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The supercritical fluid extraction (SFE) of Greek sage leaves, i.e. Salvia fruticosa, was investigated at various operation conditions. Specifically, the effect of pressure, temperature and solvent flow rate on the extraction yield was examined. Thus, it was shown that as pressure increases, yield increases as well, while the effect of temperature depends on the extraction pressure. As for the flow rate, its increase mainly enhances the extraction rate. The SFE extracts were also compared with the essential oil obtained with hydrodistillation in terms of composition, revealing practically the absence of thujone and the presence of more biologically active compounds in SFE extracts. Finally, the experimental data were correlated successfully by a mass balance model based on Lack’s plug flow model.

Wine is an alcoholic beverage of complex composition obtained through the fermentation of grape must. The consumption of wine has already been associated with a multitude of beneficial effects due to its high polyphenolic content. In this study, four Greek emblematic wines from two red (i.e., Xinomavro and Agiorgitiko) and two white (i.e., Assyrtiko and Malagouzia) varieties were analyzed for the estimation of their antioxidant profiles. To address this question, we assessed their ability to scavenge both synthetic and endogenous free radicals, such as DPPH•, ABTS+•, OH•, O2−, their potential reducing power, and their antimutagenic and antigenotoxic properties. All varieties exhibited potent antioxidant activity, as indicated by the results of methods above, with the red wines appearing more effective than the white ones regarding antioxidant capacity. Our small-scale study is the first to reveal that these wine varieties may have the ability to scavenge the most reactive endogenous radicals. In the future, this finding must be accompanied by larger studies to fill a knowledge gap in the scientific literature concerning a holistic approach of the in vitro antioxidant action of plant polyphenolic compounds. Conclusively, we believe that wines possess high bioactivity that allow them to settle in the industry of food additives and medicinal products.

In this study, Pistacia lentiscus var. chia leaves were dehydrated by freeze drying and the initial, final moisture content and the drying kinetics were examined. Soxhlet Extraction (SE), Microwave Assisted (MAE) and Ultrasound Assisted Extraction (UAE) were employed to recover extracts with high antioxidant activity, total phenolic and flavonoid content from fresh and dried leaves. Fresh leaves showed higher yield and antioxidant potential, with MAE extracts exhibiting the greatest extraction yield (48.11 ± 0.56% d.b.), followed by UAE (39.39 ± 1.13% d.b.) and SE (31.99 ± 1.55% d.b.). UAE extracts exhibited the highest antioxidant activity (IC50 = 37.13 ± 2.7 μg/mL), while SE extracts showed the highest total phenolic content (314.88 ± 0.01 mg GAE/g dry extract). UAE extracts of dried leaves exhibited total flavonoid content (106.5 ± 0.02 mg QE/g dry extract). Moreover, UHPLC-ESI–HMRS was performed to the extract with the highest antioxidant activity and confirmed the presence of isomers of galloyl quinic acid, quercetin and kaempferol glucosides, luteolin and neorehmannioside.

In the present study, four different extraction methods were employed to recover extracts from Pistacia lentiscus var. chia (mastic tree) leaves. The methods include conventional Soxhlet extraction (SE), green extraction processes such as microwave assisted (MAE) and ultrasound assisted extraction (UAE), as well as the innovative supercritical fluid extraction (SFE). Extractions were carried out in both fresh and freeze-dried leaves. Traditional hydrodistillation process (HD) was also applied for the recovery of the essential oil from fresh and dried mastic tree leaves. The efficiency and selectivity of processes were determined in terms of extraction yield and antioxidant activity. Antioxidant activity of the extracts was measured using the DPPH assay. The essential oil from HD was analyzed by GC–MS. The initial moisture of the leaves was 49.6 ± 1.31% on wet basis (w.b.), while final moisture after drying was 2.7 ± 0.27% (w.b.). The results showed that the extraction techniques and the drying procedure significantly affected the extractive yield and antioxidant activity of the extracts. Specifically, fresh mastic tree leaves showed better performance in both yield and antioxidant potential. MAE of fresh leaves using water presented the greatest extraction yield (48.11 ± 0.56% on dry basis (d.b.)) followed by UAE (39.39 ± 1.13% d.b.) and SE both using water as solvent (31.99 ± 1.55% d.b.). UAE water extracts exhibited the highest antioxidant activity (IC50 = 37.13 ± 2.7 μg/mL) followed by MAE water extracts (37.18 ± 0.99 μg/mL) and UAE ethanol extracts (38.46 ± 1.91 μg/mL). SFE had an extraction yield of 22.3% ± 0.25% (w.b.) for fresh leaves but no antioxidant activity was attributed to the extract. HD's performance was 0.06 mL/100 g dry plant matter for the fresh leaves and 0.03 mL/100 g dry plant matter for the dried ones. The presence of Myrcene, Limonene, δ-Germacrene, trans-Caryophyllene, δ-Cadinene and α-Amorphene was confirmed in the essential oils obtained by HD.

Pressurized liquid extraction (PLE) with environmentally friendly solvents namely water and ethanol was applied to olive leaves in order to optimize extraction yield, oleuropein content and antioxidant activity. The effect of various parameters was studied through a carefully designed optimization process. The study comprised of two distinct stages, a screening procedure using Plackett–Burman design followed by an optimization step using a central composite design (CCD). This led to the construction of a response surface indicating the optimal values for each parameter and response studied. Determination of the optimum extraction procedure was performed by comparison of the extracts’ yield, oleuropein content determined by HPLC and radical scavenging activity evaluated in a DPPH assay. Extraction parameters with statistical significance were shown to be the ethanol content of the solvent mixture, the temperature of the extraction and the consecutive cycles of extractions. Concerning the extraction yield, an ethanolic extraction at 190 °C for 3 consecutive cycles was found to be optimal. Regarding the oleuropein content of the extract, a mixture of H 2 O/EtOH 43:57 in 190 °C for 1 extraction cycle provided the optimal results. Finally, regarding the DPPH assay, all the samples exhibited good antioxidant activity. The experimental values obtained from two different extraction procedures could be predicted within a 95% confidence interval, thus indicating the suitability of RSM in optimizing the extraction of olive leaves.