Structural Identification of (1→6)-α-d-Glucan, a Key Responsible for the Health Benefits of Longan, and Evaluation of Anticancer Activity

Abstract

Longan is a delicious subtropical fruit with great health-beneficial effects. It has been utilized for disease prevention and health care since ancient age. To explore the chemicals responsible for the health benefits, water-soluble polysaccharides were extracted from longan flesh in this work. A pure polysaccharide (LPS1) was obtained through column purification. Analysis by gas chromatography showed LPS1 was a homopolysaccharide of glucose with glycosidic linkage of →6)-d-Glc-(1→. Nuclear magnetic resonance (NMR) spectra indicated that the configuration of anomeric carbon in glucose residual was α-form. The polysaccharide structure was further confirmed to be (1→6)-α-d-glucan by chemcial shift of C6. The molecular weight of LPS1 was calculated to be 108 kDa, which had 661 glucose residuals. Anticancer assay showed that LPS1 had anticancer activity against the growth of HepG2 cells to a certain extent. However, it did not show any cytotoxicity against MCF-7 breast cancer cells.

Structural Characterization of Two Water-Soluble Polysaccharides from Black Soybean (Glycine max (L.) Merr.)

“…20 Recently, Zhu et al isolated a (1→6)-α-D-glucan from flesh tissues of Dimocarpus longan Lour and demonstrated that the polysaccharide had anticancer activity against the growth of HepG2 cells. 22 In our previous study, BSPS-1 as a novel resource of (1→6)-α-D-glucan has been demonstrated to have potential superoxide anion and DPPH radical scavenging activities. 15 From the above literature, it could be concluded that (1→6)-α-D-glucan could be a health beneficial polysaccharide and might have wide applications in food and pharmaceutical industries.…”

“…The other carbon signals (C-2 to C-6) are identified from cross peaks in the HSQC spectrum ( Figure 3b) as well as the literature data. 18,19,22 Accordingly, the carbon chemical shifts at 71.29, 73.40, 69.53, 70.23, and 65.66 ppm can be assigned to C-2, C-3, C-4, C-5, and C-6 of glucosyl residue. However, no typical signal is observed for uronic acid groups, which is in agreement with the result of the m-hydroxydiphenyl colorimetric method.…”

Identification of phenolics in litchi and evaluation of anticancer cell proliferation activity and intracellular antioxidant activity

“…In (0-600 µM) of cinnamtannin B1 for 1 h min prior to ABAP (600 µM) treatment for 1h; 14 The control group was treated without ABAP. The values having no letters in common are significantly different (p < 0.05).…”

“…The assay was conducted folowing the protocol of Zhu et al with some modifications [14]. Cancer cells were seeded at a density of 2.5×10 5 cells/mL on a 96-well microplate in 100 µL of growth medium/well.…”

“…As described above, HepG 2 cells were cultured at a density of 5×10 5 cells/well in six-well plates and grown for 24 h, and then the cells were exposed to different concentrations of cinnamtannin B1 (0, 50, 100, 150, 200 and 250 µM) for 24 h. After treatment, the detached cells in the medium were firstly collected, and the adhering cells were harvested by trypsinisation 14 (0.25% trypsin-EDTA, Sigma Alcrich) were collected as well. After centrifugation at 1000 g and 4 o C for 5 min, the cells were washed with PBS twice, and resuspended in 400 µL of binding buffer.…”