Background: Ashwagandha (Withania somnifera) is an important herb in the Indian traditional
system of medicine for neurological disorders. However, the efforts for isolation and
characterisation of a molecule with anti-depressant activity and development as a potent dosage form
Objective: The objective of the present study was to characterize the Ashwagandha extract for its antidepressant
fraction or constituent and to improve biological benefits at low doses.
Methods: Aqueous methanol extract of Ashwagandha was prepared and fractionated into withanolides
and flavonoids rich fractions. Withanolide rich fraction was subjected to phytochemical analysis to identify
the active molecule/s. The compound was purified by using a semi-preparative HPLC system; identified
using various spectroscopic techniques and anti-depressant activity was evaluated in rats. Enteric
coating was performed on the extract and fractions after granulation and anti-depressant activity of
coated samples were evaluated in rats.
Results: Aqueous methanol extract of Ashwagandha and withanolide rich fraction showed prominent
dose-dependent anti-depressant activity in forced swim test in rats. Phytochemical analysis of active
fraction resulted in the isolation and characterization of a major withanolide glycoside present, namely
withanoside X. Enteric coated aqueous methanol extract, withanolide rich fraction and withanoside X
showed significant antidepressant activity at low doses as compared to the uncoated forms.
Conclusion: The active fraction/isolated compound is sensitive to low pH of the stomach, thus enteric
coating might be beneficial to protect the actives in the stomach, facilitating the sustainable release into
the intestine and in turn reduce the dosage.