Antibiotic Activity of Lichens

Abstract

The production by an organism of organic substances inimical to the life processes of other organisms and inhibiting their growth is known as antibiosis. The phenomenon of antibiosis has attracted wide-spread attention in recent years chiefly because of the remarkable chemotherapeutic effects of penicillin, a product of the mold Penicillium. The anabolic products of many kinds of bacteria,' molds,2 and algae,3 and substances elaborated by certain species of flowering plants4 can be readily demonstrated to have antibiotic properties when small amounts of the active materials are tested on microorganisms with suitable assay procedures. In view of the reported antibacterial activity of the green alga Chlorekla and the many antagonistic substances now known to be produced by numerous kinds of fungi, the lichens seemed to offer favorable material for antibiotic investigations, inasmuch as the bodies of these plants are comprised of mixtures of algae and fungi. Accordingly we have tested a considerable number of lichens for antagonistic action against some common species of bacteria, and offer herewith a preliminary report concerning some of our observations.Methods.-The lichens were brought in fresh condition to the laboratory, placed in shallow pans, and moistened with water for the purpose of allowing them to become physiologically more active. After a few hours of exposure to sunlight, samples of the moist lichens were separated from the substrata with a razor blade and forceps. Extracts were made by grinding, with a glass mortar and pestle, 100 mg. of lichen in 1 ml. of phosphate buffer solution adjusted to pH 7.4. The final aqueous extract was approximately pH 7.0. Extractions were carried out at room temperature and the samples were stored at 1°C. for a short time until the materials could be assayed. No attempt was made to clarify the extracts in these preliminary tests. The aqueous suspensions were assayed against Staphylococcus aureus, Escherichia co/i, Bacillus subtilis or other bacteria by means 250 PROC. N. A. S.

In vitro antimicrobial activity of the organic extract of Cladonia substellata Vainio and usnic acid against Staphylococcus spp. obtained from cats and dogs

“…This can be explained by the composition of the organic extract of C. substellata originating from the Northeast of Brazil, with approximately 98% usnic acid in its composition (Huovinen & Ahti 1986, Ahti et al 1993, Yano-Melo et al 1999). This may be primarily responsible for the antimicrobial activity demonstrated in this study and others (Burkholder et al 1944, Carrazzoni 1975, Huovinen & Ahti 1986, Ahti et al 1993, Lauterwein et al 1995, Pereira et al 1997, Honda & Vilegas 1998, Yano-Melo et al 1999, Donlan 2001, Falcão et al 2004, Ribeiro et al 2006, Moura et al 2008. Ranković et al (2012) tested the antibacterial activity of usnic acid compared to streptomycin for Bacillus mycoides (ATCC 6462), B. subtilis (ATCC 6633), S. aureus (ATCC 25923), Escherichia coli (ATCC 25922), and Klebsiella pneumoniae (ATCC 13883).…”

In vitroevaluation of the antibacterial activity of extracts from 34 species of North American lichens

“…Since Burkholder et al (1944) first reported on the antibiotic properties of lichens, a number of studies have investigated the antimicrobial activities of several lichen species against various Gram-positive, Gram-negative, and mycobacteria (Hobbs, 1986;Ingólfsdóttir et al, 1985;Kokubun et al, 2007;Lauterwein et al, 1995;Lawrey, 1989;Manojlovic et al, 2011). More specifically, studies have shown that lichen compounds either in crude extract or as purified compounds are not active against Gram-negative bacteria such as E. coli and P. aeruginosa (Francolini et al, 2004;Ingólfsdóttir, 2002;Lauterwein et al, 1995;Melgarejo et al, 2008;Paudel et al, 2012;Yilmaz et al, 2005).…”

Atividade antimicrobiana de derivados fenólicos do líquen Ramalina sorediosa (B. de Lesd.) Laundron

“…Os primeiros estudos foram realizados por Burkholder et al (1944). Posteriormente, muitos outros pesquisadores obtiveram resultados interessantes.…”