Chemical and Biological Activity of Triterpene Saponins from Medicago Species

Naturally occurring saponins are a large group of triterpene and steroid glycosides characterized by several biological and pharmacological properties. The Medicago genus represents a valuable source of saponins which have been extensively investigated. This review summarizes the chemical features of saponins from Medicago species and their biological activity, with particular attention to their antimicrobial, insecticidal, allelopathic and cytotoxic effects. Influence of saponins on animal metabolism is also reported

Volatile constituents of Festuca nigrescens, Phleum alpinum and Poa alpina from N. W. Italian Alpine pastures.

The composition of the volatile fractions of three important grasses from subalpine N.W. Italian pastures, namely Festuca nigrescens Lam. non Gaudin (chewing fescue), Phleum alpinum L. (alpine timothy) and Poa alpina L. (alpine bluegrass) was investigated. The fresh aerial parts were collected at the flowering stage during the summer season. The volatile oils obtained from green tissues by steam distillation in a Clevenger-type apparatus, were analyzed by GC/FID and GC/MS. The oil yield was 0.04 ± 0.01% weight/fresh weight bases for each of the investigated species. Several classes of compounds were found in the volatile fractions, including aldehydes, alcohols, acids, hydrocarbons, esters, ketones, terpenes, and phenolics. Qualitative and quantitative differences were observed

Unraveling the response of plant cells to cytotoxic saponins: role of metallothionein and nitric oxide

A wide range of pharmacological properties are ascribed to natural saponins, in addition to their biological activities against herbivores, plant soilborne pathogens and pests. As for animal cells, the cytotoxicity and the chemopreventive role of saponins are mediated by a complex network of signal transduction pathways which include reactive oxygen species (ROS) and nitric oxide (NO). The involvement of other relevant components of the saponin-related signaling routes, such as the Tumor Necrosis Factor (TNF)α, the interleukin (IL)-6 and the Nuclear Transcription FactorκB (NFκB), has been highlighted in animal cells. By contrast, information concerning the response of plant cells to saponins and the related signal transduction pathways is almost missing. To date, there are only a few common features which link plant and animal cells in their response to saponins, such as the early burst in ROS and NO production and the induction of metallothioneins (MTs), small cysteine-rich, metal-binding proteins. This aspect is discussed in the present paper in view of the recent hypothesis that MTs and NO are part of a novel signal transduction pathway participating in the cell response to oxidative stress

In Vitro Assessment of the Antioxidant Properties of Aqueous Byproduct Extracts of Vitis vinifera

Tekući ekstrakti stabljika vinove loze (sorte Merlot), komine (sorata Merlot i Cabernet Sauvignon) i lišća (sorte Merlot), uobičajenih nusproizvoda proizvodnje vina, dobiveni su pri niskoj temperaturi pomoću ekstraktora Naviglio. Njihova su svojstva ispitana metodom protočne citometrije na humanim kožnim fibroblastima. Ekstrakti lišća imali su najveći udjel ukupnih fenola ((47,6±3,5) mg/g) i proantocijanidina ((24,2±0,1) mg/g). U preliminarnom su kolorimetrijskom ispitivanju bojanjem pomoću 3-[4,5-dimetiltiazol-2-il]-2,5-difeniltetrazolijevog bromida (tzv. MTT test) izdvojena dva volumna udjela svakog od ekstrakata (u rasponu od 0,8 do 1 2,8 %) koja nisu imala toksični učinak, a ti su ekstrakti zatim korišteni u tri citometrijska testa. U prvom testu nije zamijećen štetni učinak ekstrakata na citoplazmatsku membranu. U drugom je testu utvrđen manji (p<0,01) postotak stanica s aktivnom polariziranom mitohondrijskom membranom ((15,7±8,3) % u usporedbi s (32,5±1,3) % u kontrolnom uzorku) nakon njihovog izlaganja ekstraktima komine sorte Cabernet Sauvignon uz dodatak 4,5 mM H202. Također je utvrđen manji (p<0,05) postotak stanica s aktivnom polariziranom mitohondrijskom membranom nakon njihovog izlaganja ekstraktima stabljika vinove loze sorte Merlot, i to (49,3±6,1) % u prisutnosti 1,5 mM H202 u usporedbi s (64,6±2,4) % u kontrolnom uzorku, te (89,7±2,4) % bez dodatka 1-1202 u usporedbi s % u kontrolnom uzorku. Nasuprot tome, mitohondrijska je aktivnost znatno (p<0,05) porasla (na (96,3±1,8) odnosno (6,4±1,4) %) nakon tretiranja s oba volumna udjela ekstrakta lišća sorte Merlot uz dodatak 0,5 mM 1-1202, u usporedbi s kontrolom ((88,2±1,1) %). Naposlijetku, u trećem je testu dokazano da ekstrakti stabljike vinove loze nisu bitno utjecali na oksidativni status stanica, dok su ekstrakti komine imali djelomičan (p<0,05), a ekstrakti lišća znatan (p<0,001) pozitivni učinak na oksidativni status nakon izlaganja stanica koncentracijama H202 od 0,5 do 4,5 mM, u usporedbi s kontrolnim uzorkom.Aqueous extracts were obtained at low temperature with the Naviglio technology from grapevine stalks (Merlot), marc (Merlot and Cabernet Sauvignon) and leaves (Merlot) as typical byproducts of winemaking industry, and their properties were evaluated cytofluorometrically on human dermal fibroblasts. Leaf extracts had the greatest total phenolic ((47.6±3.5) mg/g) and proanthocyanidin ((24.2±0.1) mg/g) contents compared to the others. The preliminary colorimetric MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) assay individuated two consecutive non-toxic volume fractions of each extract (from 0.8 to 12.8 %) that were adopted for three cytofluorometric tests. The first cell membrane test did not evidence any harmful effects against plasma membranes at the two non-toxic volume fractions. The second mitochondrial membrane test showed a decreased (p<0.01) percentage of cells ((15.7±8.3) vs (32.5±1.3) %) with active polarized mitochondrial membranes at the higher non-cytotoxic volume fractions of extracts from Cabernet Sauvignon marc in response to 4.5 mM H2O2, and from Merlot stalks (p<0.05) at 1.5 mM H2O2 ((49.3±6.1) vs (64.6±2.4) %) and without H2O2 ((89.7±2.4) vs (96.9±1.8) %), compared to the controls submitted to the same H2O2 concentration. Conversely, mitochondrial activity of leaf extracts significantly (p<0.05) increased ((96.3±1.8) and (96.4±1.4) %) after treatment with 0.5 mM H2O2 at both non-cytotoxic volume fractions compared to control (88.2±1.1) %). Finally, as evidenced by the third oxidative status test, stalk extracts did not evidence relevant effects on the cellular oxidative state, while the extracts of marc and leaves demonstrated significantly medium (p<0.05) to highly (p<0.001) positive effects following exposure to H2O2 ranging from 0.5 to 4.5 mM, compared to controls

CRISPR/Cas9-Mediated Targeted Mutagenesis of CYP93E2 Modulates the Triterpene Saponin Biosynthesis in Medicago truncatula

In the Medicago genus, triterpene saponins are a group of bioactive compounds extensively studied for their different biological and pharmaceutical properties. In this work, the CRISPR/Cas9-based approach with two single-site guide RNAs was used in Medicago truncatula (barrel medic) to knock-out the CYP93E2 and CYP72A61 genes, which are responsible for the biosynthesis of soyasapogenol B, the most abundant soyasapogenol in Medicago spp. No transgenic plants carrying mutations in the target CYP72A61 gene were recovered while fifty-two putative CYP93E2 mutant plant lines were obtained following Agrobacterium tumefaciens-mediated transformation. Among these, the fifty-one sequenced plant lines give an editing efficiency of 84%. Sequencing revealed that these lines had various mutation patterns at the target sites. Four T0 mutant plant lines were further selected and examined for their sapogenin content and plant growth performance under greenhouse conditions. The results showed that all tested CYP93E2 knock-out mutants did not produce soyasapogenols in the leaves, stems and roots, and diverted the metabolic flux toward the production of valuable hemolytic sapogenins. No adverse influence was observed on the plant morphological features of CYP93E2 mutants under greenhouse conditions. In addition, differential expression of saponin pathway genes was observed in CYP93E2 mutants in comparison to the control. Our results provide new and interesting insights into the application of CRISPR/Cas9 for metabolic engineering of high-value compounds of plant origin and will be useful to investigate the physiological functions of saponins in planta

Combined Effects of Dewatering, Composting and Pelleting to Valorize and Delocalize Livestock Manure, Improving Agricultural Sustainability

An agronomic strategy to mitigate climate change impact can be the build-up of soil organic carbon. Among agronomic management approaches, the administration of organic fertilizers like livestock manure represents an eective strategy to increase soil organic carbon. However, livestock manure usually contains a high amount of water, reducing its sustainable delocalization and impacting on greenhouse gas emissions and nutrient leaching. Furthermore, the possible presence of weed seeds and harmful microorganisms could reduce the agronomic value of the manure. To overcome these issues, the combined eects of dewatering, composting and pelleting were investigated on livestock manure to produce sustainable organic fertilizers. Our results showed that composting and pelleting can represent a feasible and sustainable solution to reduce the potential risks related to the presence of weed seeds and harmful bacteria, concentrating nutrients and allowing a sustainable valorization and delocalization of the livestock manure. In addition, the processed manures were assessed as fertilizers in the growing medium (GM), displaying an increase in water retention and nutrient availability and a decrease of GM temperature and weed seed emergences. However, further study is needed to validate, both in open field and greenhouse productions, the eects of the proposed fertilizers in real cropping systems

Characterization of the Essential oil of the Bat-Pollinated Passiflora mucronata

The genus Passiflora is an important source of food, therapeutic substances and for the horticultural economy. In the last decades, a detailed chemical composition of the essential oil of Passiflora species has been reported, but only for few species, mainly of agricultural interest, although little attention has been paid to chiropterophilous Passifloraceae, such as P. mucronata. The present study is focused on analyzing the essential oil composition of P. mucronata, a Brazilian bat-pollinated species. From GC/FID and GC/MS analyses of the volatile fraction from fresh flowers and leaves, hydrocarbons were quantified as 47.9% and 42.8% of the total volatiles of flowers and leaves, respectively, esters for 50.8% in flowers and 6.4% in leaves, and alcohols 38.2% and 0.3% of the total volatiles from leaves and flowers, respectively. Other classes of compounds, such as monoterpenes and aldehydes, together with phytol, were detected in higher concentration in leaves compared with flowers. The higher content of methyl and ethyl esters of long chain saturated and unsaturated fatty acids, i.e. ethyl linolenate (38.3%), methyl linolenate (7.0%) and ethyl palmitate (3.6%), were the most representative suggesting that esters might play a critical role for fertilization of P. mucronata acting as bat attractors

Composition of Volatile Fraction from Inflorescences and Leaves of Dendrobium moschatum (Orchidaceae)

The volatile fractions from fresh inflorescences and leaves of Dendrobium moschatum (Buchanan-Hamilton) Swartz (Orchidaceae) were isolated by steam distillation with a yield of 0.498% and 0.041% (weight/fresh weight basis), respectively. From GC/FID and GC/MS analyses, coumarin was identified to be the most abundant constituent and quantified as 48.8% and 47.8% of the total volatiles from inflorescences and leaves, respectively. Hydrocarbons, ketones, esters, acids and aldehydes were also detected. Long chain mono unsaturated hydrocarbons were quantified in higher amount in leaves and their structures were elucidated by GC/MS of their dimethyl disulfide derivatives. These compounds together with long chain ethyl esters and methyl ketones may represent a particular feature of this plant species and can play a critical role in the interaction with pollinator insect

Insights into the phytochemical composition of selected genotypes of organic kale (Brassica oleracea L. var. acephala)

Seven genotypes of kale (B. oleracea L. var. acephala), selected from a collection set up in the framework of the BRESOV H2020 Project, aimed at breeding under organic conditions, were analysed for the content in the characteristic phytochemicals of Brassica spp. The presence of prebiotic oligosaccharides was an important characteristic of this crop, with values ranging from 4.2 to 10.8 g/100 g d.w. The other detected soluble sugars were sucrose, glucose, and fructose, with glucose predominating (3.9–9.0 g/100 g d.w.). Sulphur compounds, such as sulphoxides, were detected in the form of pyruvic acid, their catabolic product (36–154 mg/100 g d.w.). In addition, the levels of main breakdown products of glucosinolates, such as sulforaphane and indole-3-carbinol, were found to be in average contents of 6.7 and 3.9 μmol/g d.w., respectively. Finally, the presence of major phytochemicals in kale, such as polyphenols and carotenoids, reported considerable concentrations (around 1400 mg/100 g d.w. and 19 mg/100 g d.w, respectively), typical for this Brassica crop

Microalgae from Biorefinery as Potential Protein Source for Siberian Sturgeon (A. baerii) Aquafeed

The demand for aquafeed is expected to increase in the coming years and new ingredients will be needed to compensate for the low fish meal and oil availability. Microalgae represent a promising matrix for the future aquafeed formulation, however, the high production cost hinders its application. The use of microalgae from biorefinery would reduce the disposal costs for microalgae production. The present study aimed to (i) verify the growth of microalgae on digestate coming from pig farming and (ii) evaluate their potential valorization as dietary ingredient in aquafeed according to a Circular Bioeconomy approach. For these purposes, a microalgae biomass was produced on an outdoor raceway reactor supplied with digestate and used for partial replacement (10% of the diet) in aquafeed for Siberian sturgeon fingerlings (Acipenser baerii). The results obtained confirm the feasibility for growing microalgae on digestate with satisfactory productivity (6.2 gDM m−2 d−1), nutrient removal efficiency and Chemical Oxygen Demand reduction; moreover, the feeding trial carried out showed similar results between experimental and control groups (p > 0.05), in term of growth performance, somatic indices, fillet nutritional composition and intestinal functionality, to indicate that microalgae from biorefinery could be used as protein source in Siberian sturgeon aquafeed