Bioactive properties of Snake fruit (Salacca edulis Reinw) and Mangosteen (Garcinia mangostana) and their influence on plasma lipid profile and antioxidant activity in rats fed cholesterol

Two exotic fruits (Snake fruit and Mangosteen) were characterized by polyphenols, proteins and antioxidant potentials and by their influence on plasma lipids and antioxidant activity in rats fed cholesterol. The content of polyphenols (14.9±1.5 and 9.2±0.8 mg GAE g⁻¹) and antioxidant potential (46.7±4.7 and 72.9±7.4 μmol TE g⁻¹) in Snake fruit was significantly higher than in Mangosteen (P<0.05). Twenty male Wistar rats were divided into four dietary groups: Control, Chol, Chol/Snake and Chol/Mangosteen. After 4 weeks of the experiment diets supplemented with Snake fruit and to a lesser degree with Mangosteen significantly hindered the rise in plasma lipids and hindered a decrease of antioxidant activity. Changes were found in fibrinogen fraction, such as solubility and mobility by the number of protein bands detected in SDS-electrophoresis: Chol/Snake differed from Chol/Mangosteen. In conclusion, Snake fruit and Mangosteen contain high quantity of bioactive compounds, therefore positively affect plasma lipid profile and antioxidant activity in rats fed cholesterol-containing diets. Such positive influence is higher in rats fed diet with added Snake fruit.     

Use of scanning electron microscopy to indicate the similarities and differences in pseudocereal and cereal proteins

Isolated and separated protein fractions from cereal and pseudocereal grains were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis and scanning electron microscopy. Prolamin, the main storage protein in cereal such as maize, showed a difference in electrophoretic patterns and fine structure in comparison with those from amaranth and soybean. In contrast glutelins from amaranth, soybean and maize showed some similarity in the distribution of protein bands and in microstructure. Amaranth and soybean were closely similar in distribution of protein fractions and their microscopic structure. As an addition to chemical analyses, microscopy helped to understand and visualize structural changes and textural differences in protein fractions. Pseudocereals can be used as a nutritive substitute of some cereals in functional foods.     

Two exotic fruits positively affect rat’s plasma composition

The aim of this investigation was to determine the bioactive compounds and the antioxidant potentials of Snake fruit and Mangosteen and their influence on plasma lipid levels and antioxidant activity in rats fed cholesterol-containing diets. It was found that total polyphenols and antioxidant potentials of Snake fruit were significantly higher than those of Mangosteen (P < 0.05). A cholesterol-containing diet supplemented with the studied exotic fruits showed a positive affect on rat’s plasma lipid levels and on the antioxidant activity during 30 days of feeding. In rat’s plasma of the Chol/Snake diet group, the fibrinogen fraction showed a decrease in the amounts and compositions of electrophoretic protein bands in the range of 110 and 14 kDa. However, all the positive results of this experiment on animals could not be automatically applied to humans.     

Characterisation of pseudocereal and cereal proteins by protein and amino acid analyses

Maize, wheat, amaranth, rice and soybean were screened for protein content. Alcohol‐soluble (A1 and A2) and glutelin (G1 and G2) fractions were isolated and compared in terms of their amino acid and protein compositions. The average proportions of nitrogen content between total alcohol‐soluble proteins (TASP) and total glutelins (TGlu) in the pseudocereals amaranth and soybean were about 1.8:26.9 and 14.9:12.3 respectively. In the cereals maize and wheat these proportions were 47.8:33.2 and 44.7:31.2 respectively. The sum of essential amino acids was 47.6 and 60.3 g per 100 g protein in amaranth and soybean respectively. The highest contents of methionine, lysine and arginine were found in the pseudocereals. The relatively high content of essential amino acids shows that pseudocereals could be used as a nutrient substitute for cereals. © 2002 Society of Chemical Industry     

Relationship between dicotyledone-amaranth, quinoa, fagopyrum, soybean and monocots- sorghum and rice based on protein analyses and their use as substitution of each other

Comparative protein studies of cereals and pseudocereals are important, especially in cases of cereal protein allergy when pseudocereal substitution is unavoidable. Therefore, ten species and cultivars belonging to different Angiosperms families (Oryza sativa normal Poaceae, bran Poaceae and Jasmin Hom Dokmali Poaceae, Sorghum technicum Battand et Traubt Poaceae, Glycine max L. Merr. Fabaceae, Fagopyrum esculentum Mnch. Polygonaceae, Chenopodium quinoa Wild Chenopodiaceae, Amaranthus hybridum v.1004 Amaranthaceae, cruentus v. R104 Amaranthaceae and hypochondriacus v.1023 Amaranthaceae) were examined by sodium dodecyl sulphate (SDS-PAGE) seed protein markers, fluorescence, circular dichroism (CD) spectra and Fourier transform infrared (FT-IR) measurements. A high degree of polymorphism of all species and cultivars was found. Amaranth species have very similar seed protein electrophoretic profiles. According to UPGMA algorithm the examined species and varieties could be clustered into two similarity groups. Soybean, quinoa, buckwheat and Amaranth (as a genus) can be considered as phylogenic distant taxa. The fluorescence properties of amaranth, soybean, quinoa, rice and buckwheat soluble protein fractions were measured by fluorescence of tryptophan at 295 nm, light intensity, peak response and shift in the maximum of emission. Relative structural stabilities of native proteins were estimated by CD and FTIR. Similarities were found between these plants, which could make them a substitution of each other as well as for cereals.Author, S. Gorinstein is affiliated with the David R. Bloom Center for Pharmacy.     

Comparative characterisation of durian,mango and avocado

The aim of this investigation was to determine the nutritional and bioactive properties of relatively less investigated exotic fruit durian (Durio zibethinus Murr.) and to compare these indices with widely used mango (Mangifera indica L.) and avocado (Persea americana). For this purpose HPLC, three‐dimensional fluorescence (3D‐FL), several radical scavenging assays and multivariate factor analysis were used. It was found a similarity in acetone extracts between durian and mango in the contents of polyphenols (1.66 ± 0.08, 1.48 ± 0.05, mg GAE g^?1 DW, respectively), and in some antioxidant assays such as ABTS (11.98 ± 0.5, 12.24 ± 0.5, μm TE g^?1DW, respectively) and DPPH (5.61 ± 0.3, 5.22 ± 0.2, μm TE g^?1 DW, respectively). Durian and avocado were similar in the contents of polyphenols, and ABTS and DPPH values in water and in methanol extracts, respectively. Based on the obtained results the nutritional and bioactive properties of durian are comparable with those indices in mango and avocado. In conclusion, durian can be recommended as a part of disease prevented diets.     

Characterization of blond and Star Ruby (red) Jaffa grapefruits using antioxidant and electrophoretic methods

Antioxidant and electrophoretic methods were used to characterize the quality differences between blond and Star Ruby (red) grapefruits. Dietary fibre, minerals and trace elements, total polyphenols, anthocyanins, flavonoids, phenolic and ascorbic acids were also determined. The antioxidant potential of red grapefruit was significantly higher than that of the blond fruit (P < 0.05) and correlated well with the total polyphenols (R² from 0.8456 to 0.9711). In both the cultivars studied, thirty‐two electrophoretic bands were detected [sodium dodecyl‐polyacrylamide gel eletrophoresis (SDS‐PAGE)]. The main electrophoretic bands occurred between 20 and 43 kDa in both grapefruits with few minor differences between the varieties. Our findings indicate the following (i) red grapefruit is preferable: it has a higher concentration of bioactive compounds and antioxidant potential than the blond; (ii) 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) test is a more sensitive method for the determination of antioxidant potential; (iii) there are some minor differences in electrophoretic patterns; (iv) antioxidant and electrophoretic methods are a good combination for characterization of differences of the same citrus fruits.     

Bioactive compounds and antioxidant potential in fresh and dried Jaffa® sweeties,a new kind of citrus fruit

Bioactive compounds in the edible parts of fresh and dried Jaffa^® sweeties, a new kind of citrus fruit, were analysed and their antioxidant capacities were assessed. Antioxidant‐rich fractions were extracted from fresh and dried sweeties with 1.2 M HCl in methanol/water (1:1 v/v), and the antioxidant activities of these extracts were evaluated. Using the β‐carotene/linoleate model system, the extracts from equivalent quantities of fresh and dried sweeties showed 89 and 87% antioxidant activity respectively. Similarly, using the DPPH radical‐scavenging method, the extracts showed 87 and 85% antioxidant activity respectively. The best correlations were between caffeic acid content and β‐carotene and DPPH antioxidant activity values (r = 0.9849 and 0.9798 respectively, p = 0.005). Both fresh and dried sweeties are bioactive natural products; when fresh fruits are not available, properly dried sweeties could be used as a substitute. Copyright © 2004 Society of Chemical Industry     

Antioxidant properties and bioactive constituents of some rare exotic Thai fruits and comparison with conventional fruits: In vitro and in vivo studies

The aim of this research was to investigate the bioactivity of durian, snake fruit and mangosteen, rare exotic Thai fruits. These fruits were compared among them and with conventional fruits: durian with mango and avocado, and snake fruit with mangosteen and kiwifruit in order to find the preferable diet for human consumption. The contents of polyphenols, flavonoids, flavanols, tannins, anthocyanins, ascorbic acid and carotenoids, and the level of antioxidant potential by ABTS, DPPH, FRAP and CUPRAC in different extracts (methanol, water, acetone, and hexane) were determined. The presence of polyphenols (flavonoids and phenolic acids) in the investigated samples was characterized by Fourier transform infrared (FT-IR) spectroscopy and three-dimensional fluorimetry (3D-FL).The in vivo studies were carried out on 25 male Wistar rats, divided into 5 diet groups, each of 5. During 30 days of the experiment the rats of all 5 groups were fed basal diet (BD), which included wheat starch, casein, soybean oil, vitamin and mineral mixtures. The rats of the Control group were fed only the BD. The BD of the other 4 groups was supplemented with 1% of nonoxidized cholesterol (NOC) (Chol group), 1% of NOC in each group and 5% of lyophilized fruits: durian (Chol/Durian), snake fruit (Chol/Snake), mangosteen (Chol/Mangosteen). After the experiment diets supplemented with exotic fruits significantly hindered the rise in plasma lipids and hindered the decrease in the plasma antioxidant activity. In conclusion, the contents of bioactive compounds and the antioxidant potential are relatively high in the studied fruits and varied among them depending on the extraction procedure. FT-IR and 3D-FL can be used as additional tools for identification and comparison of bioactive compounds. Supplementation of diets with exotic fruits positively affects plasma lipid profile and antioxidant activity in rats fed cholesterol-containing diets.