Multivalent carboxylic acids to modify the properties of zein

Methods must be developed to improve both the processability and physical properties of zein-based articles. Typical plasticizing agents that improve processability have a negative impact on physical properties at elevated humidities. Continued efforts must be employed to discover improved plasticizers. Carboxylic acids having more than one carboxylic acid moiety have been evaluated in zein melt formulations produced in a torque rheometer. These reagents were effective plasticizers for zein, lowering zein viscosity, and delaying the onset of rapid viscosity increase. These reagents altered viscosity differently than the traditional plasticizers such as triethylene glycol. These additives also lowered the tensile strength (TS) of zein formulations at 50% RH. Surprisingly, TS at 70% RH was higher than that at 50% RH at elevated levels of these additives. NMR analysis of Soxhlet extracted samples showed that these multivalent carboxylic acids do not cross-link the zein under the reaction conditions employed.     

Response of cucurbit rootstocks to Pythium aphanidermatum

Damping-off and vine decline diseases affect most greenhouse cucumber crops in Oman, with losses frequently exceeding 25% of seedlings and adult plants. As a consequence of some recent reports that disease control using metalaxyl fungicides were ineffective, seven local and introduced rootstocks were assessed for their response to Pythium aphanidermatum. The rootstocks were also tested for grafting compatibility and production potential under greenhouse conditions. During artificial inoculation trials, no damping-off symptoms were observed in the Hercules and Titan varieties, ridge gourd or sponge gourd. In three separate greenhouse trials, Titan, Hercules and squash var. Magda showed no damping-off or vine decline symptoms up to 45 days after transplanting. When cucumber was grafted onto the seven rootstocks, no symptoms were observed in the cucumber plants grafted onto Titan and Hercules rootstocks, whereas the cucumber grafted onto the other rootstocks showed varying levels of damping-off and vine decline diseases (10–40%). The Titan and Hercules rootstocks significantly increased the vegetative growth and the fruit number, weight and length compared to the self-grafted cucumbers, non-grafted cucumbers and cucumbers that were grafted onto the other rootstocks (P < 0.05). To the best of our knowledge, this study is the first to examine the influence of grafting on the resistance to Pythium and on the vegetative growth and yield of greenhouse cucumbers.     

Alkyl and phenolic glycosides from Saussurea stella

One alkyl glycoside, saussurostelloside A (1), two phenolic glycosides, saussurostellosides B1 (2) and B2 (3), and 27 known compounds, including eleven flavonoids, seven phenolics, six lignans, one neolignan, one phenethyl glucoside and one fatty acid, were isolated from an ethanol extract of Saussurea stella (Asteraceae). Their structures were elucidated by NMR, MS, UV, and IR spectroscopic analysis. Of the known compounds, (+)-medioresinol-di-O-β-d-glucoside (7), picraquassioside C (10), and diosmetin-3′-O-β-d-glucoside (27) were isolated from the Asteraceae family for the first time, while (+)-pinoresinol-di-O-β-d-glucoside (6), di-O-methylcrenatin (11), protocatechuic acid (14), 1,5-di-O-caffeoylquinic acid (17), formononetin (28), and phenethyl glucoside (29) were isolated from the Saussurea genus for the first time. The anti-inflammatory activities of three new compounds (1–3), five lignans ((−)-arctiin (4), (+)-pinoresinol-4-O-β-d-glucoside (5), (+)-pinoresinol-di-O-β-d-glucoside (6), (+)-medioresinol-di-O-β-d-glucoside (7) and (+)-syringaresinol-4-O-β-d-glucoside (8)), one neolignan (picraquassioside C (10)), and one phenolic glycoside (di-O-methylcrenatin (11)) were evaluated by testing their inhibition of the release of β-glucuronidase from PAF-stimulated neutrophils. Only compound 5 showed moderate inhibition of the release of β-glucuronidase, with an inhibition ratio of 39.1%.     

Effect of solution pH of cysteine-based pre-treatments to prevent browning of fresh-cut artichokes

Fresh-cut artichokes were treated with cysteine in the form of aqueous solutions of l-cysteine hydrochloride monohydrate at 0.5% (w/v) normal pH 2.2 adjusted to different pH values with NaOH (from 2 to 7). General appearance and colour measurements during storage at 5 °C showed different degrees of suppression of darkening on cut surfaces. Cysteine pre-treatments caused an increase in the yellow index (b* value) of fresh-cut artichokes compared to untreated samples, which was more pronounced at lower pH (47.9 versus the initial value of 28.3 after 1 day). Artichokes treated at lower pH values also had a lower appearance score and higher PPO activity than artichokes treated at higher values, closer to neutrality. Starting from 3 days of storage a negative correlation between solution pH and PPO activity was also observed, that for artichokes treated with cysteine at pH 7 was lower than for control samples. l-cysteine pre-treatments did not affect total phenolic content and antioxidant activity of fresh-cut artichokes, which showed an increasing pattern after 8 days. These data may represent an important step in prevention of browning in fresh-cut artichokes.     

The impact of simultaneous intoxication with agrochemicals on the antioxidant defense system in rat

It is known that the presence of pesticides may alter the reproductive performance of animals. We studied the effect of chronic pesticide exposure in rats injected i.p. for 5 weeks with doses between 1/50 and 1/250 LD50 of dimethoate, glyphosate and zineb, either alone or in combination. All tested agrochemicals increased the oxidative stress status in the plasma, liver, and testes, and also modified hormonal parameters involved in reproductive function. The increase in oxidative stress and damage biomarker levels, as well as the alteration of the antioxidant defence system decreased testosterone, FSH and LH levels in the plasma of pesticide-treated rats. These effects were more pronounced when pesticides were administered in combination, and should be considered indicative of involuntary exposure to residual agrochemicals.     

The competitive ability of different chickpea (Cicer arietinum) genotypes against Polygonum aviculare under field conditions

Polygonum aviculare L. is a troublesome weed in chickpea cultivated in the Mediterranean environment of Central Italy. A 2-year field study was carried out to evaluate the competitive ability and the yield response of different chickpea genotypes against P. aviculare. Experimental treatments consisted in six chickpea genotypes (Alto Lazio, C1017, C133, C134, C6150 stable lines and cultivar Sultano) cultivated in weed-free conditions and with P. aviculare at four densities (4, 8, 16, 32 plants m⁻²). The competitive ability of chickpea against P. aviculare was assessed on the basis of (i) the relative biomass total (RBT); (ii) the competitive balance index (Cb), and (iii) the competitive index (CI). The chickpea seed yield in weed-free conditions ranged from 2.6 to 2.1 t ha⁻¹ of DM and was higher in C6150 and Sultano. P. aviculare caused an average chickpea seed yield loss of 14, 46, 74 and 88% at the density of 4, 8, 16, 32 plants m⁻² compared to the weed-free crop. The relationship between the P. aviculare density and the percentage of chickpea yield loss was described by the rectangular hyperbola model with the asymptote constrained to 100% maximum yield loss. The estimated coefficient I (yield loss per unit density as density approaches zero) was lower in C133, Sultano, and C1017. RBT was higher than 1 in all chickpea genotypes at 4 plants m⁻² of P. aviculare, while at higher P. aviculare densities it was similar to 1 suggesting that there is no resource use complementarity between chickpea and the weed. Generally, at the density of 50 plants m⁻² the chickpea crop was more competitive than P. aviculare at 4 plants m⁻² (Cb > 0), equally competitive at 8 plants m⁻² (Cb = 0), and less competitive at 16 and 32 plants m⁻² (Cb < 0). No chickpea genotype achieved the objective of combining a high seed yield potential and a great competitive ability against P. aviculare. C6150 and Sultano had a high seed yield production in weed-free conditions, but they were poorly competitive against P. aviculare at intermediate and high weed infestation, while C1017 showed a satisfactory level of Cb and CI at all P. aviculare densities although its seed yield was the lowest in weed-free conditions. However, the results suggest that, from an agronomical point of view, P. aviculare plant density should be less than 4 plant m⁻² in order to prevent severe chickpea seed yield loss in field conditions.     

Quinolone alkaloids with antibacterial and cytotoxic activities from the fruits of Evodia rutaecarpa

Five new quinolone alkaloids, euocarpines A–E (16–20), four new natural products (1, 4, 12, and 14), and eleven known natural products were isolated from the fruits of Evodia rutaecarpa (Juss.) Benth. The structures of the new compounds were elucidated based on spectroscopic evidence. All compounds were evaluated for their antibacterial activity against three strains and for their cytotoxic activity against four human tumor cell lines. The results revealed that 5, 7–11, 13, 14, and 16–20 exhibited moderate antibacterial activities (MIC values: 4–128 μg/mL), and 9, 11, 14, and 17 exhibited moderate cytotoxic activities against HepG-2, Hela, BEL7402, and BEL7403 (IC₅₀ values: 15.85–56.36 μM).     

3, 4-seco-Labdane diterpenoids from the leaves of Callicarpa nudiflora and their inhibitory effects on nitric oxide production

As a part of our ongoing search for bioactive compounds from the leaves of Callicarpa nudiflora that inhibit nitric oxide (NO) production, the 90% EtOH fraction eluted by macroporous resin adsorption was found to show significant inhibitory activity against the production of NO in RAW 264.7 stimulated by lipopolysaccharide (LPS). Bioactivity-guided isolation of the fraction yielded three new bioactive diterpenoids, named ent-3, 4-seco-14-carbonyl-15, 16-epoxy-4(18), 8(17), 13(14)-labdatrien-3-oic acid (1), syn-3, 4-seco-12R-hydroxy-15, 16-epoxy-4(18), 8(17), 13(16), 14(15)-labdatetraen-3-oic acid (2) and syn-3, 4-seco-12S-hydroxy-15, 16-epoxy-4(18), 8(17), 13(16), 14(15)-labdatetraen-3-oic acid (3). Their structures and configurations were elucidated by comprehensive spectroscopic analysis. All the three compounds exhibited potent inhibitory activity on NO production in LPS-activated RAW 264.7 macrophage cells.     

Chemical characteristics and influences of two fractions of Chinese lignite humic acids on urease

Soil urease is crucial for the nitrogen cycle and its association with humic acids (HAs) is a fundamental requirement for its stability. In this work, the chemical characteristic of two HA fractions (HA1, ≥50 kDa; HA2, 10–50 kDa) extracted from lignite was evaluated, and their effects on the activity and stability of Jack Bean urease were also studied. HA1 and HA2 exhibited different structural properties in the micro-FT-IR and ¹³C NMR spectra and influences on urease stability during 12 days of incubation: HA1 stabilized the urease activity. After 12 days, the residual activity of urease, at pH 6.0, 7.0 and 8.0, was 2.1, 2.6 and 3.9 times higher in the treatment of HA1-urease than in the free urease, respectively. With pH values increasing, the stability of free urease decreased and that of HA1-urease increased, which indicated that HA1 improved the stability of urease in the solution, especially at the alkaline condition.