Saponins in Ipomoeabatatas tubers: Isolation,characterization, quantification and antioxidant properties

Triterpene saponins are a class of plant natural products with a wide range of bioactivities, which makes them an interesting research subject. This work reports, for the first time, the isolation and characterization of saponins in Ipomoeabatatas tuber flour, their quantification and antioxidant properties. Their structures were characterized on the basis of UV, FAB–MS, ESI–MS, GC–MS, polarimetry and NMR data, as: oleanolic acid-3-O-[β-d-glucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl]-28-O-β-d-glucopyranoside (sandrosaponin IX) (1) and oleanolic acid-3-O-[β-d-galactopyranosyl-(1→3)-β-d-glucuronopyranosyl]-28-O-β-d-glucopyranoside (2). A new quantitative HPLC–DAD method for saponin content determination in this tuber was developed and validated. Their total content was 200.01 mg/100 g dry weight (RSD = 7.2%; p < 0.001). The single saponin contents were: 161.20 mg/100 g dry weight (RSD = 0.58%; p < 0.001) for saponin 1 and 14.67 mg/100 g dry weight (RSD = 0.41%; p < 0.001) for saponin 2. The antioxidant activities, tested by DPPH and FRAP assay, of total phytochemical fraction and of single saponins were moderate in relation to commercial standards.     

Effect of endogenous glycosidase on stability of steroidal saponins in Taiwanese yam (Dioscorea pseudojaponica yamamoto) during drying processes

The effect of different drying methods on steroidal saponins, furostanol and spirostanol glycosides, in Dioscorea pseudojaponica Yamamoto, were studied. The yams were either steam-blanched or not blanched before drying. Results showed that solar and shaded drying without prior blanching would cause significant changes of yam saponins; hot air drying caused slight variation, and other drying methods showed almost no change. A similar phenomenon was observed in a model system containing crude yam saponin extract; it indicated that higher temperature and light exposure had very little effect on the stability of yam saponins during drying. On the other hand, the endogenous glucosidase in yam might play an important role in altering the saponin structures during drying. This was confirmed by a model experiment; a crude furostanol glycoside 26-O-β-glucosidase prepared from yam was shown to remove the glucose at position C-26 of the furostanol glycoside structure and change it to the respective spirostanol glycoside.     

Yield and nutritional content of Pleurotus sajor caju on wheat straw supplemented with raw and detoxified mahua cake

The effect of supplementation of wheat straw (WS) with raw/detoxified mahua cake (MC) on yield and nutritional quality of Pleurotus sajor caju was studied. Raw cake significantly enhanced the yield compared to control and could be tolerated up to a 10% addition. Detoxification further improved the mushroom yield giving a maximum of 1024.7 g kg⁻¹ from WS supplemented with 20% saponin free detoxified mahua cake. Chemical analysis of fruit bodies revealed that they are rich in proteins (27.4–34.8%), soluble sugars (28.6–32.2%) and minerals. Glucose, trehalose and glutamic acid, alanine were the major sugars and amino acids detected by HPLC analysis, respectively. HPLC studies further confirmed the absence of saponins (characteristic toxins present in MC) in both fruit bodies and spent. Degradation of complex molecules in spent was monitored via FTIR. The study proved beneficial for effective management of agricultural wastes along with production of nutrient rich and saponin free fruit bodies/spent.     

Nutritional and in vitro antioxidant properties of edible wild greens in Iberian Peninsula traditional diet

Wild greens are nutritionally well-balanced vegetables. Herein, nutritional and in vitro antioxidant properties of the sprouts of three commonly used species were determined. Wild asparagus revealed the highest levels of moisture (84.6 g/100 g fw), ash (12.3 g/100 g dw), proteins (22.4 g/100 g dw), total sugars (9.24 g/100 g dw), including sucrose (4.27 g/100 g dw), and of the essential n-6 fatty acid linoleic acid (44.5%); white bryony gave the highest contents of reducing sugars, including glucose (2.97 g/100 g dw), essential n-3 fatty acid α-linolenic acid (70.3%), and the best ratios of PUFA/SFA, and n-6/n-3 fatty acids (3.59 and 0.0907, respectively); black bryony showed the highest concentrations of carbohydrates (69.3 g/100 g dw), fructose and trehalose (3.83 and 1.34 g/100 g dw, respectively). Besides their culinary characteristics, their high content in vitamins (asparagus, 135 and 142 mg/100 g dw of total tocopherols and ascorbic acid, respectively), chlorophylls (white bryony, 50.9 mg/100 g dw), carotenoids (23.3 mg/100 g dw) and phenolics (black bryony, 759 mg GAE/g extract), together with the antioxidant properties (EC₅₀ values lower than 640 μg/ml) and potential health benefits increase their importance in traditional as well as in contemporary diets.     

Comparison of the cell wall composition for flesh and skin from five different plums

Cell walls were isolated from flesh and skin of five plum varieties corresponding to three species (Prunus domestica L., Prunus salicina Lindl. and Prunus insititia Lindl.) using the alcohol-insoluble solids (AIS) procedure. Yields varied from 83 to 114 g kg⁻¹ dry weight in the flesh and from 192 to 361 g kg⁻¹ dry weight in the skins. Their main sugars were uronic acid (224–322 mg g⁻¹ AIS), cellulosic glucose (139–170 mg g⁻¹ AIS), galactose and arabinose. Galactose and arabinose ratio were variable between the varieties. The degrees of methylation were high (62–84).     

Exploration of Vanilla pompona from the Peruvian Amazon as a potential source of vanilla essence: Quantification of phenolics by HPLC-DAD

This study provides the first chemical investigation of wild-harvested fruits of Vanilla pompona ssp. grandiflora (Lindl.) Soto-Arenas developed in their natural habitat in the Peruvian Amazon. Flowers were hand-pollinated and the resulting fruits were analysed at different developmental stages using an HPLC-DAD method validated for the quantification of glucovanillin and seven other compounds. The method showed satisfactory linearity (r² > 0.9969), precision (coefficient of variation <2%), recoveries (70–100%), limit of detection (0.008–0.212 μg/ml), and limit of quantification (0.027–0.707 μg/ml). The evaluation of crude and enzyme-hydrolyzed Soxhlet-extracted samples confirmed the leading role of glucosides in fruit development. LC–ESI-MS studies corroborated the identities of four glucosides and seven aglycones, among them vanillin (5.7/100 g), 4-hydroxybenzyl alcohol (3.6/100 g), and anisyl alcohol (7.1/100 g) were found in high concentrations. The attractive flavor/aroma profile exhibited by wild V. pompona fruits supports studies focused on the development of this species as a specialty crop.     

Development of polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for sodium saccharin residue in food samples

A sensitive and specific polyclonal antibody (PcAb)-based indirect competitive enzyme-linked immunosorbent assay (icELISA) for sodium saccharin is described. 6-Amino saccharin was coupled to carrier protein for artificial antigen by diazotisation. New Zealand white rabbits were immunised to obtain anti-sodium saccharin PcAb and then icELISA was developed. The assay showed high sensitivity and specificity to sodium saccharin, with the 50% inhibition value (IC₅₀) of 0.243 μg mL⁻¹, workable range (IC₃₀–IC₇₀) of 0.050–12.8 μg mL⁻¹ and limit of detection (LOD, IC₂₀) of 0.021 μg mL⁻¹. The average recoveries of sodium saccharin in spiked food samples were estimated ranging from 70.7% to 98.8%. A statistically significant correlation of results was obtained between this new ELISA and previously established HPLC approaches with the food-relevant sodium saccharin concentration range 0–320 μg mL⁻¹ (R² = 0.9887–0.9975). These results indicated that the established ELISA was a potential and useful analytical tool for rapid determination of sodium saccharin residue in food samples.     

Quantitative analysis of allantoin and allantoic acid in yam tuber,mucilage, skin and bulbil of the Dioscorea species

Allantoin and allantoic acid in yam tubers of the D. batatas (Hualien no. 3) and D. pseudojaponica Yamamoto (Keelung) were quantitatively analyzed because the compounds were thought to prevent inflammation and ulcers in humans as well as playing an important role in the storage and translocation of nitrogen in higher plants. To expand yam tuber use, yam tuber mucilage can be used as an ingredient in functional foods and as a skin protectant. The objectives of this research are to analyze the contents of allantoin and allantoic acid in D. batatas and D. pseudojaponica Yamamoto and to compare bubble separation and centrifugation for recovering allantoin and allantoic acid from the mucilage. The total amount of allantoin and allantoic acid of the following Dioscorea (yam) in both the pulp and skin, respectively, were (mean ± RSD, mmoles/g solid): tuber of Keelung yam (D. pseudojaponica Y.) 0.370 ± 6.8%, 1.130 ± 3.4%; tuber of Hualien no. 3 yam (D. batata) 0.278 ± 7.8%, 0.714 ± 9.1%; bulbil of Hualien no. 3 yam (D. batata) 0.179 ± 7.9%, 0.297 ± 3.4%. The Keelung yam was much higher in allantoin and allantoic acid content than the Hualien no. 3. The skin of yam tuber is rich in allantoin and allantoic acid. The allantoin and allantoic acid content is 305% (in Keelung yam) and 257% (in Hualien no. 3) higher than that of the pulp. Bubble separation is an appropriate procedure in the practice for maximum recovery of allantoin and allantoic acid in yams. It was found that 80% of allantoin and allantoic acid yield can be recovered from the low starch contents of mucilage of the Keelung yam using bubble separation.     

Chemical compositions and enzyme activity changes occurring in yam (Dioscorea alata L.) tubers during growth

The purpose of this study was to establish the chemical compositions, enzyme activity and nutritional values of four cultivars of yam tubers at different stages of their maturation, and compare such levels during yam growth. The results have indicated that yam tubers featured a reasonably substantial content of protein when compared with other root and tuber crops, the protein content being of the order of 10.4-13.0 g/100 g (dry basis (db)) at time of harvest (day 260 post-emergence). Starch content of the four yam tubers increased as growth progressed and remained in the range of 70.5-85.3 g/100 g (db) during their growth period. The activity of yam-contained polyphenol oxidase (PPO) decreased remarkably over the early period of harvest (day 155-225 post-emergence), and subsequently decreased only slightly as growth progressed to harvest for all tested species of yam with the exception of CH yam tubers. Contrasting this, however, the activity of α-amylase increased significantly over the growth period for all cultivars, and dioscorin content of yam tuber also increased as growth progressed for all cultivars. All yam cultivars contained remarkably substantial amounts of essential amino acids, all of which were superior to the FAO reference pattern for such amino acids except for sulfur-containing amino acids and lysine contents.     

Polyphenol and glycoalkaloid contents in potato cultivars grown in Luxembourg

The polyphenol (phenolic acids, flavanols and flavonols) and glycoalkaloid (α-chaconine and α-solanine) contents of potato tubers grown in Luxembourg were analyzed by UPLC–DAD and HPLC–MS/MS separately in peel (approx. 2 mm), outer (approx. 1 cm) and inner flesh. Polyphenol contents decreased from the peel via the outer to the inner flesh and differed among the cultivars. The cultivars Vitelotte and Luminella had the highest polyphenol contents (5202 and 572 μg/g dry weight (DW) in the outer flesh), whereas Charlotte and Bintje had the lowest contents (19.5 and 48.0 μg/g DW). Chlorogenic acid and its isomers (neo- and cryptochlorogenic acid) were the major polyphenols. Glycoalkaloid contents were highest in the peel and lowest in the inner flesh, values in the flesh were below guideline limits in all cultivars. In conclusion, potatoes contribute to the daily intake of polyphenols and their consumption, thereby, may have positive effects on health.     

Rapid quantitation of curcumin in turmeric via NMR and LC–tandem mass spectrometry

A rapid, sensitive and accurate ¹H NMR method has been developed for the quantitation of curcumin isolated from Curcuma longa rhizome (turmeric) extract, the results of which were compared with a validated LC–MS/MS method. The relative standard deviations of the methods were found to be 2.49% and 3.48% for the ¹H NMR and LC–MS/MS methods, respectively. The correlation coefficients were 0.998 for ¹H NMR and 0.995 for LC–MS/MS assay in the calibration range. The recoveries at 5 mg mL⁻¹ and 50 μg mL⁻¹ concentrations averaged to 99–101% for both techniques, respectively. The uncertainty of the measurement of curcumin via ¹H NMR spectroscopy was determined to be 5.80% while in LC–ESI-MS/MS method was 7.38%.     

Effect of canned tuna fish processing steps on lead and cadmium contents of Iranian tuna fish

The contents of Pb and Cd in two species of Iranian tuna fish (yellowfin and skipjack), which were caught from the Persian Gulf and Oman Sea, and the effects of canning processing steps on their contents were assessed by electrothermal atomic absorption spectrometry. The results revealed that the levels of lead and cadmium throughout the processing steps in yellowfin were in range of 0.154 ± 0.019–0.441 ± 0.025 μg/g and 0.029 ± 0.002–0.084 ± 0.0005 μg/g, respectively. Pb and Cd concentrations from received fish to final product in skipjack were found to be in range of 0.072 ± 0.031–0.218 ± 0.031 μg/g and 0.016 ± 0.001–0.062 ± 0.002 μg/g, respectively. The limit of detection for lead and cadmium were 0.058 μg/g (11.6022 μg/l) and 0.0007 μg/g (0.1485 μg/l), respectively. Results from paired sample t-test analysis showed that defrosting, cooking, and sterilisation by autoclave would reduce the contents of lead and cadmium, considerably.     

Monitoring and risk assessment of pesticide residues in yuza fruits (Citrus junos Sieb. ex Tanaka) and yuza tea samples produced in Korea

The objective of this study was to establish an analytical method to measure pesticides used to cultivate yuza (Citrus junos Sieb. ex Tanaka) and to analyze pesticide residue levels of yuza and yuza tea samples. Risk assessments were also performed by calculating estimated daily intake (EDI) and acceptable daily intake (ADI). An excellent linear correlation was achieved with coefficient correlation values of 0.9750–0.9999. Percent recoveries were 80.4–109.9% for most pesticides with a <6.9% relative standard deviation (RSD). The limits of quantification for the method were 0.10–0.67 μg/ml. The RSD of intra-day and inter-day variability was <15.3%. Seven pesticides in yuza (n = 80) and yuza tea (n = 75) were analyzed with the optimized analytical method. Acequinocyl, spirodiclofen and carbendazim were detected in yuza samples in the concentration range of 0.07–0.15 μg/g, 0.11–1.89 μg/g, and 0.03–5.15 μg /g, respectively, whereas chlorpyrifos, prothiofos, phosalone, and deltamethrin were not detected in yuza or yuza tea. The concentrations of acequinocyl, spirodiclofen and carbendazim ranged from 0.18–1.05 μg/g, 0.13–0.29 μg/g, and 0.17–2.36 μg/g, respectively, in yuza tea samples. The percent ratios of EDI to ADI for acequinocyl, spirodiclofen, and carbendazim were 24.6%, 22.7%, and 58.5%, respectively.     

Chemical composition of cultivated seaweed Ulva clathrata (Roth) C. Agardh

Samples of cultivated Ulva clathrata were collected from a medium scale system (MSS, 1.5 × 1.5 m tank), or from a large scale system (LSS, 0.8 ha earthen pond). MSS samples were dried directly while the LSS sample was washed in freshwater and pressed before drying. Crude protein content ranged 20–26%, essential amino acids accounting for 32–36% of crude protein. The main analysed monosaccharides were rhamnose (36–40%), uronic acids (27–29%), xylose (10–13%) and glucose (10–16%). Some notable variations between MSS and LSS samples were observed for total dietary fibre (26% vs 41%), saturated fatty acids (31% vs 51%), PUFAS (33% vs 13%), carotenoids (358 vs 169 mg kg⁻¹ dw) and for Ca (9 vs 19 g kg⁻¹), Fe (0.6 vs 4.2 g kg⁻¹), Cu (44 vs 14 mg kg⁻¹), Zn (93 vs 17 mg kg⁻¹) and As (2 vs 9 mg kg⁻¹). The chemical composition of U. clathrata indicates that it has a good potential for its use in human and animal food.     

Development of a simple capillary electrophoretic determination of glucosamine in nutritional supplements using in-capillary derivatisation with o-phthalaldehyde

A simple capillary electrophoretic method was developed for the determination of glucosamine using in-capillary derivatisation. Glucosamine in commercial products was extracted with purified water. The CE separation was achieved on an uncoated fused-silica capillary using a 20 mM borate buffer (pH 9.2) containing 5 mM o-phthalaldehyde (OPA) and 5 mM 3-mercaptopropionic acid (MPA) at 25 kV, followed by UV detection at 340 nm. The detector response was linear (r² > 0.999) in the concentration range 10–1000 μg/mL. The limit of detection (LOD) was 1.3 mg/g. Spiked glucosamine recoveries at 50 and 100 mg/g level were 95.1% and 104.3%, respectively. The method was applied to 16 commercial products. The concentrations of glucosamine were 109–705 mg/g, and the ratios of detected glucosamine content to the labelled value were 88.8–124%. No significant bias was observed (r² = 0.989, p < 0.01), between results obtained by the proposed CE method and an official colorimetric method (Japanese Health Food & Nutrition Food Association).     

Tocol and β-glucan levels in barley varieties and in pearling by-products

In order to verify a different genotype potential in barley varieties, in terms of tocols and β-glucans, and to demonstrate that pearling by-products have interesting amounts of these bioactive compounds, their content was investigated in 36 barley varieties and in the pearling by-products of a commercial hulled barley stock. The β-glucan content ranged from 2.64 g/100 g dw (dry weight) for Vanessa to 8.05 g/100 g dw for Ludine, with an average value of 3.95 g/100 g dw and 50% of the compounds were in the range between 3.45 and 4.36 g/100 g dw. The total tocol amount ranged from 50.3 mg/kg dw (Ladoga) to 88.6 mg/kg dw (Maggiodoro), with a mean value of 69.1 mg/kg dw and with most genotypes (50%) having a content between 62 and 75 mg/kg dw. Adagio and Sabel were the best source of vitamin E activity, expressed as Tocopherol Equivalents. In the pearling by-products there was no enrichment of β-glucans, on the contrary, a seven and a fivefold increase was observed for tocopherols and tocotrienols, respectively.     

Simultaneous quantification of selected compounds from Salvia herbs by HPLC method and their application

A simple and reliable reversed-phase high performance liquid chromatographic method was developed and validated for simultaneous determination of danshensu, protocatechuic aldehyde, rosemarinic acid, salvianolic acid B, dihydrotanshinone I, tanshinone I, cryptotanshinone and tanshinone IIA in Salvia herbs. The contents of these eight main components were compared between Salvia miltiorrhiza Bunge and Salvia przewalskii Maxim, which were used for treating coronary heart diseases, cerebrovascular disease, bone loss, hepatitis, hepatocirrhosis and chronic renal failure. The samples were successfully separated by the HPLC method. All the standard compounds showed a good linearity (R² > 0.9994) in the relatively wide concentration range. The limit of detection of the eight compounds was in the range of 0.05–0.5 μg/ml and the limit of quantification was in the range of 0.25–1.50 μg/ml. The intra-day variability was in the range of 0.03–8.08% and the inter-day variability was in the range of 0.18–12.36%. The recoveries of the selected compounds were in the range of 96.2–108.1%. This method was accurate, precise and reproducible, and could be successfully applied to the quality control and stable experiment for the preparations consisted of these active components, and the content comparison of the herbs from Salvia species.     

Quantification of polyphenols and ergothioneine in cultivated mushrooms and correlation to total antioxidant capacity

Agaricus bisporus, Lentinula edodes, Pleurotus ostreatus, Pleurotus eryngii and Grifola frondosa were analyzed for antioxidant capacity, as measured by oxygen radical absorbance capacity (lipophilic and hydrophilic) (ORAC_total), hydroxyl radical averting capacity (HORAC), peroxynitrite radical averting capacity (NORAC), superoxide radical averting capacity (SORAC) assays, Folin-Ciocalteu reagent and ergothioneine (ERG) content. ORAC_totalvalues ranged from 39 to 138 μmol of Trolox equivalents (TE)/g dry weight (dw). HORAC values ranged from 3.0 to 13.6 μmol of caffeic acid equivalents/g dw. NORAC values ranged from 2.0 to 9.0 μmol TE/g dw. SORAC values ranged from 0.37 to 2.6 kunit superoxide dismutate equivalents/g dw. Polyphenols ranged from 4.2 to 10.6 mg gallic acid equivalents/g dw. A. bisporus mushrooms, especially portabellas, had higher antioxidant capacity relative to the specialty mushrooms tested. ERG ranged from 0.21–2.6 mg/g dw with L. edodes, P. ostreatus, G. frondosa containing a statistically significant greater amount compared to A. bisporus. A good correlation was found between ORAC_total and polyphenols (R² = 0.86).     

Validation of a headspace solid-phase microextraction procedure with gas chromatography-electron capture detection of pesticide residues in fruits and vegetables

Headspace solid-phase microextraction (HS-SPME) was evaluated for the determination of pesticide residues in fruits and vegetables by gas chromatography with an electron capture detector (GC-ECD). The fibre used was coated with polydimethylsiloxane (100 μm thickness) and the analytical conditions employed have been developed and optimised in a previous work [Chai, M. K., Tan, G. H., & Asha, L. (2008). Optimisation of headspace solid-phase microextraction for the determination of pesticide residues in vegetables and fruits. Analytical Sciences, 24 (2), 273–276]. The results show that the HS-SPME procedure gave a better linear range, accuracy, precision, detection and quantification limits and is adequate for analysing pesticide residues in fruits and vegetables. The average recoveries obtained for each pesticide ranged between 71% and 98% at three fortification levels with the relative standard deviation of less than 5%. Repeatability (0.3–3.7%) and intermediate precision (0.8–2.5%) were shown to be satisfactory. The limits of detection (0.01–1 μg L⁻¹) and the limits of quantification (0.05–5 μg L⁻¹) of these pesticides were much lower than the maximum residue levels (MRL), allowed for fruits and vegetables in Malaysia.