Rapid in vitro propagation and bioactive compounds evaluation in Polygonum multiflorum Thunb.

Polygonum multiflorum Thunb. is an important medicinal plant with various biologically active substances such as emodin, THSG (2,3,5,4’-tetrahydroxystilben-2-O-β-D-glucoside), phenolics, flavonoids, and others. This study evaluated the effectiveness of different sterilization methods and optimized culture conditions for the rapid in vitro propagation of P. multiflorum. Silver nanoparticles (AgNPs) combined with Medipag was the most effective sterilization method compared to individual treatments for the same duration of 30 min. Subsequently, Javel was applied for 27 min to achieve further sterilization. After two weeks, the highest regeneration rate observed was 58.0%. The maximum number of shoots were induced from bud explants on MS (Murashige and Skoog, 1962) medium containing 4.0 mg/L BAP + 0.1 mg/L NAA with an average of 5.40 shoots/explant and shoot height of 20.40 mm after four weeks of culture. The highest rooting was observed in ¾ MS medium supplemented with 0.5 mg/L NAA with an average of 8.60 roots/shoot and 7.06 cm root length after five weeks of culture. Moreover, we observed that the tuber of P. multiflorum cultivated ex vitro possessed a superior total phenolic content (58.27 mg/g DW) and total flavonoid content (37.26 mg/g DW) compared to other plant parts. Similarly, the tuber extract showed the highest antioxidant activity at 94.64%. Notably, the amounts of these compounds were higher in in vitro shoots than in ex vitro leaves and stems. There was also a strong correlation between the total phenolic and flavonoid contents (r² = 0.991) and antioxidant activity. This study successfully established a comprehensive micropropagation protocol from initial explant cultivation to plantlet acclimatization under natural conditions. It further assessed the advantages of tissue-cultured plants in terms of phenolic and flavonoid compound accumulation, and their antioxidant capacity.Key message: This study developed a complete micropropagation protocol through plantlet acclimatization in natural conditions, while also highlighting the advantages of tissue-cultured plants in secondary compound accumulation and antioxidant activity. [ABSTRACT FROM AUTHOR]