Phytochemical Investigation of Stachys hissarica: Antioxidant Activity, Flavonoid Characterization, and In Silico Analysis.

Evaluating Stachys hissarica extracts via DPPH, FRAP, and ABTS assays revealed that the aqueous methanolic fraction exhibited strong, ascorbic acid-comparable antioxidant activity. This high potency confirms that hydrophilic phenolic compounds are the primary drivers of its radical-scavenging effect. HPLC-PDA/ESI-MS/MS analysis of the aqueous methanolic extract led to the tentative annotation of 35 metabolites, including hydroxycinnamic acid derivatives, flavonoid glycosides, acetylated and methoxylated flavones, consistent with the phytochemical profile of the Stachys genus. The antioxidant activities of these polyphenolic constituents likely support the strong radical-scavenging activity observed. In addition, five compounds were isolated from the polar extract of S. hissarica, and their chemical structures were elucidated using NMR and high-resolution mass spectrometry. Computer simulations showed that hydrophilic phenolics, such as naringenin and hesperidin, possess favorable oral bioavailability, low toxicity, and strong, stable binding affinities to the target protein. However, these computational predictions require experimental validation through biochemical and pharmacological assays.