacological Effects and Health Benefits of Platycodon grandiflorus—A Medicine Food Homology Species. Foods 2020, 9 (2), 142. DOI: https://doi.org/10.3390/foods9020142

(3) Ishimaru, N.; Suzuki, S.; Shimokawa, T.; et al. Kikyo-to for Acute Upper Respiratory Tract Infection-Associated Sore Throat Pain: A Multicenter Randomized Controlled Trial. J. Integr. Complement. Med. 2022, 28 (9), 768–774. DOI: 10.1089/jicm.2021.0433