95% ethanol is commonly used in plant extraction due to its unique properties that make it effective for extracting a wide range of plant compounds. Here are the reasons:
1. Polarity Balance
Ethanol is a polar solvent, and its polarity at 95% concentration is well-suited for extracting both polar and non-polar compounds.
It can dissolve a broad spectrum of bioactive compounds such as alkaloids, flavonoids, terpenes, and glycosides.
2. Water Content
The 5% water in 95% ethanol improves its ability to extract water-soluble compounds, such as some phenolics and glycosides, which pure ethanol might not dissolve effectively.
This balance allows for a more comprehensive extraction of plant constituents compared to pure ethanol or water alone.
3. Preservation of Bioactive Compounds
Ethanol at this concentration minimizes the degradation of heat-sensitive or unstable bioactive compounds during extraction.
4. Antimicrobial Properties
Ethanol acts as a preservative, preventing microbial growth in the extract, which is particularly beneficial for long-term storage.
5. Volatility
Ethanol is volatile, meaning it can be easily removed from the extract by evaporation, leaving behind the concentrated plant compounds.
6. Food and Pharmaceutical Safety
Ethanol is considered safe for human consumption in controlled amounts and is approved for use in food and pharmaceutical products.
Using 95% ethanol ensures the extracts are suitable for applications like herbal medicine, cosmetics, or food products.
7. Availability and Cost-Effectiveness
95% ethanol is widely available and cost-effective for industrial and laboratory-scale extractions.
In summary, the combination of polarity, water content, effectiveness in preserving bioactive compounds, and safety for human use makes 95% ethanol an ideal solvent for plant extraction.