# Effects of Culture Period and Plant Growth Regulators on In Vitro Biomass Production and Phenolic Compounds in Seven Species of Hypericum

## TL;DR

This study shows how different culture conditions affect biomass and phenolic compound production in seven Hypericum species grown in the lab.

## Contribution

The study identifies optimal culture conditions for biomass and specific phenolic compound production in various Hypericum species.

## Key findings

- MS medium with 0.2 mg/L BA significantly increased biomass, especially in H. olympicum, H. perforatum, and H. triquetrifolium.
- H. kalmianum had the highest total phenolic content, while H. olympicum produced the most hypericin and pseudohypericin.
- Phenolic profiles were species-specific and influenced by the culture period.

## Abstract

This study evaluated biomass accumulation and phenolic compound production in seven Hypericum species (H. androsaemum, H. calycinum, H. hirsutum, H. kalmianum, H. olympicum, H. perforatum, and H. triquetrifolium) cultivated in vitro under varying growth regulator treatments and culture periods. Shoots were grown on Murashige and Skoog (MS) medium supplemented with benzyladenine (BA) or meta-topoline (mT) and analyzed after 40 and 60 days. MS medium supplemented with 0.2 mg/L BA was the most effective condition for promoting biomass across all species, with shoot fresh weight increasing significantly at 60 days, particularly in H. olympicum, H. perforatum, and H. triquetrifolium. High-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (HPLC-DAD-ESI-MS) identified 13 phenolic compounds, including flavonols, hydroxycinnamic acids, anthocyanins, phloroglucinols, and naphthodianthrones. Phenolic profiles were species-specific and influenced by culture period. H. kalmianum accumulated the highest total phenolic content (37.6 mg/g DW), while H. olympicum was the top producer of hypericin and pseudohypericin. These results highlight the crucial role of culture conditions in regulating both biomass and phytochemical production and provide a promising approach for producing bioactive metabolites in Hypericum species through in vitro systems.