| Isothiocyanates (ITCs) are abundant in cruciferous vegetables, and they are the hydrolysis products of glucosinolates (GLS) by the enzyme myrosinase. ITCs are of interest because of their chemopreventive activities. ITCs have been commercially produced abroad and have not deeply being studied in China currently. This work consisted of the following parts:(1) Preparation of ITCs extracts by using the dichloromethane solvent extraction and supercritical fluid extraction-CO2 technologies. (2) Research on the antioxidant activity and antisenescence properties of ITCs extracts. (3) Preparation and characterization of inclusion complexes of ITCs inβ-cyclodextrin cavity.The following major progresses were achieved in this work:ITCs crude extracts were prepared by methylene chloride solvent extraction method from broccoli seeds. The concentration of resulted extractum was up to 80%. The methylene chloride residue was determined and the technology was built to insure solvent residue to met safety requirements. It was favorable for further development the efficacy of ITCs extracts.The trouble was still focused on use of much organic solvents, and the consequence of contamination and safety worry was caused by the residual solvents. The supercritical fluid extraction-CO2 technology of ITCs was preliminarily constructed. The yield reached comparatively to 82% that of solvents extraction method.The antioxidant properties of ITCs extracts were evaluated by using the in vitro bioassays, including superoxide anion radical (02·-), hydroxyl radical (OH·), and 2, 2-diphenyl-l-picrylhydracyl (DPPH·) radical-scavenging methods, lipid peroxidation assay, and reducing power assay. The ITCs extracts exhibited significant antioxidant activities (P<0.01). The extracts due to purity disturbance were separated through Amberchrom CG161M reverse phase column in AKTA purifier 100 apparatus and analyzed further by GC-MS. Sulforaphane (SFN) was successfully separated and identified. The antioxidant activity of SFN was approximately one tenth to one fifth of that of vitamin C (Vc). It was experimented to be the dominating contributor to antioxidant capacity of ITCs extracts. However, there was no direct antioxidant activity found for benzyl isothiocyanate (BITC) in vitro. Therefore, the group (CH3-SO-CH2-) was the probable part to offer reactive hydrogen resulting in interdiction of free radical chain-reaction and lipid peroxidation. The antioxidant activity of ITCs extracts was sensitive to heat and light. Although its antioxidant-stability was affected by temperature and storage condition, it was more stable than Vc.The effect of ITCs extracts on senescence of melanogasters was studied. The life-span, sexual potency and reproduction ability of melanogasters were consistently improved in spite of no significant found for the prolongation of life-span. The activity of SOD enzyme was advanced and the accumulation of MDA was also inhibited in melanogasters in vivo. It is not well known about the antisenescence of ITCs extracts. This work is open to add knowledge to this area.The poor water-solubility of ITCs compounds is favorable for forming the inclusion complexes withβ-Cyclodextrin (β-CD), which is P-CD-ITC. In this work, P-CD-BITC,β-CD-PEITC (phenylethyl isothiocyanates, PEITC) andβ-CD-SFN inclusion complexes were prepared by co-precipitation processes. The UV spectrum was applied to quantity BITC, PEITC and SFN. Response surface design (RSD) was applied to optimize the preparation conditions. The association constants and inclusion ratios of three inclusion complexes were calculated. The inclusion complexes prepared were respectively analyzed by thermal methods (TG and DSC), Fourier transformation-infrared spectroscopic (FTIR), X-ray powder diffraction (XRD) and SEM micrographs means in order to characterize the inclusion behavior of ITCs andβ-CD. The results indicated that the interaction between the guest (BITC, PEITC and SFN) and host ((3-CD) molecules did occur except that the UV spectrum was kept unalterable. Hence, under proper inclusion conditions, it is the hydrophobic interaction force that forces the inclusion reaction. The thermal-stability of complexes was improved.
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