Bioactivity-guided isolation of anticonvulsant and anxiolytic constituents from Stachys and Teucrium species

Species of the genera Stachys L. and Teucrium L. (Lamiaceae) have been traditionally used in folk medicine for the management of neurological disorders, including epilepsy and anxiety. However, experimental evidence supporting these traditional claims remains limited for several taxa.

The present study aimed to evaluate the anticonvulsant and anxiolytic activities of selected Stachys and Teucrium taxa and to isolate and characterazide the bioactive constituents responsible for these effects through bioactivity-guided fractionation.

Hydroethanolic (70:30, v/v) extracts prepared from the aerial parts of Stachys byzantina, S. officinalis subsp. balcanica, S. cretica subsp. anatolica, Teucrium chamaedrys subsp. chamaedrys, and T. montanum were evaluated using the pentylenetetrazole (PTZ)-induced seizure model and the elevated plus maze test in mice. The most active extract was subjected to bioactivity-guided fractionation using solvent partitioning and silica gel column chromatography. Isolated compounds were structurally elucidated by spectroscopic methods.

Among the tested taxa, S. byzantina exhibited the most pronounced anticonvulsant and anxiolytic effects. In the PTZ model, the total extract significantly increased seizure latency (60.17 ± 2.66 s) compared to the control group (42.17 ± 3.32 s, p < 0.05). The aqueous fraction (AF) showed enhanced activity, prolonging seizure latency to 68.83 ± 4.11 s. Subsequent fractionation yielded two active fractions (ACF-3 and ACF-4), which demonstrated significant anticonvulsant effects (68.83 ± 3.52 s and 59.8 ± 4.96 s, respectively; p < 0.05). Further isolation led to the identification of four compounds: 4'-O-methylhypoaletin-7-O-[6‴-O-acetyl-β-D-allopyranosyl-(1 → 2)]-β-D-glucopyranoside, chlorogenic acid, verbascoside, and luteolin 7-O-β-glucoside. Chlorogenic acid exhibited the highest seizure latency (78.4 ± 4.01 s) and significantly reduced seizure number (1.4 ± 0.20), with effects comparable to valproic acid.

The findings provide experimental evidence supporting the traditional use of S. byzantina in neurological disorders and identify chlorogenic acid as a major bioactive constituent contributing to its anticonvulsant activity. These results highlight the therapeutic potential of S. byzantina as a source of plant-derived anticonvulsant and neuroprotective agents and warrant further pharmacological and mechanistic investigations.