Ethnic, economic, and therapeutic applications of lichens as a source of bioactive secondary metabolites: An integrative review

Abstract

Interest in and research on lichens is increasing day by day due to their benefits to human health and their uses in various fields. This study aims to reveal the potential uses of lichens in human life, from traditional to modern, through a broad literature review. Producing many unique secondary metabolites as a result of their symbiotic lifestyle, lichens are among the natural resources used in various fields such as medicine, pharmaceuticals, cosmetics, chemical dyes, textiles, and the food industry. Their increasingly discovered biological effects—antifungal, antibacterial, antioxidant, antitumor, anticarcinogenic, and antiviral—highlight the significant potential of lichens in health biotechnology. Some lichens are known to provide habitat material and food for various animals and are also consumed by humans. Ethnic uses of lichens can be seen in mummification, traditional clothing, costumes, and ornaments in various cultures from ancient times to the present. Today, lichens are frequently encountered in artistic designs, accessories, floriculture, terrariums, and decorative wall hangings. Historical medical research has revealed various therapeutic uses of lichens. Many lichen species have been documented as sources of active pharmaceutical ingredients in medicines and as components of cosmetic products. Current studies on lichen extracts and lichen secondary metabolites indicate that lichen species exhibit antibacterial, antioxidant, antiviral, and antifungal activities, and have medical potential as therapeutic agents against a variety of diseases. This review briefly examines the biology and contributions of lichens to nature, followed by information on their versatile uses from various sources dating back approximately 80 years.