The study investigated the effect of hydrophobic, blackcurrant seed extract (Ribes nigrum L.) obtained under supercritical CO₂ conditions on the anti-irritant properties of hand dishwashing liquids. A range of liquids differing in extract concentration (0–0.5 wt%) were prepared. The product prototypes were subjected to tests focusing on their anti-irritating property and functionality. Based on the zein values and measurements of changes in the pH level of the bovine albumin solution, the liquids were shown to be markedly safer to use. It was noted that an increase in extract concentration in a product leads to a deterioration of detergent and foaming properties. The highest concentration of the extract allowing the achievement of acceptable results was 0.3 wt%. The results suggest that hydrophobic plant extract, for example, from blackcurrant seed can be an interesting raw material for reducing the irritating potential of liquid agents designed for hand dishwashing. GRAPHICAL ABSTRACT

We investigated the effect of hydrophobic extract concentration on the safety of using hand dishwashing liquids (HDL). A series of formulations was prepared, differing in the concentration of the hydrophobic chamomile extract obtained in supercritical CO₂ conditions (from 0 to 0.7 %). We found that an increase in the concentration of the extract led to a decrease in the zein number, and reduced changes in the pH level of bovine serum albumin solution (i.e., two parameters determining the irritant activity of the formulations). It was also found that the additives reduced transepidermal water loss and improved the skin hydration level. Based on the findings of the study, a mechanism has been proposed, according to which hydrophobic plant extracts form aggregates in the volume phase of the washing bath. The surface of the aggregates is the adsorption area for surfactant monomers responsible for the irritant effect. Increasing the addition of the extract was shown to reduce the negative impact of the formulations on the skin of the hands, thus contributing to a greater safety of use of HDL.

The present work reports a method for green synthesis of silver nanoparticles (AgNPs) by reducing Ag ions from silver nitrate solution using alcoholic, aqueous and alcoholic-aqueous Stevia rebaudiana extracts. Depending on a particular extract different sizes of AgNPs could be observed – 40 nm in aqueous and aqueous-alcoholic extracts and significantly bigger 170 nm in case of alcoholic extract. Synthesis of AgNPs was analyzed within spectra range of 300–700 nm. The performed research provided information that aqueous and aqueous-alcoholic extracts are excellent sources for synthesis of AgNPs; however AgNPs were unstable in the case of alcoholic extract. The aqueous-alcoholic extract showed the best properties during studies. Antioxidant potential, antimicrobial properties and cytotoxicity were determined. The 2,2-diphenyl-1-(2,4,6-triphenyl-hydrazyl) method showed that antioxidant activity of an extract containing AgNPs was higher compared to Stevia extract alone. Bacterial inhibition studies had shown substantial antibacterial properties of AgNPs, which was much higher than Stevia extract alone and silver nitrate.