For decades, industrial solvents have been effective yet harmful to the environment and, at times, to human health. But now, a cleaner and safer solution is taking centre stage. These are green solvents.

Green solvents are emerging as a gamechanger in both the pharmaceutical and food industries. They offer a way to produce, extract, and process substances with less harm to our health and to the environment.

These solvents are biodegradable, often non-toxic, and derived from renewable resources. More importantly, they are already making a real difference in laboratories and factories around the world.

WHAT MAKES A SOLVENT‘ GREEN’?

Not all solvents are created equal. Traditional solvents like chloroform, acetone, or hexane are effective but volatile and often hazardous. Green solvents, by contrast, are designed to minimise toxicity and waste. Many are made from renewable raw materials. Water, ethanol, ionic liquids( ILs), supercritical carbon dioxide( CO2), and deep eutectic solvents( DESs) are among the most studied and promising options. Each of these has unique properties.

Supercritical fluids, for example, exist in a state where they behave like both gas and liquid. This allows them to extract compounds efficiently without using high temperatures that could damage sensitive nutrients or medicinal properties. Supercritical CO₂ has proven particularly effective in extracting antioxidants from turmeric( Le Tan et al., 2025). This allows cleaner herbal supplements and food ingredients to be produced without chemical residues.

Deep eutectic solvents( DESs) are another family of green solvents. DESs are created by mixing components that form a stable, low-melting liquid. They are affordable and biodegradable, and they perform very well in extracting valuable compounds from natural products. For instance, DESs have been successfully used to extract curcumin from turmeric and polyphenols( Sahu et al., 2025). This preserves the health

BY AMAL A. M. ELGHARBAWY

International Institute for Halal Research and Training( INHART), International Islamic University Malaysia

BY Nor Azrini Nadiha Azmi

Halal Products Research Institute, Universiti Putra Malaysia

benefits of these compounds without the use of hazardous chemicals.

Healing without harm

The pharmaceutical industry has long depended on organic solvents, many of which are toxic and non-renewable. Green solvents are now providing safer and more sustainable alternatives.

In drug development, green solvents are being used in the synthesis of active pharmaceutical ingredients, formulation processes, and drug delivery systems. For example, water and ethanol are increasingly used as reaction media. ILs and DESs help stabilise and solubilise poorly water-soluble drug molecules( Mohd Noor et al., 2024). This improves how well medicines are absorbed and how effective they are.

One success story comes from the production of Melitracen hydrochloride, an antidepressant. When researchers switched to greener solvents like 2-MeTHF and IPA, they achieved an impressive 99.75 per cent yield and 99.85 per cent purity: while producing far less waste( Narukulla & Kaki, 2025).

This shows how green chemistry can boost efficiency, cut costs, and protect the environment at the same time. Green solvents are also advancing cancer research. In some studies, anticancer compounds have been synthesised using DESs, helping to develop potentially less toxic treatments.

GREENER CHEMISTRY

Green solvents are playing a similar role in the food industry, especially in processing and quality assurance. Food extraction processes often rely on solvents, and when unsafe or non-biodegradable ones are used, they can leave behind residues in the final product. Green solvents help eliminate this risk.

For instance, DESs have been used to extract antioxidants from ingredients like ginger and turmeric. These solvents allow processors to preserve the sensitive bioactive compounds while using less energy. For example, supercritical CO₂ can extract curcuminoids from turmeric at lower temperatures( Kongpol et al., 2022). This preserves the antioxidant properties better than traditional heat-based methods.

Natural solvents such as limonene,

which is extracted from citrus peels, and ethyl lactate, derived from fermented corn, are also gaining popularity. These substances are non-toxic and leave no harmful residues. This makes them ideal for use in food production.

In addition to processing, green solvents are used in food safety testing. Modern analytical methods are now applied to detect chemical contaminants, pesticide residues, and heavy metals in food products. This ensures that the food is not only nutritious but also safe for consumers.

THE ENVIRONMENTAL EDGE

Green solvents offer a safer, less toxic alternative that produces minimal hazardous waste and lowers the risk of environmental contamination. They also help reduce carbon emissions. For instance, ethanol used in catalytic hydrogenation can cut emissions by 40 %. Supercritical CO₂ replaces volatile organic solvents while remaining scalable for industrial use.

Many green solvents are biodegradable. Natural options like limonene and ethyl lactate break down easily, while newer solvents such as DESs and ILs are being developed for environmental safety. These solvents also improve energy efficiency. Supercritical fluids often require less heat and pressure, reducing energy use and operational costs. Additionally, they enhance drug purity by minimising toxic residues.

BARRIERS TO BROADER USE

Although green solvents offer many benefits, their widespread adoption still faces some challenges. For instance, DESs can be highly viscous, slowing mass transfer in some processes. This can limit their use in fast-paced industrial operations. Scalability is another issue.

What works well in a research laboratory may not translate easily to a commercial production environment. Equipment and process changes may be needed, which can be costly and time-consuming.

The cost of green solvents is also a factor. While long-term savings are likely, the initial cost of switching from traditional methods may discourage some companies. Regulatory approval can also be slow, especially in highly regulated industries like pharmaceuticals and food.