Volatile and non-volatile profiles of olive pomace and its potential uses

Olive pomace is an environmentally harmful waste from the olive oil industry, containing large amounts of bioactive compounds that could be used in several areas. In the present study, the olive pomace, by-products, was fractionated successively using organic solvents of increasing polarity (cyclohexane (CYHA), ethanol (EtOH) and distilled water) to determine their biochemical composition (total phenolic content, total flavonoid content, HPLC, and GC-MS) and biological activities (antioxidant and antibacterial activities). In addition, the olive pomace was extract directly by the distilled water to determine its physicochemical characteristics (pH, humidity and quantity of oil). The study proved that olive pomace has a low content of total phenolic content in the three extracts (from 0.81 to 2.24 mg GAE/g dry residue). Likewise, for the content of total flavonoids, it presents in the CYHA and EtOH extracts of 0.5 and 0.4 mg QE/g dry residue, respectively. GC-MS data showed the detection of 6 volatile compounds in the cyclohexane extract which contains two major compounds were hexadecanoic acid (2.23%) and 9-octadecenoic acid (8.67%). Moreover, HPLC data showed that chrysin compound was the major one among the four detected ones in the organic extracts of olive pomace. The results showed that the CYHA extract exhibited the best antioxidant power exceeds 50% on the other hand, it is less than 25% for the ethanoic and aqueous extract. In the aqueous extract there is a stronger antibacterial activity against the strain L. monocytogenes (13 mm) than the reference (ampicillin) and the bacterial strain B. cereus (11 mm) associated with their phenolic activity

Long-term mannitol-induced osmotic stress leads to stomatal closure, carbohydrate accumulation and changes in leaf elasticity in Phaselous vulgaris leaves

The effect of long-term osmotic stress was investigated in leaves of two common bean lines, with contrasting tolerance: Flamingo (tolerant) and coco blanc (sensitive). Water relations, organic solute, ion accumulation and amino acids content as well as osmotic adjustment (OA) were studied during an extended exposure to osmotic stress. Osmotic stress was applied by means of 50 mM mannitol for 15 days. At the end of the stress period, both osmotic potential at full turgor (psi(100)) and at turgor loss point (psi(0)) decreased significantly in stressed plants compared with the control. The decrease being greater in the sensitive line, showed a greater OA compared with flamingo. Sugars contents increased in stressed plants and seem to be the major components of osmotic adjustment in stressed common bean leaves. The increase was more marked in coco blanc. Osmotic stress tolerance could thus not be associated with higher OA. The possible role of decreased leaf cell elasticity (epsilon(max)) is discussed in relation to osmotic stress tolerance in this species.This work was supported by the AQUARHIZ Project: “Modulation of plant-bacteria interactions to enhance tolerance to water deficit for grain legumes in the Mediterranean dry lands” PT6 Project INCO-CT-2004-509115, and by the Tunisian Ministry of Higher Education and Scientific Research (LR10CBBC02)

Polysaccharides from South Tunisian <i>Moringa alterniflora</i> Leaves: Characterization, Cytotoxicity, Antioxidant Activity, and Laser Burn Wound Healing in Rats

Phytochemical properties have recently increased the popularity of plant polysaccharides as wound dressing materials. This work aims at studying the structural characteristics of polysaccharides extracted from Moringa leaves (Moringa Leaves Water Soluble Polysaccharide: MLWSP), and its antioxidant activities, cytotoxic effects, and laser burn wound healing effects in rats. This MLWSP was structurally characterized. Results showed 175.21 KDa and 18.6%, respectively, for the molecular weight and the yield of the novel extracted polysaccharide. It is a hetero-polysaccharide containing arabinose, rhamnose, and galactose. XRD suggested a semi-crystalline structure of the studied polymer and FT-IR results revealed a typical polysaccharide structure. It is composed of 50 to 500 µm rocky-shaped units with rough surfaces and it was found to inhibit the proliferation of the human colon (HCT-116) (IC50 = 36 ± 2.5 µg/mL), breast (MCF-7) (IC50 = 48 ± 3.2), and ovary cancers (IC50 = 24 ± 8.1). The MLWSP showed significant antioxidant effects compared to Trolox (CI50 = 0.001 mg/g). Moreover, promising wound healing results were displayed. The effect of MLWSP hydrogel application on laser burn injuries stimulated wound contraction, re-epithelization, and remodeling phases 8 days after treatment. The wound healing potential of MLWSP may be due to its significant antioxidant activity and/or the huge amount of monosaccharide molecules

Date-Palm Compost as Soilless Substrate Improves Plant Growth, Photosynthesis, Yield and Phytochemical Quality of Greenhouse Melon (<i>Cucumis melo</i> L.)

The selection of adequate substrate for soilless culture is based on technical and economic considerations. Therefore, the search for alternatives by the valorization of natural by-products is gaining importance. The main objective of this study was to compare the effects of local farm resources, date-palm waste, as culture substrate, to coconut fiber (CF) (commonly used in soilless culture) on melon (Cucumis melo L.) plant growth, water relations, photosynthesis, chlorophyll fluorescence as well as phytochemical analysis under hydroponics culture system. Two growing substrates were tested: the compost of date palm waste added to animal manure (7:3 w w−1) (DPAM) and the date palm trunk compost (DPT). Coconut fiber and soil were used as positive and negative controls, respectively, in randomized blocks. Results showed that the vegetative growth was improved under DPT and CF substrates while CF substrate enhanced fruit yield and phytochemical properties: Total soluble solids TSS (% Brix), total dissolved solutes (TDS); Titratable acidity (as citric acid); Sugar content and juice pH of melon fruit. Date-palm waste-based substrates enhanced the vegetative growth and the fruit yield of melon as compared to soil-based culture. It seems that date palm waste-based substrates, especially trunk compost, could be promising and cheaper alternatives compared to coconut fiber substrates commonly used in Tunisia in soilless cultures

Optimizing Alternative Substrate for Tomato Production in Arid Zone: Lesson from Growth, Water Relations, Chlorophyll Fluorescence, and Photosynthesis

Soilless culture is considered the mostpromising, intensive, and sustainable approach with various advantages for plant production in terms of saving water and nutrients. It can provide consumers with sufficient and high-quality food. However, the commonly used growing substrate for soilless cultivation, coconut fiber (CF), is usually imported and expensive or even unavailable. The objectives of this study were to investigate the impact of local organic farm resources substrates on tomato (Solanum lycopersicum L.) plant growth, water relations, photosynthesis, chlorophyll fluorescence, and phytochemical analysis of fruits in a hydroponics culture system. Two growth substrates were evaluated: date-palm waste composted with animal manure (7:3 w/w) (DPAM) and date-palm trunk compost (DPT). CF and local soil were utilized as positive and negative controls, respectively, in randomized blocks. The results revealed that DPAM substrate enhanced plant growth and physiology: shoot development, leaves tissues hydration, and photosynthetic parameters, as well as chlorophyll fluorescence. However, DPT and CF improved fruit quality: water, mineral, sugar, and protein content. The antioxidant activity of the fruit extract was the greater in DPAM, reaching 13.8 mg GAEg−1 DW. This value wasdecreased in soil by 40%. Photosynthesis activity was the most important in DPAM with 12 µmol CO2 m−2 s−1, and only 6.4 µmol CO2 m−2 s−1 in the soil condition. However, regarding the non-photochemical quenching, the dissipated light energy was greater in soil (0.096 ± 0.02) than in DPAM (0.025 ± 0.04). Date-palm waste-based substrates improved tomato vegetative growth and fruit quality as compared to soil-based culture. Date-palm waste-based substrates supplemented with manure appear to be promising and less expensive alternatives to the coconut fiber substrate extensively used in soilless crops in North Africa

Soil fertilization practices affect growth, yield and quality of essential oil of Matricaria Recutita grown in Tunisian oases

Both quality and quantity of medicinal plant production is influenced by the physico-chemical properties of soil. It has been demonstrated that different soil amendments can affect the production of plants. The aim of this study was to determine the effect of soil amendments on the soil bulk density (SBD), porosity (SP), pH and potassium (K), phosphorus (P) contains and its effects on Matricaria recutita growth, yield and essential oil (EO) quality. A field experiment was carried out using three common soil amendments: compost (C), manure (M) and sand (S) compared with the native soil in the littoral oases of Gabes, Tunisia. C, M and S were incorporated up to a depth of 10–15 cm at a rate of 440 Kg ha−1. A randomized complete block experimental design was used and the plots planted with Matricaria recutita. Results shown that the different fertilization systems affected chamomile yield and improved its EO quality and composition. The amendment with S ameliorated the quality of the EO and enhanced the accumulation of α-Bisabolol oxide, while the application of M and C fertilization improved the quantity of Chamazulen and the antioxidant activity. However, the overall results of this study revealed that soil amended with organic fertilizers could be a potential dose for maximum growth yield and better quality of EO extracted from capitula of chamomile. Thus, the introduction of chamomile culture into the Tunisian oases could be of great interest