Evaluation of the Cytotoxic Activity of the Usnea barbata (L.) F. H. Wigg Dry Extract

Abstract

The secondary metabolites of lichens have proven to be promising sources of anticancer drugs; one of the most important of these is usnic acid, which is a phenolic compound with dibenzofuran structure that is responsible for the numerous biological actions of lichens of genus Usnea. As a result, in this study, we related to this phenolic secondary metabolite. The aim of the present study is the evaluation of the cytotoxic activity of Usnea barbata (L.) F. H. Wigg dry acetone extract (UBE). In advance, the usnic acid content was determined in various extracts of Usnea barbata (L.) F. H. Wigg: the liquid extracts were found in water, ethanol, acetone, and the dry acetone extract; the highest usnic acid quantity was found in the dry acetone extract. First, the cytotoxic action of UBE was assessed using Brine Shrimp Lethality (BSL) test; a significant lethal effect was obtained after 24 h of treatment at high used concentrations of UBE, and it was quantified by the high mortality rate of the Artemia salina (L.) larvae. Secondly, in vitro cytotoxicity of UBE was evaluated on human tongue squamous cells carcinoma, using CAL 27 (ATCC ® CRL-2095™) cell line. The most intense cytotoxic effect of UBE on CAL 27 cells was registered after 24 h; this response is directly proportional with the tested UBE concentrations. The obtained results have been reported regarding usnic acid content of UBE, and the data show that CAL 27 cells death was induced by apoptosis and high oxidative stress.Molecules 2020, 25, 1865 2 of 17 therapeutic tools for the total destruction of cancer cells with limited effects on normal cells [1]. It is known that carcinogenesis is a complex process, involving cellular and molecular alterations, mediated by endogenous and/or exogenous factors: oxidative DNA damage, chromosomal abnormalities, and oncogene activation are responsible for the development of cancer and may be induced by prolonged oxidative stress [2]. Thus, in cancer pathology, the reactive oxygen species (ROS) have dual role, confirmed by many studies: first, ROS are cytotoxic, having an important contribution in the etiology and progression of cancer [3]. At the same time, many antitumor agents can destroy the cancer cells through intense oxidative stress, generating ROS production in high quantities [4]. Increasing ROS levels through redox modulation could in the future be an effective strategy for the selective destruction of cancer cells (not normal cells) [5]; this method is called "oxidative therapy" [6], and it was developed by inducing cytotoxic oxidation as a stress factor in cancer cells in the treatment of cancer [7].One of the most invasive malignancies is the oral squamous cell carcinoma (OSCC), which is the most common cancer of oral cavity; it can affect any part of the oral cavity including lips, tongue, gums, buccal epithelium, and salivary glands [8]. Despite that, the oral cavity is easily accessible for the direct visual examination, and the mortality from oral cancer remains still high because in the early stages, the pat...

Studies on Preparation and UHPLC Analysis of the Usnea Barbata (L) F.H.Wigg Dry acetone extract

“…In the cold macerated acetone extract of Usnea barbata harvested from Anatolia (Turkey), Cansaran et al quantified 2.16% usnic acid; a value very close to the one mentioned above, was also found in the acetone extract obtained by cold maceration of Usnea barbata from the Calimani Mountains (2.12%) [5,6,15].…”

“…In the present study, the research has focused on the quantification of usnic acid in Usnea barbata dry acetone extract. Compared to cold maceration in acetone, where the amount of usnic acid was 2.12%, the solubility of usnic acid significantly increased in reflux condition, 8 h at 70 o C, obtaining 16.5 ± 6.53% (mean ± RSD) [15].…”

“…The scientific literature shows that the lichens of the genus Usnea Adans. are used in traditional medicine for thousands of years to treat various diseases [12,14,15]. For all lichens of this genus, the common secondary metabolite is the usnic acid, an organic compound with dibenzofuranic structure [10,16,17,19].…”

Antioxidant and Cytotoxic Activities of Usnea barbata (L.) F.H. Wigg. Dry Extracts in Different Solvents

“…Our previous studies on UBDE in acetone proved in vivo cytotoxic effects on Artemia sp. larvae and in vitro antitumor activity on human tongue squamous cells carcinoma (CAL 27 cell line) by involving the apoptotic mechanism [ 34 ]. U. barbata dry extract in acetone has a high UAC, and usnic acid induces ROS-dependent apoptosis of tumor cells [ 35 , 36 ].…”

Microwave-Assisted Extraction and HPLC-UV-CD Determination of (S)-usnic Acid in Cladonia foliacea

“…They were used to prepare a pilot extract by an in-house consolidated microwave-assisted extraction (MAE) protocol [ 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. The natural matrix was subjected to microwave irradiation, using acetone as extractive solvent [ 52 ].…”