Zohar Kerem

The biological action of saponins in animal systems: a review

Saponins are steroid or triterpenoid glycosides, common in a large number of plants and plant products that are important in human and animal nutrition. Several biological effects have been ascribed to saponins. Extensive research has been carried out into the membrane-permeabilising, immunostimulant, hypocholesterolaemic and anticarcinogenic properties of saponins and they have also been found to significantly affect growth, feed intake and reproduction in animals. These structurally diverse compounds have also been observed to kill protozoans and molluscs, to be antioxidants, to impair the digestion of protein and the uptake of vitamins and minerals in the gut, to cause hypoglycaemia, and to act as antifungal and antiviral agents. These compounds can thus affect animals in a host of different ways both positive and negative.

Concomitant Induction of Systemic Resistance to Pseudomonas syringae pv. lachrymans in Cucumber by Trichoderma asperellum (T-203) and Accumulation of Phytoalexins

ABSTRACT Most studies on the reduction of disease incidence in soil treated with Trichoderma asperellum have focused on microbial interactions rather than on plant responses. This study presents conclusive evidence for the induction of a systemic response against angular leaf spot of cucumber (Pseudomonas syringae pv. lachrymans) following application of T. asperellum to the root system. To ascertain that T. asperellum was the only microorganism present in the root milieu, plants were grown in an aseptic hydroponic growth system. Disease symptoms were reduced by as much as 80%, corresponding to a reduction of 2 orders of magnitude in bacterial cell densities in leaves of plants pretreated with T. asperellum. As revealed by electron microscopy, bacterial cell proliferation in these plants was halted. The protection afforded by the biocontrol agent was associated with the accumulation of mRNA of two defense genes: the phenylpropanoid pathway gene encoding phenylalanine ammonia lyase (PAL) and the lipoxygenase pathway gene encoding hydroxyperoxide lyase (HPL). This was further supported by the accumulation of secondary metabolites of a phenolic nature that showed an increase of up to sixfold in inhibition capacity of bacterial growth in vitro. The bulk of the antimicrobial activity was found in the acid-hydrolyzed extract containing the phenolics in their aglycone form. High-performance liquid chromatography analysis of phenolic compounds showed a marked change in their profile in the challenged, preelicited plants relative to that in challenged controls. The results suggest that similar to beneficial rhizobacteria, T. asperellum may activate separate metabolic pathways in cucumber that are involved in plant signaling and biosynthesis, eventually leading to the systemic accumulation of phytoalexins.

Enhancement of laccase activity in liquid cultures of the ligninolytic fungus Pleurotus ostreatus by cotton stalk extract

Laccase is one of the enzymes suggested to play a role in fungal ligninolytic systems. Cotton stalks were found to be an excellent substrate for Pleurotus cultivation. In this work, the effects of cotton-stalk extract (CSE) were studied. It was found to stimulate both fungal growth in surface cultures and extracellular laccase activity in submerged cultures. Induction of laccase activity was dependent upon the concentration of the supplemented extract. The stimulation of laccase was observed as early as 3 h after amendment of CSE. Laccase activity staining after separation by gel electrophoresis revealed two major bands in both control and the CSE-induced cultures.

Biodegradation of lignocellulosic agricultural wastes by Pleurotus ostreatus

Abstract Cotton plant stalks are available in vast quantities in all cotton-growing areas. The material poses agrotechnical problems since the stalks have a fibrous structure resembling that of hardwood and contain 46% cellulose, 20% hemicellulose and 21% lignin. Two potential uses for this material are as a fuel in rural areas and as a substrate for the ‘oyster mushroom’, Pleurotus. In this work, degradation of the lignocellulosic component of cotton stalks by Pleurotus is described. This fungus degrades lignocellulose with obvious selectivity for lignin, resulting in increased digestibility of the remaining organic matter.

Reconsidering Domestication Of Legumes Versus Cereals In The Ancient Near East

In this paper, we discuss, from both biological and cultural perspectives, the ancient human-plant liaison that gave rise to Near Eastern agriculture. We explain the biological aspects of Near Eastern plant domestication by a comparative analysis of legume vs. cereal crop evolution. This comparison is illustrated by the natural distribution, ecological affinity, physiology, population structure, floral biology, growth habit, plant stature, seed dispersal mode, and seed dormancy of both wild and domesticated plants of these crop groups. We discuss the differences between Near Eastern legumes and cereals with regard to each of the above aspects, and we highlight the relevance of these differences with regard to Neolithic decision-making, adoption for farming, and subsequent evolution under domestication. We reached the following conclusions: (1) Near Eastern legumes underwent different evolutionary trajectories under domestication as compared with their companion cereals, despite apparent similarities between selection under domestication of both crop groups. (2) Careful comparison of pea, lentil, and chickpea shows that each of the Near Eastern legume crops has a unique evolutionary history in its own right, and this also holds true for the cereal crops. (3) The evolutionary history of each of the Near Eastern crops, prior to as well as after domestication, is well-reflected in its adaptation profile in present-day cropping systems, which determines each crops relative economic importance in different world regions (e.g., chickpea is a major pulse in the Indian subcontinent, and pea is a more important crop in temperate regions, while barley has the widest adaptation, extending from high-latitude temperate regions to semi-arid Mediterranean systems). (4) Ancient choice-making, as reflected in the founder crops repertoire, involved nutritional considerations that may have outweighed grain yield per area and/or time unit criteria.

Color, sugars and organic acids composition in aril juices and peel homogenates prepared from different pomegranate accessions.

The current study describes differences in pomegranate fruit size and aril weight of 29 accessions grown in Israel. The contents of sugars and organic acids in their aril juices and peel homogenates, as well as color parameters, were determined. While the levels of total soluble solids (TSS) and soluble sugars in the aril juices differ only slightly, those of titratable acidity (TA) and citric acid changed significantly, suggesting that they are the main contributors to juice taste. In general, significant positive correlations were found between TA values and the red color parameters, and these two parameters, as well as TSS, appeared to be higher in the juices of accessions harvested late in the season. Peel homogenates exhibited lower levels of TSS, TA, soluble sugars and organic acids than aril juices. Some red color parameters, TA and citric acid were found to correlate significantly between the aril juices and peel homogenates.

Utilization of lignocellulosic waste by the edible mushroom, Pleurotus

Lignocellulosic waste represents huge amounts of unutilized renewable resource. The use of the polysaccharides in the lignocellulosic complex is limited due to their high lignin content. White rot fungi are capable of selectively degrading lignin, thereby upgrading it. The focus of this article is on the potential utilization of edible mushrooms of the genus Pleurotus, via solid state fermentation, using cotton plant stalks as a substrate. This material poses agrotechnical problems since the stalks have a fibrous structure similar to that of hardwood. Potential uses for this material are as a fuel in rural areas, a substrate for mushrooms, an animal feed and substrate for paper making. In this study, degradation of cotton stalks by Pleurotus is described using chemical analyses and scanning electron microscopy. During four weeks of solid state fermentation, lignin content significantly decreased and in vitro digestibility was increased. The fermentation product was consumed by ruminants at a level of up to 40% of their diet.

Interactions between CYP3A4 and Dietary Polyphenols

The human cytochrome P450 enzymes (P450s) catalyze oxidative reactions of a broad spectrum of substrates and play a critical role in the metabolism of xenobiotics, such as drugs and dietary compounds. CYP3A4 is known to be the main enzyme involved in the metabolism of drugs and most other xenobiotics. Dietary compounds, of which polyphenolics are the most studied, have been shown to interact with CYP3A4 and alter its expression and activity. Traditionally, the liver was considered the prime site of CYP3A-mediated first-pass metabolic extraction, but in vitro and in vivo studies now suggest that the small intestine can be of equal or even greater importance for the metabolism of polyphenolics and drugs. Recent studies have pointed to the role of gut microbiota in the metabolic fate of polyphenolics in human, suggesting their involvement in the complex interactions between dietary polyphenols and CYP3A4. Last but not least, all the above suggests that coadministration of drugs and foods that are rich in polyphenols is expected to stimulate undesirable clinical consequences. This review focuses on interactions between dietary polyphenols and CYP3A4 as they relate to structural considerations, food-drug interactions, and potential negative consequences of interactions between CYP3A4 and polyphenols.

Partial Identification of Antifungal Compounds from Punica granatum Peel Extracts

Aqueous extracts of pomegranate peels were assayed in vitro for their antifungal activity against six rot fungi that cause fruit and vegetable decay during storage. The growth rates of Alternaria alternata , Stemphylium botryosum , and Fusarium spp. were significantly inhibited by the extracts. The growth rates were negatively correlated with the levels of total polyphenolic compounds in the extract and particularly with punicalagins, the major ellagitannins in pomegranate peels. Ellagitannins were also found to be the main compounds in the bioactive fractions using bioautograms, and punicalagins were identified as the main bioactive compounds using chromatographic separation. These results suggest that ellagitannins, and more specifically punicalagins, which are the dominant compounds in pomegranate peels, may be used as a control agent of storage diseases and to reduce the use of synthetic fungicides.

Sarcopoterium spinosum extract as an antidiabetic agent: In vitro and in vivo study

ETHNOPHARMACOLOGICAL RELEVANCE Sarcopoterium spinosum (L.) sp., a common plant in the Mediterranean region, is widely used as an antidiabetic drug by Bedouin healers. However, the antidiabetic properties of Sarcopoterium spinosum had not been fully validated using scientific tools. AIM OF THE STUDY To determine the effectiveness of Sarcopoterium spinosum extract as an antidiabetic agent in vitro and in vivo. MATERIALS AND METHODS RINm pancreatic beta-cells, L6 myotubes, 3T3-L1 adipocytes and AML-12 hepatocytes were treated with an aqueous Sarcopoterium spinosum extract (0.001-10mg/ml). The effect of the extract on specific physiological functions, including insulin secretion, pancreatic beta-cell viability, GSK3 beta phosphorylation, lipolysis and glucose uptake was measured. In vivo studies were performed using KK-A(y) mice, given the extract for several weeks. IPGTT was performed, and plasma insulin, FFA, food consumption and body weight were measured. In addition, diabetic KK-A(y) mice were given a single dose of the extract, and IPGTT was performed. RESULTS Sarcopoterium spinosum extract increased basal and glucose/forskolin-induced insulin secretion in RINm cells, and increased cell viability. The extract inhibited lipolysis in 3T3-L1 adipocytes, and induced glucose uptake in these cells as well as in AML-12 hepatocytes and L6 myotubes. GSK3 beta phosphorylation was also induced in L6 myotubes, suggesting increased glycogen synthesis. Sarcopoterium spinosum extract had a preventive effect on the progression of diabetes in KK-A(y) mice. Catechin and epicatechin were detected in Sarcopoterium spinosum extract using hyphenated LC-MS/MS. CONCLUSIONS Sarcopoterium spinosum extract has effects that mimic those of insulin and provide the basis for antidiabetic activity of the extract.