Solvent Mixture Optimization in the Extraction of Bioactive Compounds and Antioxidant Activities from Garlic (Allium sativum L.)

Abstract

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.

Methods of Isolation of Active Substances from Garlic (Allium sativum L.) and Its Impact on the Composition and Biological Properties of Garlic Extracts

“…Bioactive compounds are obtained with the use of different extraction methods and types of solvents, which affect the extraction yield and biological properties of extracts [ 15 ]. The disadvantages of traditional extraction methods include high temperature during the process, large amounts of solvents used, the toxicity of some solvents, long processing times, and low selectivity [ 27 ].…”

“…The selection of the method and type of solvent is important and depends on the types of plant material and isolated compounds [ 15 ]. The use of water has numerous advantages, such as the positive environmental impact (water is non-flammable and non-toxic to humans and the environment, provides the possibility of clean processing and prevents pollution), selective extraction of bioactive compounds (depending on the type of solvent, it allows avoiding extraction of unwanted components) [ 38 , 39 , 40 ].…”

“…Similarly, water extracts obtained from lyophilized garlic powder exhibited the highest content of AC = 12.35 ng/mg, while the levels of MMTS, AS, and DADS were on average 1.42, 1.31, and 0.16 ng/mg, respectively [ 9 ]. In turn, a comparative analysis of ultrasound-assisted extraction (60 Hz, room temperature) with the use of water, ethanol, acetone, and mixtures of the solvents carried out by Cavalcanti et al [ 15 ] proved the effectiveness of the water-based extraction method. The use of water resulted in the highest recovery of thiosulfinates (TS) at a level of 6.42 µmol/g dry weight (dw), while the amount of total phenolic compounds (TPC) expressed as gallic acid equivalent (GAE) was 3.82 mg/g dw [ 15 ].…”

“…In turn, a comparative analysis of ultrasound-assisted extraction (60 Hz, room temperature) with the use of water, ethanol, acetone, and mixtures of the solvents carried out by Cavalcanti et al [ 15 ] proved the effectiveness of the water-based extraction method. The use of water resulted in the highest recovery of thiosulfinates (TS) at a level of 6.42 µmol/g dry weight (dw), while the amount of total phenolic compounds (TPC) expressed as gallic acid equivalent (GAE) was 3.82 mg/g dw [ 15 ]. A high extraction yield in a process with the use of water as a solvent (26.50%) from garlic shell (GH) was also demonstrated by Kallel et al [ 50 ].…”

“…Each solvent used in the extraction of active compounds is characterized by different polarities, which may be important in terms of the solubility of bioactive compounds and, consequently, the extraction efficiency [ 14 , 15 ]. Moreover, the volume ratio of individual solvents (in extractions with solvent mixtures) is also important and may correlate with the amount of recovery of individual bioactive compounds [ 15 ]. For this reason, the choice of the extraction method should be based on the following factors: the nature of the plant material, the nature of isolated compounds, the impact of the extraction method on the degradation of compounds, and the development of undesirable microorganisms [ 13 ].…”