A sustainable alternative to replace the use of toxic and non-biodegradable conventional solvents for the extraction of active principles from plants is natural deep eutectic solvents (NADESs). Larrea cuneifolia Cav. (Zygophyllaceae) is a plant widely distributed in semiarid areas of western Argentina. Several studies validate its popular medicinal use by demonstrating its biological activities such as antibacterial, antifungal, antioxidant, anti-inflammatory, and anticarcinogenic properties, among others. The aim of this work was to compare the bioactive compounds and the in vitro antioxidant and antibacterial activity of L. cuneifolia extracts using non-conventional vs. conventional solvents. Aqueous, ethanolic, and four NADES extracts were prepared. The extracts were phytochemically characterized, and extracted compounds were identified by UHPLC-MS/MS. Antioxidant activity was determined by evaluating the hydrogen peroxide and free radical scavenging capacity using ABTS^•+. The antibacterial activity of the extracts and NADESs was evaluated against Gram-positive and Gram-negative multidrug-resistant strains. The extracts of L. cuneifolia presented a variable content of total phenolic compounds between 4163.4 and 24,371.63 µg GAE/mL. Phenolic acids, flavonoid glycosides, flavanones, flavones, flavonols, alkaloids, lignans (nordihydroguaiaretic acid and its derivatives), and other compounds were tentatively identified in extracts of L. cuneifolia obtained with conventional and non-conventional solvents. A heatmap cluster and a bubble plot were created to compare the diversity and relative abundance of identified compounds, and the extracts were classified into two major groups. All extracts were able to scavenge > 40% of hydrogen peroxide and the ABTS radical cation (ABTS^•+) (CD₅₀ = 3.15–5.13 µg GAE/mL). The LAS extract exhibited the highest bacterial growth inhibition (MIC = 75–37.5 µg GAE/mL). In conclusion, the results show that NADESs represent a sustainable alternative for the extraction of compounds with antioxidant and antibacterial activity and could therefore replace traditional solvents in the pharmaceutical, cosmetic, or food industries.

Staphylococcus epidermidis is an opportunistic pathogen that, under certain conditions, can induce aggravated infectious processes, mainly in immunosuppressed patients. Moreover, S. epidermidis is one of the leading causes of medical device- and implant-associated infections and is also recognized as a canonical biofilm producer. Fabiana punensis, F. densa and F. patagonica are three medicinal plants that grow in arid environments in Argentina (Altoandina, Puna, Prepuna and Monte regions). In this work, we studied the antimicrobial activity of alcoholic extracts of these plant species obtained via maceration (M) and ultrasound-assisted extraction (UAE) against S. epidermidis. In addition, the antibiofilm activity of the F. densa extract was also evaluated. It was found that the extracts obtained via M did not present differences with those obtained via UAE regarding the chemical profile. F. densa showed the lowest minimum inhibitory concentration (MIC) value (75 µg GAE/mL). At concentrations higher than the MIC, the extract induced the release of cellular constituents. At the concentration of 1/8× MIC, the extract inhibited biofilm formation by 78%, reducing metabolic activity by 67%. On the other hand, it presented a low percentage of preformed biofilm removal. In all assays, gallic acid (GA) has been used as a reference antimicrobial compound. Finally, it was shown via microscopy visualization that the extract reduces adhesion to hydrophobic and hydrophilic surfaces. Thus, F. densa extracts could potentially be used for the antibiotic treatment of infections produced by S. epidermidis or as an inhibitor agent of production biofilm, avoiding infections caused by medical devices.

Gochnatia glutinosa is a shrub that grown in the Argentinean semiarid region (Monte region) used in the ancestral medicine as an antiseptic and anti-inflammatory agent.

Fabiana punensis S. C. Arroyo is a subshrub or shrub that is indigenous to the arid and semiarid region of northern Argentina and is known to possess several medicinal properties. The objective of this study was to optimize the extraction conditions so as to maximize the yield of bioactive total phenolic compound (TPC) and flavonoids (F) of F. punensis’ aerial parts by using non-conventional extraction methods, namely ultrasound-assisted extraction, UAE, and microwave-assisted extraction, MAE, and to compare the biological activities and toxicity of optimized extracts vs. conventional extracts, i.e., those gained by maceration. Response Surface Methodology (RSM) was used to apply factorial designs to optimize the parameters of extraction: solid-to-liquid ratio, extraction time, ultrasound amplitude, and microwave power. The experimental values for TPC and F and antioxidant activity under the optimal extraction conditions were not significantly different from the predicted values, demonstrating the accuracy of the mathematical models. Similar HPLC-DAD patterns were found between conventional and UAE- and MAE-optimized extracts. The main constituents of the extracts correspond to phenolic compounds (flavonoids and phenolic acids) and apigenin was identified. All extracts showed high scavenger capacity on ABTS^•+, O₂^•− and H₂O₂, enabling the inhibition of the pro-inflammatory enzymes xanthine oxidase (XO) and lipoxygenase (LOX). They also showed an antimutagenic effect in Salmonella Typhimurium assay and cytotoxic/anti-proliferative activity on human melanoma cells (SKMEL-28). Toxicological evaluation indicates its safety. The results of this work are important in the development of efficient and sustainable methods for obtaining bioactive compounds from F. punensis for the prevention of chronic degenerative diseases associated with oxidative stress, inflammation, and DNA damage.

In recent years, numerous studies have emerged on the biological activities of bryophytes and their potential for therapeutic use. However, mosses appear to be a relatively overlooked group. The objective of this study was to conduct a phytochemical analysis of one hydroalcoholic extract of Syntrichia laevipila and to evaluate its potential as an antioxidant and antimicrobial agent. The moss was collected in the Chaco Serrano region of Argentina, specifically on Jacaranda mimosifolia, and subsequently extracted by maceration in ethanol/water. UHPLC/ESI/MS/MS analysis identified 32 peaks, including phenolic compounds (phenolic acids, lignans, chalcones, and flavonoids) and non-hydrophilic compounds (terpenoids, fatty acids, and brassinosteroids). Maslinic and oleanolic acids, two triterpenoids present in S. laevipila, were also detected in J. mimosifolia, a substrate of this moss. The concentration of phenolic compounds was 19.05 ± 0.21 µg GAE/mL, while the total flavonoid concentration was 13.13 ± 0.33 µg QE/mL. The determination of reducing and total sugars yielded 0.22 ± 0.03 mg GE/mL and 1.26 ± 0.24 mg GE/mL, respectively, while the concentration of soluble proteins was 90.60 ± 4.50 µg BSAE/mL. The extract exhibited antioxidant properties by scavenging ABTS^•+, H₂O₂, AAPH, and HO^• radicals. Additionally, it demonstrated antibacterial activity by inhibiting the growth of four strains of Staphylococcus aureus. The data obtained suggest that the hydroalcoholic extract of S. laevipila possesses significant potential as a natural antioxidant and antimicrobial agent, making it a promising candidate for the development of phytotherapeutic and cosmetic products.