A Review of Tannin Compounds in Avocado as Antioxidants

Abstract

Avocados, a fruit from Persea americana, are highly nutritious and energy-dense. However, some people eat the tasty fruit and rarely use other plant parts that can benefit their health. Rarely used plant parts like seeds, leaves, and fruit peels are known to contain active secondary metabolites, including tannin. Tannins are polyphenolic chemicals with antioxidant properties. Antioxidants can protect against oxidation reactions induced by reactive species like hydrogen peroxide, hydroxyl radicals, and superoxide anion radicals. These reactive organisms can cause a variety of degenerative illnesses in humans. The study aimed to identify the potential of tannin compounds in avocado trees as antioxidants that may benefit human health. The literature review was conducted by searching national and international scientific journals using Science Direct, Google Scholar, and PubMed search engines. Tannins demonstrate antioxidant action by reducing free radicals, chelating transition metals, and inhibiting pro-oxidative enzymes. Condensed tannin molecules such as catechins, epicatechins, procyanidins, and proanthocyanidins were considered responsible for avocados’ antioxidant action. Further investigation into the potential health benefits of avocado tannins through a multidisciplinary approach, including biochemical characterisation, bioavailability studies, and clinical investigations, is recommended.