ARTICLE | doi:10.20944/preprints202008.0077.v1
Subject: Chemistry, Medicinal Chemistry Keywords: anti-oxidant activity; anti-oxidant enzymes, anti-proliferative activity; maslinic acid; melanoma; Olea europaea; ROS levels
Online: 4 August 2020 (04:57:13 CEST)
Maslinic acid (MA) is a natural triterpene from Olea europaea whose pharmacological functions have been showed. The objective of this study was to examine MA effect on cell viability (by MTT assay), reactive oxygen species (ROS levels, by flow cytometry) and key anti-oxidant enzyme activities (by spectrophotometry) in murine skin melanoma (B16F10) cells compared to healthy cells (A10). MA induced cytotoxic effects in cancer cells (IC50 42 µM) whereas no effect was found in A10 cells treated with MA (up to 210 µM). In order to produce a stress situation in cells, 0.15 mM of H2O2 were added. Under stressful conditions, MA protected both cell lines against oxidative damage, decreasing intracellular ROS, being higher in B16F10 than in A10 cells. The treatment with H2O2 and without MA produced different responses in anti-oxidant enzymes activities depending on cell line. In A10 cells, all enzymes were up-regulated, but in B16F10 cells only superoxide dismutase, glutathione S-transferase and glutathione peroxidase increased their activities. MA restored the enzyme activities to similar levels than control group in both cell lines, highlighting that in A10 cells the highest MA doses induced values lower than control. Overall, these findings demonstrate the great anti-oxidant capacity of MA.
ARTICLE | doi:10.20944/preprints202202.0195.v1
Subject: Chemistry, Applied Chemistry Keywords: olea europaea; olive stone; agro-waste; slow pyrolysis; bimetallic nano-alloys; catalyzed dye degradation; Trash-to-Treasure
Online: 16 February 2022 (06:41:46 CET)
Biochar is a carbon allotrope obtained by pyrolysis of biomass, usually agro-waste. Owing to the demand for sustainable development, biochar is continuously raising much hope in the scientific community. However, in order to impart it with new properties, its modification is required, either in situ during pyrolysis, or after the carbonization process. Herein, we propose a new direct approach to obtain bimetallic copper/nickel nanoparticle-loaded on olive stone biochar. The bimetallic-coated biochar and the reference materials bare biochar, copper-loaded and nickel-loaded biochar were prepared at 400 °C under a stream of dinitrogen from olive pit powder particles impregnated first with citric acid (CA), and then with copper and nickel nitrates. We have employed citric acid in the process in order to check its effect on the structural and textural properties of biochar supporting the metallic nanoparticles. Surprisingly, citric acid induced the formation of agglomerated or even raspberry-shaped, bimetallic copper/nickel nanoparticles. Large 450-500 nm-sized agglomerates of ~80 nm bimetallic CuNi NPs were noted for B-CA@CuNi. Interestingly, for biochar material prepared with initial Cu/Ni=10 molar ratio (B-CA@CuNi10/1), the bimetallic NPs formed unusual nano-raspberries (1748 nm in size) which are agglomerates of individual 10-20 nm-sized CuNi10/1 nanoparticles. The B-CA@CuNi and reference materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and magnetometry. The B-CA@CuNi and B-CA@Ni materials could be attracted efficiently with a magnet, but not B-CA@CuNi10/1 due to a low nickel loading. B-CA@CuNi was tested as a catalyst for the degradation of methyl orange (MO). Discoloration was noted within 10 min, much faster than a similar material prepared in the absence of CA. B-CA@CuNi could be recycled at least 3 times with exhibit as fast discoloration catalysis performance. This paper stresses the important role of citric acid in shaping the bimetallic nanoparticles loaded in situ on biochar during the slow pyrolysis process and to enable faster catalysed discoloration of organic dye solution.
ARTICLE | doi:10.20944/preprints202201.0308.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Olive pruning; compost; recycling; Capsicum annuum L.; soil organic carbon (SOC); soil organic matter (SOM); olive young tree; Olea europaea L.; peat replacement.
Online: 20 January 2022 (14:26:24 CET)
To substitute of conventional manure and peat with alternatives sourcing from environmental conservation concerns, several promising alternatives has been attracting scientific parties’ interest, recently. However, among them compost perform the best, mostly and support carbon sequestration and mitigation against climate change. The article describes the made locally produced 70% in volume olive pruning branches compost (COMP) performance in two trials as an organic amendment in pepper production and an olive sapling substrate during 2019-2021 organic management in Turkey. The application of COMP to pepper trial conducted using factorial randomised block design with 4 replications and 6 treatments increased total organic matter and soil organic carbon, significantly (p<0.05) as compared to non-used plots in two locations. The olive sapling trial was conducted using a randomised plot design with 4 replications and 4 treatments. After the 12 months of growth, compost had the largest architecture rooted plants significantly different (p<0.05). Fresh volume (cm3) of COMP used saplings were obtained 35% less than 40% peat treatment, significantly (p<0.05) while 6th month measurement was found as 40%. It is concluded that to enhance circular economy recycling and composting olive pruning branches is lucrative for the country to reduce external input usage in organic horticultural production.