Prevention of azoxymethane/dextran sodium sulfate-induced mouse colon carcinogenesis by processed Aloe vera gel

Aloe vera-An Extensive Review Focused on Recent Studies

Since ancient times, Aloe vera L. (AV) has attracted scientific interest because of its multiple cosmetic and medicinal properties, attributable to compounds present in leaves and other parts of the plant. The collected literature data show that AV and its products have a beneficial influence on human health, both by topical and oral use, as juice or an extract. Several scientific studies demonstrated the numerous biological activities of AV, including, for instance, antiviral, antimicrobial, antitumor, and antifungal. Moreover, its important antidepressant activity in relation to several diseases, including skin disorders (psoriasis, acne, and so on) and prediabetes, is a growing field of research. This comprehensive review intends to present the most significant and recent studies regarding the plethora of AV's biological activities and an in-depth analysis exploring the component/s responsible for them. Moreover, its morphology and chemical composition are described, along with some studies regarding the single components of AV available in commerce. Finally, valorization studies and a discussion about the metabolism and toxicological aspects of this "Wonder Plant" are reported.

Oat Beta-Glucan as a Metabolic Regulator in Early Stage of Colorectal Cancer-A Model Study on Azoxymethane-Treated Rats

Factors that reduce the risk of developing colorectal cancer include biologically active substances. In our previous research, we demonstrated the anti-inflammatory, immunomodulatory, and antioxidant effects of oat beta-glucans in gastrointestinal disease models. The aim of this study was to investigate the effect of an 8-week consumption of a diet supplemented with low-molar-mass oat beta-glucan in two doses on the antioxidant potential, inflammatory parameters, and colonic metabolomic profile in azoxymethane(AOM)-induced early-stage colorectal cancer in the large intestine wall of rats. The results showed a statistically significant effect of AOM leading to the development of neoplastic changes in the colon. Consumption of beta-glucans induced changes in colonic antioxidant potential parameters, including an increase in total antioxidant status, a decrease in the superoxide dismutase (SOD) activity, and a reduction in thiobarbituric acid reactive substance (TBARS) concentration. In addition, beta-glucans decreased the levels of pro-inflammatory interleukins (IL-1α, IL-1β, IL-12) and C-reactive protein (CRP) while increasing the concentration of IL-10. Metabolomic studies confirmed the efficacy of oat beta-glucans in the AOM-induced early-stage colon cancer model by increasing the levels of metabolites involved in metabolic pathways, such as amino acids, purine, biotin, and folate. In conclusion, these results suggest a wide range of mechanisms involved in altering colonic metabolism during the early stage of carcinogenesis and a strong influence of low-molar-mass oat beta-glucan, administered as dietary supplement, in modulating these mechanisms.

Consumption of Feed Supplemented with Oat Beta-Glucan as a Chemopreventive Agent against Colon Cancerogenesis in Rats

Colorectal cancer (CRC) accounts for 30% of all cancer cases worldwide and is the second leading cause of cancer-related deaths. CRC develops over a long period of time, and in the early stages, pathological changes can be mitigated through nutritional interventions using bioactive plant compounds. Our study aims to determine the effect of highly purified oat beta-glucan on an animal CRC model. The study was performed on forty-five male Sprague-Dawley rats with azoxymethane-induced early-stage CRC, which consumed feed containing 1% or 3% low molar mass oat beta-glucan (OBG) for 8 weeks. In the large intestine, morphological changes, CRC signaling pathway genes (RT-PCR), and proteins (Western blot, immunohistochemistry) expression were analyzed. Whole blood hematology and blood redox status were also performed. Results indicated that the histologically confirmed CRC condition led to a downregulation of the WNT/β-catenin pathway, along with alterations in oncogenic and tumor suppressor gene expression. However, OBG significantly modulated these effects, with the 3% OBG showing a more pronounced impact. Furthermore, CRC rats exhibited elevated levels of oxidative stress and antioxidant enzyme activity in the blood, along with decreased white blood cell and lymphocyte counts. Consumption of OBG at any dose normalized these parameters. The minimal effect of OBG in the physiological intestine and the high activity in the pathological condition suggest that OBG is both safe and effective in early-stage CRC.

A New Biomaterial Derived from Aloe vera-Acemannan from Basic Studies to Clinical Application

Aloe vera is a kind of herb rich in polysaccharides. Acemannan (AC) is considered to be a natural polysaccharide with good biodegradability and biocompatibility extracted from Aloe vera and has a wide range of applications in the biomedical field due to excellent immunomodulatory, antiviral, antitumor, and tissue regeneration effects. In recent years, clinical case reports on the application of AC as a novel biomedical material in tissue regenerative medicine have emerged; it is mainly used in bone tissue engineering, pulp-dentin complex regeneration engineering, and soft tissue repair, among other operations. In addition, multiple studies have proved that the new composite products formed by the combination of AC and other compounds have excellent biological and physical properties and have broader research prospects. This paper introduces the preparation process, surface structure, and application forms of AC; summarizes the influence of acetyl functional group content in AC on its functions; and provides a detailed review of the functional properties, laboratory studies, clinical cutting-edge applications, and combined applications of AC. Finally, the current application status of AC from basic research to clinical treatment is analyzed and its prospects are discussed.

Aloe vera gel extract: Safety evaluation for acute and chronic oral administration in Sprague-Dawley rats and anticancer activity in breast and lung cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe vera (L.) Burm. f. is a typical traditional Chinese medicine (TCM) collected in the Pharmacopoeia of the People's Republic of China (version 2015). It has been traditionally used for the treatment of constipation, and its potential therapeutic activities have been widely evaluated, including anti-tumor, anti-inflammatory and immune regulatory effects. The wide application of Aloe vera in food and therapy has raised safety issues and there are multiple safety assessments with a diverse toxicity and adverse effects from clinics and animals.

AIM OF THE STUDY

This study aimed to investigate the safety of Aloe vera barbadensis extract C (AVBEC) in rats and analyze its anticancer activity in cell lines.

MATERIALS AND METHODS

We administrated AVBEC orally in an acute toxicity study and a 6-month chronic toxicity study to observe and confirm its safety in Sprague-Dawley (SD) rats. Additionally, we explored the cytotoxicity of AVBEC in cancer cells and non-cancer cells. We further investigated the anti-tumor activity of AVBEC, and in the meantime, probed the function of component from AVBEC.

RESULTS

No deaths or substance-relative toxicity were observed in the acute toxicity study or the 6-month chronic toxicity study with doses of 44.8 g·kg^-1 and 4.48 g·kg^-1, respectively. In the chronic toxicity study, AVBEC did not cause organ toxicity, including crucial organ structure and chemical function, and peripheral and central immune system damage. Additionally, we found that AVBEC could induce cancer cell apoptosis with a relatively higher apoptotic ratio than in non-cancer cells by decreasing adenosine triphosphate (ATP) concentration and enhancing reactive oxygen species (ROS) production. We also identified components in AVBEC using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) and probed the function of malic acid. This demonstrated that under the same circumstances, malic acid induced cell necrosis in cancer cells and non-cancer cells, while AVBEC did not.

CONCLUSIONS

These results reveal a novel mechanism of aloe gel extract in regulating cancer cell apoptosis via modulating the mitochondrial metabolism and imply a possible application of AVBEC for the treatment of malignant cancer with the safety evaluation from rats and anticancer investigation from cancer cells and non-cancer cells.

The Renaissance of Plant Mucilage in Health Promotion and Industrial Applications: A Review

Plant mucilage is a renewable and cost-effective source of plant-based compounds that are biologically active, biodegradable, biocompatible, nontoxic, and environmentally friendly. Until recently, plant mucilage has been of interest mostly for technological purposes. This review examined both its traditional uses and potential modern applications in a new generation of health-promoting foods, as well as in cosmetics and biomaterials. We explored the nutritional, phytochemical, and pharmacological richness of plant mucilage, with a particular focus on its biological activity. We also highlighted areas where more research is needed in order to understand the full commercial potential of plant mucilage.

Aloe polysaccharides ameliorate acute colitis in mice via Nrf2/HO-1 signaling pathway and short-chain fatty acids metabolism

Aloe polysaccharides (APs) are acetyl polysaccharides. It has been reported APs could protect mice from ulcerative colitis (UC), but the complex interactions between APs and the intestinal barrier were unclear. Here, we investigated the relationship between APs and UC, and determined the synergistic effects of Nrf2/HO-1 signaling pathway and short-chain fatty acids (SCFAs) metabolism on protecting intestinal barrier in acute UC mice. Results showed APs could scavenge free radicals in vitro. In vivo, APs had the antioxidant and anti-inflammatory effect both in serum and colon. Besides, the pathological results showed APs could alleviate colonic lesions. Furthermore, our study indicated treatment with APs effectively increased SCFAs production. The inhibition of acute UC in mice was correlated with the APs-mediated effects on improving the expression of ZO-1, occludin, Nrf2, HO-I, and NQO1. Thus, APs effectively promoted the intestinal barrier via Nrf2/HO-1 signaling pathway and SCFAs metabolism, effectively ameliorating acute colitis in mice.

Animal Models of Colorectal Cancer: From Spontaneous to Genetically Engineered Models and Their Applications

Colorectal cancer is one of the most common gastrointestinal malignancies in humans, affecting approximately 1.8 million people worldwide. This disease has a major social impact and high treatment costs. Animal models allow us to understand and follow the colon cancer progression; thus, in vivo studies are essential to improve and discover new ways of prevention and treatment. Dietary natural products have been under investigation for better and natural prevention, envisioning to show their potential. This manuscript intends to provide the readers a review of rodent colorectal cancer models available in the literature, highlighting their advantages and disadvantages, as well as their potential in the evaluation of several drugs and natural compounds’ effects on colorectal cancer.

Study on fecal fermentation characteristics of aloe polysaccharides in vitro and their predictive modeling

Aloe polysaccharides (APs) are well-known plant polysaccharides, but little is known about their digestion and fermentation characteristics in vitro. In this study, the molecular weight of APs had no significant changes after gastric and intestinal digestion. During the fecal fermentation, the content of volatiles and pH value decreased continuously, while the short-chain fatty acids (SCFAs) concentration increased significantly. Additionally, the abundance of the microbiota associated with the metabolism of SCFAs was increased, including Prevotella, Catenibacterium, Lachnospiraceae, and Coprococcus, while the harmful microbiota was decreased, like Escherichia-Shigella, and Veillonella. Moreover, bioinformatics analysis indicated that APs boosted fructose and mannose metabolism, and the gene expressions of enzymes, containing mannose-6-phosphate isomerase [EC:5.3.1.8]. Structural equation modeling also highlighted that SCFAs-producing microbiota were primary degraders of APs, suggesting APs may facilitate the manufacture of functional foods with the purpose of maintaining intestinal health.

Inhibitory Effects of Bound Polyphenol from Foxtail Millet Bran on Colitis-Associated Carcinogenesis by the Restoration of Gut Microbiota in a Mice Model

Colorectal cancer (CRC) is a common malignant tumor occurring in the colon. It has been known that the gut microbiota is a complex ecosystem and plays an important role in the pathogenesis of colorectal cancer. Our previous study showed that bound polyphenol of the inner shell (BPIS) from foxtail millet bran exhibited significant antitumor activities in cancer cells and nude mice models. In the present study, the anticancer potential of BPIS is evaluated in the azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced mouse CRC model. Results showed that BPIS could decrease the number and volume of tumors and protect the epithelial architecture from damage. Certain biomarkers associated with CRC formation, such as COX-2, EMR1, PCNA, and caspase-3, were strongly changed by BPIS. Moreover, by 16S rRNA gene sequence analysis, it was found that BPIS could remodel the overall structure of the gut microbiota from tumor-bearing mice toward that of the normal counterparts, including two phyla and eight genera, together with regulations on several genes that are responsible for 17 signaling pathways.

Ameliorative Effect of Heat-Killed Lactobacillus plantarum L.137 and/or Aloe vera against Colitis in Mice

Inflammatory bowel disease (IBD) is one of the predominant intestinal diseases associated with chronic inflammation and ulceration of the colon. This study explored the ameliorative effect of Aloe vera extract (Aloe) and/or heat-killed Lactobacillus plantarum L.137 (HK L.137) on dextran sodium sulfate (DSS)-induced colitis in mice. Aloe and/or HK L.137 were supplied for 9 days and the mice were challenged with DSS for 7 days. The DSS group demonstrated bloody diarrhea, colitis of high histologic grade, increased nuclear factor-kappa B (NF-κB) p65, inducible nitric oxide synthase (iNOS), myeloperoxidase (MPO), interleukin (IL)-6, and tumor necrosis factor (TNF)-α, and decreased IL-10 expression. These alterations were dwindled in DSS-induced mice treated with Aloe and HK L.137 separately. Aloe and HK L.137 together have augmented the therapeutic effect of each other. In conclusion, our findings demonstrated that Aloe and/or HK L.137 ameliorated DSS-induced colitis by promoting the secretion of anti-inflammatory cytokines and suppressing pro-inflammatory mediators. This study indicated that A. vera may function synergistically with HK L.137 to confer an effective strategy to prevent colitis.

Medicinal Plants in the Prevention and Treatment of Colon Cancer

The standard treatment for cancer is generally based on using cytotoxic drugs, radiotherapy, chemotherapy, and surgery. However, the use of traditional treatments has received attention in recent years. The aim of the present work was to provide an overview of medicinal plants effective on colon cancer with special emphasis on bioactive components and underlying mechanisms of action. Various literature databases, including Web of Science, PubMed, and Scopus, were used and English language articles were considered. Based on literature search, 172 experimental studies and 71 clinical cases on 190 plants were included. The results indicate that grape, soybean, green tea, garlic, olive, and pomegranate are the most effective plants against colon cancer. In these studies, fruits, seeds, leaves, and plant roots were used for in vitro and in vivo models. Various anticolon cancer mechanisms of these medicinal plants include induction of superoxide dismutase, reduction of DNA oxidation, induction of apoptosis by inducing a cell cycle arrest in S phase, reducing the expression of PI3K, P-Akt protein, and MMP as well; reduction of antiapoptotic Bcl-2 and Bcl-xL proteins, and decrease of proliferating cell nuclear antigen (PCNA), cyclin A, cyclin D1, cyclin B1 and cyclin E. Plant compounds also increase both the expression of the cell cycle inhibitors p53, p21, and p27, and the BAD, Bax, caspase 3, caspase 7, caspase 8, and caspase 9 proteins levels. In fact, purification of herbal compounds and demonstration of their efficacy in appropriate in vivo models, as well as clinical studies, may lead to alternative and effective ways of controlling and treating colon cancer.

A Systematic Review Exploring the Anticancer Activity and Mechanisms of Glucomannan

Glucomannan, long recognized as the active ingredient of the traditional Chinese medicinal herb Konjac glucomannan, is a naturally occurring polysaccharide existing in certain plant species and fungi. Due to its special property to also serve as a dietary supplement, glucomannan has been widely applied in clinic to lower body weight and circulation cholesterol level and to treat constipation, diabetes, and arterial sclerosis. Besides the regulatory role engaged with gastroenterological and metabolic syndrome, recently, its therapeutic effect and the underlying mechanisms in treating cancerous diseases have been appreciated by mounting researches. The present review aims to emphasize the multifaceted aspects of how glucomannan exerts its anti-tumor function.

Extraction, Purification, Structural Characteristics, Biological Activities and Pharmacological Applications of Acemannan, a Polysaccharide from Aloe vera: A Review

Aloe vera is a medicinal plant species of the genus Aloe with a long history of usage around the world. Acemannan, considered one of the main bioactive polysaccharides of Aloe vera, possesses immunoregulation, anti-cancer, anti-oxidation, wound healing and bone proliferation promotion, neuroprotection, and intestinal health promotion activities, among others. In this review, recent advancements in the extraction, purification, structural characteristics and biological activities of acemannan from Aloe vera were summarized. Among these advancements, the structural characteristics of purified polysaccharides were reviewed in detail. Meanwhile, the biological activities of acemannan from Aloe vera determined by in vivo, in vitro and clinical experiments are summarized, and possible mechanisms of these bioactivities were discussed. Moreover, the latest research progress on the use of acemannan in dentistry and wound healing was also summarized in details. The structure-activity relationships of acemannan and its medical applications were discussed. Finally, new perspectives for future research work on acemannan were proposed. In conclusion, this review summarizes the extraction, purification, structural characteristics, biological activities and pharmacological applications of acemannan, and provides information for the industrial production and possible applications in dentistry and wound healing in the future.

The inhibitory effect of polysaccharide from Rhizopus nigricans on colitis-associated colorectal cancer

An extracellular polysaccharide (EPS1-1) of Rhizopus nigricans was found to enhance immunity and reduce colon cancer cell proliferation. Here, the effect of EPS1-1 on a mouse model of colitis-associated cancer (CAC) induced by azoxymethane (AOM)/dextran sodium sulfate (DSS) was investigated. Pathological symptoms, including weight loss, piloerection, hematochezia and insensitivity caused by AOM/DSS, were relieved by EPS1-1. Anatomical results showed a 100% tumor incidence, a series of neoplasms, disordered cell structure and hyperplastic glands in the model group, while the abnormal behaviors were relieved and the tumors decreased in the EPS1-1 group. Compared with the model group, the EPS1-1 group showed decreased oncogenic protein (COX-2, β-catenin, CyclinD1 and C-Myc) expression. TUNEL staining showed that EPS1-1 increased the apoptosis of colon cancer cells in mice. Furthermore, the expression of proliferative proteins (Ki-67 and PCNA) and an antiapoptotic gene transcript (Bcl-2) were significantly down regulated by EPS1-1, while apoptotic gene transcripts (p53 and Bax) were enhanced. In addition, EPS1-1 notably decreased the number of cells positive for CD68, F4/80 and NF-κB and reduced the concentrations of inflammatory factors (TNF-α and IL-6) in serum compared with those in the model group. Taken together, these results suggest that EPS1-1 may be a therapeutic option for the prevention and treatment of CAC.

Glucocorticoids promote the development of azoxymethane and dextran sulfate sodium-induced colorectal carcinoma in mice

BACKGROUND

Stress has been suggested as a promoter of tumor growth and development. Glucocorticoids (GCs) are the main stress hormones and widely prescribed as drugs. However, the effect of GCs on the development and progression of colorectal carcinoma (CRC) is unclear.

METHODS

We evaluated the effect of corticosterone (CORT) on azoxymethane and dextran sulfate sodium (AOM/DSS)-induced carcinogenesis in the colorectum of C57BL/6 strain mice. Plasma level of CORT was detected by radioimmunoassay. The expression of proliferation markers (Ki-67 and PCNA), nuclear factor (NF)-κB p65 and phosphoto-p65 (P-p65), as well as cyclooxygenase (COX)-2 were determined by immunohistochemistry. Inflammation in colorectum was evaluated by histopathology.

RESULTS

CORT feeding in drinking water of mice not only significantly elevated plasma CORT concentration, but also significantly increased the incidence and neoplasms burden (number and size of neoplasms) in colorectum. CORT also significant enhanced the expression of cell proliferation marker (Ki-67 and PCNA), NF-κB p65 and P-p65 as well as COX-2 in colorectal neoplasm of AOM/DSS-treated mice.

CONCLUSION

In this study, we have found for the first time that CORT at stress level potentially promotes the growth and development of AOM/DSS-induced colorectal adenoma and carcinoma in mice. Up-regulation of NF-κB and COX-2 may be involved in the promoting effect of CORT.

Emu Oil Improves Clinical Indicators of Disease in a Mouse Model of Colitis-Associated Colorectal Cancer

BACKGROUND/AIMS

Ulcerative colitis is a remitting and relapsing inflammatory bowel disorder. Current treatments are limited, and if poorly controlled, colitis may progress to colorectal cancer. Previously, Emu Oil protected the intestine in experimental models of gut damage. We aimed to determine whether Emu Oil could reduce the severity of chronic colitis and prevent the onset of neoplasia in a mouse model of colitis-associated colorectal cancer.

METHODS

Female C57BL/6 mice were injected (day 0) with azoxymethane, followed by ad libitum access to three dextran sulfate sodium/water cycles (7 days of dextran sulfate sodium and 14 days of water). Mice (n = 9/group) were orally administered either water or Emu Oil (low dose 80 µL or high dose 160 µL), thrice weekly for 9 weeks. Bodyweight and disease activity index were measured daily. Colitis progression was monitored by colonoscopy on days 20, 41 and 62. At killing, tumor number and size were recorded.

RESULTS

Azoxymethane/dextran sulfate sodium induced significant bodyweight loss (maximum 24%) which was attenuated by Emu Oil treatment (low dose days 9, 10, 14: maximum 7%; high dose days 7-15, 30-36: maximum 11%; p < 0.05). Emu Oil reduced disease activity index of azoxymethane/dextran sulfate sodium mice at most time points (maximum 20%; p < 0.05). Additionally, Emu Oil reduced colonoscopically assessed colitis severity (days 20 and 62) compared to disease controls (p < 0.05). Finally, in azoxymethane/dextran sulfate sodium mice, low-dose Emu Oil resulted in fewer small colonic tumors (p < 0.05) compared to controls.

CONCLUSIONS

Emu Oil improved clinical indicators and reduced severity of colitis-associated colorectal cancer, suggesting therapeutic potential in colitis management.

Chemopreventive Strategies for Inflammation-Related Carcinogenesis: Current Status and Future Direction

A sustained and chronically-inflamed environment is characterized by the presence of heterogeneous inflammatory cellular components, including neutrophils, macrophages, lymphocytes and fibroblasts. These infiltrated cells produce growth stimulating mediators (inflammatory cytokines and growth factors), chemotactic factors (chemokines) and genotoxic substances (reactive oxygen species and nitrogen oxide) and induce DNA damage and methylation. Therefore, chronic inflammation serves as an intrinsic niche for carcinogenesis and tumor progression. In this article, we summarize the up-to-date findings regarding definitive/possible causes and mechanisms of inflammation-related carcinogenesis derived from experimental and clinical studies. We also propose 10 strategies, as well as candidate agents for the prevention of inflammation-related carcinogenesis.