Organisms with long history of therapeutic use

Lichens, according to Dr. Weerakoon, are some of the most unique organisms on this planet.

They are products of a symbiotic association between a fungus and photosynthetic partner, usually an alga, which have evolved together to behave and look like an entirely new being, with almost no resemblance to either partners.

Lichens can be found on tree-trunks or rock faces at Horton Plains, Hakgala, Nuwara Eliya, Pidurutalalgala and Samanala Kanda. They cling to trees, rocks and even man-made signboards, fences and boundary markers.

Usnea lichens, found all over the world, arise from a symbiosis between fungi from the Ascomycota phylum (often known as Sac fungi) and green alga of the Chlorophyta division. Although widespread, these lichens are highly sensitive to environmental disturbance, especially air pollution such as sulfur dioxide, says Dr. Weerakoon.

Known commonly as Usnea lichens, Usnea longissima, Beard moss and Tree moss, they have a long history of medicinal use in Asia, Europe and America, with Christopher Hobbs writing a thorough review titled: ‘ Usnea: The Herbal Antibiotic’, the Sunday Times learns.

The active constituents being lichen acids (usnic acid C18H16O7 which acts as an antibiotic), polysaccharides (as an immunostimulant), mucilage, anthraquinones (endocrocin-laxative), fatty acids, all the essential amino acids, vitamins and carotenoids, it is valued medicinally for its antimicrobial, anti-fungal, immunomodulating, demulcent, laxative and nutritive actions, she says.

“It has a documented history of therapeutic use dating over 3,000 years in Chi-