IMPORTANCE OF LICHENS AS ENVIRONMENTAL BIOINDICATORS AND PROMISING SOURCE OF ANTI-CANCER COMPOUNDS

Abstract

A large quantity of natural products and biomolecules have been isolated and characterized from plants, lichens, fungi and sea organisms; in particular, more than 110 thousand secondary metabolites have been extracted from plants. In this regard, it is estimated that a significant number of substances will be discovered in the coming years, taking into consideration that only a low proportion has been analyzed from available natural sources. Lichens are stable symbiotic life forms, which are made up by a fungus (mycobiont) and up to two algae autotrophs and/or cyanobacteria autotrophs (photobiont). Up to date, between 17,500 and 20 thousand variants have been identified, including 1,500 lichenicholous fungi. This type of organism has the capacity to synthesize more than 1000 secondary metabolites. With regard to their medicinal use, lichens are used in the treatment of pulmonary tuberculosis and as vermicide. Also, they are used to control fevers, relieve pain, and as expectorant, among others. Likewise, they are used in the field of cosmetics and in pharmaceutical preparations. In relation to their biological activity, lichens are used as antioxidants to delay cell aging; antiviral compound against the Acquired Immunodeficiency Disease Syndrome and the Human Papilloma Virus, and antibacterial compound used in Gram positive bacteria inhibition. Also, these organisms present antitumor action inhibiting different types of cancer. On the other hand, lichens are used as bio monitors of environmental contamination. In this study their therapeutic uses and status as bio indicators of environmental contamination are indicated.