Preparation and antioxidant activity of Pteridium aquilinum-derived oligosaccharide

Structure characterization of novel heteropolysaccharides from Pteridium revolutum with antioxidant and antiglycated activities

This study aims to analysis the structures of polysaccharides isolated from Pteridium revolutum and their antioxidant and antiglycated activities. Three novel water-soluble heteropolysaccharides, named PRP0, PRP1, and PRP2, were isolated from P. revolutum. The average molecular weight was determined by high performance gel permeation chromatography analysis as 1.04 × 106, 8.39 × 105, and 7.37 × 105 Da, respectively. Their structures were characterized using physicochemical and spectroscopic methods. The antioxidant and antiglycated activities were assayed in vitro. PRP0, PRP1, and PRP2 consist of l-Ara, l-Rha, d-Man, d-Xyl, d-Fuc, d-Gal, and d-Glc in different proportions. PRP1 mainly has a backbone of (1 → 3,6)-linked d-Man and (1 → 3)-linked d-Gal on main chain. PRP2 is mainly composed of (1 → 2,4)-linked d-Man and (1 → 3)-linked d-Gal on main chain. All polysaccharides have strong scavenging power on 2,2-difenil-1-picril-hidrazil and hydroxyl radicals and significantly antiglycated activity in Bovine serum albumin-Glucose model, which showing that the polysaccharides have potential application value on the functional food.

Structural and physicochemical properties of bracken fern (Pteridium aquilinum) starch

Introduction

Bracken fern (Pteridium aquilinum) starch is a non-mainstream, litter-researched starch, thus the starch characteristics remain largely unknown.

Methods

The structural and physicochemical properties of two bracken starches were systematically investigated, by use of various techniques that routinely applied in starch analysis.

Results and Discussion

The starches had amylose contents of 22.6 and 24.7%, respectively. The starch granules possessed C-type polymorph with D (4,3) ranging from 18.6 to 24.5 μm. During gelatinization event, the bracken starches showed lower viscosity than typical for rice starch, and lower gelatinization temperature than typical for cereal starches. After gelatinization event, bracken starches formed much softer and sticky gel than rice and potato starch. The molecular weight and branching degree (indexed by Mw, Mn and Rz values) of bracken starches were much higher than starches of many other sources. The branch chain length distributions showed that the bracken starches were structurally similar to some rice varieties (e. g. BP033, Beihan 1#), as reflected by proportions of A, B1, B2, and B3 chains. Notable differences in some starch traits between the two bracken starches were recorded, e. g. amylose content, gel hardness, gelatinization temperature and traits of structural properties. This study provides useful information on the utilization of bracken starch in both food and non-food industries.

Anti-Alzheimer's disease potential of traditional chinese medicinal herbs as inhibitors of BACE1 and AChE enzymes

Alzheimer's disease (AD) is a common neurodegenerative disease that often occurs in the elderly population. At present, most drugs for AD on the market are single-target drugs, which have achieved certain success in the treatment of AD. However, the efficacy and safety of single-target drugs have not achieved the expected results because AD is a multifactorial disease. Multi-targeted drugs act on multiple factors of the disease network to improve efficacy and reduce adverse reactions. Therefore, the search for effective dual-target or even multi-target drugs has become a new research trend. Many of results found that the dual-target inhibitors of the beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and acetylcholinesterase (AChE) found from traditional Chinese medicine have a good inhibitory effect on AD with fewer side effects. This article reviews sixty-six compounds extracted from Chinese medicinal herbs, which have inhibitory activity on BACE1 and AChE. This provides a theoretical basis for the further development of these compounds as dual-target inhibitors for the treatment of AD.

Structure Characterization, Antioxidant and Immunomodulatory Activities of Polysaccharide from Pteridium aquilinum (L.) Kuhn

Pteridium aquilinum (L.) Kuhn (Pteridaceae family) has been widely used as a food and medicine in China and Korea. Previous studies indicate that P. aquilinum contains a variety of bioactive chemical components such as flavonoids, phenols, terpenoids, saponins, polysaccharides, and so on. In the present study, a novel polysaccharide (named as PAP-3) with average molecular weight of 2.14 × 10⁵ Da was obtained from P. aquilinum. The structure was studied through physicochemical and spectroscopic analysis. The results indicated that PAP-3 consists of arabinose, rhamnose, fucose, galactose, mannose, and xylose in a molar ratio of 1.58:1.00:3.26:4.57:4.81:3.33. The polysaccharide is mainly composed of (1→2)-linked xylose and (1→3,6)-linked mannose on the main chain, with (1→2)-linked xylose, (1→6)-linked mannose, and (1→6)- and (1→3,6)-linked galactose as side chains. Galactose, fucose, and xylose are located at the end of the side chains. The in vitro immunomodulatory and antioxidant activities were assayed. PAP-3 has strong free-radical scavenging activity on DPPH and ABTS radicals and significant immunomodulatory activity on RAW264.7 cells. These data provide useful information for further study on the polysaccharides of P. aquilinum and their applications in the food and medical industries.

Novel Therapeutic Effects of Pterosin B on Ang II-Induced Cardiomyocyte Hypertrophy

Pathological cardiac hypertrophy is characterized by an abnormal increase in cardiac muscle mass in the left ventricle, resulting in cardiac dysfunction. Although various therapeutic approaches are being continuously developed for heart failure, several studies have suggested natural compounds as novel potential strategies. Considering relevant compounds, we investigated a new role for Pterosin B for which the potential life-affecting biological and therapeutic effects on cardiomyocyte hypertrophy are not fully known. Thus, we investigated whether Pterosin B can regulate cardiomyocyte hypertrophy induced by angiotensin II (Ang II) using H9c2 cells. The antihypertrophic effect of Pterosin B was evaluated, and the results showed that it reduced hypertrophy-related gene expression, cell size, and protein synthesis. In addition, upon Ang II stimulation, Pterosin B attenuated the activation and expression of major receptors, Ang II type 1 receptor and a receptor for advanced glycation end products, by inhibiting the phosphorylation of PKC-ERK-NF-κB pathway signaling molecules. In addition, Pterosin B showed the ability to reduce excessive intracellular reactive oxygen species, critical mediators for cardiac hypertrophy upon Ang II exposure, by regulating the expression levels of NAD(P)H oxidase 2/4. Our results demonstrate the protective role of Pterosin B in cardiomyocyte hypertrophy, suggesting it is a potential therapeutic candidate.

Response of total phenols, flavonoids, minerals, and amino acids of four edible fern species to four shading treatments

Total phenols, flavonoids, minerals and amino acids content were investigated in leaves of four fern species grown under four shading treatments with different sunlight transmittance in 35% full sunlight (FS), 13% FS, 8% FS and 4% FS. The leaves of four fern species contain high levels of total phenols and flavonoids, abundant minerals and amino acids, and these all were strongly affected by transmittance. Total phenols and flavonoids content were significantly positively correlated with transmittance, while minerals and total amino acids content were significantly negatively correlated with transmittance, a finding that supports research into how higher light intensity can stimulate the synthesis of phenols and flavonoids, and proper shading can stimulate the accumulation of minerals and amino acids. Matteuccia struthiopteris (L.) Todaro (MS) had the highest total phenols content, Athyrium multidentatum (Doll.) Ching (AM) showed the highest total amino acids, total essential amino acids content, Osmunda cinnamomea (L) var. asiatica Fernald (OCA) exhibited the highest total non-essential amino acids and flavonoids content. Pteridium aquilinum (L.) Kuhn var. latiusculum (Desy.) Underw. ex Heller (PAL) exhibited the highest minerals content. This research can provide a scientific basis for the cultivation and management of those four fern species.

Nutrient values and bioactivities of the extracts from three fern species in China: a comparative assessment

Pteridium aquilinum, Osmunda cinnamomea Linn, and Athyrium multidentatum (Doll.) Ching are three fern species widely consumed as potherbs and traditional medicinal herbs in China. Nevertheless, no detailed comparative assessments of their nutrient values and bioactivities have been reported. In this paper, we examined the nutrient content of these ferns and the bioactivities of their extracts with a comparative method. The results indicated that they were nutrient dense for proteins, carbohydrates, fat and minerals. Compared with Pteridium aquilinum and Osmunda cinnamomea Linn, the extract from Athyrium multidentatum (Doll.) Ching was found to possess the strongest antioxidant activity, protective effects on biomolecules, cellular antioxidant activity, and antiproliferative effects owing to its highest total phenolic (476.52 ± 11.26 mg GAE per g extract) and total flavonoid (924.81 ± 4.25 mg RNE per g extract) contents. Further, Athyrium multidentatum (Doll.) Ching can lead to caspase-3 activation, poly ADP-ribose polymerase cleavage, mitochondrial membrane potential (MMP) reduction and inhibition of wound-healing in a dose-dependent manner in HepG2 cells. These results demonstrate the remarkable potential of Pteridium aquilinum, Osmunda cinnamomea Linn, and Athyrium multidentatum (Doll.) Ching as valuable sources of nutrients and natural antioxidants, and among which Athyrium multidentatum (Doll.) Ching has potential anticancer properties.

Fern-synthesized nanoparticles in the fight against malaria: LC/MS analysis of Pteridium aquilinum leaf extract and biosynthesis of silver nanoparticles with high mosquitocidal and antiplasmodial activity

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum strains resistant to chloroquine. There is an urgent need to investigate new and effective sources of antimalarial drugs. This research proposed a novel method of fern-mediated synthesis of silver nanoparticles (AgNP) using a cheap plant extract of Pteridium aquilinum, acting as a reducing and capping agent. AgNP were characterized by UV-vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Phytochemical analysis of P. aquilinum leaf extract revealed the presence of phenols, alkaloids, tannins, flavonoids, proteins, carbohydrates, saponins, glycosides, steroids, and triterpenoids. LC/MS analysis identified at least 19 compounds, namely pterosin, hydroquinone, hydroxy-acetophenone, hydroxy-cinnamic acid, 5, 7-dihydroxy-4-methyl coumarin, trans-cinnamic acid, apiole, quercetin 3-glucoside, hydroxy-L-proline, hypaphorine, khellol glucoside, umbelliferose, violaxanthin, ergotamine tartrate, palmatine chloride, deacylgymnemic acid, methyl laurate, and palmitoyl acetate. In DPPH scavenging assays, the IC50 value of the P. aquilinum leaf extract was 10.04 μg/ml, while IC50 of BHT and rutin were 7.93 and 6.35 μg/ml. In mosquitocidal assays, LC50 of P. aquilinum leaf extract against Anopheles stephensi larvae and pupae were 220.44 ppm (larva I), 254.12 ppm (II), 302.32 ppm (III), 395.12 ppm (IV), and 502.20 ppm (pupa). LC50 of P. aquilinum-synthesized AgNP were 7.48 ppm (I), 10.68 ppm (II), 13.77 ppm (III), 18.45 ppm (IV), and 31.51 ppm (pupa). In the field, the application of P. aquilinum extract and AgNP (10 × LC50) led to 100 % larval reduction after 72 h. Both the P. aquilinum extract and AgNP reduced longevity and fecundity of An. stephensi adults. Smoke toxicity experiments conducted against An. stephensi adults showed that P. aquilinum leaf-, stem-, and root-based coils evoked mortality rates comparable to the permethrin-based positive control (57, 50, 41, and 49 %, respectively). Furthermore, the antiplasmodial activity of P. aquilinum leaf extract and green-synthesized AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. IC50 of P. aquilinum were 62.04 μg/ml (CQ-s) and 71.16 μg/ml (CQ-r); P. aquilinum-synthesized AgNP achieved IC50 of 78.12 μg/ml (CQ-s) and 88.34 μg/ml (CQ-r). Overall, our results highlighted that fern-synthesized AgNP could be candidated as a new tool against chloroquine-resistant P. falciparum and different developmental instars of its primary vector An. stephensi. Further research on nanosynthesis routed by the LC/MS-identified constituents is ongoing.

Preparation and characterisation of the oligosaccharides derived from Chinese water chestnut polysaccharides

Hydrogen peroxide (H2O2) is a strong oxidant that cleaves glycosidic bonds in polysaccharides. In this study, the oligosaccharides were prepared by removing the starch from Chinese water chestnuts through hydrolysis using α-amylase and then hydrolysing the remaining polysaccharides with H2O2, during which the oligosaccharide yield was monitored. The yield of oligosaccharide was affected by reaction time, temperature, and H2O2 concentration. Extended reaction times, high temperatures, and high H2O2 concentrations decreased oligosaccharide yield. Under optimum conditions (i.e., reaction time of 4h, reaction temperature of 80°C, and 2.5% H2O2 concentration), the maximum oligosaccharide yield was 3.91%. The oligosaccharides derived from Chinese water chestnuts polysaccharides exhibited strong hydroxyl and 2,2-diphenyl-β-picrylhydrazyl radical scavenging activity when applied at a concentration of 100 μg/mL. The results indicate that the oligosaccharides derived from Chinese water chestnuts polysaccharides possessed good antioxidant properties and can be developed as a new dietary supplement and functional food.