Alkaloid Extraction using a Probe-Ultrasonicator

Alkaloids are bioactive compounds, which can be efficiently extracted from plants using ultrasonication. Alkaloids exhibit a wide array of biological effects and are thereby used as pharmaceuticals and therapeutics. Ultrasonic extraction is the preferred technique to produce high quality alkaloid extracts from plant material. Ultrasonic extraction results in very high alkaloid yields, whilst extraction time is short and the ultrasonic equipment is safe and easy to operate.

High-Efficient Alkaloid Extraction using Power-Ultrasound

How does ultrasonic extraction promote the isolation of alkaloids?
Ultrasonic extraction uses low-frequency ultrasound waves (e.g. 20-26kHz frequency) and ultrasound’s effect of acoustic cavitation. High-intensity ultrasound waves create cavitation bubbles that collapse, generating locally energy-dense pressure and temperature differentials as well as powerful shear forces, which perforate and break plant cell walls and plant tissue open. The liquid streaming generated by cavitation promotes mass transfer between the intracellular matrix and the surrounding solvent so that the alkaloids are efficiently released. For ultrasonic alkaloid extraction, the plant material (e.g. ground dried leaves) are placed in a solvent, which is typically a mixture of water and an organic solvent such as aqueous ethanol. Polar solvents such as methanol and ethanol have been found to be most efficient for high alkaloid yields. After a short ultrasonic treatment of the slurry – consisting in plant material and solvent – the alkaloids are released from the plant cells and are present in the solvent, from where they can be isolated and purified (e.g. using a rotor-evaporator).

Main Advantages of Ultrasonic Alkaloid Extraction

Ultrasonic extraction is considered as superior extraction technique for the isolation of alkaloids from plant materials as it offers several advantages, including:

1. Increased extraction efficiency: Ultrasonic extraction can increase the yield of alkaloids by more than 200% compared to traditional extraction methods.
2. Reduced extraction time: Ultrasonic extraction can significantly reduce the extraction time, allowing for faster and more efficient processing of large volumes of plant material.
3. Lower solvent consumption: Ultrasonic extraction can reduce the amount of solvent required for extraction, resulting in reduced solvent consumption and decreased environmental impact.
4. Selective extraction: Ultrasonic extraction can be used to selectively extract certain alkaloids by choosing the suitable solvent, process parameters and extraction temperature. As unwanted compounds are left behind, the purity of the final product is improved.
5. Easy to scale-up: Ultrasonic extraction can be easily scaled up to handle larger volumes of plant material, making it suitable for commercial production. Ultrasonic processes can be scaled linearly, which facilitates the implementation on industrial scale.

Overall, ultrasonic extraction offers a faster, more efficient, and more environmentally friendly approach to isolating alkaloids from plant materials.

Ultrasonic Alkaloid Extraction from the Leaves of the Soursop Tree

Nolasco-González et al. (2022) investigated the effectiveness and efficiency of ultrasonic extraction of bioactive compounds including phenolic compounds, alkaloids, acetogenins (all with with high antioxidant capacity) from the leaves of the plant species Annona muricata (soursop tree). For ultrasonic extraction, they used the probe-type ultrasonicator UP400S at following conditions: 80% amplitude, 0.7 s pulse-cycle, for 4.54 min. Total soluble phenols (TSP) were extracted using 0.5 g of dried leaves powder and 20 mL of acetone: water (80:20 v/v). The ultrasonically produced extract contained 178.48 mg/100 mL of soluble phenols, 20.18 mg/100 mL of total flavonoids, 27.81 mg/100 mL of hydrolyzable polyphenols, 167.07 mg/100 mL of condensed tannins, 30.44 mg/100 mL of total alkaloids and 14.62 mg/100 mL of total acetogenins. The extract isolated with the U400S probe-type ultrasonicator (see picture left) exhibited a high antioxidant capacity and a higher content of bioactive compounds from ~6 to ~927-fold than decoction or infusion, depending on the type of compound. Twenty-four different phenolic compounds were identified in the samples, and the ultrasonically isolated extract produced the highest concentration.
[cf. Nolasco-González et al., 2022]

Antioxidant capacity of extracts obtained by the optimal conditions of ultrasound-assisted extraction (UAE), decoction and infusion. Ultrasonic extracts consistently show significantly higher antioxidant capacity.
(Study and graphic: ©Nolasco-González et al., 2022)

HPLC chromatogram of phenolic compounds from ultrasonically isolated extract of Annona muricata leaves using the ultrasonicator UP400S.
(1) shikimic acid, (2) gallic acid, (3) protocatechuic acid, (4) neochlorogenic acid,
(5) 3,4-dihydroxyphenylacetic, (6) 4-hydroxybenzoic acid, (7) chlorogenic acid, (8) 4-hydroxyphenyl acetic, (9) vanillic acid, (10) syringic acid, (11) 3-hydroxybenzoic acid, (12) caffeic acid, (13) 4-hydroxybenzaldehyde, (14) homovanillic acid, (15) 3-(4-hydroxyphenyl), (16) p-coumaric acid, (17) trans-ferulic acid, (18) trans-cinnamic acid, (19) gallocatechin, (20) epigallocatechin, (21) catechin,(22) epicatechin, (23) rutin, (24) ellagic acid.
(Study and graphic: ©Nolasco-González et al., 2022)

Lee et al. (2021) had similar confirmed results as they report 2.3-fold more alkaloids from A. muricata leaves extracted under ultrasonication (340 W, 56◦C, 30 min) compared to Soxhlet extraction (7 h, 80◦C).

Indole Alkaloid Extraction from Mimosa Root Bark and Ayahuasca using an Ultrasonicator

Mimosa root bark as well as ayahuasca leaves contains the alkaloid N,N-dimethyltryptamine (DMT). Dimethyltryptamine (DMT) is currently researched in clinical trials for its hallucinogenic effects and therefore as a potential drug to treat depression and post-traumatic stress disorders (PTSD). Ultrasonication effectively promotes the release and isolation of the alkaloid from the Mimosa hostilis roots and Psychotria viridis leaves (ayahuasca). Ultrasonic DMT extraction produces high yields within very short time. Compatible with almost any solvent, Hielscher probe-type ultrasonicators are used for the production of pharma-grade bioactive compounds for use under research and medical settings as well as for sample prep before analytical quality and potency testing. Therefore, Hielscher ultrasonicators can facilitate medical DMT and botanical research in numerous ways.
The most common source of the indole akaloid N,N-dimethyltryptamine (DMT) in jurema tree, it comes from Mimosa hostilis roots (commonly known as jurema preta). Ayahuasca is the traditional name for another plant species, in which the leaves of the shrub Psychotria viridis are rich in DMT.
Both, mimosa root bark (also mimosa tenuiflora, Mimosa Hostilis Root Bark; abbrev. MHRB) and ayahuasca leaves contain various bioactive compounds, which are currently researched in clinical trials regarding their potential as therapeutic drug. Mimosa root bark contains tannins, saponins, tryptamines, alkaloids, lipids, phytoindoles, xylose, phytosterols, glucosides, rhamnose, arabinose, methoxychalcones, lupeol and kukulkanins. These bioactive compounds can be efficiently extracted from the root bark using probe-type ultrasonicators. Ultrasonic extraction is the superior technique to isolate target substances such as alkaloids from botanical material such as mimosa root bark and ayahuasca leaves. Sonication excels by giving high yields within a very short extraction time. Mild process conditions ensure highest extract quality preventing unwanted degradation of the active molecules.

Extraction setup for botanical isolation: Probe-type ultrasonicator UP400ST, Büchi vacuum filter and rotor-evaporator for the extraction of phytochemicals such as alkaloids and phenols.

Hielscher Ultrasonicators for Efficient Alkaloid Extraction

Hielscher Ultrasonics designs, manufactures and distributes high-performance ultrasonic extractors, which are used for scientific research as well as the production of pharma-grade extracts.
Superior Extraction Efficiency:Ultrasound-assisted extraction is a scientifically proven technique with an extraordinary high efficiency regarding the extraction of bioactive compounds from plants. Whilst traditional methods often take a long time (several hours up to days), ultrasonic botanical extraction takes only a few minutes.

High Extraction Yield and Superior Extract Quality with Hielscher Ultrasonicators

Ultrasound-driven extraction allows for the complete release of bioactive compounds from the plant material. Ultrasonic cavitation breaks the cellular matrix and releases the bioactive molecules efficiently into the surrounding solvent. Comparative studies demonstrated that sonication gives higher extract yields than other extraction techniques (e.g. Soxhlet, maceration, decoction, infusion). Ultrasonic extraction is compatible with any solvent and allows thereby also for the use of very mild solvent such as water or aqueous ethanol. Regarding to specific extraction requirements, polar and non-polar solvents can be chosen and switching between solvents is no problem. Precise control over process parameters (e.g. amplitude), use of mild solvents and exact temperature control prevent the degradation and contamination of bioactive compounds (e.g. alkaloids, polyphenols, flavonoids, cannabinoids etc.) during ultrasonic extraction.

Versatile Application of Hielscher Ultrasonicators

Whilst alternative extraction techniques (e.g., supercritical CO2, solvent extraction, percolation etc.) are often only applicable to the extraction of specific molecules depending on molecular weight, solubility and heat-sensitivity, the extraction with Hielscher high-performance ultrasonicators allow for the versatile extraction of any botanical compound. Ultrasound-assisted extraction can be reliably applied for the extraction of broad-spectrum extracts containing bioactive compounds such as polyphenols, alkaloids, anthraquinones, flavonoids, glycosides, lipids, pectin, and polysaccharides.

Excellent Energy Efficiency and Environmental-Friendliness

The energy consumption of ultrasound-assisted extraction is less by far than the traditional methods in the extraction of medicinal compounds from plants.

Reliability due to Process Standardization with Hielscher Ultrasonics

Hielscher ultrasonicators allow for the precise control over all ultrasonic process parameters such as amplitude, intensity, duration, and temperature. The process parameters can be easily controlled and are continuously monitored. Additionally, all process parameters are automatically protocolled as CSV file on an built-in SD-card. This enables the operator to revise sonication runs, to optimize the extraction process and to ensure consistent extract quality. Hielscher ultrasonicators enable manufacturers to produce botanical extracts of superior quality and facilitate the fulfilment of Good Manufacturing Practice (GMP).

The table below gives you an indication of the approximate processing capacity of our ultrasonicators: