Free Radical Scavenging Activity and Comparative Metabolic Profiling of In Vitro Cultured and Field Grown Withania somnifera Roots

Free radical scavenging activity (FRSA), total phenolic content (TPC), and total flavonoid content (TFC) of in vitro cultured and field grown Withania somnifera (Ashwagandha) roots were investigated. Withanolides analysis and comprehensive metabolic profiling between 100% methanol extracts of in vitro and field grown root tissues was performed using high performance thin layer chromatography (HPTLC) and gas chromatography-mass spectrometry (GC-MS), respectively. Significantly higher levels of FRSA, TPC, and TFC were observed in in-vitro cultured roots compared with field grown samples. In addition, 30 day-cultured in vitro root samples (1MIR) exhibited a significantly higher FRSA (IC50 81.01 μg/mL), TPC (118.91 mg GAE/g), and TFC (32.68 mg CE/g) compared with those in 45 day-cultured samples (1.5MIR). Total of 29 metabolites were identified in in vitro cultured and field grown roots by GC-MS analysis. The metabolites included alcohols, organic acids, purine, pyrimidine, sugars, and putrescine. Vanillic acid was only observed in the in vitro cultured root samples, and higher level of the vanillic acid was observed in 1MIR when compared to 1.5MIR. Therefore, it is suggested that 1MIR might serve as an alternative to field grown roots for the development of medicinal and functional food products.

本研究探究了体外培养与大田种植的南非醉茄（Withania somnifera, Ashwagandha）根的自由基清除活性（Free radical scavenging activity, FRSA）、总酚含量（Total phenolic content, TPC）及总黄酮含量（Total flavonoid content, TFC）。本研究分别采用高效薄层色谱（High performance thin layer chromatography, HPTLC）与气相色谱-质谱联用（Gas chromatography-mass spectrometry, GC-MS），对两类根组织的100%甲醇提取物开展醉茄内酯分析与全面代谢组谱分析。相较于大田种植样品，体外培养根的FRSA、TPC及TFC水平显著更高。此外，培养30天的体外根样品（1MIR）相较于培养45天的样品（1.5MIR），其FRSA（半抑制浓度IC50为81.01 μg/mL）、TPC（118.91 mg 没食子酸当量每克，mg GAE/g）及TFC（32.68 mg 儿茶素当量每克，mg CE/g）均显著更高。通过GC-MS分析，本研究在体外培养与大田种植的根中共鉴定出29种代谢物，涵盖醇类、有机酸、嘌呤、嘧啶、糖类及腐胺。香草酸仅在体外培养的根样品中被检出，且1MIR中的香草酸水平高于1.5MIR。因此，本研究认为1MIR可作为大田种植根的替代原料，用于药用及功能性食品的开发。