Lichens represent a significant source of antioxidants due to numerous metabolites that can reduce free radicals. Usnea barbata (L.) F.H. Wigg. has been recognized and used since ancient times for its therapeutic effects, some of which are based on its antioxidant properties. The present study aims to analyze the phytochemical profile and to evaluate the antioxidant and cytotoxic potential of this lichen species. Five dry extracts of U. barbata (UBDE) in different solvents (acetone, ethyl acetate, ethanol, methanol, water) were prepared by refluxing at Soxhlet to achieve these proposed objectives and to identify which solvent is the most effective for the extraction. The usnic acid content (UAC) was quantified by ultra-high performance liquid chromatography (UHPLC). The total polyphenols content (TPC) and tannins content (TC) were evaluated by spectrophotometry, and the total polysaccharides (PSC) were extracted by a gravimetric method. The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical method was used to assess the antioxidant activity (AA) and the Brine Shrimp Lethality (BSL) assay was the biotest for cytotoxic activity evaluation. The ethyl acetate extract had the highest usnic acid content, and acetone extract had the highest content of total polyphenols and tannins. The most significant antioxidant effect was reported to methanol extract, and all the extracts proved high cytotoxicity. The water extract has the lowest cytotoxicity because usnic acid is slightly soluble in this solvent, and it was not found at UHPLC analysis. All extracts recorded a moderate correlation between the content of usnic acid, polyphenols, tannins, and AA; furthermore, it has been observed that the cytotoxicity varies inversely with the antioxidant effect.

Phenolic compounds represent an essential bioactive metabolites group with numerous pharmaceutical applications. Our study aims to identify and quantify phenolic constituents of various liquid and dry extracts of Usnea barbata (L.) Weber ex F.H. Wigg (U. barbata) from Calimani Mountains, Romania, and investigate their bioactivities. The extracts in acetone, 96% ethanol, and water with the same dried lichen/solvent ratio (w/v) were obtained through two conventional techniques: maceration (mUBA, mUBE, and mUBW) and Soxhlet extraction (dUBA, dUBE, and dUBW). High-performance liquid chromatography with diode-array detection (HPLC-DAD) was performed for usnic acid (UA) and different polyphenols quantification. Then, the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity (AA) were determined through spectrophotometric methods. Using the disc diffusion method (DDM), the antibacterial activity was evaluated against Gram-positive and Gram-negative bacteria known for their pathogenicity: Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 49619), Pseudomonas aeruginosa (ATCC 27853), and Klebsiella pneumoniae (ATCC 13883). All extracts contain phenolic compounds expressed as TPC values. Five lichen extracts display various UA contents; this significant metabolite was not detected in dUBW. Six polyphenols from the standards mixture were quantified only in ethanol and water extracts; mUBE has all individual polyphenols, while dUBE shows only two. Three polyphenols were detected in mUBW, but none was found in dUBW. All U. barbata extracts had antiradical activity; however, only ethanol and acetone extracts proved inhibitory activity against P. aeruginosa, S. pneumoniae, and S. aureus. In contrast, K. pneumoniae was strongly resistant (IZD = 0). Data analysis evidenced a high positive correlation between the phenolic constituents and bioactivities of each U. barbata extract. Associating these extracts’ properties with both conventional techniques used for their preparation revealed the extraction conditions’ significant influence on lichen extracts metabolites profiling, with a powerful impact on their pharmacological potential.

Studies of total phenolic content and identification and quantification of phenolic compounds by HPLC-DAD from hydro-alcoholic and alcoholic macerates of Lavandula angustifolia L flowers from Dobrogea area are reported. The total phenolic content and the phenolic profile have been measured using Folin-Ciocalteau method, respectively adapted USP30 HPLC method in macerates of Lavandula angustifolia L flowers after 5 days of contact with either methanol (M1) or methanol: water 1 : 1 (V : V) mixture (M2). The values of TPC show that macerate M2 is more rich in phenolic compounds (3520 mg/100g d.w.), than in the case of macerate M1 (2860 mg/100 g d.w.). The obtained data of phenolic compounds determined by HPLC-DAD method were compared with the available authentic standards. Four individual phenolic compounds were found in macerate M1 and six individual phenolic compounds in macerate M2. Among gallic acid and chlorogenic acid, as major phenolic compounds, high concentrations of ellagic acid in M2 (514.249 mg/100 g d.w.) and M1 (499.487 mg/100g d.w.) were found. The antimicrobial activity of tested macerates indicates that Lavandula sp. has a moderate effect on the bacterial and Candida growth.

The total phenols concentration in two sage macerates has been estimated by Folin-Ciocâlteau method, identified and quantified using HPLC-DAD method in order to assess the biological activity. The results for total phenols values of Folin Ciocalteau method indicate that Salvia officinalis L macerate S2, presents a higher amount of phenolic compounds than macerate S1. By HPLC-DAD method, six individual phenolic compounds were identified in sage macerates among which where cinnamic acid was found in highest concentration (652.478 mg/100g d.w. in S2 and 473.381 mg/100g d.w. in S1). The antioxidant activity of sage macerates was evaluated using DPPH Radical Scavenging test. Sage macerates exhibited high antioxidant activity, between 439.5 mg GAE /mL and 400 mg GAE /mL. Antibacterial activity of sage macerates was evaluated against 20 Gram positive and Gram negative bacterial strains isolated from clinical specimens. Both macerates showed significant but variable antibacterial activity with inhibition zones ranging from 4.97 mm (S2) to 7.28.mm (S1). The effect was stronger on Gram positive (Enterococcus, Staphyococcus) than Gram negative bacteria (Escherichia sp, Proteus sp, Klebsiella sp). Eleven metals concentrations were determined by AAS method in sage leaves; it has been found that Cd, Ni and Pb concentrations are below the detection limits.

A polyphenolic extract of Robinia pseudoacacia L. flowers was prepared using a hydro-ethanolic extraction phase. The chemical analysis of the extract consisted in the assessment of the total polyphenolic content (Folin-Ciocalteu method) and the flavonoid fingerprint of the extract determined by high-performance thin-layer chromatography (HPTLC). Two methods ferric reducing antioxidant power (FRAP) and radical scavenging activity with DPPH were used to measure the antioxidant activity of the extract. The cytotoxic and antitumor effects were evaluated on two cell lines: palatal mesenchymal stem cells (pMSCs) and epithelial cells derived from human cervical adenocarcinoma (HeLa (ATTC® CCL-2™)). The chemical content of Robinia pseudoacacia L. flowers extract reveals the presence of apigenin-7-glucoside and rutin. Results indicated high antioxidant activity with both methods (FRAP and DPPH). No cytotoxic effects of the extract were observed on the pMSCs cell line. The extract induced significant necrosis and apoptosis of the HeLa cells, proving an antitumor effect in vitro. The data confirm the antioxidant and antitumor effects of the polyphenols and the therapeutic potential of Robinia pseudoacaia flowers extract. In the last years, the therapeutic effect of the compounds from Robinia pseudoacacia flowers is less discussed; even the traditional medicine mentions them as helpful medicinal means. The present paper points out the correlation between Robinia pseudoacacia flowers polyphenolic compounds and their chemical and biological effects.