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. 2012 Nov 12;13(11):14707-22.
doi: 10.3390/ijms131114707.

Biological activities of Toninia candida and Usnea barbata together with their norstictic acid and usnic acid constituents

Branislav Ranković  1 , Marijana Kosanić, Tatjana Stanojković, Perica Vasiljević, Nedeljko Manojlović
Affiliations

Biological activities of Toninia candida and Usnea barbata together with their norstictic acid and usnic acid constituents

Branislav Ranković et al. Int J Mol Sci. .

Abstract

The aim of this study was to investigate the chemical composition of acetone extracts of the lichens Toninia candida and Usnea barbata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts together with some of their major metabolites. The chemical composition of T. candida and U. barbata extracts was determined using HPLC-UV analysis. The major phenolic compounds in these extracts were norstictic acid (T. candida) and usnic acid (U. barbata). Antioxidant activity was evaluated by free radical scavenging, superoxide anion radical scavenging, reducing power and determination of total phenolic compounds. Results of the study proved that norstictic acid had the largest antioxidant activity. The total content of phenols in the extracts was determined as the pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration using the broth microdilution method. The most active was usnic acid with minimum inhibitory concentration values ranging from 0.0008 to 0.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using the microculture tetrazolium test. Usnic acid was found to have the strongest anticancer activity towards both cell lines with IC(50) values of 12.72 and 15.66 μg/mL.

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Figures

Figure 1
Figure 1
Chromatogram of the standards used for identification of the compounds present in Toninia candida and Usnea barbata.
Figure 2
Figure 2
HPLC chromatograms acquired at 254 nm of the acetone extracts of Toninia candida (A) and Usnea barbata (B). Chromatographic peak identities are reported in Table 1.
Figure 3
Figure 3
Structures of the identified compounds. (A) Norstictic acid; (B) Usnic acid.
See this image and copyright information in PMC

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