One-pot extraction and enrichment of diallyl trisulfide in garlic oil using an eco-friendly solvent-free microwave extraction method

Abstract

The H2S-releasing donor capabilities of garlic polysulfanes, particularly diallyl trisulfide, have been shown to exhibit cardioprotective, antiatherosclerotic, and anticarcinogenic effects. These properties lead to the ubiquitous use of garlic oil in pharmaceuticals; nevertheless, there is a lack of a simple, optimal, and environmentally friendly approach for increasing diallyl trisulfide levels. This study aimed to establish a one-pot extraction and enrichment method for diallyl trisulfide in garlic oil using solvent-free microwave extraction (SFME). In the SFME processes, a face-centered central composite design (FCCCD) was applied by treating the moisture content, microwave power, and irradiation time as independent factors, whereas the response was volatile oil yield. The extraction method was optimized using response surface methodology and Derringer’s desirability function. Under optimal conditions, SFME was implemented to assure the maximum qualitative and quantitative quality of garlic oils collected from different origins. The volatile oils obtained were analyzed by gas chromatography−mass spectrometry. The optimum conditions for SFME were a 68% moisture content and irradiation at 640 W for 20 min, yielding 0.30 ± 0.02% w/w garlic oil. The proposed SFME conditions were more efficient than hydrodistillation (HD) in production yields and the proportion of diallyl trisulfides. When the proposed conditions were implemented, garlic oil yields varied between 0.14% w/w and 0.32% w/w, with a high proportion of the target diallyl trisulfide. This finding highlights an appropriate model for extracting diallyl trisulfide-rich garlic oil using an eco-friendly technology that is more efficient than the conventional HD method.