Analysis of Extraction, Isolation, Structural Characterization, and Functional Activities of Oligosaccharides from Capparis Spinosa L.

OBJECTIVE To investigate the structural characterization and functional activities of oligosaccharides from Capparis spinosa L.

METHODS The oligosaccharides were extracted by water-ethanol extraction and purified sequentially with AB-8 macroporous resin, DEAE-650M cellulose column, and HW-40F gel filtration to obtain 2 fractions(C-O-1 and C-O-2). Their structures were characterized by 1-phenyl-3-methyl-5-pyrazolone(PMP) pre-column derivatization, methylation analysis, ultraviolet-visible spectroscopy(UV-Vis), Fourier transform infrared spectroscopy(FTIR), and high performance liquid chromatography(HPLC). Antioxidant activities were evaluated via 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) cationic radical(ABTS⁺·), 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical(DPPH·), hydroxyl radical scavenging assays, and Fe²⁺ reducing power. In vivo antioxidant and anti-melanogenic effects of C-O-1 were further assessed in zebrafish model.

RESULTS Both C-O-1 and C-O-2 contained O-H and C-H bonds. C-O-1 was composed of glucose and mannose(89.4 : 10.6), while C-O-2 consisted solely of glucose. Glycosidic linkage analysis indicated terminal glucopyranose(T-Glcp) linkages in both samples. C-O-1 was hypothesized to be a tetrasaccharide with a molecular weight of approximately 671.37; whereas C-O-2 was a disaccharide with a molecular weight of approximately 387.11. In vitro, C-O-1 and C-O-2 exhibited significantly stronger scavenging activities against ABTS⁺, DPPH, and hydroxyl radicals compared to the positive control(stachyose). At safe concentrations(0.25–2 mg·mL^–1), C-O-1 reduced ROS generation by 43.8% and inhibited melanin synthesis by 35.2% in zebrafish.

CONCLUSION  C-O-1 and C-O-2 both exhibit well-defined structures. C-O-1 demonstrates remarkable antioxidant and skin-whitening effects, suggesting its potential for functional applications.