Physicochemical and release characterisation of garlic oil-β-cyclodextrin inclusion complexes
Research highlights
► A new process method to enhance physicochemical property of garlic oil was showed. ► Garlic oil could be efficiently complexed with β-CD to form an inclusion complex. ► The solubility and stability of garlic oil were increased by inclusion in β-CD. ► The release rate of garlic oil from the inclusion complex was controlled.
Introduction
Garlic (Allium sativum L.) is a widely distributed plant and is used throughout the world not only as a spice and a food, but also as a folk-medicine, and many of the beneficial health-related biological effects have been attributed to its characteristic organosulphur compounds (Rybak, Calvey, & Harnly, 2004). Steam distillation is widely used to extract and condense the volatile organosulphur compounds in garlic, and the final oily product is called garlic oil (GO) (Wu et al., 2002). The compounds of GO mainly are diallyl disulphide (DADS), diallyl trisulphide (DATS), allyl propyl disulphide, a small quantity of disulphide and probably diallyl polysulphide (Pranoto, Salokhe, & Rakshit, 2005). GO is recognised to be more potent than aqueous extracts of garlic and exhibit a wide range of pharmacological properties including antimicrobial, antidiabetic, antimutagenic, and anticarcinogenic effects (Agarwal, 1996). However, the application of GO in the food industry is limited due to its volatility, strong odour, insolubility in water, and low physicochemical stability (Corzo-Martínez, Corzo, & Villamiel, 2007). Interestingly, theses disadvantages can be addressed by complexation with cyclodextrins (CDs) in aqueous solutions. It has been reported that the inclusion complexes of guest compounds with CDs can enhance guest stability, improve the aqueous solubility, protect against oxidation, light-induced decomposition, and heat-induced changes, and mask or reduce unwanted physiological effects, and reduce volatility (Hedges, 1998). For example, the natamycin/CDs complexes have allowed a homogeneous delivery system of natamycin to the shredded cheese surface without the clogging of spray nozzles during cheese production (Koontz & Marcy, 2003).
CDs are non-toxic macrocyclic oligosaccharides, consisting of (α-1,4)-linked α-d-glucopyranose units, with a hydrophilic outer surface and hollow hydrophobic interior (Szente & Szejtli, 2004). CDs are widely used in the food industry as food additives, for stabilization of flavours, for elimination of undesired tastes or other undesired compounds such as cholesterol and to avoid microbiological contaminations and browning reactions (Astray, Gonzalea-Barreiro, Mejuto, Riao-Otero, & Simal-Gándara, 2009). They have the ability to form inclusion complexes with a wide variety of organic compounds, which enter partly or entirely into the relatively hydrophobic cavity of CDs simultaneously expelling the few high-energy water molecules from inside (Karathanos, Mourtzinos, Yannakopoulou, & Andrikopoulos, 2007). The most common CDs used as formulation vehicles are α-, β- and γ-CDs containing six, seven and eight glucopyranose units, respectively. Amongst the CDs, β-CD is widely used since its cavity size is suitable for common guests with molecular weights between 200 and 800 g/mol and also due to its availability and reasonable price (Waleczek, Marques, Hempel, & Schmidt, 2003). Hadaruga, Hadruga, Rivis, Gruia, and Pinzaru (2007) have reported the thermal and oxidative stability of the A. sativum L. bioactive compounds/α and β-CD nanoparticles and discussed that the DADS and DATS were suitably encapsulated in a higher concentration. It has also been reported that the molecular inclusion complexes could be successfully formed by hydrogen bonding between GO and β-CD and an improvement of stability, solubility, and bioavailability of the guest molecule in the inclusion complex was obtained (Ayala-Zavala et al., 2008). Stellenboom, Hunter, Caira, Bourne, and Barbieri (2009) described the preparation of the inclusion complex formed between the allicin mimic S-p-tolyl t-butylthiosulphinate and β-CD by both kneading and co-precipitation methods. Bai et al. (2010) have recently reported that two major GO components of DADS and DATS had higher water solubility caused by hydroxypropyl β-cyclodextrin (HP-β-CD) and DATS was better suited to be encapsulated by HP-β-CD compared to DADS.
However, to the best of our knowledge, there are, so far, few reports on the inclusion complex of GO and β-CD in the scientific literature. In this study, the inclusion complex of GO/β-CD was prepared by the co-precipitation method and the formation of the inclusion complex of GO with β-CD was analysed by different analytical techniques including UV–visible spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Furthermore, the solubility and release characterisation of the inclusion complexes of GO in β-CD were determined.
Section snippets
Materials
Garlic oil (GO) (purity > 90%, containing three major constituents, about 35% of diallyl disulphide (DADS), 42% of diallyl trisulphide (DATS), and 16% of diallyl sulphide), stored at 4 °C, was purchased from Xunyang Ltd. Co., Guangdong, China. β-cyclodextrin (β-CD) was purchased from Sinopharm Chemical Reagent Beijing Co., Ltd., Beijing, China. All other chemicals and solvents were of analytical grade.
Preparation of GO and β-CD Complex
The complex of GO and β-CD was prepared by using a co-precipitation method described by
Preparation of GO/β-CD complex
In recent years, β-CD has gained appreciable acceptance amongst the various types of cyclodextrins. The inclusion complexes of β-CD have been successfully used to improve solubility, chemical stability and bioavailability of a number of poorly soluble compounds. Various known methods used for the formation of the inclusion complexes like co-precipitation, neutralisation, kneading, spray drying, freeze-drying, solvent evaporation, and ball-milling and sealed-heating in the laboratory have been
Conclusions
The results of this study clearly demonstrated that GO could be efficiently complexed with β-CD to form an inclusion complex by the co-precipitation method in a molar ratio of 1:1. The results of UV–visible spectroscopy, FT-IR, DSC and XRD demonstrated that GO/β-CD complex has different physicochemical characteristics from free GO. The aqueous solubility and stability of GO were significantly increased by inclusion in β-CD. The GO release rate from the GO/β-CD complex was controlled.
Acknowledgement
This work was supported by a grant from the National High Technology Research and Development Program of China (863 Program) (No. 2007AA10Z306) and Funding Project for Academic Human Resources Development in Institutions of Higher Learning, Beijing New Century BaiQianWan Talent Project and Beijing Nova Program (No. 2008B07).
References (26)
Therapeutic actions of garlic constituents
Medicinal Research Reviews
(1996)- et al.
A review on the use of cyclodextrins in foods
Food Hydrocolloids
(2009) - et al.
Microencapsulation of cinnamon leaf (Cinnamomum zeylanicum) and garlic (Allium sativum) oils in β-cyclodextrin
Journal of Inclusion Phenomena Macrocyclic Chemistry
(2008) - et al.
Comparison of encapsulation properties of major garlic oil components by hydroxypropyl β-cyclodextrin
European Food Research and Technology
(2010) - et al.
Release properties on gelatin-gum arabic microcapsules containing camphor oil with added polystyrene
Colloids and Surfaces B: Biointerfaces
(2006) - et al.
Biological properties of onions and garlic
Trends in Food Science & Technology
(2007) - et al.
Controlled release of antifungal volatiles of thyme essential oil from β-cyclodextrin capsules
Journal of Inclusion Phenomena Macrocyclic Chemistry
(2010) - et al.
Thermal and oxidative stability of the Allium sativum L. Bioactive compounds/α- and β-cyclodextrin nanoparticles
Revista de Chimie
(2007) - et al.
Encapsulation of bovine serum albumin within β-cyclodextrin/gelatin-based polymeric hydrogel for controlled protein drug release
IRBM
(2010) Industrial application of cyclodextrins
Chemical Reviews
(1998)
Phase solubility techniques
Advance in Analytical Chemistry and Instrumentation
Study of the solubility, antioxidant activity and structure of inclusion complex of vanillin with β-cyclodextrin
Food Chemistry
Thermal decomposition of cyclodextrin (α, β, γ, and modified β-CyD and metal-(β-CyD) complexes in the solid phase
Thermochimica Acta
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