Effect of successive extracts of Stachys tibetica Vatke (Lamiaceae) in anxiety

Abstract

Stachys tibetica Vatke (Lamiaceae) is an important medicinal plant in the folk medicine of Ladakh, India and Tibet for the treatment of various mental disorders. Infusion and decoction of the whole plant is used as a cup of tea in severe fever, headache and to relieve tension. Present study is aimed to evaluate the anxiolytic effect of successive extracts of Stachys tibetica Vatke (SES). Stachys tibetica Vatke (1 kg) was subjected to successive extraction in a soxhlet apparatus with different solvents of increasing polarity like petroleum ether (40–60 °C), chloroform, ethyl acetate, methanol and finally decocted with water (yield 7.08 %, 3.98 %, 2.02 %, 16.40 % and 21.53 % w/w respectively). All successive extracts were subjected to phytochemical screening. Rutin was identified by TLC method in the extracts. SES were evaluated for anxiolytic activity using elevated plus maze and light/dark arena tests in rats. Phytochemical studies showed the presence of flavonoids, terpenoids, saponins, glycosides, tannins, alkaloids etc. which might be responsible for anxiolytic activity. TLC analysis of the extracts also showed the presence of flavonoids (rutin). SES increased number of entries and time spent in open arms on the elevated plus maze test while as in the light/dark arena test; they showed an increase in number of crossings and time spent in light arena. The results of both the models of anti-anxiety studies were reflected on the 1st, 3rd and 7th day. Methanol and aqueous showed the most, chloroform and petroleum ether (40–60 °C) intermediate and ethyl acetate the least anxiolytic activity (*P < 0.05, **P < 0.01, ***P < 0.001) in both the models. The results strongly justify the use of this plant for treatment of anxiety. Further studies are in progress in our laboratory to isolate and identify the components responsible for anxiolytic activity and the mechanism of action involved.