Assessing high-temperature and pressure extraction of bioactive water-soluble polysaccharides from passion fruit mesocarp.

The mesocarp (albedo) of passion fruit is considered a waste product but rich in soluble fibers, especially pectins. Biological activity and health benefits of pectins have recently emerged, especially in colorectal cancer and attenuating inflammation. Pectin conventional extraction often uses mineral acids, which can be hazardous to the environment, and alternatives can be costly. Here, we assessed a high-temperature and pressure method to extract pectin from the passion fruit albedo and evaluated the differences from the water-soluble fractions extracted. HPSEC, HPAEC, FTIR-ATR, and HSQC-NMR were performed to identify and confirm the highly methylated homogalacturonan structures. The heat-modified samples showed a decreased molecular size compared to the untreated sample. Colorectal cancer cell lines showed reduced viability after being treated with different doses of modified samples, with two of them, LW-MP3 and 4, showing the most potent effects. All samples were detected inside cells by immunofluorescence assay. It was observed that LW-MP3 and 4 upregulated the p53 protein, indicating cell-cycle arrest and the cleaved caspase-9 in one of the cell lines, with LW-MP4 enhancing cell death by apoptosis. Since the modified samples were composed of hydrolyzed homogalacturonans, those probably were the responsible structures for these anti-cancer effects.

Ripe papaya pectins inhibit the proliferation of colon cancer spheroids and the formation of chemically induced aberrant crypts in rats colons.

Pectins are a class of soluble polysaccharides that can have anticancer properties through several mechanisms. This study aimed to characterize the molecular structure of water-soluble fractions (WSF) derived from ripe and unripe papayas and assess their biological effects in two models: the 3D colon cancer spheroids to measure cell viability and cytotoxicity, and the in vivo model to investigate the inhibition of preneoplastic lesions in rats. WSF yield was slightly higher in ripe papaya, and both samples mainly consisted of pectin. Both pectins inhibited the growth of colon cancer HT29 and HCT116 spheroids. Unripe pectin disturbed HT29/NIH3T3 spheroid formation, decreased HCT116 spheroid viability, and increased spheroid cytotoxicity. Ripe pectin had a more substantial effect on the reduction of spheroid viability for HT29 spheroids. Furthermore, in vivo experiments on a rat model revealed a decrease in aberrant crypt foci (ACF) formation for both pectins and increased apoptosis in colonocytes for ripe papaya pectins. The results suggest potential anticancer properties of papaya pectin, with ripe pectin showing a higher potency.

Nature's soothing solution: Harnessing the potential of food-derived polysaccharides to control inflammation.

Reducing inflammation by diet is a major goal for prevention or lowering symptoms of a variety of diseases, such as auto-immune reactions and cancers. Natural polysaccharides are increasingly gaining attention due to their potential immunomodulating capacity. Structures of those molecules are highly important for their effects on the innate immune system, cytokine production and secretion, and enzymes in immune cells. Such polysaccharides include ß-glucans, pectins, fucoidans, and fructans. To better understand the potential of these immunomodulatory molecules, it is crucial to enhance dedicated research in the area. A bibliometric analysis was performed to set a starting observation point. Major pillars of inflammation, such as pattern recognition receptors (PRRs), enzymatic production of inflammatory molecules, and involvement in specific pathways such as Nuclear-factor kappa-B (NF-kB), involved in cell transcription, survival, and cytokine production, and mitogen-activated protein kinase (MAPK), a regulator of genetic expression, mitosis, and cell differentiation. Therefore, the outcomes from polysaccharide applications in those scenarios are discussed.

Unveiling Plant-Based Pectins: Exploring the Interplay of Direct Effects, Fermentation, and Technological Applications in Clinical Research with a Focus on the Chemical Structure.

Pectin, a plant-derived polysaccharide, possesses immense technological and biological application value. Several variables influence pectin's physicochemical aspects, resulting in different fermentations, interactions with receptors, and other functional properties. Some of those variables are molecular weight, degree of methylation and blockiness, and monosaccharide composition. Cancer cell cytotoxicity, important fermentation-related byproducts, immunomodulation, and technological application were found in cell culture, animal models, and preclinical and clinical assessments. One of the greater extents of recent pectin technological usage involves nanoencapsulation methods for many different compounds, ranging from chemotherapy and immunotherapy to natural extracts from fruits and other sources. Structural modification (modified pectin) is also utilized to enhance the use of dietary fiber. Although pectin is already recognized as a component of significant importance, there is still a need for a comprehensive review that delves into its intricate relationships with biological effects, which depend on the source and structure of pectin. This review covers all levels of clinical research, including cell culture, animal studies, and clinical trials, to understand how the plant source and pectin structures influence the biological effects in humans and some technological applications of pectin regarding human health.

Valorization of polyphenolic compounds from food industry by-products for application in polysaccharide-based nanoparticles.

In the last decades, evidence has indicated the beneficial properties of dietary polyphenols. In vitro and in vivo studies support that the regular intake of these compounds may be a strategy to reduce the risks of some chronic non-communicable diseases. Despite their beneficial properties, they are poorly bioavailable compounds. Thus, the main objective of this review is to explore how nanotechnology improves human health while reducing environmental impacts with the sustainable use of vegetable residues, from extraction to the development of functional foods and supplements. This extensive literature review discusses different studies based on the application of nanotechnology to stabilize polyphenolic compounds and maintain their physical-chemical stability. Food industries commonly generate a significant amount of solid waste. Exploring the bioactive compounds of solid waste has been considered a sustainable strategy in line with emerging global sustainability needs. Nanotechnology can be an efficient tool to overcome the challenge of molecular instability, especially using polysaccharides such as pectin as assembling material. Complex polysaccharides are biomaterials that can be extracted from citrus and apple peels (from the juice industries) and constitute promising wall material stabilizing chemically sensitive compounds. Pectin is an excellent biomaterial to form nanostructures, as it has low toxicity, is biocompatible, and is resistant to human enzymes. The potential extraction of polyphenols and polysaccharides from residues and their inclusion in food supplements may be a possible application to reduce environmental impacts and constitutes an approach for effectively including bioactive compounds in the human diet. Extracting polyphenolics from industrial waste and using nanotechnology may be feasible to add value to food by-products, reduce impacts on nature and preserve the properties of these compounds.

Dietary fiber as a wide pillar of colorectal cancer prevention and adjuvant therapy.

Colorectal cancer is the third most incident and second most lethal type of cancer worldwide. Lifestyle and dietary patterns are the key factors for higher disease development risk. The dietary fiber intake from fruits and vegetables, mainly formed by food hydrocolloids, can help to lower the incidence of this type of neoplasia. Different food polysaccharides have applications in anti-tumoral therapy, such as coadjuvant to mainstream drugs, carriage-like properties, or direct influence on tumoral cells. Some classes include inulin, ß-glucans, pectins, fucoidans, alginates, mucilages, and gums. Therefore, it is fundamental to discuss colorectal cancer mechanisms and the roles played by different polysaccharides in intestinal health. Genetic, environmental, and immunological modulation of mutated pathways regarding colorectal cancer has been explored before. Microbial diversity, byproduct formation (primarily short-chain fatty acids), inflammatory profile control, and tumoral mutated pathways regulation are thoroughly explored mechanisms by which dietary fiber sources influence a healthy gut ambiance.

Effects of pectins on colorectal cancer: targeting hallmarks as a support for future clinical trials.

The intake of dietary fibers has been associated with a reduction in the risk of colorectal cancer. Pectins - a class of dietary fibers - are polysaccharides that have a complex structure with a wide range of direct and indirect biological beneficial effects on humans. Direct effects include dilution of carcinogens, reduction in cholesterol levels, and interaction with immune cells. Indirect effects include the fermentation and production of short-chain fatty acids. All these biological effects have implications for colon cancer development; however, the exact mechanisms are not fully understood. In this review, we explore the clinical trials regarding dietary fibers and colorectal cancer, thus indicating the potential anti-cancer effects of pectins and modified pectins. We focused on the emerging biological effects of pectins through targeting colorectal cancer hallmark effects and the enabling characteristics. We provide an overview of the mechanisms for each hallmark capability and how the different pectins might exert that anti-cancer effect, such as induction of apoptosis, reduction in cancer cell proliferation and metastasis. The data compilation described herein can guide future clinical trials to investigate how to target specific pectin structures to act as an adjuvant in colon cancer treatment.

Systems Biology Applied to the Study of Papaya Fruit Ripening: The Influence of Ethylene on Pulp Softening.

Papaya is a fleshy fruit that undergoes fast ethylene-induced modifications. The fruit becomes edible, but the fast pulp softening is the main factor that limits the post-harvest period. Papaya fast pulp softening occurs due to cell wall disassembling coordinated by ethylene triggering that massively expresses pectinases. In this work, RNA-seq analysis of ethylene-treated and non-treated papayas enabled a wide transcriptome overview that indicated the role of ethylene during ripening at the gene expression level. Several families of transcription factors (AP2/ERF, NAC, and MADS-box) were differentially expressed. ACO, ACS, and SAM-Mtase genes were upregulated, indicating a high rate of ethylene biosynthesis after ethylene treatment. The correlation among gene expression and physiological data demonstrated ethylene treatment can indeed simulate ripening, and regulation of changes in fruit color, aroma, and flavor could be attributed to the coordinated expression of several related genes. Especially about pulp firmness, the identification of 157 expressed genes related to cell wall metabolism demonstrated that pulp softening is accomplished by a coordinated action of several different cell wall-related enzymes. The mechanism is different from other commercially important fruits, such as strawberry, tomato, kiwifruit, and apple. The observed behavior of this new transcriptomic data confirms ethylene triggering is the main event that elicits fast pulp softening in papayas.

Enzymatic modification of arabinoxylans from soft and hard Argentinian wheat inhibits the viability of HCT-116 cells.

Dietary fiber plays an important role in the prevention of colorectal cancer, and arabinoxylans are an important source of this in grains, with some studies reporting the inhibition of cancer cell growth. However, very few studies have been conducted on this, and most previous studies have used oligosaccharides derived from arabinoxylans of specific molecular weight. The aim of this work is to extract, isolate, and analyze arabinoxylans from two different Argentinian genotypes of wheat (hard and soft) and study if they have the capacity to decrease the cellular viability of a colon cancer line (HCT-116). To determine whether the molecular size influences the inhibition of HCT-116 cell viability, specific hydrolysis was performed with endoxylanase, and the cells were exposed to the hydrolyzed arabinoxylans. The arabinoxylans treatment resulted in HCT-116 cell viability of 74% for the soft genotype and 64% for the hard genotype in comparison to nontreated cells. Hydrolyzed-arabinoxylans result in HCT-116 cell viability of 68% for soft and 36% for hard genotypes (the lowest IC50 values) compared to nontreated cells. More importantly, no decrease after the arabinoxylans treatment was observed in the viability of murine noncancer cells known to rapidly respond to polysaccharide presence. The arabinoxylans from hard wheat showed more disubstituted xylose and α-1,2/α-1,3 linkages than the arabinoxylans from soft wheat, the possible cause for showing the best in vitro biological effect. The results showed other beneficial effects than the prebiotic ones and support the use of enzymatic treatment to increase the biological impacts of arabinoxylans.

The purification of pectin from commercial fruit flours results in a jaboticaba fraction that inhibits galectin-3 and colon cancer cell growth.

Fruits are a prime source of nutrients, bioactive compounds, and dietary fibers. Some products available on the Brazilian market use fruit by-products and claim to have useful effects on human health due to their dietary fiber content. The study aimed to extract and purify the total (28-47 w/w yield) and soluble dietary fiber (4-7 w/w yield) from jaboticaba, papaya, and plum commercial flours sold in Brazil and to study the in vitro biological effects of the fractions. The purified water-soluble fractions consisted mainly of pectin-derived oligosaccharides (5-15 KDa molecular weight) with a negligible content of polyphenols, protein, ashes, and starch. Jaboticaba sample was 95% galacturonic acid while plum and papaya samples were 40% galacturonic acid and 40% galactose (mol%), approximately. The samples were tested for recombinant human galectin-3 inhibition and changes in the cell viability of human colorectal cancer cells. Only the jaboticaba sample inhibited galectin-3 and decreased HCT116 cell viability after 48 h of treatment (p ≤ 0.01) while the plum sample decreased the cell viability after 24 h treatment (p ≤ 0.05). The results obtained in this study demonstrate the relationship between the structure of the soluble fibers extracted from jaboticaba flour and the possible beneficial effects of their consumption.

The acid and neutral fractions of pectins isolated from ripe and overripe papayas differentially affect galectin-3 inhibition and colon cancer cell growth.

The water-soluble fractions of pectin extracted from the pulp of ripe papayas have already been found to exert positive effects on cancer cell cultures. However, the mechanisms that lead to these beneficial effects and the pectin characteristics that exert these effects are still not well understood. Characteristics such as molecular size, monosaccharide composition and structural conformation are known as polysaccharide factors that can cause alterations in cellular response. During fruit ripening, a major polysaccharide solubilization, depolymerization, and chemical modification occur. The aims of this work are to fractionate the pectin extracted from the pulp of papayas at two stages of ripening (fourth and ninth day after harvesting) into uronic and neutral fractions and to test them for the inhibition of human recombinant galectin-3 and the inhibition of colon cancer cell growth. The structures of the fractions were chemically characterized, and the uronic fraction extracted from the fourth day after harvesting presented the best biological effects across different concentrations in both galectin-3 inhibition and viability assays. The results obtained may help to establish a relationship between the chemical structures of papaya pectins and the positive in vitro biological effects, such as inhibiting cancer cell growth.

Metabolome and proteome of ethylene-treated papayas reveal different pathways to volatile compounds biosynthesis.

Papayas undergo fast postharvest changes triggered by the plant hormone ethylene. Some important pathways have been analyzed in limited studies (transcriptomics and targeted metabolomics); however, broad use of proteomics or untargeted metabolomics have not yet been used in papayas. In this study, two groups of green papayas (150 days after anthesis-physiological maturity for papayas) were treated with ethylene at different times (6 and 12 h) and their metabolic changes in fruit pulp were evaluated with untargeted metabolomics (general metabolites and volatile compounds) and proteomics. Polar metabolites exhibited distinct patterns, especially with regard to some amino and fatty acids during stimulated ripening. In particular, glutamate increased through a possible gamma aminobutyric acid (GABA) shunt and/or proteases activity. Moreover, the stimulated ripening altered the volatile compounds and the protein profiles. The results suggest that changes in membrane breakdown and the resulting oxidative processes could be responsible for volatile compound production, altering some sensorial qualities of papayas, such as pulp softening and the specific papaya linalool volatile compound increment. Thus, GABA levels could also be a strong biological marker for papaya development and ripening stages. This study applied two "omic" techniques that provided insight into how the plant hormone ethylene could influence papaya postharvest quality.

Ingestion of Non-digestible Carbohydrates From Plant-Source Foods and Decreased Risk of Colorectal Cancer: A Review on the Biological Effects and the Mechanisms of Action.

The hypothesis that links the increase in the intake of plant-source foods to a decrease in colorectal cancer (CRC) risk has almost 50 years. Nowadays, systematic reviews and meta-analysis of case-control and cohort studies confirmed the association between dietary patterns and CRC risk, in which the non-digestible carbohydrates (NDC) from plant-source foods are known to play beneficial effects. However, the mechanisms behind the physicochemical properties and biological effects induced by NDC on the decrease of CRC development and progression remain not fully understood. NDC from plant-source foods consist mainly of complex carbohydrates from plant cell wall including pectin and hemicellulose, which vary among foods in structure and in composition, therefore in both physicochemical properties and biological effects. In the present review, we highlighted the mechanisms and described the recent findings showing how these complex NDC from plant-source foods are related to a decrease in CRC risk through induction of both physicochemical effects in the gastrointestinal tract, fermentation-related effects, and direct effects resulting from the interaction between NDC and cellular components including toll-like receptors and galectin-3. Studies support that the definition of the structure-function relationship-especially regarding the fermentation-related effects of NDC, as well as the direct effects of these complex carbohydrates in cells-is crucial for understanding the possible NDC anticancer effects. The dietary recommendations for the intake of NDC are usually quantitative, describing a defined amount of intake per day. However, as NDC from plant-source foods can exert effects that vary widely according to the NDC structure, the dietary recommendations for the intake of NDC plant-source foods are expected to change from a quantitative to a qualitative perspective in the next few years, as occurred for lipid recommendations. Thus, further studies are necessary to define whether specific and well-characterized NDC from plant-source foods induce beneficial effects related to a decrease in CRC risk, thereby improving nutritional recommendations of healthy individuals and CRC patients.

Fast and Furious: Ethylene-Triggered Changes in the Metabolism of Papaya Fruit During Ripening.

Papaya is a climacteric fleshy fruit characterized by fast ripening after harvest. During the relatively short postharvest period, papaya fruit undergoes several changes in metabolism that result in pulp softening and sweetening, as well as the development of a characteristic aroma. Since papaya is one of the most cultivated and appreciated tropical fruit crops worldwide, extensive research has been conducted to not only understand the formation of the quality and nutritional attributes of ripe fruit but also to develop methods for controlling the ripening process. However, most strategies to postpone papaya ripening, and therefore to increase shelf life, have failed to maintain fruit quality. Ethylene blockage precludes carotenoid biosynthesis, while cold storage can induce chilling injury and negatively affect the volatile profile of papaya. As a climacteric fruit, the fast ripening of papaya is triggered by ethylene biosynthesis. The generation of the climacteric ethylene positive feedback loop is elicited by the expression of a specific transcription factor that leads to an up-regulation of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC-oxidase (ACO) expression, triggering the system II ethylene biosynthesis. The ethylene burst occurs about 3 to 4 days after harvest and induces pectinase expression. The disassembling of the papaya cell wall appears to help in fruit sweetness, while glucose and fructose are also produced by acidic invertases. The increase in ethylene production also results in carotenoid accumulation due to the induction of cyclases and hydroxylases, leading to yellow and red/orange-colored pulp phenotypes. Moreover, the production of volatile terpene linalool, an important biological marker for papaya's sensorial quality, is also induced by ethylene. All these mentioned processes are related to papaya's sensorial and nutritional quality. We describe the understanding of ethylene-triggered events that influence papaya quality and nutritional traits, as these characteristics are a consequence of an accelerated metabolism during fruit ripening.

Migration and proliferation of cancer cells in culture are differentially affected by molecular size of modified citrus pectin.

While chemically and thermally modified citrus pectin (MCP) has already been studied for health benefits, it is unknown how size-fractionated oligo- and polysaccharides differentially affect cancer cell behavior. We produced thermally MCP and fractionated it by molecular size to evaluate the effect these polymers have on cancer cells. MCP30/10 (between 30 and 10 kDa) had more esterified homogalacturonans (HG) and fewer rhamnogalacturonans (RG-I) than MCP and MCP30 (higher than 30 kDa), while MCP10/3 (between 10 and 3 kDa) showed higher amounts of type I arabinogalactans (AGI) and lower amounts of RG-I. MCP3 (smaller than 3 kDa) presented less esterified HG and the lowest amount of AGI and RG-I. Our data indicate that the enrichment of de-esterified HG oligomers and the AGI and RG-I depletions in MCP3, or the increase of AGI and loss of RGI in MCP30/10, enhance the anticancer behaviors by inhibiting migration, aggregation, and proliferation of cancer cells.

Chelate-soluble pectin fraction from papaya pulp interacts with galectin-3 and inhibits colon cancer cell proliferation.

Colorectal cancer has an overexpression of galectin-3 that is related to cancer progression. A decreased risk of colon cancer can be related to consumption of dietary fibers, but the entire mechanism by which this protection occurs remains unclear. Pectin is a type of dietary fiber that possesses ß-galactosides and can bind and inhibit galectin-3-mediated effects. Papaya fruit has a massive cell wall disassembling during ripening that naturally changes its pectin structure. Our work shows that different points in the ripening time of papaya fruit exhibit pectins (chelate-soluble fractions; CSF) that can or cannot inhibit galectin-3. The fraction that inhibits galectin-3 (3CSF) also diminishes the proliferation of colon cancer cell lines, and it is derived from an intermediate point of papaya ripening. Therefore, we related this to a papaya pectin structure-dependent effect, and the papaya fruit seems to have a pectin structure that is promising in decreasing the risk of colon cancer development.

Ripening-induced chemical modifications of papaya pectin inhibit cancer cell proliferation.

Papaya (Carica papaya L.) is a fleshy fruit with a rapid pulp softening during ripening. Ripening events are accompanied by gradual depolymerization of pectic polysaccharides, including homogalacturonans, rhamnogalacturonans, arabinogalactans, and their modified forms. During intermediate phases of papaya ripening, partial depolymerization of pectin to small size with decreased branching had enhanced pectin anti-cancer properties. These properties were lost with continued decomposition at later phases of ripening. Pectin extracted from intermediate phases of papaya ripening markedly decreased cell viability, induced necroptosis, and delayed culture wound closing in three types of immortalized cancer cell lines. The possible explanation for these observations is that papaya pectins extracted from the third day after harvesting have disrupted interaction between cancer cells and the extracellular matrix proteins, enhancing cell detachment and promoting apoptosis/necroptosis. The anticancer activity of papaya pectin is dependent on the presence and the branch of arabinogalactan type II (AGII) structure. These are first reports of AGII in papaya pulp and the first reports of an in vitro biological activity of papaya pectins that were modified by natural action of ripening-induced pectinolytic enzymes. Identification of the specific pectin branching structures presents a biological route to enhancing anti-cancer properties in papaya and other climacteric fruits.

Análise da expressão gênica durante o amadurecimento do mamão papaia e identificação de genes relacionados com a qualidade pós-colheita do fruto / Analysis of the gene expression during papaya fruit ripening and identification of genes related with the postharvest quality

Durante o amadurecimento ocorrem profundas alterações na composição química dos frutos e a expressão gênica desempenha papel fundamental no controle desse processo. Apesar da importância comercial do mamão, as informações a respeito da expressão gênica durante o amadurecimento são limitadas. Assim, nessa tese, técnicas de estabelecimento de perfis de RNA mensageiro, como Differential Display-PCR, cDNA-AFLP e Cross-Species Microarray, foram aplicadas para a identificação de genes com expressão alterada. Alguns genes ligados ao metabolismo e transporte de açúcares, de lipídeos e carotenóides, à degradação de parede celular e stress, e fatores de transcrição dependentes e independentes de hormônios vegetais pareceram apresentar diferenças de expressão durante o amadurecimento do mamão papaia. O isolamento dos genes diferencialmente expressos permitiu traçar um panorama da expressão gênica do fruto e, dessa maneira, a relação das funções dos genes com o amadurecimento do mamão contribuiu para o aumento do entendimento acerca da qualidade pós-colheita do fruto.

Papaya fruit ripening: response to ethylene and 1-methylcyclopropene (1-MCP).

Ripening affects the quality and nutritional contents of fleshy fruits, and papayas are climacteric fruits very susceptible to postharvest losses due to the fast softening caused by ethylene. This paper reports the changes in respiration, ethylene production, and pulp color and firmness, along with the contents of soluble sugars and major carotenoids, during ripening of 'Golden' papaya, an important Brazilian cultivar that has been exported to North American and European markets. The results obtained for nontreated and ethylene- or 1-MCP-treated papaya suggest that 1-MCP can decrease the quality of treated fruit and that even the use of ethylene for triggering or inducing homogeneous ripening can result in lower quality when compared to that of fruit allowed to ripe naturally.