Evaluation of changes in the growth and chemical constituents of Anoectochilus formosanus Hayata grown under hydroponic conditions

Anoectochilus formosanus Hayata is an important medicinal plant with various pharmaceutical properties. In this study, A. formosanus plants were hydroponically cultivated in different nutrient solutions to achieve enhanced biomass and secondary metabolites production. Three months-old A. formosanus plants were grown for 8 weeks under controlled environment in plastic pots containing Murashige and Skoog (MS), Nitrophoska Foliar (NF), Hydro Green (HG), or Hydro Bee (HB) media. Among 4 nutrient solutions tested, HB was the most efficient medium for the plant growth with the highest fresh weight (FW, 2.56 g/plant) and dry weight (DW, 0.18 g/plant) values. The results of phytochemical screening showed the presence of alkaloids, flavonoids, terpenoids, glycosides, and steroids in the extracts of A. formosanus cultivated in HB, HG, and MS medium. The level of these compounds was significantly different in plants cultivated in tested media. The highest alkaloids (34.87 μg/g DW) and terpenoids (56.43 μg/g DW) contents were obtained on HG medium, whereas flavonoids were present in highest amounts (90.13 μg QE/g DW) in plants grown in NF medium. On the other hand, HB medium stimulated the production of the highest glycoside (64.33 μg/g DW) and steroids (22.83 μg/g DW) levels. The antioxidant activity of the extracts was also tested using the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity assay and the results demonstrated strong antioxidant activities of A. formosanus extracts with IC₅₀ of 136.19 to 248.85 μg/ml. Concluding, the hydroponic-cultivation of A. formosanus is a promising way for obtaining highly valuable compounds for pharmaceutical and nutraceutical industries.