Optimization of a Pressurized Extraction Process Based on a Ternary Solvent System for the Recovery of Neuroprotective Compounds from Eucalyptus marginata Leaves

Green chemistry focuses on reducing the environmental impacts of chemicals through sustainable practices. Traditional methods for extracting bioactive compounds from Eucalyptus marginata leaves, such as hydro-distillation and organic solvent extraction, have limitations, including long extraction times, high energy consumption, and potential toxic solvent residues. This study explored the use of supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), and gas-expanded liquid (GXL) processes to improve efficiency and selectivity. These techniques were combined in a single mixture design, where CO2 was used in the experiments carried out under SFE, while water and ethanol were used for the PLE and GXL experiments by varying the concentration of the solvents to cover all the extraction possibilities. The neuroprotective activity of the extracts was evaluated by measuring their antioxidant, anti-inflammatory, and acetylcholinesterase inhibition properties. The optimization resulted in a novel GXL extraction with an optimal ternary mixture of 27% CO2, 55% ethanol, and 18% water, with a high degree of desirability (R2 = 88.59%). Chromatographic analysis carried out by GC-MS and HPLC-ESI-MS/MS identified over 49 metabolites. The designed sustainable extraction process offers a promising approach for producing phenolic-rich plant extracts in industrial applications.

Effect of geographical origin on the chemical characteristics of Q. canariensis acorns: profiling fatty acids, tocopherols, and phenolic composition

The impact of geographical origin on the chemical composition of acorns from Quercus species has significant attention. This study aimed to explore the phenolic composition of methanolic extracts, tocopherol content, and fatty acid composition of acorn oils from six different populations of Q. canariensis acorns. The obtained results revealed that acorn oil from BniMtir exhibited high levels of α-tocopherol (58 mg/kg). The fatty acids identified across all samples were Z-vaccenic + oleic acids (38.44-58.58%). In addition, the data highlighted the presence of quinic (32.514-60.216 µg/g DW) and gallic acids (1.674-10.849 µg/g DW), as well as catechin (+) (0.096-12.647 µg/g DW) in all populations. These variations in chemical composition from different regions are likely linked to their geographical origin. In conclusion, this study's finding should significance for the industry, offering valuable insights into the potential production of bioactive compounds from Q. canariensis acorns, which could have various applications.

Ultrasound-Assisted Extraction of Verbascoside from Clerodendrum glandulosum Leaves for Analysis of Antioxidant and Antidiabetic Activities

Verbascoside (VER) is a phenylethanoid glycoside compound found in Clerodendrum species and is an important part of traditional medicine. It is found in the leaves of Clerodendrum glandulosum, which is taken as a soup or vegetable and also utilized in traditional medicine by the people of Northeast India, especially against hypertension and diabetes. In the present study, VER was extracted from C. glandulosum leaves using ultrasound-assisted extraction through the solvent extraction method (ethanol-water, ethanol, and water). The ethanol extract had the highest phenolic and flavonoid contents, viz., 110.55 mg GAE/g and 87.60 mg QE/g, respectively. HPLC and LC-MS were used to identify the active phenolic compound, and VER was found to be the main component present in the extraction with a molecular weight of 624.59 g/mol. NMR (¹H, 2D-COSY) analysis showed the presence of hydroxytyrosol, caffeic acid, glucose, and rhamnose in the VER backbone. Further, different antioxidant activities and antidiabetic and antihyperlipidemia enzyme markers' inhibition against VER-enriched ethanol extract were evaluated. The results showed that ultrasound extraction of polyphenols using ethanol from C. glandulosum could be a promising technique for the extraction of bioactive compounds.

Antibacterial and Antibiofilm Activity of Different Species of Fabiana sp. Extract Obtained via Maceration and Ultrasound-Assisted Extraction against Staphylococcus epidermidis

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.