Organic supercritical CO₂ extraction of medicinal Althaea rosea extract.

1. Introduction

The extraction of medicinal Althaea rosea extract by organic supercritical CO₂ is a topic of great significance in the domain of natural product extraction. Supercritical CO₂, as an extraction medium, has emerged as a clean and highly efficient option. Althaea rosea, which has a long history of use in traditional medicine, contains a variety of valuable components. The supercritical CO₂ extraction method is able to precisely target these components, which holds great potential for the development of new pharmaceuticals and health - care products.

2. Althaea rosea in Traditional Medicine

Althaea rosea, also known as Hollyhock, has been utilized in traditional medicine for centuries. In different traditional medical systems, it has been used to address a wide range of health issues.

2.1 Skin - related Applications

One of the notable uses of Althaea rosea in traditional medicine is for skin diseases. It has been used topically in the form of poultices or ointments. The plant is believed to possess properties that can soothe irritated skin, reduce inflammation, and promote the healing of wounds. For example, in some traditional remedies, the crushed leaves or flowers of Althaea rosea were mixed with other natural substances like beeswax and olive oil to create a salve for treating minor cuts, burns, and skin rashes.

2.2 Immune - boosting Properties

Another important aspect of Althaea rosea in traditional medicine is its potential role in enhancing the immune system. It has been consumed as a herbal tea or tincture in some cultures. The plant contains certain bioactive compounds that are thought to stimulate the body's natural defense mechanisms. This could potentially help the body to fight off infections more effectively and maintain overall health.

3. Supercritical CO₂ as an Extraction Medium

Supercritical CO₂ has unique properties that make it an ideal extraction medium for Althaea rosea.

3.1 Properties of Supercritical CO₂

Supercritical CO₂ exists in a state where it has properties of both a liquid and a gas. It has a relatively low critical temperature (31.1°C) and a critical pressure (73.8 bar). This allows it to be easily manipulated in extraction processes. It has a high diffusivity, which means it can penetrate into the matrix of the Althaea rosea plant material quickly. Additionally, it has a low viscosity, enabling it to flow easily through the extraction system. These properties together make it very efficient at extracting the desired components from the plant.

3.2 Advantages over Traditional Extraction Methods

Compared to traditional extraction methods such as solvent extraction using organic solvents like ethanol or hexane, supercritical CO₂ extraction has several advantages.

• Clean and Environment - friendly: Supercritical CO₂ is a non - toxic, non - flammable, and easily recyclable medium. There is no need to deal with the disposal of large amounts of organic solvents, which can be harmful to the environment. For example, in solvent extraction, the used solvents often need to be carefully treated before disposal to prevent pollution.
• Selectivity: Supercritical CO₂ extraction can be highly selective. By adjusting the pressure and temperature conditions, it is possible to target specific components in Althaea rosea. This is in contrast to some traditional extraction methods where a mixture of components is obtained, and further purification steps are required.
• Controllability and Reproducibility: The extraction process using supercritical CO₂ can be precisely controlled. The pressure, temperature, and flow rate of CO₂ can be adjusted accurately, which results in high reproducibility of the extraction process. In traditional extraction methods, factors such as the quality of the solvent and the extraction time may vary, leading to less consistent results.

4. Targeted Extraction of Valuable Components in Althaea rosea

The supercritical CO₂ extraction can precisely target the valuable components in Althaea rosea.

4.1 Active Ingredients for Skin Diseases

For treating skin diseases, there are specific active ingredients in Althaea rosea that can be effectively extracted by supercritical CO₂. These may include mucilage, flavonoids, and phenolic compounds.

• Mucilage: Mucilage in Althaea rosea has moisturizing and soothing properties for the skin. Supercritical CO₂ extraction can isolate this mucilage without degrading its properties. The extracted mucilage can be used in the development of skincare products such as creams and lotions.
• Flavonoids: Flavonoids are known for their antioxidant and anti - inflammatory effects. They can help protect the skin from oxidative stress and reduce inflammation associated with skin diseases. Supercritical CO₂ extraction can selectively extract these flavonoids, providing a more concentrated source for potential pharmaceutical or cosmeceutical applications.
• Phenolic Compounds: Phenolic compounds in Althaea rosea also contribute to its skin - healing properties. By using supercritical CO₂ extraction, these phenolic compounds can be obtained in a pure form, which can be further studied for their effectiveness in treating various skin conditions.

4.2 Components for Immune System Improvement

In terms of improving the immune system, certain polysaccharides and other bioactive compounds in Althaea rosea can be targeted by supercritical CO₂ extraction.

• Polysaccharides: Polysaccharides are believed to play a role in modulating the immune response. Supercritical CO₂ extraction can extract these polysaccharides with high efficiency, allowing for further research on their potential as immune - boosting agents. For example, they could be formulated into dietary supplements or used in the development of new drugs for immunotherapy.
• Other Bioactive Compounds: There are other bioactive compounds in Althaea rosea that may also contribute to immune system enhancement. The supercritical CO₂ extraction method can help in the isolation and identification of these compounds, which is crucial for understanding their mechanisms of action and developing effective immune - related products.