Oregano Extraction – Increase Yields with Sonication!

Oregano is an aromatic herb with a high content of phenolic compounds and essential oils, which are used in food, medicinal and cosmetic products. Ultrasonic extraction is a mild, yet highly efficient technique to isolate bioactive compounds and essential oils from oregano and other herbs. Sonication gives higher yields and superior extract quality within a short processing time.

Oregano Extracts – Higher Yields with Sonication

Hielscher sonicators work efficiently for botanical extract production. Ultrasound is a non-thermal extraction technique, so delicate bioactive molecules are isolated from the plant matrix without a thermal load. Sonication applies purely mechanical forces, which prevents the degradation of heat-sensitive compounds. This makes it possible to prepare a full-spectrum extract of oregano containing numerous bioactive molecules that interact with each other, the so-called entourage effect. An ultrasonic oregano extract typically carries carvacrol, thymol, p-cymene, γ-terpinene, linalool, terpinen-4-ol and sabinene hydrate from the essential oil fraction, along with rosmarinic acid, cinnamic and caffeic acid derivatives, caffeoyl- and luteolin-7-O-glucoside, apigenin, naringenin and the triterpenic acids such as ursolic and oleanolic acid. The choice of solvent influences the solubility of polar and non-polar compounds.
For an oregano extract, the bioactive compounds are isolated from the leaves and flower tops of Origanum vulgare L. (Lamiaceae), including cultivars and related species such as Origanum majorana and Greek oregano. Oregano extract is used as a flavouring agent and as a natural antimicrobial and antioxidant ingredient in the food, feed, cosmetic and pharmaceutical industries.

How does the Production of Oregano Extract Work using a Probe-type Sonicator?

The production of oregano extract using a probe-type ultrasonicator typically involves the following steps:

1. Preparation of the Oregano: The oregano leaves are cleaned, dried, and ground into a fine powder.
2. Extraction: The ground oregano leaves are mixed with a solvent such as aqueous ethanol, ethanol or water, and the mixture is sonicated using a probe-type ultrasonicator. The ultrasonicator uses high-intensity, low-frequency ultrasound waves to create cavitation bubbles, which facilitate breaking down the plant material and releasing bioactive compounds (such as carvacrol and thymol).
3. Filtration: The mixture is filtered to remove any remaining plant material, leaving behind a liquid extract.
4. Concentration: The liquid extract is concentrated using a rotary evaporator or other suitable method, to increase the concentration of the active compounds.
5. Drying: The concentrated extract is dried using a suitable method, such as spray drying or freeze drying (lyophilization) in order to produce an extract in dry powder form.
6. Packaging: The dry powder is then packaged and stored in a cool, dry place until it is ready for use.

Büchner Funnel Vacuum Filtration After Ultrasonic Extraction

The use of a probe-type sonicator in the extraction process results in the effective cell disruption so that the full spectrum of phytochemicals are released from the oregano leaves. This makes sonication the ideal technique for the production of high-quality extracts – preparing the bioactive compounds at high concentration.
Additionally, this method can be used on a large scale, making it suitable for commercial production. Hielscher ultrasonicators allow for precise process parameter control and the linear scale-up of extraction process to any desired volume.

Scientifically-Proven: Ultrasonic Oregano Extraction

In their scientific research report, Psichoudaki et al. (2025) investigate a green, pulse-mode ultrasound-assisted extraction method for recovering carvacrol, total phenolic compounds and total flavonoids from Origanum dubium. Using a Box–Behnken experimental design and Response Surface Methodology, they evaluate extraction time, temperature, ethanol concentration and ultrasonic amplitude.

Highlights of the Study:

• The optimal combined conditions were 26 minutes at 70°C, using a 60% v/v ethanol–water solution and 100% ultrasonic amplitude.
• Under these conditions, the extracts contained 14.93 mg/g dry mass of carvacrol, 60.03 mg GAE/g of total phenolics and 23.78 mg QE/g of total flavonoids.
• Temperature significantly affected all three responses. Extraction time and ethanol concentration were important for optimum carvacrol recovery.

Protocol for Ultrasonic Oregano Extraction

The pulse-mode ultrasound-assisted extraction was performed using a Hielscher UP200Ht probe-type ultrasonic processor fitted with a 14 mm titanium sonotrode. Ground, dried Origanum dubium material (0.50 g) was mixed with 10 mL of 60% v/v ethanol–water solution. The probe was immersed 2 cm into the sample, and extraction was conducted at 26 kHz and 100% amplitude for 26 minutes using a 50% duty cycle. A heated water bath maintained the temperature at 70 ± 2°C. After extraction, the mixture was centrifuged at 10,000 rpm for 15 minutes. The supernatant was collected, filtered through a 0.2 µm PES syringe filter and diluted as required for analysis.