HPLC Determination of the Alkamide Affinin in Fresh and Dry Roots of Heliopsis longipes (Asteraceae) and HS-SPME-GC-MS-TOF Analysis of Volatile Components

Abstract

Heliopsis longipes (Asteraceae) is a plant whose roots are commonly used in Mexican cuisine as a substitute for hot pepper. This plant is also used in traditional medicine for its therapeutical properties. Previous reports detected the presence of affinin—an alkamide with analgesic properties—in extracts of H. longipes. Here, we describe the development of a high-performance liquid chromatography-UV detector method for the determination of the alkamide affinin (1) as the major component in fresh and dry roots of H. longipes. Compound 1 was quantitatively determined employing a Kromasil 100 C₁₈ 3 μm particle size column, using the isocratic mobile phase acetonitrile-water (55 + 45). The flow rate was 0.8 mL/min and the UV detection was at 213 nm. The limits of detection and quantitation were 0.0009 and 7.6 μg/mL, respectively. Compound 1 showed good linearity in the 75 to 150 μg/mL range; recovery was within 99.3 and 101.9 %. Quantities of affinin measured by this method ranged between 6.9 and 8.5 mg per gram of the dry and fresh roots; thus 1 could be used as marker for H. longipes. The LC method described here proved to be reliable, reproducible, accurate, and could be used for quality control of H. longipes medicinal materials. In addition, its volatile chemical composition is described and was assessed via GC-MS using headspace solid-phase microextraction; compounds were identified by matching against the standard mass spectral database of the National Institute of Standards and Technology (NIST). Twenty-eight recognized compounds represent 99.9 % of the total relative content of constituents from H. longipes roots.