Bioactive caffeic acid esters from Glycyrrhiza glabra

Abstract

Thin layer chromatography bioautography (using DPPH spray reagent) guided fractionation of Glycyrrhiza glabra led to the isolation of two caffeic acid derivative esters, viz. eicosanyl caffeate (1) and docosyl caffeate (2). The two compounds exhibited potent elastase inhibitory activity, with IC₅₀ values of 0.99 µg mL⁻¹ and 1.4 µg mL⁻¹ for 1 and 2, respectively. The compounds also showed moderate antioxidant activity in DPPH and ABTS scavenging assays. The results indicate a possible role of caffeic acid derivatives, in addition to flavonoids in the anti-ulcer properties of G. glabra.

Keywords:

• ABTS
• antioxidant
• docosyl caffeate
• DPPH
• eicosanyl caffeate
• elastase
• Glycyrrhiza glabra

Acknowledgements

The authors thank Mr Swamy, Mr Mohan, and Ms Chandrakala of the NMR Research Centre, IISc, Bangalore for NMR spectra, Mr Prakash for ESI-MS and Ms Padmaja Rani, Ms Meenakshi Das, Ms Sreeja and Mr Sandeep of the Department of Bioassay, Natural Remedies Pvt. Ltd. We are grateful to Mr R.K. Agarwal for providing the necessary faculties.