Gentiana capitata Buch.-Ham. ex D.Don Cell Suspension Culture as a New Source of Isosaponarin and 3,7,8-Trimethoxy-9-oxo-9H-xanthen-1-yl 6-O-ß-D-ribopyranosyl-ß-D-allopyranoside and Their Effect on PC-12 Cell Viability.

Some species of the Gentianaceae family are a valuable source of secondary metabolites. However, the phytochemical knowledge of some of these species remains insufficient. Therefore, this work focused on the isolation of the two main secondary metabolites in the methanolic extract from a Gentiana capitata cell suspension using preparative HPLC and the determination of their structure using UHPLC-DAD-IT-MS/MS and NMR methods. Their content in the methanolic extract was quantified using a previously validated HPLC method. The toxicity of the extract and two isolated compounds was also tested on the PC-12 cell line. The structures of the main secondary metabolites were identified as isosaponarin and 3,7,8-Trimethoxy-9-oxo-9H-xanthen-1-yl 6-O-ß-D-ribopyranosyl-ß-D-allopyranoside by comparing the UHPLC-DAD-IT-MS/MS and NMR results with the literature data. The content of isosaponarin was determined to be 0.76 ± 0.04%, and the content of 3,7,8-trimethoxy-9-oxo-9H-xanthen-1-yl 6-O-ß-D-ribopyranosyl-ß-D-allopyranoside was found to be 0.31 ± 0.02% in the dry extract. Additionally, a two-fold increase in the viability of the PC-12 cell line was observed compared to the control after treatment with the methanolic extract at a concentration of 500 µg/mL. These results suggest the potential use of G. capitata cell suspension methanolic extract as a new source of isosaponarin and 3,7,8-trimethoxy-9-oxo-9H-xanthen-1-yl 6-O-ß-D-ribopyranosyl-ß-D-allopyranoside, highlighting their lack of toxicity to the PC-12 (rat pheochromocytoma) cell line.

Huperzine A and Huperzine B Production by Prothallus Cultures of Huperzia selago (L.) Bernh. ex Schrank et Mart.

This is the first report of an efficient and effective procedure to optimize the biosynthesis of huperzine A (HupA) and huperzine B (HupB) in vitro from Huperzia selago gametophytes. Axenic tissue cultures were established using spores collected from the sporophytes growing in the wild. The prothalia were obtained after 7-18 months. Approximately 90 up to 100% of the gametophytes were viable and grew rapidly after each transfer on to a fresh medium every 3 months. The best biomass growth index for prothallus calculated on a fresh (FW) and dry weight (DW) basis, at 24 weeks of culture, was 2500% (FW) and 2200% (DW), respectively. The huperzine A content in the gametophytes was very high and ranged from 0.74 mg/g to 4.73 mg/g DW. The highest yield HupA biosynthesis at >4 mg/g DW was observed on W/S medium without growth regulators at 8 to 24 weeks of culture. The highest HupB content ranged from 0.10 mg/g to 0.52 mg/g DW and was obtained on the same medium. The results demonstrate the superiority of H. selago gametophyte cultures, with the level of HupA biosynthesis approximately 42% higher compared to sporophyte cultures and 35-fold higher than when the alkaloid was isolated from H. serrata, its current source for the pharmaceutical industry. Moreover, the biosynthesis of HupB was several-fold more efficient than in H. selago sporophytes growing in the wild. HPLC-HR-MS analyses of the extracts identified eight new alkaloids previously unreported in H. selago: deacetylfawcettine, fawcettimine, 16-hydroxyhuperzine B, deacetyllycoclavine, annopodine, lycopecurine, des-N-methylfastigiatine and flabelline.