From Raw Herb to Active Molecule: Unlocking Sage Bioactives with Technology-Enhanced Extraction

Introduction: Sage (Salvia officinalis L.) leaves have been found to possess anticancer, antioxidant, antimicrobial and antimutagenic activities. Unfortunately, the production of liquid extracts requires a large amount of raw materials and solvents. To improve efficiency, new technologies are being developed to reduce resource use and boost yields of biologically active compounds through enhanced extraction.

Materials and Methods: The process of extracting sage leaves was conducted through ultrasonic extraction techniques (35 kHz, 40 °C temp., 30 min.). Two concentrations of ethanol (70% and 96%) and 1% of excipients (citric acid, sodium chloride, sodium hydrogen carbonate, magnesium alumino-metasilicate or sucrose) were used for extraction of biologically active compounds. Extraction was performed at 1:10, 1:20 and 1:30 raw material to solvent volume ratios, respectively. Antioxidant activity and total flavonoid content were assessed using spectrophotometric methods.

Results: Remarkably, 70% ethanol proved to be the most effective extrahent, achieving the highest compound yield (10.998 TE µg/mg) at a 1:30 ratio with magnesium alumino-metasilicate. Slightly higher values were observed with citric acid (11.925 TE µg/mg, 1:20 ratio) and sodium chloride (11.813 TE µg/mg, 1:10 ratio). Compared to the control samples, only sodium chloride increased the number of active compounds at the corresponding concentration (p < 0.05). With 96% ethanol, the combination of citric acid and a 1:30 ratio led to the highest overall antioxidant activity (12.078 µg TE/mg), suggesting a strong synergy between low-polarity solvent and acidic excipient conditions. For flavonoid extraction, sodium chloride once again demonstrated a striking effect—particularly at a 1:10 ratio with 70% ethanol, producing the highest concentration (0.028 mg RE/g; p < 0.05).

Conclusions: The study found that no single substance positively impacted all three parameters, necessitating selective excipient choice for compounds being extracted. The observed differences indicate excipient-driven modulation of solubility and release, offering valuable tools for rational extraction design.