Fe3O4-Coated CNTs-Gum Arabic Nano-Hybrid Composites Exhibit Enhanced Anti-Leukemia Potency Against AML Cells via ROS-Mediated Signaling.

Background: Prior studies on magnetite (Fe3O4) NPs and carbon nanotubes (CNTs) cytotoxic effects against acute myeloid leukemia (AML) are inconclusive rather than definitive. Purpose: Investigation of the effects of Gum Arabic (GA)-stabilized/destabilized Fe3O4 NPs and CNTs, alone or in combination, on AML cell proliferation. Methods: Hybrid NPs were synthesized, characterized, and assessed for their cytotoxicity against Kasumi-1, HL-60, and THP-1 in comparison to normal primary bone marrow CD34+ cells. The molecular pathways of nanostructures' cytotoxicity were also investigated. Results: The Fe3O4 NPs were effectively synthesized and attached to the surface of the CNTs, resulting in the formation of a novel hybrid through their interaction with the GA colloidal solution in an aqueous media. Although the evaluated nanostructured nanoparticles had significant growth suppression ability against the leukemia cell lines, with IC50 values ranging from 42.437 to 189.842 µg/mL, they exhibited comparatively modest toxicity towards normal hematopoietic cells (IC50: 113.529‒162.656 µg/mL). The incorporation of Fe3O4 NPs with CNTs in a hybrid nanocomposite significantly improved their effectiveness against leukemia cells, with the extent of improvement varying depending on the specific cell type. The nanostructured particles were stabilized by GA, which enhances their ability to inhibit cell proliferation in a manner that depends on the specific cell type. Also, nanoparticles exhibit cytotoxicity due to their capacity to stimulate the production of intracellular ROS, halt the cell cycle at the G1 phase, and induce apoptosis. This is supported by the activation of p53, BAX, cytochrome C, and caspase-3, which are triggered by ROS. The nanostructures lead to an increase in the expression of genes encoding proteins related to oxidative stress (SIRT1, FOXO3, NFE2L2, and MAP3K5) and cyclin-dependent kinase inhibitors (CDKN1A and CDKN1B) in response to ROS. Conclusion: We provide an effective Fe3O4 NPs/CNTs nano-hybrid composite that induces apoptosis and has strong anti-leukemic capabilities. This hybrid nanocomposite is promising for in vivo testing and validation.

Co-Supplementation of Baobab Fiber and Arabic Gum Synergistically Modulates the In Vitro Human Gut Microbiome Revealing Complementary and Promising Prebiotic Properties.

Arabic gum, a high molecular weight heteropolysaccharide, is a promising prebiotic candidate as its fermentation occurs more distally in the colon, which is the region where most chronic colonic diseases originate. Baobab fiber could be complementary due to its relatively simple structure, facilitating breakdown in the proximal colon. Therefore, the current study aimed to gain insight into how the human gut microbiota was affected in response to long-term baobab fiber and Arabic gum supplementation when tested individually or as a combination of both, allowing the identification of potential complementary and/or synergetic effects. The validated Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), an in vitro gut model simulating the entire human gastrointestinal tract, was used. The microbial metabolic activity was examined, and quantitative 16S-targeted Illumina sequencing was used to monitor the gut microbial composition. Moreover, the effect on the gut microbial metabolome was quantitatively analyzed. Repeated administration of baobab fiber, Arabic gum, and their combination had a significant effect on the metabolic activity, diversity index, and community composition of the microbiome present in the simulated proximal and distal colon with specific impacts on Bifidobacteriaceae and Faecalibacterium prausnitzii. Despite the lower dosage strategy (2.5 g/day), co-supplementation of both compounds resulted in some specific synergistic prebiotic effects, including a biological activity throughout the entire colon, SCFA synthesis including a synergy on propionate, specifically increasing abundance of Akkermansiaceae and Christensenellaceae in the distal colon region, and enhancing levels of spermidine and other metabolites of interest (such as serotonin and ProBetaine).

Tyrosol-gold nanoparticle functionalized acacia gum-PVA nanofibers for mitigation of Candida biofilm.

Increasing incidences of fungal infections and prevailing antifungal resistance in healthcare settings has given rise to an antifungal crisis on a global scale. The members of the genus Candida, owing to their ability to acquire sessile growth, are primarily associated with superficial to invasive fungal infections, including the implant-associated infections. The present study introduces a novel approach to combat the sessile/biofilm growth of Candida by fabricating nanofibers using a nanoencapsulation approach. This technique involves the synthesis of tyrosol (TYS) functionalized chitosan gold nanocomposite, which is then encapsulated into PVA/AG polymeric matrix using electrospinning. The FESEM, FTIR analysis of prepared TYS-AuNP@PVA/AG NF suggested the successful encapsulation of TYS into the nanofibers. Further, the sustained and long-term stability of TYS in the medium was confirmed by drug release and storage stability studies. The prepared nanomats can absorb the fluid, as evidenced by the swelling index of the nanofibers. The growth and biofilm inhibition, as well as the disintegration studies against Candida, showed 60-70 % biofilm disintegration when 10 mg of TYS-AuNP@PVA/AG NF was used, hence confirming its biological effectiveness. Subsequently, the nanofibers considerably reduced the hydrophobicity index and ergosterol content of the treated cells. Considering the challenges associated with the inhibition/disruption of fungal biofilm, the fabricated nanofibers prove their effectiveness against Candida biofilm. Therefore, nanocomposite-loaded nanofibers have emerged as potential materials that can control fungal colonization and could also promote healing.

Effect of cevimeline and different concentration of gum arabic on parotid salivary gland function in methotrexate-induced xerostomia: a comparative study.

OBJECTIVE: This study assessed the effect of cevimeline and different concentrations of gum arabic on the parotid gland of rats being given xerostomia-inducing methotrexate. METHODS: One hundred twenty-five rats were divided into five equal groups of twenty-five each. The rats in Group I received basic diets, while those in Groups II, III, IV, and V received 20 mg/kg MTX as a single intraperitoneal dose on day one. Group III received 10 mg/kg CVM dissolved in saline orally and daily, and the other two groups received a 10% W/V aqueous suspension of GA. Therefore, Group IV received 2 ml/kg suspension orally and daily, while Group V received 3 ml/kg suspension orally and daily. After 9 days, the parotid glands were dissected carefully and prepared for hematoxylin and eosin (H&E) staining as a routine histological stain and caspase-3 and Ki67 immunohistochemical staining. Quantitative data from α-Caspase-3 staining and Ki67 staining were statistically analysed using one-way ANOVA followed by Tukey's multiple comparisons post hoc test. RESULTS: Regarding caspase-3 and Ki67 immunohistochemical staining, one-way ANOVA revealed a significant difference among the five groups. For Caspase-3, the highest mean value was for group II (54.21 ± 6.90), and the lowest mean value was for group I (15.75 ± 3.67). The other three groups had mean values of 31.09 ± 5.90, 30.76 ± 5.82, and 20.65 ± 3.47 for groups III, IV, and V, respectively. For Ki67, the highest mean value was for group I (61.70 ± 6.58), and the lowest value was for group II (18.14a ± 5.16). The other three groups had mean values of 34.4 ± 9.27, 48.03 ± 8.40, and 50.63 ± 8.27 for groups III, IV, and V, respectively. CONCLUSION: GA, rather than the normally used drug CVM, had a desirable effect on the salivary glands of patients with xerostomia.

Self-healing hydrogel based on poly (vinyl alcohol)-poly (lysine)-gum arabic accelerates diabetic wound healing under photothermal sterilization.

Diabetic wounds are a significant clinical challenge. Developing effective antibacterial dressings is crucial for preventing wound ulcers caused by bacterial infections. In this study, a self-healing antibacterial hydrogel (polyvinyl alcohol (PVA)-polylysine-gum arabic, PLG hydrogels) with near-infrared photothermal response was prepared by linking PVA and a novel polysaccharide-amino acid compound (PG) through borate bonding combined with freeze-thaw cycling. Subsequently, the hydrogel was modified by incorporating inorganic nanoparticles (modified graphene oxide (GM)). The experimental results showed that the PLGM3 hydrogels (PLG@GM hydrogels, 3.0 wt%) could effectively kill bacteria and promote diabetic wound tissue healing under 808-nm near-infrared laser irradiation. Therefore, this hydrogel system provides a new idea for developing novel dressings for treating diabetic wounds.

Construction of nanoparticles from blueberry anthocyanins-lecithin/gum Arabic improves lipid droplet accumulation and gut microbiota disturbance in HFD-induced obese mice.

The digestive instability of anthocyanins (ACNs) limits their application in food nutrition, especially precision nutrition. Blueberry ACNs-loaded nanoparticles (Lipo/GA-ACNs NPs) were prepared using gum arabic (GA) as the delivery carrier and liposomal vesicles (Lipo) prepared from soy lecithin as the targeting scaffold. The average particle size of the NPs was 99.4 nm, and the polydispersion index (PDI) was 0.46. The results showed that the presence of the Lipo-GA matrix enhanced the NPs' in vitro stability and antioxidant activity. In addition, the in vitro biocompatibility, uptake ability, lipid-lowering activity, and free-radical scavenging ability were improved to a certain extent. In a high-fat diet (HFD)-induced obese mouse model, oral administration of ACNs-LNP (LNP, liver-targeted nanoparticle) showed better effects on body weight, liver injury, and lipid droplet accumulation in the liver than ACNs. In addition, ACNs-LNP also played a role in regulating HFD-induced gut microbiota imbalance. These results provide a promising ACNs delivery strategy with the potential to be developed into a functional food that targets the liver to prevent fatty liver.

Nutritional profiling, fiber content and in vitro bioactivities of wheat-based biscuits formulated with novel ingredients.

This study evaluated the nutritional profile and fiber content of innovative formulations of wheat-based biscuits enriched with chia seeds, carob flour and coconut sugar. The in vitro antioxidant, cytotoxic, anti-inflammatory and antimicrobial activities were also investigated to understand the potential health advantages of the incorporation of these new ingredients. The novel biscuits demonstrated significant improvements in protein and mineral content, with increases of 50% and 100% in chia biscuits, and up to 20% and 40% in carob biscuits, respectively. Fiber also notably increased, particularly in samples containing 10% carob flour, which increased four times as compared to wheat-based samples. The new ingredients exhibited antibacterial and antifungal activity, particularly against Yersinia enterocolitica (minimum inhibitory concentration 1.25 mg mL-1 in coconut sugar) and Aspergillus fumigatus (minimum inhibitory concentration/minimum fungicidal concentrations 2.5/5 mg mL-1 in chia seeds). However, the final biscuits only displayed antifungal properties. Carob flour and chia seeds had a remarkably high capacity to inhibit the formation of TBARS and promoted greater antioxidant activity in biscuit formulations, with EC50 values decreasing from 23.25 mg mL-1 (control) to 4.54 mg mL-1 (15% defatted ground chia seeds) and 1.19 mg mL-1 (10% carob flour). Only chia seeds exhibited cellular antioxidant, anti-inflammatory and cytotoxic activity, attributes that were lost when seeds were added into the biscuits. These findings highlight the potential health benefits of these ingredients, particularly when incorporated in new wheat-based formulations.

Gum Arabic assisted the biomass synthesis of bimetallic silver copper oxide nanoparticles using gamma-rays for improving bacterial and viral wound healing: Promising antimicrobial activity against foot and mouth disease.

In this work, gamma irradiation was used to create bimetallic silver­copper oxide nanoparticles (Ag-CuO NPs) in an ecologically acceptable way using gum Arabic (GA) polymer as a capping and reducing agent. Bimetallic Ag-CuO NPs were investigated through UV-Vis. spectroscopy, HR-TEM, SEM, DLS, and XRD examinations. The potency of antimicrobial and antibiofilm activities against a few bacterial isolates and Candida sp. had been investigated. Clinical investigations of 30 cows and 20 buffaloes from different sites in Egypt's Sharkia governorate found ulcerative lesions on the mouth and interdigital region. The cytotoxic assay of the generated NPs on BHK-21 was examined. The bimetallic Ag-CuO NPs had an average diameter of 25.58 nm, and the HR-TEM results showed that they were spherical. According to our results, Ag-CuO NPs exhibited the highest antibacterial efficacy against S. aureus (26.5 mm ZOI), K. pneumoniae (26.0 mm ZOI), and C. albicans (28.5 mm ZOI). The growth of biofilms was also successfully inhibited through the application of Ag-CuO NPs by 88.12 % against S. aureus, 87.08 % against C. albicans, and 74.0 % against B. subtilis. The ulcers on the mouth and foot of diseased animals healed in 4-5 days and 1 week, respectively, following topical application of bimetallic Ag-CuO NPs. The results examined the potential protective effects of a dosage of 3.57 µg/mL on cells before viral infection (cell control). According to our research, bimetallic Ag-CuO NPs limit the development of the virus that causes foot-and-mouth disease (FMD). The reduction of a specific FMD virus's cytopathic impact (CPE) on cell development represented the inhibitory effect when compared to identical circumstances without pretreatment with bimetallic Ag-CuO NPs. Their remarkable antibacterial properties at low concentration and continued-phase stability suggest that they may find widespread use in a variety of pharmacological and biological applications, especially in the wound-healing process.

Antibacterial biofilm efficacy of calcium hydroxide loaded on Gum Arabic nanocarrier: an in-vitro study.

BACKGROUND: An innovative intracanal medication formulation was introduced in the current study to improve the calcium hydroxide (Ca(OH)2) therapeutic capability against resistant Enterococcus faecalis (E. faecalis) biofilm. This in-vitro study aimed to prepare, characterize, and evaluate the antibacterial efficiency of Ca(OH)2 loaded on Gum Arabic (GA) nanocarrier (Ca(OH)2-GA NPs) and to compare this efficiency with conventional Ca(OH)2, Ca(OH)2 nanoparticles (NPs), GA, and GA NPs. MATERIALS AND METHODS: The prepared nanoparticle formulations for the tested medications were characterized using Transmission Electron Microscope (TEM) and Fourier-Transform Infrared Spectroscopy (FTIR). 141 human mandibular premolars were selected, and their root canals were prepared. Twenty-one roots were then sectioned into 42 tooth slices. All prepared root canals (n = 120) and teeth slices (n = 42) were divided into six groups according to the intracanal medication used. E. faecalis was inoculated in the samples for 21 days to form biofilms, and then the corresponding medications were applied for 7 days. After medication application, the residual E. faecalis bacteria were assessed using CFU, Q-PCR, and SEM. Additionally, the effect of Ca(OH)2-GA NPs on E. faecalis biofilm genes (agg, ace, and efaA) was investigated using RT-PCR. Data were statistically analyzed at a 0.05 level of significance. RESULTS: The synthesis of NPs was confirmed using TEM. The results of the FTIR proved that the Ca(OH)2 was successfully encapsulated in the GA NPs. Ca(OH)2-GA NPs caused a significant reduction in the E. faecalis biofilm gene expression when compared to the control (p < 0.001). There were significant differences in the E. faecalis CFU mean count and CT mean values between the tested groups (p < 0.001) except between the Ca(OH)2 and GA CFU mean count. Ca(OH)2-GA NPs showed the least statistical E. faecalis mean count among other groups. SEM observation showed that E. faecalis biofilm was diminished in all treatment groups, especially in the Ca(OH)2-GA NPS group when compared to the control group. CONCLUSIONS: Ca(OH)2 and GA nanoparticles demonstrate superior anti-E. faecalis activity when compared to their conventional counterparts. Ca(OH)2-GA NPs showed the best antibacterial efficacy in treating E. faecalis biofilm. The tested NP formulations could be considered as promising intracanal medications.

Gum acacia dietary fiber: Significance in immunomodulation, inflammatory diseases, and cancer.

Gum arabic/acacia (GA), derived from Acacia trees, is a versatile natural product offering a broad spectrum of applications. Its rich content of soluble dietary fibers, coupled with a low caloric profile, renders GA a valuable dietary component associated with numerous health benefits. Furthermore, its fermentation by gut microbiota yields short-chain fatty acids, renowned for their positive impact on health. Immunomodulation, a crucially regulated mechanism in the body, serves to fend off pathogenic infections by releasing pro-inflammatory cytokines. However, prolonged synthesis of these cytokines can lead to chronic inflammation, tissue damage, and potentially contribute to the development of autoimmune diseases and cancer. Hence, there is an urgent need to identify plant-based biomolecules that can effectively reduce inflammation and inhibit inflammation-induced complications or disorders. In this context, edible biomolecules like GA are gaining prominence for their noteworthy immunomodulatory properties. Therefore, in the present review we have explored the role of GA in immunomodulation, inflammation, and inflammation-associated metabolic diseases, and cancer.

Preventive role of gum Arabic administration on STZ induced diabetic kidney disease in rats; renal antioxidant and histopathological evidence / Función preventiva de la administración de goma arábiga en la enfermedad renal diabética inducida por STZ en ratas; antioxidante renal y evidencia histopatológica

This study was set to investigate the effect of gum Arabic (G.A.) on diabetic kidney disease. We divided sixty male Sprague rats randomly into six groups. Normal control, normal rats treated with G.A., untreated diabetic rats, diabetic rats treated with insulin, diabetic rats treated with G.A., and diabetic rats treated with both insulin and G.A. Diabetes was induced by a single intraperitoneal injection of STZ. Forty eight hr post injections. Insulin was injected subcutaneously (1.6/IU/100g/day). We provided G.A. in drinking water (10 %w/ v).). At the end of the twelve weeks, blood was drawn for measurement of blood glucose, glycosylated hemoglobin (HbA1C), serum lipids, serum creatinine, and blood urea. Renal tissue oxidative stress (O.S.) was assessed by measuring the activities of superoxide dismutase (SOD) and catalase (CAT), and the concentrations of reduced glutathione (GSH) and malondialdehyde (MDA). For histological assessments, sections from segments of kidneys were processed and stained with hematoxylin and eosin (H&E) for assessment under the light microscope. STZinduced diabetes caused an elevation of blood glucose, HbA1c, urea and creatinine, triglycerides LDL and cholesterol, MDA with reduction of HDL, GSH level, and CAT and SOD activities. Histologically, kidneys from diabetic rats showed marked glomerular and tubular changes. Administration of G.A. alone to diabetic rats had a significant hypoglycemic, hypolipidemic, and antioxidant effect, although the levels achieved remained significantly abnormal compared with the untreated group with no effect on urea and creatinine levels. Co-administration of G.A. with insulin reversed the impact of D.M. on all parameters evaluated including the histological changes and led to normal urea and creatinine levels. We concluded that G.A., in combination with insulin, improves chemically-induced diabetes and its renal complications, possibly by modulation of oxidative stress.

En este estudio se evaluó el efecto de la goma arábiga (GA) en la enfermedad renal diabética. Dividimos sesenta ratas macho Sprague Dawley al azar en seis grupos. Control normal, ratas normales tratadas con GA, ratas diabéticas no tratadas, ratas diabéticas tratadas con insulina, ratas diabéticas tratadas con GA y ratas diabéticas tratadas con insulina y GA. La diabetes fue inducida por una sola inyección intraperitoneal de STZ. Cuarenta y ocho horas después se inyectó insulina por vía subcutánea (1,6 / UI / 100 g / día). A los animales se les dió GA en agua potable (10 % p / v)). Al final de las doce semanas, se extrajo sangre para medir la glucosa, la hemoglobina glicosilada (HbA1C), los lípidos en suero, la creatinina en suero y la urea en sangre. El estrés oxidativo del tejido renal (SO) se evaluó midiendo las actividades de la enzima superóxido dismutasa (SOD) y la catalasa (CAT), y las concentraciones de glutatión reducido (GSH) y malondialdehído (MDA). Para las evaluaciones histológicas, se procesaron secciones de segmentos de riñones y se tiñeron con hematoxilina y eosina (H & E) para análisis bajo microscopio óptico. La diabetes inducida por STZ causó una elevación de la glucosa en sangre, HbA1c, urea y creatinina, triglicéridos LDL y colesterol, MDA con reducción de las actividades de HDL, GSH y CAT y SOD. Histológicamente, los riñones de ratas diabéticas mostraron marcados cambios glomerulares y tubulares. La administración de GA solo en las ratas diabéticas tuvo un efecto hipoglucémico, hipolipidémico y antioxidante significativo, aunque los niveles alcanzados permanecieron significativamente anormales en comparación con el grupo no tratado, sin ningún efecto sobre los niveles de urea y creatinina. La dministración conjunta de GA con insulina revirtió el impacto de DM en todos los parámetros evaluados, incluidos los cambios histológicos y condujeron a niveles normales de urea y creatinina. Concluimos que GA en combinación con insulina, mejora la diabetes inducida químicamente y sus complicaciones renales, posiblemente mediante la modulación del estrés oxidativo.

Protective effect of gum arabic/insulin against histological changes in testes of diabetic rats / Efecto protector de la goma arábiga / insulina contra los cambios histológicos en los testículos de ratas diabéticas

Diabetes mellitus is a serious disease with a high incidence of occurrence in our community. Gum Arabic (GA) is a branched-chain polysaccharide which has strong antioxidant properties, and has been used to reduce the experimental toxicity. Yet, the effects of GA on testicular tissue in type I diabetic rats have not been enough investigated. This study was designed to investigate histological changes in testes of male Wistar rats and investigate the protective potential of GA against diabetes- induced testicular toxicity in rats. Fifty adult male Wistar rats were assigned into five groups (n = 10 of each): Group 1 (non-diabetic rats) served as control, Group 2 served as diabetic group injected with Alloxan, Group 3 diabetic group plus insulin, Group 4 diabetic group given 15 % GA in drinking water and Group 5 diabetic group plus insulin and GA for 4 weeks. Compared to control group, histopathological examinations of testicular tissue from the diabetic rats group, showed degeneration, necrosis and atrophy of seminiferous with presence of giant cells. Necrosis and hemorrhage in the renal tissue. On the other hand, treatment with GA ameliorated all the previous histological changes. Overall, oral administration of GA alone or with insulin daily for 4 weeks successfully ameliorated the testicular histological changes. These data demonstrated that GA significantly improved diabetes complication in rat testis. This study suggested that GA might have a protective effect against oxidative stress-induced impaired testicular functions in diabetic rats. The possible mechanisms of this action might be ascribed to their antioxidant and anti-inflammatory properties.

La diabetes mellitus es una enfermedad grave con una alta incidencia en nuestra comunidad. La goma arábiga (GA) es un polisacárido con propiedades antioxidantes importantes, y se ha utilizado para reducir la toxicidad experimental. Sin embargo, los efectos de GA sobre el tejido testicular en ratas diabéticas tipo I no se ha investigado lo suficiente. El estudio fue diseñado para pesquisar los cambios histológicos en los testículos de ratas Wistar macho e investigar el potencial protector de GA contra la toxicidad testicular inducida por la diabetes en ratas. Fueron asignadas cincuenta ratas Wistar macho adultas en cinco grupos (n = 10 de cada una): el grupo 1 (ratas no diabéticas) sirvió como control, el grupo 2 sirvió como grupo diabético inyectado con Alloxan, grupo diabético del grupo 3 más insulina. El grupo 4 diabético recibió 15 % de GA en agua potable, y el grupo diabético 5 más insulina y GA durante 4 semanas. Al comparar con el grupo control, los exámenes histopatológicos del tejido testicular del grupo de ratas diabéticas mostraron degeneración, necrosis y atrofia de los túbulos seminíferos con presencia de células gigantes, necrosis y hemorragia en el tejido renal. Por otra parte, el tratamiento con GA mejoró todos los cambios histológicos previos. En general, la administración oral de GA solamente, o con insulina diariamente durante 4 semanas mejoró los cambios histológicos testiculares. Estos datos demostraron que GA mejoró significativamente los efectos de la diabetes en testículos de rata. Este estudio sugiere que GA podría tener un efecto protector contra las funciones testiculares deterioradas, inducidas por el estrés oxidativo en ratas diabéticas. Los posibles mecanismos de esta acción podrían atribuirse a sus propiedades antioxidantes y antiinflamatorias.

Gum arabic and red propolis protecteting colorectal preneoplastic lesions in a rat model of azoxymethane

Abstract Purpose: To evaluate red propolis, gum arabic and L-lysine activity on colorectal preneoplastic lesions induced by azoxymethane (AOM). Methods: The study featured 4 control groups (I-IV) and 4 experimental groups (V-VIII), totaling 48 rats. Once a week for 2 weeks, animals on control groups received saline, while animals in experimental groups received azoxymethane (15 mg/kg i.p.). The follow up along 16 weeks included daily oral gavage to administer water (I and V), L-lysine (150 mg/kg)(II and VI), própolis (100mg/5ml/kg)(III and VII), or gum arabic (5ml/kg)(IV and VIII). Was performed surgery on the animals in the end of this time in order to collect blood for biological assays (TBARS, GSH), followed by their sacrifice to tissue extract. Results: Oxidative stress (TBARS) and the number of aberrant crypt foci (ACF) in distal colon were lower using própolis (p<0.01 for both parameters). Gum arabic reduced preneoplastic lesions (ACF ≤ 4 crypts) on distal colon and on the entire colon (p<0.05). Conclusions: Red propolis reduced AOM-induced oxidative stress (TBARS) and total number of ACF in the distal colon. L-lysine neither protected against nor enhanced AOM-induced ACF. Gum arabic reduced the number of ACF.