Evaluation of Optimal Harvesting Time for Selaginella doederleinii Hieron at a Fixed Location Using HPLC Fingerprinting and In Vitro Antiproliferation Assays.

In this study, a strategy for determining the optimal harvesting time of medicinal plants was proposed and implemented, using the antitumor herb Selaginella doederleinii Hieron (S. doederleinii) as a case study, based on HPLC fingerprinting profiles and in vitro activity assays. A total of 12 batches of S. doederleinii samples were collected from a fixed geographic location from January to December. An HPLC-based fingerprint was then established, followed by similarity analysis, principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA) on the 80% ethanol extracts of these samples. Meanwhile, in vitro viability was assessed using Calcein/PI cell viability assays and Western blotting analysis. By combining the chemometrics and biological activity results, it is inferred that the optimal harvesting time for S. doederleinii is in April and May. Furthermore, the following compounds were tentatively identified as quality control markers for this medicinal herb at the fixed geographic location: 2″,3″-Dihydro-3',3‴-biapigenin, 3',3‴-binaringenin, Delicaflavone, 2,3-Dihydrohinokiflavone, Chrysocauloflavone I, and 2″,3″-Dihydro-3',3‴-biapigenin methyl ether. This study provides a feasible strategy for selecting harvesting time of medicinal plants grown at a fixed geographic location.