Optimization of an Ultrasound-Assisted Extraction Method for the Extraction of Gingerols and Shogaols from Ginger (Zingiber officinale)

Abstract

The goal of this study is to optimize a UAE method for the extraction of the main bioactive compounds present in the ginger rhizome (gingerols and shogaols). Ginger rhizome (Zingiber officinale) has a considerable content of bioactive compounds, in particular gingerols and shogaols, with interesting pharmacological activities such as anti-inflammatory, antioxidant, anti-cancer, and antimicrobial properties, among others. The isolation of these compounds requires an efficient extraction process with short extraction times and the employment of specific non-toxic solvents for humans. In this work, the optimization of an ultrasound-assisted extraction (UAE) method for the extraction of the main pungent compounds in the ginger rhizome, i.e., gingerols and shogaols, has been carried out. For this purpose, a Box–Behnken design (BBD) has been used to optimize the experimental design through a response surface methodology (RSM). The percentage of ethanol in the extraction solvent, the temperature, the amplitude, and the cycle of the ultrasounds, as well as the sample-to-solvent ratio, were the variables to be studied. Thus, the percentage of ethanol in the extraction solvent was identified as the most influential factor. Once the compounds were extracted, the identification of gingerols and shogaols was performed by ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole-time-of-flight mass spectrometer (Q-ToF-MS), and the quantification by UHPLC coupled to a diode array detector (DAD) detector. Finally, the optimized UAE method required only 10 min of extraction time, presenting good repeatability and intermediate precision levels (<5%). The method was applied to extract gingerols and shogaols from diverse sources, thereby demonstrating its applicability and highlighting the potential variations in compound concentrations across different samples based on factors such as origin, and growing conditions, among others.

Determination of Gingerols and Shogaols Content from Ginger (Zingiber officinale Rosc.) through Microwave-Assisted Extraction

“…Given the previously mentioned importance of ginger, this study will use ginger purchased at a local market in Veracruz (Veracruz, Mexico), precisely situated at coordinates 19 • 12 14.1 N; 96 • 09 41.3 W. To increase the contact surface between the ginger sample and the extraction solvent and thus favor the extraction of the compounds of interest, the ginger sample was subjected to pre-treatment. Such pre-treatment, which allows transforming fresh ginger into ginger powder, has been previously described in detail in other previous studies by our research group [23]. In addition to the ginger samples from Mexico, the optimized extraction method was tested on other ginger samples collected from Spain, Germany, and Morocco.…”

“…The identification of gingerols and shogaols within the ginger extracts was accomplished using UHPLC-Q-ToF-MS analysis. The analytical method previously developed by our research group [23] was used. The individual identification of the compounds relied on their distinctive elution order and their molecular weight [M+Na] + , as they form adducts with Na.…”

“…where y is the predicted response (Y TGSC ); β 0 is the model constant; X i and X j are the independent variables; β i are the linear coefficients; β ij are the coefficients corresponding to the interactions; β ii are the quadratic coefficients; and r is the sum of the mean squares of the error. The statistical analyses were conducted following those described by Gonzalez-Gonzalez et al [23] through the software application Statgraphic Centurion Version XVIII (Statgraphics Technologies, Inc., Los Llanos, VA, USA).…”

Water Extraction of Bioactive Components from Ginger Powder Using Response Surface Methodology

“…The ginger rhizome, which grows as an endemic species in Asia, has great importance in both cuisine and traditional medicine. In folk medicine, this miraculous plant is employed to treat various ailments, including headaches, nausea, colds, and muscle aches [2]. The healing properties of ginger are attributed to bioactive components, particularly polyphenol components such as 6-gingerol, with antioxidant activity, found in extracts obtained from ginger through various extraction methods [1].…”

“…The most important factors in selecting an extraction method are that the method should be simple and feasible, not costly, and can be carried out with high efficiency in a short time. Ultrasonic extraction emerges as the most suitable method for this purpose [2].…”