Tracing the stability of Andrographis Herb through 1H NMR-based metabolomics and titrimetric approaches

Andrographis Herb, defined as the aerial parts of Andrographis paniculata (Burm. f.) Nees, is one of the widely used herbal products, officially recommended for the symptomatic relief of common cold. The herb, however, has a very short-termed stability, which has been a major problem in the storage and distribution of its raw materials and products. To monitor the chemical degradation and stability of Andrographis Herb holistically, a H-1 NMR-based metabolomics workflow was used to map the chemical profiles in the raw materials stored in the standard storage conditions over a 6-month period. Principal component analysis (PCA) on the NMR data from the CHCl3 and aq MeOH extracts of the herb traced the decomposition of diterpene lactones, particularly through the changes in contents and composition ratios, as indicators that signified the stability of Andrographis Herb. Specifically, 14-deoxy-11,12-didehydroandrographolide was suggested by PCA as a potential candidate to be a stability and/or age marker of the herb. In parallel, the degradation of active constituents in Andrographis Herb was also examined through the determination of total lactones content using the standard titrimetric method, from which t(90%)s were estimated to be as short as 3-5 months. Graphic abstract