Analysis of other phenolics (capsaicin, gingerol, and alkylresorcinols)

Phenolic compounds exhibit a wide variety of biological effects because of their antioxidant properties. Phenolic compounds have widespread occurrence in nature and are consumed by humans through diet consisting of fruits and vegetables. The gradually increasing interest in phenolic acids profile is directly proportional to their antioxidant activity and potential benefits for health as they protect the human body from free radicals and their formation is associated with normal natural metabolism of aerobic cells. Protective phenylpropanoid metabolism pathways in plants have been well-documented which results in the biosynthesis of phenolic compounds. The antiradical activity of phenolics and flavonoids is chiefly based on the reduction-oxidation properties of the hydroxyl group they contain as well as the structural relationships between different parts of the chemical structures of these compounds. Epidemiological data have exhibited various benefits of antioxidant compounds in the prevention of a wide range of disease states like cancer, cardiovascular disease, and neurodegenerative disorders. From the past few years, identification and development of phenolic compounds from various plants has become a major area of health and medical-related research studies. This chapter provides an updated and comprehensive overview on capsaicin, gingerol, and alkylresorcinols extraction, purification, and quantification as well as their antioxidant properties. The extraction of capsaicin, gingerol, and alkylresorcinols from source material is the first step involved in their analysis. They are extracted by solvent extraction, which is a conventional method, and modern methods such as subcritical fluid extraction (SFE) and ultrasonic-assisted extraction. The content of capsaicin, gingerol, and alkylresorcinols in the extract is determined using chemical, chromatographic, and spectrometric analysis. Thin layer chromatography (TLC), gas chromatography coupled with mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), and liquid chromatography tandem mass spectrometry (LC-MS/MS) are employed for the identification and quantification of the individual compounds present.