Optimization of Extraction Conditions of Bioactive Compounds From Kurdistan Species Urtica dioica

Abstract

Introduction: Phytotherapeutics derived from medicinal plants treat various illnesses, including viral infections such as SARS, MERS, and SARSCoV-2, as well as bacterial and fungal diseases. It highlights ongoing research into the chemical compositions of plant components for developing new drugs, with a particular emphasis on anti-cytotoxic agents for anticancer drugs. Traditional extraction methods have limitations, leading to the exploration of environmentally friendly technologies such as ultrasound-assisted, supercritical fluid, microwave-assisted, and accelerated solvent extraction. The paragraph concludes by stating the aim of a specific study to optimize extraction conditions of bioactive compounds from Urtica dioica in Kurdistan, comparing conventional and non-conventional extraction methods, solvents, and extraction times.

Materials and methods: The study was conducted between June 2022 and August 2022, fresh leaves and stems of U. dioica plant were collected and sequentially underwent four extraction methods (maceration, Soxhlet, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) by using petroleum ether, chloroform, ethanol, and distilled-water as solvents.

Results: The results highlighted significant variations in the yields of bioactive compounds based on the extraction method, solvent type, and duration. Among conventional methods, Soxhlet was the most powerful method and had the most extraction yields, while maceration had the lowest yields. The modern techniques surpassed the conventional methods by producing high extraction yields within a shorter time (a few minutes) and using a lesser amount of solvent. Consequently, UAE and MAE emerge as the most efficient techniques. Hence, MAE effectively produced the highest extraction yields and is considered the preferred technique. The choice of solvents significantly influenced the extraction yields, with ethanol consistently emerging as an effective solvent across various extraction methods. In contrast, petroleum ether demonstrated the lowest efficacy as a solvent. Furthermore, the results unveiled the impact of extraction time on yields, indicating a correlation between increased time and extraction yield in certain cases.

Conclusion: Extraction is a very critical step in the study of medicinal plants. The amount of extracted compounds is significantly affected by the extraction method, solvent, and time. Ethanol stands out as the most effective solvent, producing the highest yields of bioactive compounds, while petroleum ether yields the least. Additionally, extraction yield shows a direct relation with extraction time. Soxhlet being the most powerful among conventional methods and maceration yields the least. Modern techniques, particularly UAE and MAE, surpass conventional methods by achieving high yields in shorter times with less solvent. MAE, in particular, offers advantages such as shortened extraction time, increased efficiency, reduced labor, and enhanced selectivity, making it the preferred method for extracting bioactive compounds from aerial parts U. dioica.

Keywords: bioactive compounds; conventional extraction methods; extraction conditions; non-conventional extraction techniques; urtica dioica.

Figure 1. Maceration extraction of Urtica dioica leaves and stems using (petroleum ether, chloroform, ethanol, and distilled water) solvents.

Figure 2. Soxhlet extraction of Urtica dioica leaves and stems using (petroleum ether, chloroform, ethanol, and distilled water) solvents.

Figure 3. Ultrasound assisted extraction of Urtica dioica leaves and stems using (petroleum ether, chloroform, ethanol, and distilled water) solvents.

Figure 4. Microwave-assisted extraction of Urtica dioica leaves and stems using (petroleum ether, chloroform, ethanol, and distilled water) solvents.

Figure 5. Urtica dioica leaves and stem extracts prepared by using (petroleum ether, chloroform, ethanol, and distilled water) solvents.