A review on extraction, composition, structure, and biological activities of polysaccharides from different parts of Nelumbo nucifera.

Nelumbo nucifera (lotus plant) is an important member of the Nelumbonaceae family. This review summarizes the studies conducted on it since the past 15 years to provide an understanding on future areas of focus. Different parts of this plant, that is, leaves, roots, and seeds, have been used as food and for the treatment of various diseases. Polysaccharides have been extracted from different parts using different methods. The manuscript reviews the methods of extraction of polysaccharides used for leaves, roots, and seeds, along with their yield. Some methods can provide better yield while some provide better biological activity with low yield. The composition and structure of extracted polysaccharides have been determined in some studies. Although monosaccharide composition has been determined in various studies, too little information about the structure of polysaccharides from N. nucifera is available in the current literature. Different useful biological activities have been explored using in vivo and in vitro methods, which include antioxidant, antidiabetic, antitumor, anti-osteoporotic, immunomodulatory, and prebiotic activities. Antitumor activity from polysaccharides of lotus leaves is yet to be explored, besides lotus root has been underexplored as compared to other parts (leaves and seeds) according to our literature survey. Studies dedicated to the successful use of combination of extraction methods can be conducted in future. The plant provides a therapeutic as well as nutraceutical potential; however, antimicrobial activity and synergistic relationships of polysaccharides from different parts of the plant need further exploration.

Blue honeysuckle extracts retarded starch digestion by inhibiting glycosidases and changing the starch structure.

Blue honeysuckle rich in anthocyanins can inhibit starch-digesting enzyme activity. This study evaluated the inhibitory effect and mechanism of blue honeysuckle extract (BHE) on glycosidases (α-amylase and α-glucosidase). BHE was a mixed glycosidase inhibitor with an IC50 of 2.36 ± 0.14 and 0.06 ± 0.01 for α-amylase and α-glucosidase, respectively. Fourier transform infrared (FTIR) spectroscopy, multi-fluorescence spectroscopy, and isothermal titration calorimetry (ITC) confirmed that BHE caused the secondary structure change and static fluorescence quenching of glycosidases, and the interaction was an enthalpy-driven exothermic reaction. Molecular docking proved that the main anthocyanin monomers in BHE interacted with glycosidases through hydrogen bonds and van der Waals forces. Moreover, BHE changed the starch structure and prevented starch from being digested by glycosidases. In vivo, BHE and starch-BHE complexes effectively slowed postprandial hyperglycemia. This research provided a theoretical basis for BHE in antidiabetic healthy food research and development.

Apple phlorizin attenuates oxidative stress in Drosophila melanogaster.

Apple phlorizin has a lot of applications owing to its antioxidant and hepatoprotective properties. This study explored the antioxidant effects and life span-prolonging activity of apple phlorizin in Drosophila melanogaster. Treatment with apple phlorizin was found to significantly extend the life span and ameliorate the age-related decline of locomotor function. This life span-extending activity was associated with the increased activity of superoxide dismutase, catalase, mRNA expression of glutamate-cysteine ligase catalytic subunit, cap-n-collar (cnc, homologue of mammalian Nrf2 gene), Keap1, and deacetylase sir2, as well as the downregulation of methuselah. Computational analysis suggested phlorizin could work as a Nrf2 activator and exert its biological activities by interfering with the Keap1 and Nrf2 binding. Therefore, it was concluded that the antioxidant and anti-aging effects of phlorizin might, at least in part, be mediated through the cooperation with the endogenous stress defense system. PRACTICAL APPLICATIONS: Phlorizin, from apple peel, has been used as a nutrient for over 100 years. To date, despite extensive research on phlorizin, a report on its effect on the antioxidant system in fruit flies is yet lacking. This report demonstrates that phlorizin can exert a protective effect on antioxidant issues and prolong life in fruit flies, which is valuable in the rational utilization of phlorizin in functional foods.

Colonization and Gut Flora Modulation of Lactobacillus kefiranofaciens ZW3 in the Intestinal Tract of Mice.

This study evaluated the distribution and colonization of Lactobacillus kefiranofaciens ZW3 and determined its capacity to modulate the gut microbiota in an animal model. Based on (1) fluorescence imaging, (2) flow cytometry, and (3) qPCR, we found that ZW3 successfully adhered to mouse mucous tissue and colonized the mouse ileum. Gut microbiota profiling was performed using high-throughput sequencing. After continuous intubation with ZW3 for 1 week, the proportion of Lachnospiraceae, a family of butyric acid-producing bacteria, increased at day 7 (11.9% at day 0 versus 18.4% at day 7). In addition, Lactobacillaceae showed an increasing trend (4% at day 0 versus 13% at day 7) that was accompanied by an observable decline in the Rikenellaceae family (1.58% at day 7, 0.14% at day 14, and 0.75% at day 21) in the tested mouse. The results demonstrate that ZW3 could successfully adhere to and colonize the mouse gut throughout the course of the experiment. The profiling analysis of the gut microbiota also provided evidence supporting the function of ZW3 in improving the intestinal flora of mice.

Rosemary Extract-Mediated Lifespan Extension and Attenuated Oxidative Damage in Drosophila melanogaster Fed on High-Fat Diet.

Rosemary extract has a potent antioxidant activity and is widely used in the food industry. In this study, the lifespan prolonging and antioxidant activity of rosemary extract was evaluated by high-fat-induced oxidative damage in Drosophila melanogaster. The results revealed that the lifespan and climbing ability of fruit flies was enhanced significantly by feeding rosemary extract. Furthermore, feeding with rosemary extract significantly increased the enzyme activity of superoxide dismutase (SOD) and catalase (CAT), and significantly decreased the level of malonaldehyde. The gene expression of SOD, CAT, and nuclear factor erythroid-2 related factor 2 was enhanced and that for methuselah was significantly reduced. The comet assay showed that high-fat diet-induced DNA lesion was significantly reduced in larvae treated with the rosemary extract. Our results suggest that feeding with rosemary extract is effective to the extended lifespan in fruit flies by strengthening of the resistance to high-fat-induced oxidative stress and by stimulating, at least in part, the endogenous antioxidant response.