Coumarins from Angelica archangelica Linn. and their effects on anxiety-like behavior

TRADITIONAL RELEVANCE: Angelica archangelica Linn. (Apiaceae) is an herb distributed in tropical and subtropical regions of the world. Both in Chinese and Indian system of medicine, it is used for nervous disorders including anxiety, anorexia, migraine and other cerebral diseases.

To evaluate the anxiolytic potential of non polar coumarins isolated from A. archangelica Linn.

A. archangelica Linn. (1 kg) was subjected to extraction in a soxhlet apparatus with petroleum ether (40-60 °C), yield 6.9% w/w. The extract of petroleum ether produced a yellow colored precipitate (YP) which was evaluated for anxiolytic like effect using EPM test and was found significant (**P<0.01) in doses of 5 and 10 mg/kg, po. The precipitate was shown to be a mixture of seven constituents in HPTLC and six on the TLC plate which were further subjected to separation by preparative TLC. Non polar coumarins were isolated namely imperatorin (IM) and isoimperatorin (IIM). YP, IM, IIM were tested for anxiolytic like effects in a dose of 5mg/kg, po along with DZ (1mg/kg, po) using EPM, Light & dark arena and hole board models in rats. All the test drugs were found to have significant (*P<0.05, **P<0.01) activity. IM and IIM have the potential to reduce anxiety but yellow precipitate showed the most promising activity as compared to isolated coumarins. This effect may be due to the synergistic action of all compounds present in the YP or by multiple mechanism of action. The test drugs may have the potential for different receptors.

The mixture of coumarins isolated from A. archangelica and its constituents imperatorin and isoimperatorin have the potential to reduce anxiety but it is the mixture which have more significant activity as compared to its individual components.