Release Of Phytochemicals Research Articles

Does the Invasive Heracleum mantegazzianum Influence Other Species by Allelopathy?

Heracleum mantegazzianum is an invasive species in middle Europe. The mode of action of its invasiveness is still not known. Our study focuses on observation of potential allelopathic influence by the production and release of phytochemicals into its environment. Plant material was collected four times within one season (April, May, June, July 2019) at locality Lekárovce (eastern Slovakia) for comparison of differences in composition and potential allelopathy. Water extracts from collected samples were used for different biological assays. The total phenols and flavonoids were determined spectrophotometrically. The profile and content of phenolic components, including coumarins, were determined by two techniques of liquid chromatography along with in vitro evaluation of the free radical scavenging activity of extracts (DPPH, Hydroxyl, Superoxide, and FRAP). The changes in composition in extracts in different seasonal periods were evident as well as potential phytotoxic activity in some concentrations on specific model plants. The slight antioxidant activity was noted. The invasiveness of the current species could be supported by the excretion of its phytochemicals into its surroundings and by different modes of action influencing living organisms in its environment.

Are the invasive Acacia melanoxylon and Eucalyptus globulus drivers of other species invasion? Testing their allelochemical effects on germination

Many invasive alien species (IAS) produce secondary metabolites that affect how other plants function (allelopathic compounds) and can drive other species invasion, as proposed by the invasional meltdown hypothesis. Acacia melanoxylon and Eucalyptus globulus are two of such species. In this study, we analyzed the germination response of seven IAS (Acacia dealbata, Acacia mearnsii, Acacia melanoxylon, Acacia longifolia, Eucalyptus globulus, Paraserianthes lophantha, Phytolacca americana) and a native biotest species (Lactuca sativa) to the application of two different aqueous extracts at two different concentrations of donor species A. melanoxylon and E. globulus. Extract compounds were identified by UHPLC-ESI-QTOF-MS. Eucalyptus aqueous extracts significantly reduced germination in three species (A. dealbata, E. globulus, P. americana). The germination of all the species tested was reduced with acacia aqueous extracts. Our results support the postulates of the Biochemical Recognition Hypothesis in that seeds gauge establishment potential based on phytochemical release of other plants. Furthermore, A. melanoxylon and E. globulus lowered their own germination, suggesting that these species exhibit intraspecific biochemical recognition. We also found support for the Novel Weapons Hypothesis in the case of L. sativa as a native species. Our research shows that phytochemicals are a component of plant-plant interactions, including the invasion process.

Phenolic composition and antioxidant capacity of betel inflorescence extract in a simulated oral environment

The addition of betel inflorescence (BI) and slaked lime (calcium hydroxide) to betel quid (BQ) formulation may be detrimental to human health. Here, we assessed BI extracts prepared using artificial saliva or aqueous solution with or without adding slaked lime to mimic the release of phytochemicals from BI in the oral cavity. The extracts were also profiled by HPLC-DAD-ESI-QTOF-MS/MS to understand the quality and quantity of phytochemicals released. The results indicate that slaked lime facilitates the extraction of phenolics, likely due to a high pH. In a simulated oral environment with artificial saliva, the addition of slaked lime promotes the release of safrole, a well-known carcinogen. Dominant phytochemicals detected also include eugenol, acetyl eugenol and methyl eugenol, and only a fraction of these compounds is released in the simulated oral environment. This study reveals that environmental conditions can considerably affect the extraction of phytochemicals and triggers further investigation on how chewing practices may influence the release and activity of carcinogens.

Oral administration of Huanglian-Houpo herbal nanoemulsion loading multiple phytochemicals for ulcerative colitis therapy in mice

How to achieve stable co-delivery of multiple phytochemicals is a common problem. This study focuses on the development, optimization and characterization of Huanglian-HouPo extract nanoemulsion (HLHPEN), with multiple components co-delivery, to enhance the anti-ulcerative colitis (UC) effects. The formulation of HLHPEN was optimized by pseudo-ternary phase diagram combined with Box-Behnken design. The physicochemical properties of HLHPEN were characterized, and its anti-UC activity was evaluated in DSS-induced UC mice model. Based on preparation process optimization, the herbal nanoemulsion HLHPEN was obtained, with the droplet size, PDI value, encapsulation efficiency (EE) for 6 phytochemicals (berberine, epiberberine, coptisine, bamatine, magnolol and honokiol) of 65.21 ± 0.82 nm, 0.182 ± 0.016, and 90.71 ± 0.21%, respectively. The TEM morphology of HLHPEN shows the nearly spheroidal shape of particles. The optimized HLHPEN showed a brownish yellow milky single-phase and optimal physical stability at 25 °C for 90 days. HLHPEN exhibited the good particle stability and gradual release of phytochemicals in SGF and SIF, to resist the destruction of simulated stomach and small intestine environment. Importantly, the oral administration of HLHPEN significantly restored the shrunk colon tissue length and reduced body weight, ameliorated DAI value and colon histological pathology, decreased the levels of inflammatory factors in DSS-induced UC mice model. These results demonstrated that HLHPEN had a significant therapeutic effect on DSS-induced UC mice, as a potential alternative UC therapeutic agent.

Reuse of almond by-products: Functionalization of traditional semolina sourdough bread with almond skin

Almond production generates large amounts of by-products rich in polyphenols. In this study, almond skin was explored as a valuable food ingredient in bread making. To this purpose, almond skin was used to produce functional products modifying a traditional sourdough bread recipe. The doughs were prepared replacing semolina with powdered almond skin (PAS) at 5 and 10 % (w/w). Sourdough inoculum was started with a mix of lactic acid bacteria (LAB) and propagated in semolina until reaching pH 3.7. The pH of PAS added breads was higher than that of control (CTR) breads before and after fermentation. Plate counts showed a similar evolution of LAB and total mesophilic microorganisms, but members of Enterobacteriaceae and coliform were detectable in PAS doughs. Illumina data clearly showed a dominance of lactobacilli in all trials, but PAS doughs displayed the presence of Bacillus. The final bread characteristics were influenced by PAS and its addition percentage; in particular, crust and crumb colour resulted darker, the alveolation decreased and, regarding sensory attributes, odour intensity increased, while bread odour diminished. In presence of PAS, bread emissions were characterized by lower percentages of alcohols and aromatic hydrocarbons and higher percentages of the other volatile compound classes, especially terpenoids like β-pinene, β-myrcene and limonene than CTR trial. After in vitro simulated digestion, the final release of phytochemicals from 10 % PAS bread was almost 100 %. Thus, PAS determined an increase of the antioxidant capacity of the breads. Phytochemicals released from digested PAS-fortified bread can provide antioxidant protection in a complex biological environment such as human intestinal-like cells. Besides the positive functional properties of PAS, this work also evidenced the hygienic issues of almond skin and, in order to avoid potential risks for the human health, highlighted the need to preserve its microbiological characteristics during storage for their reuse in bread production.

Enteric-Coated Cologrit Tablet Exhibit Robust Anti-Inflammatory Response in Ulcerative Colitis-like In-Vitro Models by Attuning NFκB-Centric Signaling Axis

Ulcerative colitis (UC) is an inflammatory bowel disease that affects the patients' colorectal area culminating in an inflamed 'leaky gut.' The majority of UC treatments only provide temporary respite leading to its relapse. Therefore, this study investigated the efficacy of the enteric-coated 'Cologrit' (EC) tablet in alleviating UC-like inflammation. Cologrit is formulated using polyherbal extracts that have anti-inflammatory qualities according to ancient Ayurveda scriptures. Phytochemical profiling revealed the presence of gallic acid, rutin, ellagic acid, and imperatorin in Cologrit formulation. Cologrit treatment decreased inflammation in LPS-induced transformed THP-1 macrophages, and TNF-α-stimulated human colorectal (HT-29) cells through the modulation of NFκB activity, IL-6 production, and NFκB, IL-1β, IL-8, and CXCL5 mRNA expression levels. Cologrit also lessened human monocytic (U937) cell adhesion to HT29 cells. Methacrylic acid-ethylacrylate copolymer-coating of the enteric Cologrit tablets (EC) supported their dissolution, and the release of phytochemicals in the small intestine pH 7.0 environment in a simulated gastrointestinal digestion model. Small intestine EC digestae effectively abridged dextran sodium sulfate (2.5% w/v)-induced cell viability loss and oxidative stress in human colon epithelial Caco-2 cells. In conclusion, the enteric-coated Cologrit tablets demonstrated good small intestine-specific phytochemical delivery capability, and decreased UC-like inflammation, and oxidative stress through the regulation of TNF-α/NFκB/IL6 signaling axis.

Gastrointestinal fate of phenolic compounds and amino derivatives from the cocoa shell: An in vitro and in silico approach

The objective of this study was to assess how in vitro gastrointestinal digestion influenced the bioaccessibility and potential bioavailability of phenolic compounds and methylxanthines in thecocoa shell (CS) in the form of flour (CSF) and aqueous extract (CSE). To comprehend how these phytochemicals behaved during gastrointestinal digestion, we also modeled in silico the colonic microbial biotransformation of the phenolic compounds in the CS. Different groups of phenolic compounds (mainly gallic andprotocatechuic acids, and catechin) and methylxanthines (theobromine and caffeine)could be found in the CS. Methylxanthines and phenolic compounds were released differently during gastrointestinal digestion. Whereas digestion triggered the release of hydroxybenzoic acids (67–73%) and flavan-3-ols (73–88%) during the intestinal phase, it also caused the degradation of flavonols and flavones. Besides, the release of phytochemicals was significantly influenced by the CS matrix type. Phenolic compounds were protected by the CSF matrix. Phenolic acids from CSF were more bioaccessible in the intestinal (1.2-fold, p < 0.05) and colonic (1.3-fold, p < 0.05) phases than those from the CSE. Methylxanthines were also more bioaccessible in the intestinal (1.8-fold, p < 0.01) and colonic phases (1.3-fold, p < 0.001) and bioavailable (1.8-fold, p < 0.001) in the CSF. Colonic metabolism demonstrated that the gut microbiota could biotransform non-absorbed phenolic compounds into other lower molecular weight and more bioavailable metabolites. These findings support the CS’s potential as a source of bioaccessible, bioavailable, and active phytochemicals.

Allelopathy by the invasive garden lupine inhibits the germination of native herbs

Allelopathy is the stimulatory or inhibitory effect of one plant on another plant by release of phytochemicals. It can affect the competitive interactions between plants, but the strength of the effect may depend on the tissue of the donor plant and the phylogenetic relatedness of the interacting species. Here, we examined the allelopathic effects of the invasive garden lupine Lupinus polyphyllus Lindl. (Fabaceae) on six native herbs from three families (Asteraceae, Caryophyllaceae, Fabaceae). We exposed the test species to aqueous leachates prepared from root or shoot tissue of L. polyphyllus and measured germination rate and germination time. Both leachates inhibited germination in all species (13%–84%), but shoot leachate was more allelopathic than root leachate in case of Fabaceae and Caryophyllaceae. Plants from closely related Fabaceae were least affected by L. polyphyllus leachates in terms of germination rate, but leachates delayed their germination. These results demonstrate that the invasive L. polyphyllus can inhibit the germination of co-occurring native species and suggest that allelopathy likely contributes to its invasion success. Our results have implications for management of invasive L. polyphyllus populations, emphasising the importance of the removal of mown plant material to diminish inhibitory allelopathic effects on local plants.

The Synergistic Effects of Sonication and Microwave Processing on the Physicochemical Properties and Phytochemicals of Watermelon (Citrullus lanatus) Juice

In recent years, consumers have increasingly demanded nutritious, healthy, and fresh-like food products with high organoleptic quality. Watermelon is rich in water, which is 92% mandatory for body functioning, and contains several vitamins, amino acids, antioxidants, carotenoids, and lycopenes with various health benefits. The present study examines the combined effect of ultrasound (US) and microwave (MW) on the physico-chemical and phytochemicals of watermelon juice during storage (up to 120 days). Sonication was employed for different time intervals, particularly from 2 to 8 min at 20 kHz frequency and 525 W power, while microwave was applied at two different time intervals (1 min 50 s and 2 min) at 1000 W power and a frequency of 2450 MHz. The product was stored at 4 °C up to 120 days for further examination. Our results revealed that treatment T5 (10 min ultrasound &amp; 1 min 50 s microwave) manifested the maximum cloud value (3.00), acidity (0.15%), vitamin C content (202.67 mg/100 mL), phenolics (852.57 mgGAE/100 mL), flavonoids (1970.9 µg CE/100 mL), and total antioxidant activity (8650.3 µg equivalent of ascorbic acid/mL of juice). Sonication in combination with microwave proved to be an efficient technique for increasing the antioxidant potential of watermelon juice. Thus, US and MW treatments may be incorporated for enhancing the phytochemical release and shelf life of watermelon juice.

The invasive cactus Opuntia stricta creates fertility islands in African savannas and benefits from those created by native trees

The patchy distribution of trees typical of savannas often results in a discontinuous distribution of water, nutrient resources, and microbial communities in soil, commonly referred to as “islands of fertility”. We assessed how this phenomenon may affect the establishment and impact of invasive plants, using the invasion of Opuntia stricta in South Africa’s Kruger National Park as case study. We established uninvaded and O. stricta-invaded plots under the most common woody tree species in the study area (Vachellia nilotica subsp. kraussiana and Spirostachys africana) and in open patches with no tree cover. We then compared soil characteristics, diversity and composition of the soil bacterial communities, and germination performance of O. stricta and native trees between soils collected in each of the established plots. We found that the presence of native trees and invasive O. stricta increases soil water content and nutrients, and the abundance and diversity of bacterial communities, and alters soil bacterial composition. Moreover, the percentage and speed of germination of O. stricta were higher in soils conditioned by native trees compared to soils collected from open patches. Finally, while S. africana and V. nilotica trees appear to germinate equally well in invaded and uninvaded soils, O. stricta had lower and slower germination in invaded soils, suggesting the potential release of phytochemicals by O. stricta to avoid intraspecific competition. These results suggest that the presence of any tree or shrub in savanna ecosystems, regardless of origin (i.e. native or alien), can create favourable conditions for the establishment and growth of other plants.

Biogenic nanosized gold particles: Physico-chemical characterization and its anticancer response against breast cancer

With the advancement of nanotechnology, the nano-sized particles make an imprint on our daily lives.The present investigation revealed that biomolecules present in seed exudates of Vigna radiata are responsible for the synthesis of AuNPs, confirmed by the routine characterization techniques. Anticancer efficacy showed by AuNPs might be due to the release of phytochemicals in the exudate which is being adsorbed on the surface of AuNPs referencing their anticancer efficacy against the tested breast cancer cell lines. Inhibition of clonogenicity and cell cycle arrest at G2/M phase then apoptosis of AuNPs was also observed, but found nontoxic to the human PBMC cells which further confirms its biocompatible property Among the various physicochemical study, present AuNPs shows unique information, they show photoluminescent property which may be used for bioimaging purposes. However, further molecular analysis needs to be explored to understand the underlying mechanism for therapeutic and biomedical application.

MOF-Based Erodible System for On-Demand Release of Bioactive Flavonoid at the Polymer-Tissue Interface.

Plant-derived compounds incite applications virtually on every biomedical field due to the expedient antioxidant, anti-inflammatory and antimicrobial properties in conjunction with a natural character. Here, quercetin (QCT), a flavonoid with therapeutic potentials relevant to the oral environment, was encapsulated within metal-organic frameworks (MOFs) to address the concept of on-demand release of phytochemicals at the biointerface. We verified the applicability of a microporous MOF (ZIF-8) as a controlled-release system for QCT, as well as investigated the incorporation of QCT@ZIF-8 microparticles into a dental adhesive resin for desirable therapeutic capabilities at the tooth-restoration interface. QCT was encapsulated within the frameworks through a water-based, one-step synthetic process. The resulting QCT@ZIF-8 microparticles were characterized with respect to chemical composition, crystal structure, thermal behavior, micromorphology, and release profile under acidic and physiological conditions. A model dental adhesive formulation was enriched with the bioactive microparticles; both the degree of conversion (DC) of methacrylic double bonds and the polymer thermal behavior were accounted for. The results confirm that crystalline QCT@ZIF-8 microparticles with attractive loading capacities, submicron sizes, high thermal stability and responsiveness to environmental pH change were successfully manufactured. The concentration of QCT@ZIF-8 in the resin system was a key factor to maintain an optimal DC plateau and rate of polymerization. Essentially, one-step encapsulation of QCT in biocompatible ZIF-8 matrices can be easily achieved, and QCT@ZIF-8 microparticles proved as smart platforms to carry bioactive compounds with potential use to prevent microbial and enzymatic degradation of hard tissues and extracellular matrix components.

(Poly)phenolic Content and Profile and Antioxidant Capacity of Whole-Grain Cookies are Better Estimated by Simulated Digestion than Chemical Extraction.

It is widely recognized that the biological effects of phytochemicals cannot be attributed to the native compounds present in foods but rather to their metabolites endogenously released after intake. Bioavailability depends on bioaccessibility, which is the amount of the food constituent that is released from the matrix in the gastrointestinal tract. The use of chemical extraction to evaluate the content and profile of phytochemicals does not mirror the physiological situation in vivo, and their bioaccessibility should be considered while assessing their nutritional significance in human health. The current study was designed to compare the (poly)phenolic profile and content and antioxidant capacity of whole-grain (WG) cookies using chemical extraction and a more physiological approach based on simulated digestion. Three types of organic WG cookies (made with durum, Italian khorasan, or KAMUT® khorasan wheat) were considered, either fermented by Saccharomyces Cerevisiae or sourdough. Although the flour type and the fermentation process influenced the release of phytochemicals from the cookie matrix, in almost all samples, the simulated digestion appeared the most efficient procedure. Our results indicate that the use of chemical extraction for evaluation of the phytochemicals content and antioxidant capacity of food could lead to underestimation and underline the need for more physiological extraction methods.

Impact of cooking method on phenolic composition and antioxidant potential of four varieties of Phaseolus vulgaris L. and Glycine max L.

The present study aimed to investigate the effects of different cooking conditions - atmospheric (100 °C) and pressure cooking (115 °C) - on the phenolic composition and antioxidant activity of methanolic extracts of four Phaseolus vulgaris varieties and soy (Glycine max). Contrary to soy, in P. vulgaris varieties both cooking methods increased drastically the total phenolic, flavonoid, and ortho-diphenol content, as well as antioxidant capacity. These results were corroborated by HPLC analysis, where an overall increase of phenolic acids and flavonoids was detected in processed samples. However, draining the cooking water significantly decreased phenolic acids, flavonoids and antioxidant activity in all P. vulgaris varieties and as well as soy. The hypothesis that cooking increases the compound accessibility and nutritional value through increased release of phytochemicals was verified in the present study for P. vulgaris varieties. Keeping the cooking water is crucial to the increased nutritional value of all Phaseolus varieties. Overall, compared with the tested varieties of Phaseolus, soy, to which many health benefits are attributed, is not the best legume source of antioxidants.

Synthesis of a Block Copolymer Exhibiting Cell-Responsive Phytochemical Release for Cancer Therapy.

Phytochemicals constitute a promising class of therapeutics for the treatment of various diseases, but their delivery poses significant challenges. In this work, a nanoscale polyactive emulsion was designed for smart, cell-responsive delivery of a curcumin prodrug (curcumin dicarboxylate, CDA) that was chemically conjugated to enzymatically labile oligo-peptides with polycaprolactone (PCL) as the carrier. Matrix metalloproteinase (MMP)-sensitive (PLGLYAL) or nonsensitive (GPYYPLG) peptides were used as spacers for conjugating CDA and PCL. This CDA nanoemulsion incorporating the MMP-sensitive sequence exhibited markedly higher anti-cancer activity, cell internalization, and generation of reactive oxygen species in cancer cells in vitro than the control with the nonsensitive oligopeptide. Moreover, the nanopolyactives induced minimal cytotoxicity in noncancerous cell line. This work presents a unique strategy to engineer smart nano-polyactives for efficient and targeted delivery of phytochemicals.

Microstructural and Physiological Changes in Plant Cell Induced by Pressure: Their Role on the Availability and Pressure-Temperature Stability of Phytochemicals

High pressure processing (HPP) is the most widespread nonthermal food pasteurization technology. The stability during HPP treatments of chemical compounds with health-enhancing properties found in plants has been intensively studied. A rising research interest is the elucidation of the mechanisms by which HPP may enhance their biosynthesis and bioavailability. Pressure levels under 100 MPa appear to induce oxidative stress in plant tissue leading to the activation of metabolic pathways related to the biosynthesis of secondary metabolites. Likewise, treatments at ∼150–200 MPa result in cellular membrane rupture, increased cell wall permeability, and nearly complete cell viability loss while metabolic activity gradually ceases at higher pressure. Major structural changes occur during treatments at higher pressure levels influencing the bioavailability of phytochemicals. Carotenoids attached to polymeric structures on cell walls, or entrapped inside cellular organelles, are released into the media by pressure treatments at 200–400 MPa, which may also initiate their degradation. Depending on the food matrix, phenolic compounds and vitamin C are released, degraded, or remain unaffected by 200–600 MPa treatments. At high pressure, phenolics are highly susceptible to oxidation and enzymatic reactions, whereas ascorbic acid stability depends largely on the dissolved oxygen concentration. Future work should focus on pressure come-up time (CUT) effects, development of kinetic models coupling the biosynthesis and/or release of phytochemicals with its pressure-temperature stability, and determinations of their in vitro and in vivo bioavailability.

Encapsulation and release studies of strawberry polyphenols in biodegradable chitosan nanoformulation

Polyphenols (negative groups) of strawberry extract interacts with positively protonated amino groups of chitosan which helps in maximum encapsulation. This approach can improve the bioavailability and sustained release of phytochemicals having lower bioavailability. The optimum mass ratio of chitosan-tripolyphosphate and polyphenols (PPs) loading was investigated to be 3:1 and 0.5mg/ml of strawberry extract, respectively. Prepared nanoformulation were characterized by UV⿿vis spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The formed particles size ranged between 300 and 600nm and polydispersity index (PDI) of⿿0.5. The optimized formulation showed encapsulation efficiency of 58.09% at 36.47% of polyphenols loading. Initial burst and continuous release of PPs was observed at pH 7.4 of in vitro release studies. PPs release profile at this pH was found to be non-Fickian analomous diffusion and the release was followed first order kinetics. And at pH 1.4, diffusion-controlled Fickian release of PPs was observed.

The interaction between iron nutrition, plant species and soil type shapes the rhizosphere microbiome

Plant-associated microorganisms can stimulate plants growth and influence both crops yield and quality by nutrient mobilization and transport. Therefore, rhizosphere microbiome appears to be one of the key determinants of plant health and productivity. The roots of plants have the ability to influence its surrounding microbiology, the rhizosphere microbiome, through the creation of specific chemical niches in the soil mediated by the release of phytochemicals (i.e. root exudates) that depends on several factors, such as plants genotype, soil properties, plant nutritional status, climatic conditions.In the present research, two different crop species, namely barley and tomato, characterized by different strategies for Fe acquisition, have been grown in the RHIZOtest system using either complete or Fe-free nutrient solution to induce Fe starvation. Afterward, plants were cultivated for 6 days on two different calcareous soils. Total DNA was extracted from rhizosphere and bulk soil and 454 pyrosequencing technology was applied to V1–V3 16S rRNA gene region. Approximately 5000 sequences were obtained for each sample.The analysis of the bacterial population confirmed that the two bulk soils showed a different microbial community. The presence of the two plant species, as well as the nutritional status (Fe-deficiency and Fe-sufficiency), could promote a differentiation of the rhizosphere microbiome, as highlighted by non-metric multidimensional scaling (NMDS) analysis. Alphaproteobacteria, Actinobacteria, Chloracidobacteria, Thermoleophilia, Betaproteobacteria, Saprospirae, Gemmatimonadetes, Gammaproteobacteria, Acidobacteria were the most represented classes in all the samples analyzed even though their relative abundance changed as a function of the soil, plant species and nutritional status. To our knowledge, this research demonstrate for the first time that different plants species with a diverse nutritional status can promote the development of a peculiar rhizosphere microbiome, depending on the growth substrate.

Longevity extension by phytochemicals.

Phytochemicals are structurally diverse secondary metabolites synthesized by plants and also by non-pathogenic endophytic microorganisms living within plants. Phytochemicals help plants to survive environmental stresses, protect plants from microbial infections and environmental pollutants, provide them with a defense from herbivorous organisms and attract natural predators of such organisms, as well as lure pollinators and other symbiotes of these plants. In addition, many phytochemicals can extend longevity in heterotrophic organisms across phyla via evolutionarily conserved mechanisms. In this review, we discuss such mechanisms. We outline how structurally diverse phytochemicals modulate a complex network of signaling pathways that orchestrate a distinct set of longevity-defining cellular processes. This review also reflects on how the release of phytochemicals by plants into a natural ecosystem may create selective forces that drive the evolution of longevity regulation mechanisms in heterotrophic organisms inhabiting this ecosystem. We outline the most important unanswered questions and directions for future research in this vibrant and rapidly evolving field.

Phytochemical content, antioxidants and cell wall metabolism of two loquat (Eriobotrya japonica) cultivars under different storage regimes

Changes in quality, phytochemical content and cell wall metabolism of two loquat cultivars (Eriobotrya japonica cvs. ‘Morphitiki’, ‘Karantoki’) under different storage regimes were studied. The fruit were harvested at commercial maturity stage and analyzed after 1, 3, 5, 7, and 11days maintenance at room temperature (RT, ∼20°C) or after cold storage (14days at 4°C) and additional ripening at RT for 1, 3 and 5days, respectively. Compositional analysis revealed substantial cultivar differences; the ‘Morphitiki’ fruit was more acidic and showed higher contents of total phenolics, flavonoids and hydroxycinnamic acid-derivatives as well as greater antioxidant potency. Although firmness did not change markedly during storage, the cell wall exhibited extensive remodeling. Greater changes were observed in the pectin backbones than in polyuronide side chains and cross-linking glycans. Polygalacturonase (PG) showed better association with cell wall solubilization at RT than the enzymes involved in arabinan or galactan disassembly. During postharvest ripening after harvest, ‘Karantoki’ showed more extensive pectin solubilization than ‘Morphitiki’. Interestingly, cold storage inhibited the cell wall disassembly in ‘Karantoki’ but not in ‘Morphitiki’, suggesting that the cultivars may differ in their susceptibility to chilling-related wall disorders. Low temperature-induced alterations in wall disassembly may impact juice and phytochemical release upon consumption.