Evaluating the Effects of Acetic Acid and d-Limonene on Four Aquatic Plants

The foundation of most aquatic weed management programs in Florida is synthetic herbicides because many of these U.S. Environmental Protection Agency (USEPA)-registered products are effective, selective, and inexpensive compared with other strategies such as mechanical harvesting. However, stakeholders have expressed concern regarding their use and managers are interested in exploring alternative methods for aquatic weed control. To that end, we evaluated the efficacy, selectivity, and costs of the “natural” products acetic acid and d-limonene (alone and in combination with each other and citric acid) on the invasive floating plants waterhyacinth (Eichhornia crassipes) and waterlettuce (Pistia stratiotes), and the native emergent plants broadleaf sagittaria (Sagittaria latifolia) and pickerelweed (Pontederia cordata). These products, plus an industry-standard synthetic herbicide (diquat dibromide), were applied once as foliar treatments to healthy plants, which were grown out for 8 weeks after treatment to allow development of phytotoxicity symptoms. A 0.22% concentration of diquat dibromide eliminated all vegetation, but neither “natural” product alone provided acceptable (>80%) control of floating weeds, even when applied at the maximum concentrations under evaluation (20% acetic acid, 30% d-limonene). Citric acid (5% or 10%) had no effect on the activity of acetic acid or d-limonene, but some combinations of acetic acid and d-limonene controlled floating weeds effectively without causing unacceptable damage to native plants. However, these treatments are much more expensive than the synthetic standard and managers would realize a 22- to 26-fold increase in product cost alone without factoring in other expenses such as additional labor and application time. Combinations of acetic acid and d-limonene may have utility in some areas where the use of synthetic herbicides is discouraged, but broad-scale deployment of this strategy would likely be prohibitively expensive.

In-vitro evaluation of antioxidant and antiradical potential of successive extracts, semi-purified fractions and biosynthesized silver nanoparticles of Rumex vesicarius

The aim of the present study was to assess in vitro the antiradical and antioxidant activities of successive extracts and semi-purified fractions from Rumex vesicarius L. In the present work, three extracts (n-Hexane, ethyl acetate and methanol) and 22 column fractions of methanolic extract (as promising extract) were evaluated against 2,2-diphenyl- 1-picrylhydrazyl (DPPH•) and 2,2-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) radical scavenging methods as antiradical and antioxidant activities compared with Butylated hydroxytoluene (BHT) as synthetic standard and silver nanoparticles of methanolic extract (Ag-NPs-Me), in addition to analysis of chemical constituents of extract and fraction using Gas chromatography–mass spectrometry (GC-MS). The obtained results revealed that, both methods go parallel showing that the concentration of extract and incubation time are dependent and proportional with phenolic compounds concentration. Absolute methanol extract recorded the highest antioxidant activity when compared with the other crude extracts with 79.3 and 78.8% against DPPH and ABTS respectively when compared with BHT as synthetic standard (89.4 and 89.9%) against DPPH and ABTS respectively. Calculation of the antiradical activity units showed the highest values of methanolic extract and its promising fraction (No. 12) after 300 seconds (5 minutes) comparing with antioxidant activity (30 min). Also, the antioxidant activity increased with synthetic Ag-NPs-Me when compared with methanolic extract by (IC50= 53.9 and 74.6 µg/ml respectively). Thus, the GC-MS analysis of successive extracts of R. vesicarius L showed a highly complex profile, containing approximately 24 different components. One pure compound was identified from fraction No. 12. The identified compound was l-(+)- ascorbic acid 2, 6-dihexadecanoate. The data also revealed presence of closely similar antioxidant activities in methanolic extract or its pure compounds with BHT when mixed at different proportions. From the obtained results it could be concluded that R. vesicarius methanolic extracts and fractions can be extensively used in the production of potential antioxidant, antiradical and AgNPs-Me for biomedical application on the consumer’s health.

PHYTOCHEMICAL SCREENING AND ANTIOXIDANT POTENTIAL OF PTEROCARPUS SANTALINUS L.F. PLANT PARTS

Objective: Oxidation is a normal process in many biological metabolisms in living beings, but in this technology era radiation, pollution, irregular life style, and unhealthy diet leads to excessive oxidation resulting in imbalance between antioxidants and free radicals in body called oxidative stress, which may result in cardiac problems, diabetes, and carcinogenic diseases. Therefore, exploration of natural antioxidants in flora and fauna is becoming important. In this motive a phytochemical study was taken up on various parts of Pterocarpus santalinus L.f. plant belonging to Leguminosae family to check the presence of antioxidant activity (AA). Methods: The leaves, flowers, fruits, and roots of this plant were extracted with six different organic solvents from polar to non-polar. To estimate the AA of these extracts, four types of antioxidant tests were done on them, namely, α, α – Diphenyl – β – Picryl - Hydrazyl free radical scavenging activity (DPPH RSA) assay, relative reducing power (RRP) assay, Ferric thiocyanate (FTC) assay, and β - carotene bleaching assay with Butylated Hydroxy Toluene (BHT) as synthetic standard. Results: In extraction, Me extracts showed highest yields. Qualitative phytochemical screening has revealed many bioactive components in the Me and Et extracts of plant parts majorly. In DPPH RSA assay, Me extracts of leaves showed RSA activity almost equal to reference standard. In RRP assay, Me floral extracts showed AA higher than standard. FTC and β – Carotene assays showed that Me sample extracts possess good AA than BHT. In FTC assay, lower absorption values specify high AA, whereas in β – Carotene assay, high absorption values indicate high AA of the sample extracts. Conclusion: Among six solvents methanol showed highest extraction efficiency and also revealed highest number of phytochemicals in its extracts. These four AA assays revealed that the methanol extracts of all plant parts, that is., leaves, roots, fruits, and flowers possess better AA compared other solvent extracts.

5,7,3ʹ,4ʹ-Tetrahydroxyflav-2-en-3-ol 3-O-glucoside, a new biosynthetic precursor of cyanidin 3-O-glucoside in the seed coat of black soybean, Glycine max

The seed coat of mature black soybean, Glycine max, accumulates a high amount of cyanidin 3-O-glucoside (Cy3G), which is the most abundant anthocyanin in nature. In the pod, it takes two months for the seed coat color change from green to black. However, immature green beans rapidly adopt a black color within one day when the shell is removed. We analyzed the components involved in the color change of the seed coat and detected a new precursor of Cy3G, namely 5,7,3ʹ,4ʹ-tetrahydroxyflav-2-en-3-ol 3-O-glucoside (2F3G). Through quantitative analysis using purified and synthetic standard compounds, it was clarified that during this rapid color change, an increase in the Cy3G content was observed along with the corresponding decrease in the 2F3G content. Chemical conversion from 2F3G to Cy3G at pH 5 with air and ferrous ion was observed. Our findings allowed us to propose a new biosynthetic pathway of Cy3G via a colorless glucosylated compound, 2F3G, which was oxidized to give Cy3G.

Establishing adequate conditions for mercury determination in environmental samples by INAA

Mercury (Hg) is a toxic element released into the environment mainly by anthropic activities. Consequently, the improvement for Hg determination in environmental samples is of great interest. Instrumental Neutron Activation Analysis (INAA) is considered an adequate method to determine several elements. However, Hg determination by INAA is often hampered by its volatility, which causes losses. The aim of this study was to establish adequate irradiation conditions for Hg determination in environmental samples by INAA. The following parameters were evaluated: irradiation time, container for irradiation and spectral gamma ray interferences. For the study, aliquots of certified reference materials (CRMs) and tree bark samples were irradiated together with Hg synthetic standard at the IEA-R1 nuclear research reactor. Gamma ray activities of 197Hg and 203Hg were measured in a spectrometer coupled to a HGe detector. Obtained results indicated that polyethylene capsules or envelopes can be used as container for sample irradiation and the Hg impurities in these containers were negligible. Irradiation time of one hour was adequate for Hg determination and in long irradiations of 8 h problems of spectral interference of 198Au and 75Se were observed. In addition, Hg loss during the irradiation of 1 h and after irradiation was not observed. Quality control of Hg results, obtained in the CRMs analyses using one hour of irradiation, indicated good precision and accuracy with HORRAT < 2 and |Z score| < 2. The experimental conditions established in this study were applied to tree bark samples. Detection limits in these analyses were between 0.14 and 1.9 µg g-1.

Evaluation of Measurement Uncertainty for the Determination of MgO in Magnesia Refractories by XRF

The method of X-ray fluorescence spectrometry (XRF) for the determination of MgO in magnesia refractories was introduced. The uncertainty of the MgO in refractory materials was analyzed by melting method of XRF. The measurement uncertainty was evaluated, and the related mathematical models was established. The uncertainty of synthetic standard was calculated by the evaluation of the uncertainty of each component standard. And eventually converted to the measurement results to expand the uncertainty. The effects of two melting methods on the uncertainty of magnesium oxide content were compared.

Antimicrobial activity of three medicinal plants against acne-inducing bacteria Propionibacterium acnes

The antimicrobial activities of three medicinal plants (Senna alata L., Azadirachta indica A. Juss, and Aloe vera (L.) Burm.f.) against pimples causing bacterium Propionibacterium acnes was studied using disc diffusion method. Extracts from each plant were used on the bacterium at three different dosage concentrations (0.1 mL, 0.15 mL and 0.2 mL). Their Zone of inhibition was measured in millimeter (mm) and compared against a known synthetic standard (Gentamycin). Results indicate that the plants differ significantly in their activity against the studied microorganism. S. alata had the highest inhibitory effect of all the plants used (26.00 mm, 30.67 mm and 36.00 mm, for 0.1 mL, 0.15 mL and 0.2 mL dosage concentration, respectively). This was followed by A. indica with 9.33 mm, 15.67 mm and 16.67 mm zone of inhibition for 0.1 mL, 0.15 mL and 0.2 mL dosage concentration, respectively. A. vera had no effect (0.0 mm zone of inhibition) at 0.1 mL and 0.15 mL dosage concentrations, but at 2.0 mL dosage concentration, 4.0 mm zone of inhibition was achieved. Gentamycin showed zones of inhibition of 17.33 mm, 26.67 mm and 22.67 mm, for 0.1 mL, 0.15 mL and 0.2 mL dosage concentration, respectively. A comparison of all result obtained from the three plant extracts and gentamycin shows that S. alata have a significantly higher (p > 0.05) inhibitory effect against the pimples causing bacterium; Propionibacterium acnes than all the other treatments. The trend follows S. alata > Gentamycin > A. indica > A. vera, respectively, in terms of their inhibitory effect. Therefore, S. alata is more active and is the most appropriate plant to be used for treating of acne vulgaris among the three plant species selected for this experiment.

Risk Premia and the VIX Term Structure

The shape of the Chicago Board Options Exchange Volatility Index (VIX) term structure conveys information about the price of variance risk rather than expected changes in the VIX, a rejection of the expectations hypothesis. The second principal component, SLOPE, summarizes nearly all this information, predicting the excess returns of synthetic Standard & Poor’s (S&P) 500 variance swaps, VIX futures, and S&P 500 straddles for all maturities and to the exclusion of the rest of the term structure. SLOPE’s predictability is incremental to other proxies for the conditional variance risk premia, economically significant, and inconsistent with standard asset pricing models.