Rapid and Sensitive HPLC Method for the Determination of Polyphenols in Various Lichen Species of Himalayan Origin

Abstract

A reversed‐phase high performance liquid chromatograph (HPLC) with photodiode array detection method was developed to determine bioactive polyphenolic substances, methyl β‐orcinolcarboxylate (MBO) and ethyl haematommate (EH) in thalli of various lichen species. The MBO and EH were separated by RP‐HPLC (C₁₈ column, 150 mm×4.6 mm, 5 µm) using isocratic elution systems of acetonitrile:water (0.1% acetic acid). Base line separation of the compounds was obtained in less than 20 min. The method was validated for linearity, repeatability, limits of detection (LOD), and limits of quantification (LOQ). Repeatability (inter‐ and intra‐day, n=6) showed less than 1.5% relative standard deviation (RSD). The LOD and LOQ were found to be 5.97 and 15.51 ng for MBO and 42.63 and 69.03 ng for EH, respectively. The validated HPLC method was employed to quantify MBO and EH in eleven lichen species, used in folklore/traditional systems of medicine collected from the Himalayan region of India.

Keywords:

• Lichen
• Polyphenol
• Methyl β‐orcinolcarboxylate (MBO)
• Ethyl haematommate (EH)
• RP‐HPLC

Acknowledgments

We are thankful to Dr. D. K. Upreti, National Botanical Research Institute (CSIR), Lucknow, for his help in identification of lichen species. The financial help from Council of Scientific and Industrial Research (CSIR), New Delhi is duly acknowledged.