Xylitol: a review on bioproduction, application, health benefits, and related safety issues

Xylitol is a pentahydroxy sugar-alcohol which exists in a very low quantity in fruits and vegetables (plums, strawberries, cauliflower, and pumpkin). On commercial scale, xylitol can be produced by chemical and biotechnological processes. Chemical production is costly and extensive in purification steps. However, biotechnological method utilizes agricultural and forestry wastes which offer the possibilities of economic production of xylitol by reducing required energy. The precursor xylose is produced from agricultural biomass by chemical and enzymatic hydrolysis and can be converted to xylitol primarily by yeast strain. Hydrolysis under acidic condition is the more commonly used practice influenced by various process parameters. Various fermentation process inhibitors are produced during chemical hydrolysis that reduce xylitol production, a detoxification step is, therefore, necessary. Biotechnological xylitol production is an integral process of microbial species belonging to Candida genus which is influenced by various process parameters such as pH, temperature, time, nitrogen source, and yeast extract level. Xylitol has application and potential for food and pharmaceutical industries. It is a functional sweetener as it has prebiotic effects which can reduce blood glucose, triglyceride, and cholesterol level. This review describes recent research developments related to bioproduction of xylitol from agricultural wastes, application, health, and safety issues.

Potential protective properties of flax lignan secoisolariciresinol diglucoside

Lignans are a group of phytonutrients which are widely distributed in the plant kingdom. Flaxseed is the richest source of providing lignan precursor such as secoisolariciresinol diglucoside (SDG). This article reviews the studies relevant to experimental models in animals and humans demonstrating the possible nutraceutical actions of SDG to prevent and alleviate lifestyle-related diseases. A local and international web-based literature review for this project was carried out to provide information relating to the study. The major key word "SDG" was selected to gather information using the electronic databases pertaining to the current state of flaxseed lignans composition, bioactive compounds, metabolism and to find out their role in terms of chemopreventive action. The extraction methods vary from simple to complex depending on separation, fractionation, identification and detection of the analytes. The majority of studies demonstrate that SDG interferes with the development of different types of diseases like cardiovascular, diabetic, lupus nephritis, bone, kidney, menopause, reproduction, mental stress, immunity, atherosclerosis, hemopoietic, liver necrosis and urinary disorders due to its various biological properties including anti-inflammatory, antioxidant, antimutagenic, antimicrobial, antiobesity, antihypolipidemic and neuroprotective effects. Moreover, SDG has a defending mediator against various cancers by modulating multiple cell signaling pathways. As discussed in this review, SDG has shown therapeutic potential against a number of human diseases and can be recommended for discerning consumers.

Honey and cancer: A mechanistic review

BACKGROUND

Globally, cancer ranks among the most common causes of death. Multiple experimental and clinical studies have investigated anticancer effects of honey with promising results. This study focused on potential background mechanisms of this effect.

METHODS

The current literature was reviewed for potential anticancer pathways which are suggested for honey and its ingredients.

RESULTS

Flavonoids (kaempferol, catechin, and quercetin) and phenolic acids (caffeic acid and gallic acid) are the most important ingredients of honey with known anti-cancer activity. The main suggested mechanisms for anti-cancer activity of honey and its ingredients are antioxidant, apoptotic, tumor necrosis factor inhibiting, antiproliferative, immunomodulatory, anti-inflammatory and estrogenic effects.

CONCLUSION

This review collates the current scientific understanding on the mechanism of anti-cancer activity of honey.

Phytopreventive antihypercholesterolmic and antilipidemic perspectives of zedoary (Curcuma Zedoaria Roscoe.) herbal tea

BACKGROUND

Metabolic syndrome is an increasingly prevalent problem, not only in industrialized developed countries, but in developing countries as well. The modern healthcare to reduce the dysfunction of metabolic syndrome is burdened with great problems of unsafe medicines and certain degree of side effects. Medicinal plants and derived component products are becoming increasingly popular in modern society as natural alternatives to synthetic multiple drugs for the treatment of hypercholesterolemia and hypertriglyceridemia. The present research work was carried out to evaluate the zedoary (Curcuma zedoaria Roscoe.) herbal tea (ZHT) for antihypercholestrolemic and antilipidemic perspectives in discerning consumers.

METHODS

Zedoary rhizome dried powder (ZRDP) after proximate composition analysis was used to prepared ZHT samples as T1 (500 mg ZRDP), T2 (1 g ZRDP) and T3 (1.5 g ZRDP) in 200 mL boiling water for 5 minutes, respectively. ZHT samples were characterized for total phenolic compounds (TPC), DPPH inhibition, total flavonoids, color tonality (L*, a* and b* value), pH, acidity, total soluble solids (TSS) and sensory acceptance. Thirty mild-hypercholestrolemic male human volunteers were randomly allocated to three groups (G1, G2 and G3) and each group consisting of 1o mild-hypercholestrolemic male human subjects. The volunteers were assigned ZHT samples for consecutive two months. The blood drawn for day 0, day 30 and day 60 after an overnight 12 h fast was analyzed for serum parameters such as total cholesterol (TC), high-density lipoprotein cholesterol (HDL-cholesterol), low-density lipoprotein cholesterol (LDL-cholesterol) and triglycerides (TG) concentration.

RESULTS

The ZRDP possessed abundantly the crude protein (13.5 ± 0.68 %), total dietary fiber (21.86 ± 0.71 %), acid detergent fiber (13.22 ± 0.44 %), neutral detergent fiber (18.68 ± 0.53 %) and mineral contents. Highest TPC, DPPH inhibition and total flavonoids values were observed 9.74 ± 0.64 (mg GAE/g DW), 47.28 ± 1.62 (%) and 17.12 ± 0.75 (QE mg/g), respectively in T3. L* value was significantly (p ≤ 0.05) low for T3 samples. In contrast, a* value and b* value was significantly (p ≤ 0.05) higher for T3 when compared with T1 and T2. T3 samples showed lower pH (5.13 ± 0.13) and higher acidity (0.25 ± 0.08) values than T1 (5.64 ± 0.25, 0.17 ± 0.05) and T2 (5.42 ± 0.21, 0.21 ± 0.06), respectively. Similarly, an increasing trend in TSS contents was observed. Sensory scores assigned to color, flavor, aroma and overall acceptability attributes varied in a quite narrow range for all ZHT samples. The lowest evaluation scores were recorded for T3 samples. The G3 showed the more reduction in body weight and BMI during efficacy study as compared to G1 and G2. The decrease in serum TC for G1, G2 and G3 on day 60 was observed 9 %, 14 % and 17 %, respectively when compared with reference value at day 0. The consumption of T3 resulted in significant increase (6.8 %) of HDL-cholesterol after two months. A trend in decrease of serum LDL-cholesterol (5.6 %) and TG (12.5 %) was also observed after consumption of T3 at day 60.

CONCLUSIONS

The results of the present study conclude that the strong phenolic contents and radical scavenging activity of zedoary rhizome have protective role against hypercholesterolemic and lipidemic conditions.

Antihyperlipidemic efficacy of aqueous extract of Stevia rebaudiana Bertoni in albino rats

BACKGROUND

Stevia (Stevia rebaudiana Bertoni) natural, safe, non-toxic, non-caloric sugar substitute is rich source of pharmacologically important glycoside stevioside that is linked to the pathology and complications of hyperlipidemia.

METHODS

The present research was carried out to explore the anti-hyperlipidemic effect of aqueous extract of Stevia rebaudiana Bertoni leaves in albino rats. For this purpose, hyperlipidemia was induced by administration of Cholesterol (90% E, Appli Chem, Darmstadt, Germany) mixed at dose of 400 mg/kg body weight of rats in their daily routine feed. The hyperlipidemic rats were administered with aqueous stevia extract at different dose levels (200, 300, 400 and 500 ppm/kg b.w.) for 8 weeks; the control rats were fed basal diet during this period. Ethical approval for the current research was obtained from Institutional Review Board Faculty of Science & Technology Government College University, Faisalabad, Pakistan.

RESULTS

Stevia aqueous extract decreased the body weight gain by lowering the feed intake of hyperlipidemic rats. Furthermore, administration of stevia extract at different levels significantly (P < 0.05) lowered the TC (125.22 ± 5.91 to 110.56 ± 5.81 mg/dL), TG (102.13 ± 6.89 to 98.62 ± 7.22 mg/dL), LDL (33.02 ± 4.79 to 22.77 ± 4.36 mg/dL), VLDL (21.22 ± 5.79 to 19.33 ± 5.95 mg/dL) levels and LDL/HDL ratios (0.83 ± 1.22 to 0.54 ± 1.66 mg/dL) from H1 to H4. Conversely, it improved the HDL (39.76 ± 4.34 to l42.02 ± 4.39 mg/dL) level in hyperlipidemic rats compared with untreated rats after eight weeks study period.

CONCLUSION

It is concluded that aqueous extract of stevia has anti-hyperlipidemic effects in albino rats, and therefore could be a promising nutraceutical therapy for the management of hyperlipidemia and its associated complications.

Effect of microcapsules of chia oil on Ω-3 fatty acids, antioxidant characteristics and oxidative stability of butter

Background

Ω-3 fatty acids perform several therapeutic functions in the body, however, their applications are limited due to the inferior oxidative stability. To improve the oxidative stability and release properties of Ω-3 fatty acids, microencapsulation is performed. Butter is a good source of fat-soluble vitamins and antioxidant systems however, it is not a good source of Ω-3 fatty acids. Supplementation of butter with microcapsules of vegetable oils rich in Ω-3 fatty acids is not reported in literature.

Methods

Microcapsules of chia oil (MCO) were prepared using chitosan as encapsulating material by spray drying at lower temperature. Unsalted butter prepared from cultured cream using Lactococcus lactis ssp. Lactis at 21 °C for 16 Hrs. Cream was churned at 12 °C and microcapsules of chia oil were added to the butter during the working stage at four different concentrations i.e. 2, 4, 6 and 8% (T₁, T₂, T₃ and T₄, respectively). Butter without supplementation of MCO were kept as control. Butter samples were stored for 90 days at -10 °C. Butter composition, antioxidant capacity, fatty acid profile, induction period, free fatty acids, peroxide value and sensory evaluation were performed at 0, 45 and 90 days of storage.

Results

Addition of MCO in butter did not have any effect on standards of identity of butter. Microencapsulation had no effect on fatty acid profile of microcapsules of chia oil. Concentration of alpha-linolenic acid (ALA) in control, T₁, T₂, T₃ and T₄ were 0.49, 4.29, 8.41, 13.21 and 17.44%, respectively. Concentration of ALA in fresh and 90 days stored butter samples were 17.44 and 17.11%, respectively. After 90 days of storage, loss of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) were 0.07%, 0.05 and 0.03%, respectively. At 0, 45 and 90 days of storage, 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) free radical scavenging activity of free chia oil was 39.81, 71.22 and 62.18%, respectively. However, microcapsules of chia oil had superior antioxidant activity. DPPH free radical scavenging activity of microcapsules at 0, 45 and 90 days of storage was 36.51, 36.43 and 35.96%, respectively (p > 0.05). Total antioxidant capacity of microcapsules at 0, 45 and 90 days of storage was 70.53, 69.88 and 68.52%, respectively (p > 0.05). It was recorded that induction period of free chia oil and microcapsules was only 2.86 h and 8.55 h. Among the butter samples, control revealed the lowest induction period. While, induction period of experimental samples was not different from each other. Peroxide value and free fatty acids of the butter samples at the end of storage period (90 days) was less than the European Union standards limit (10MeqO₂/kg and 0.2%). Sensory characteristics of experimental samples were similar to the control. MCO can be added in butter to improve its functional value.

Conclusion

Concentration of Ω-3 fatty acids in butter up to 8% can be increased through microcapsules of chia oil with reasonable oxidative stability and no effect on sensory characteristics.

Biochemical perspectives of xylitol extracted from indigenous agricultural by-product mung bean (Vigna radiata) hulls in a rat model

BACKGROUND

The production of xylitol from lignocellulosic material is of great interest around the world. It can be used as bulk sweetener and its possible lower energy value has increased acceptance for discerning consumers. Xylitol was produced from indigenous agricultural by-product (mung bean hulls) through Candida tropicalis fermentation. Further, xylitol incorporation at different concentrations (0, 100 and 200 g kg⁻¹) was carried out with the purpose of appraising the suitability and claimed health benefits of this dietetic ingredient in food products. Asserted biochemical perspectives of the xylitol intake were evaluated through biological studies for normal and streptozotocin-induced diabetic rats.

RESULTS

The addition of xylitol significantly affected feed intake, weight gain, liver and cecum weight in both normal and diabetic rats. The biochemical profile of serum was improved with xylitol incorporation in the diet. Serum glucose, cholesterol and triglycerides levels were decreased depending on xylitol intake level.

CONCLUSION

The results of the present study demonstrated that mung bean hulls have high potential as a new feedstock for xylitol production. In addressing the current concerns of obesity and diabetes, xylitol extracted from such agricultural waste should be considered in diet-based therapies for weight loss programmes.

Retention and stability of bioactive compounds in functional peach beverage using pasteurization, microwave and ultrasound technologies

The peach functional beverages pasteurized for 10 min at 90 °C, microwaved for 1.5 min at 850 W of power and sonicated for 90 min at 20 kHz of frequency were selected to keep in storage for up to 30 days in refrigerator to examine the changes happened to their physicochemical characteristics and functional components. It was observed that the pH and the cloud values of all processed juice samples reduces with the storage time, whereas, the total soluble solids almost remain consistent particularly in microwave and ultrasound treated samples. While storage period causes the decrement in total phenolic content (TPC) and total flavonoid content of treated beverage samples, but ultrasound processing showed greater retention of TPC value up to 5.7% more than other techniques during storage. The similar trend was observed for antioxidant activity where the ultrasound treatment showed improved free radicals (2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activities except ferric ion reducing antioxidant power after 30 days of storage.

Impact of extrusion processing conditions on lipid peroxidation and storage stability of full-fat flaxseed meal

Background

The full-fat flaxseed (Linum usitatissimum L.) meal has obtained relatively new flourished concept as food or feedstuff for the development of healthier products. It provides favorable balance of polyunsaturated, monounsaturated and saturated fatty acids. However, flaxseed meal may be susceptible to oxidation by exposure to various storage conditions which is extremely undesirable and produces toxic compounds to human health. Another consideration in the application of flaxseed meal relates to the presence of anti-nutritional compounds that need to be minimized using appropriate processing method. The present research work was conducted to evaluate the impact of extrusion processing conditions and storage of full-fat flaxseed meal on functional characteristics such as α-linolenic acid content, lipid peroxidation and sensory attributes.

Methods

The raw flaxseed meal was analyzed for cyanogenic glycosides, tannin and mucilage anti-nutritional compounds. Fatty acids composition was quantified by gas chromatography. The meal was extruded at barrel exit temperature (100–140 °C), screw speed (50–150 rpm), feed rate (30–90 kg/h) and feed moisture (10–30 %) for reduction of anti-nutritional compounds. The raw and extruded meals were stored for a ninety-day period under room conditions (20–25 °C). Lipid peroxidation was analyzed by peroxide, free fatty acids, conjugated dienes, total volatiles and malondialdehyde assay. Color, aroma and overall acceptability attributes were evaluated by sensory multiple comparison tests.

Results

The raw flaxseed meal possessed significant amount of anti-nutritional compounds, lipid and α-linolenic acid contents. The extrusion processing at high barrel exit temperature (140 °C) significantly reduced the cyanogenic compounds (84 %), tannin (73 %) and mucilage (27 %) in the flaxseed meal. The α-linolenic acid content and lipid peroxidation did not significantly change after extrusion processing or during storage at the end of 60 days. Fluctuations in sensory attributes occurred during storage, but at the end of 90 days, only the extruded samples presented negative effect and showed lowest consumer acceptability.

Conclusions

The present study suggested that extrusion of flaxseed meal at optimum conditions and stored for 60 days did not change the stability of full-fat flaxseed meal and can be used as supplement or ingredient for the production of various healthier products.

Changes in fatty acids composition, antioxidant potential and induction period of UHT-treated tea whitener, milk and dairy drink

Background

In developing and developed countries, several versions of safe and shelf-stable Ultra High Temperature, UHT-treated products are manufactured. Terminologies and formulations of UHT-treated tea whitener, milk and dairy drink considerably vary. Comprehensive studies have been performed on UHT-treated milk; however, fatty acids compositional changes and oxidation status of UHT-treated tea whitener and dairy drink at different storage intervals have not been reported in literature.

Methods

UHT-treated tea whitener, milk and dairy drink samples (450 each) of the same manufacturing date were purchased from the market and stored at ambient temperature (25-30 °C) for 90 days. At the time of collection, all the samples were only one week old. Samples of UHT-treated tea whitener, milk and dairy drink were regarded as treatments and every treatment was replicated five times. Chemical composition, fatty acid profile, 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) radical scavenging activity, total antioxidant activity, reducing power, antioxidant activity in linoleic acid system and induction period were determined at 0, 45 and 90 days of storage.

Results

Fat content in freshly collected samples of UHT treated-tea whitener, milk and dairy drink were 6 and 3.5%. UHT treated milk had highest total antioxidant capacity, antioxidant activity in linoleic acid and 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) free radical scavenging activity followed by UHT tea whitener and dairy drink. In freshly collected samples of UHT-treated milk, concentrations vitamin A and E were 0.46 μg/100 g and 0.63 mg/100 g, respectively. UHT-treated tea whitener had the lowest concentrations of vitamin A and E. With the progression of storage period, amount of vitamin A and E decreased. In freshly collected samples, amount of short, medium and unsaturated fatty acids in UHT-treated milk were 10.54, 59.71 and 27.44%, respectively. After 45 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 7%, 7.1 and 5.8%, respectively. After 90 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 8.53, 13.51 and 11.88%, accordingly. After 45 days of storage of UHT-treated tea whitener, the loss of medium and unsaturated fatty acid was 1.6 and 0.99%, respectively. After 90 days of storage, the loss of medium and unsaturated fatty acids were 8.2 and 6.6%, respectively. The induction period of fresh UHT-treated tea whitener, milk and dairy drink was 15.67, .74 and 7.27 h. Strong correlations were recorded between induction period and peroxide value of UHT-treated products.

Conclusion

This investigation disclosed that UHT-treated tea whitener had 6% fat content with no short-chain fatty acids. Antioxidant capacity of UHT-treated milk was higher than dairy drink and tea whitener. Due to the presence of partially hydrogenated fat, oxidative stability of UHT-treated tea whitener was better than UHT-treated milk and dairy drink. Vitamin A and E was not found in UHT-treated tea whitener. For the anticipation of oxidative stability of UHT-treated milk, dairy drink and tea whitener, induction period/ Rancimat method can be used.

Phytochemical composition, antilipidemic and antihypercholestrolemic perspectives of Bael leaf extracts

BACKGROUND

In recent times, focus on plant research has improved all over the world and essential parts of plants provide bioactive compounds in human diet. The bael (Aegle marmelos) has enormous traditional uses in the treatment of chronic diarrhea, dysentery, peptic ulcers and as a laxative. The main focus of this study was characterization of bael leaf extract for its bioactive constituents, antihypercholestrolemic and antilipidemic perspectives.

METHODS

After proximate composition of bael powder, the aqueous extract of bael leaf was used for phytochemical profiling (alkaloids, total phenolic content and total flavonoid content). Afterwards, normal rats group G0 was administrated basal diet while G1 and G2 normal rat groups were fed diets containing bael leaf extract 125 mg and 250 mg, respectively for consecutive 60 days. In a similar way, hyperlipidemic rats group Gh0 was administrated basal diet while Gh1 and Gh2 hyperlipidemic rat groups were fed diets containing bael leaf extract 125 mg and 250 mg, respectively for consecutive 60 days. The blood drawn on day 0, day 30 and day 60 was analyzed for serum parameters, such as total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides concentration and free and ester cholesterol.

RESULTS

Bael leaf powder is a rich source of crude fiber (14.50 ± 0.10 g/100 g). Aqueous extract of bael leaf contains alkaloids (15.58 ± 0.05 mg/g), flavonoids (64.00 ± 0.05 mg/g), phenolics (30.34 ± 0.01 GAEmg/g). From the In vivo studies, the lowest weight gain was observed in group G2 and in Gh2 as compared to control of both groups. The decrease in serum TC for G1-15.06%, G2-17.27% while in Gh1-22.46% and Gh2-34.82% after day 60, respectively. The maximum decrease was observed in group G2 (- 14.33%) and in Gh2 (- 24.79%) for triglycerides after 60 days. For HDL-cholesterol, significant increase (11.20%) in G2 and (49.83%) in Gh2 was observed of after 60 days. A trend in decrease of serum LDL-cholesterol in G2 (- 9.63%) and in Gh2 (- 44.65%) was also observed at day 60, and - 19.05% and - 30.06% decrease was noted in G2 and Gh2, respectively and decreasing trend was observed in free and total cholesterol - 22.30% and - 81.49% for groups G2 and Gh2 after day 60.

CONCLUSIONS

The results of the present study demonstrated that the extract contents of bael leaf provide protective role against hypercholesterolemic and hyperlipidemic conditions.

Functional quality of optimized peach-based beverage developed by application of ultrasonic processing

The influence of thermal treatment (at 90°C for 10 min) and sonication (at 20 kHz and 130 W for 30, 60, and 90 min on room temperature) on the physicochemical properties, bioactive compounds, antioxidant activity, and organic acids of fresh formulated functional peach beverage was investigated. The results indicated that conventional pasteurization and sonication treatment did not show any significant changes in pH value and Brix amount of juice, and however, a rise in cloud value was observed under all processing conditions. The thermal treatment caused the decrement in total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (assessed by diphenyl dipicryl hydrazyl (DPPH), ferric ion reducing antioxidant power (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)), and organic acids of juice, whereas sonication treatment for 90 min increased maximum the activity of bioactive compounds (TPC: 600.61 µg/100 ml; TFC: 177 µg CE/100 ml), antioxidants (DPPH: 51.87%; FRAP: 506.13 µmol Trolox/L; ABTS: 1,507.375 µmol Trolox/L), and organic acids (malic acid: 998; citric acid: 128; oxalic acid: 145; shikimic acid: 63 µg/100 ml) as compared to other treatment conditions and control. Multivariate data analysis was done by principal component analysis as it identifies patterns in data by comparing data sets which is further expressed based on their similarities and discriminations, respectively.

Development and optimization of processing techniques for intermediate moisture muskmelon chunks

Muskmelon (Cucumis melo ) fruit is a best source of vitamins, minerals, and bioactive components. Ingestion of high sugary drinks leads to numerous ailments such as diabetes mellitus, obesity, and tooth decay. This study intended at formulation of intermediate moisture food with various combinations of sugar and glycerol and same levels of potassium metabisulphite, potassium sorbate, calcium chloride, and citric acid. It was observed a gradual decrease in TSS (56.53-53.28), vitamin C level in all treatments with the passage of time. The declining trend in ascorbic acid (25.49-21.63 mg/100 g) content of muskmelon chunks was increased as a function of storage. Sensory results showed that there was declining trend in the scores obtained for color parameter, that is, L * from 60.23 to 55.98. The overall results showed that combination of different additives contributed best values (T3) for flavor (7.70), taste (8.15), vitamin C (25.60 mg/100 g), and pH (5.16) as compared to other treatments. Conclusively, developed chunks of treatment 3 are physicochemical and organoleptically considered best, as it is helpful to sustain life stability of muskmelon and enhance its marketability.

Gut microbiota and their derivatives in the progression of colorectal cancer: Mechanisms of action, genome and epigenome contributions

Gut microbiota interacts with host epithelial cells and regulates many physiological functions such as genetics, epigenetics, metabolism of nutrients, and immune functions. Dietary factors may also be involved in the etiology of colorectal cancer (CRC), especially when an unhealthy diet is consumed with excess calorie intake and bad practices like smoking or consuming a great deal of alcohol. Bacteria including Fusobacterium nucleatum, Enterotoxigenic Bacteroides fragilis (ETBF), and Escherichia coli (E. coli) actively participate in the carcinogenesis of CRC. Gastrointestinal tract with chronic inflammation and immunocompromised patients are at high risk for CRC progression. Further, the gut microbiota is also involved in Geno-toxicity by producing toxins like colibactin and cytolethal distending toxin (CDT) which cause damage to double-stranded DNA. Specific microRNAs can act as either tumor suppressors or oncogenes depending on the cellular environment in which they are expressed. The current review mainly highlights the role of gut microbiota in CRC, the mechanisms of several factors in carcinogenesis, and the role of particular microbes in colorectal neoplasia.