Nutritional, biochemical, and clinical applications of carob: A review

Carob is botanically called as Ceratonia siliqua and belongs to the Legumes family. The fruit is derived from hermaphrodite trees and hard in shape. The carob contains high sugar contents in pulp, fat in seed and minerals like potassium, calcium, and phosphorus are present in pods. Polyphenols and antioxidants are abundant in leaves and pods. It can be used for enhancing human health due to its high nutritional profile. Carob gum is used in the pharmaceutical industry in the form of pomades, anti-celiac ingredients, pills, and dental paste. The clinical carob can aid as an anti-cancer, anti-reflux, anti-diabetic, anti-diarrheal, anti-hyperlipidemia, anti-bacterial, anti-microbial, and anti-fungal. Nowadays, carob seeds are being used as an alternative to cocoa powder in food items whereas the leaves, pods, and seeds of carob are also historically used as food for animal feed. However, these parts of carob are available in markets with reasonable prices. Carob production, though with a rising contribution, contributes to the local economy. In this sense, we can incorporate knowledge on the chemical properties and the biological effect of carob fruits on human health. In this study, the supportive and health-promoting impacts of carob are discussed along with the clinical testing obtained from natural constituents of carob. In addition, further studies can be performed to extract and separate polyphenols and antioxidant potential for the development of functional that play a valuable role in pharmaceutical and food sectors.

The synergistic ramification of insoluble dietary fiber and associated non-extractable polyphenols on gut microbial population escorting alleviation of lifestyle diseases

Most of the pertinent research which aims at exploring the therapeutic effects of polyphenols usually misapprehends a large fraction of non-extractable polyphenols due to their poor aqueous-organic solvent extractability. These polymeric polyphenols (i.e., proanthocyanins, hydrolysable tannins and phenolic acids) possess a unique property to adhere to the food matrix polysaccharides and protein sowing to their structural complexity with high glycosylation, degree of polymerization, and plenty of hydroxyl groups. Surprisingly resistance to intestinal absorption does not hinder its bioactivity but accelerates its functionality manifolds due to the colonic microbial catabolism in the gastrointestinal tract, thereby protecting the body from local and systemic inflammatory diseases. This review highlights not only the chemistry, digestion, colonic metabolism of non-extractable polyphenols (NEPP) but also summarises the synergistic effect of matrix-bound NEPP exerting local as well as systemic health benefits.

Carob Extract Supplementation Together with Caloric Restriction and Aerobic Training Accelerates the Recovery of Cardiometabolic Health in Mice with Metabolic Syndrome

Carob, the fruit of Ceratonia siliqua L. exerts antidiabetic, anti-inflammatory, and antioxidant effects and could be a useful strategy for the treatment and/or prevention of metabolic syndrome (MetS). The aim of this study was to analyze whether supplementation with a carob fruit extract (CSAT+®), alone or in combination with aerobic training, accelerates the recovery of cardiometabolic health in mice with MetS subjected to a caloric restriction. For this purpose, mice were fed with a high fat (58% kcal from fat)/high sugar diet for 23 weeks to induce MetS. During the next two weeks, mice with MetS were switched to a diet with a lower caloric content (25% kcal from fat) supplemented or not with CSAT+® (4.8%) and/or subjected to aerobic training. Both caloric reduction and aerobic training improved the lipid profile and attenuated MetS-induced insulin resistance measured as HOMA-IR. However, only supplementation with CSAT+® enhanced body weight loss, increased the circulating levels of adiponectin, and lowered the plasma levels of IL-6. Moreover, CSAT+® supplementation was the only effective strategy to reduce the weight of epidydimal adipose tissue and to improve insulin sensitivity in the liver and in skeletal muscle. Although all interventions improved endothelial function in aorta segments, only supplementation with CSAT+® reduced obesity-induced hypertension, prevented endothelial dysfunction in mesenteric arteries, and decreased the vascular response of aorta segments to the vasoconstrictor AngII. The beneficial cardiometabolic effects of CSAT+® supplementation, alone or in combination with aerobic training, were associated with decreased mRNA levels of pro-inflammatory markers such as MCP-1, TNFα, IL-1β, and IL-6 and with increased gene expression of antioxidant enzymes, such as GSR, GPX-3, and SOD-1 in the liver, gastrocnemius, retroperitoneal adipose tissue, and aorta. In conclusion, supplementation with CSAT+®, alone or in combination with aerobic training, to mice with MetS subjected to caloric restriction for two weeks enhances body weight loss, improves the lipid profile and insulin sensitivity, and exerts antihypertensive effects through its anti-inflammatory and antioxidant properties.

Carob: A Sustainable Opportunity for Metabolic Health

Carob (Ceratonia siliqua L.) is an evergreen tree that belongs to the Leguminosae family and grows in the arid and semi-arid regions of the Mediterranean basin. The carob tree is resistant to droughts and salinity, while its deep root systems allow CO₂ to sink, mitigating global warming effects. Traditionally, carob has been used to produce animal feed, but for many years, it was excluded from the human diet. Nowadays, agricultural and industrial sectors exploit carob fruit, also referred to as carob pod, and its primary products (i.e., flour, powder and syrup) to develop a variety of foods and beverages. The nutritional composition varies depending on the carob part but also on genetic, cultivar, seasonal and environmental factors. Despite the high sugar content, the carob pod is rich in insoluble fiber and microconstituents including phenolic compounds, inositols (mainly d-pinitol) and vitamins. In the present review article, we aimed to (a) highlight the role of carob cultivation in addressing climate change challenges and the need for sustainability, and (b) summarize the effects of carob consumption on obesity and related metabolic disorders.

Carob fruit extract-enriched meat, as preventive and curative treatments, improves gut microbiota and colonic barrier integrity in a late-stage T2DM model

Epidemiological and experimental studies have suggested that dietary fiber and proanthocyanidins play an important role on gut microbiota (GM), colonic integrity and body health. Type 2 Diabetes Mellitus (T2DM) is a prevalent disease in which the modifications in the GM and colonic markers stand out. This manuscript hypothesizes the consumption of functional meat enriched in carob fruit extract [CFE; CFE-restructured meat (RM)] ameliorates the dysbiosis and colonic barrier integrity loss in a late-stage T2DM rat model induced by the conjoint action of a high-saturated-fat/high-cholesterol diet (Chol-diet) and a low dose of streptozotocin (STZ) plus a nicotinamide (NAD) injection. Three groups of eight rats were used: (1) D group, a T2DM control group, fed the Chol-diet; (2) ED group, a T2DM preventive strategy group fed the CFE-Chol-diet since the beginning of the study; and (3) DE group, a T2DM curative treatment group, fed the CFE-Chol-diet once the diabetic state was confirmed. The study lasted 8 weeks. Amount and variety of GM, feces short-chain-fatty acids (SCFAs), colonic morphology [crypt depth and density, goblet cells, proliferating cell nuclear antigen (PCNA) and transferase dUTP nick end labelling (TUNEL) indexes] and tight junctions were evaluated. A global colonic index combining 17 markers (GC_index) was calculated. ED rats displayed higher levels of GM richness, SCFAs production, crypt depth, and goblet cells than the D group. DE group showed lower Enterobacteriaceae abundance and greater TUNEL index and occludin expression in the distal colon than D counterpart. GC_index differentiated the colonic health status of the experimental groups in the order (ED > DE > D; P < 0.001) as a 17-51 range-quotation, ED, DE, and D groups displayed the values 43, 32.5, and 27, respectively. Thus, CFE-RM used as a T2DM preventive therapy could induce higher GM richness, more adequate SCFAs production, and better colonic barrier integrity. Furthermore, CFE-RM used with curative purposes induced more modest changes and mainly at the distal colonic mucosa. Further studies are needed to confirm this study's results, to ascertain the benefits of consuming proanthocyanidins-rich fiber during different T2DM stages.

Carob fruit extract-enriched meat improves pancreatic beta-cell dysfunction, hepatic insulin signaling and lipogenesis in late-stage type 2 diabetes mellitus model

The inclusion of functional bioactive compounds of dietary fiber in meat products has been demonstrated to exert a significant impact on human health. Carob fruit extract (CFE) is a dietary fiber rich in proanthocyanidins with known antioxidant, hypolipidemic and hypoglycemic effects. Consumption of CFE-enriched meat (CFE-RM) may provide interesting benefits in late-stage type 2 diabetes mellitus (T2DM). To explore the antidiabetic mechanisms of CFE-RM, we used a model of late-stage T2DM in Wistar rats fed a high-saturated-fat/high-cholesterol diet (Chol-diet) and injected streptozotocin plus nicotinamide (D group). The effects of CFE-RM were tested by incorporating it into the diet as preventive strategy (ED group) or curative treatment (DE group). CFE-RM had a positive effect on glycemia, enhancing hepatic insulin sensitivity and improving pancreatic β-cell regeneration in both ED and DE groups. Western blotting and immunohistochemistry suggested that CFE-RM increased levels of insulin receptor β and phosphatidylinositol-3-kinase, as well as the downstream target phospho-Akt (at Ser⁴⁷³). CFE-RM also up-regulated glucose transporter 2, which improves the insulin-mediated glucose uptake by the liver, and promoted phosphorylation of glycogen synthesis kinase-3βprotein (at ser⁹), consequently increasing the hepatic glycogen content. In addition, CFE-RM decreased fatty liver by suppressing de novo lipogenesis activation due to down-regulation of liver X receptor-α/β, sterol regulatory element binding protein-1c and carbohydrate-response element-binding protein transcription factors. Our findings suggest that the consumption of CFE-RM included in the diet as a functional food should be considered as a suitable nutritional strategy to prevent or manage late-stage T2DM.

Can Carob-Fruit-Extract-Enriched Meat Improve the Lipoprotein Profile, VLDL-Oxidation, and LDL Receptor Levels Induced by an Atherogenic Diet in STZ-NAD-Diabetic Rats?

Carob fruit extract (CFE) has shown remarkable in vitro antioxidant properties and reduces postprandial hyperglycemia and hyperlipidemia in healthy animals. Development of functional meat products that contain bioactive components are presented as a great nutritional strategy. Until now, the effect of the consumption of restructured meat enriched with CFE in a murine model of diabetes has not been investigated. The objective of this study was to evaluate the effect on glycemia, lipemia, lipoprotein profile, Ldlr, arylesterase (AE), and very low-density lipoproteins (VLDL) and liver oxidation in streptozotocin-nicotinamide (STZ-NAD) growing Wistar diabetic rats fed restructured meat in the frame of a high cholesterol/high saturated-fat diet. In the present study, three groups (D, ED and DE) were fed cholesterol-enriched (1.4% cholesterol and 0.2% cholic acid) and high saturated-fat diets (50% of total energy from fats and 20.4% from saturated fatty acids). Rats were subjected to a STZ-NAD administration at the 3rd week. Group D did not receive CFE, while ED and DE rat groups received CFE before and after the diabetic induction, respectively. After eight weeks, D rats showed hyperglycemia and hypercholesterolemia, an increased amount cholesterol-enriched VLDL (β-VLDL), IDL and LDL particles and triglyceride-enriched HDL. ED and DE partially blocked the hypercholesterolemic induction with respect to D group (p < 0.001) and improved glycemia, cholesterol levels, lipoprotein profile, Ldlr, plasma AE activity and liver oxidation (p < 0.001). Fecal fat, moisture and excretion were higher while dietary digestibility was lower in ED and DE vs. D counterparts (p < 0.0014). In conclusion, CFE-enriched meat shows, for the first time, hypoglycemic and hypolipidemic effects in STZ-NAD animals fed high cholesterol/high saturated-fat diets. Likewise, it manages to reverse possible diabetes lipoprotein alterations if CFE-enriched meat is consumed before pathology development or improves said modifications if Type 2 Diabetes Mellitus is already established.

Effects of Fiber Purified Extract of Carob Fruit on Fat Digestion and Postprandial Lipemia in Healthy Rats

Increased postprandial lipemia is a cardiovascular disease (CVD) risk factor. Carob fruit extract (CFE) contains condensed tannins, and their intake has been inversely related to CVD. The objective was to evaluate the in vitro pancreatic lipase activity in the presence of CFE and the in vivo effect of CFE on postprandial lipemia of healthy Wistar rats in acute and subchronic digestibility studies and to relate it with changes in fat digestion and absorption. CFE significantly reduced pancreatic lipase activity. A peak delay and a dose-dependent decrease in plasma triglyceride and cholesterol areas under the curve were observed, effects that increased after the subchronic treatment. The levels of nondigested, nonabsorbed triglycerides of the remaining intestinal lumen fat were significantly higher in the maximum dose of CFE administrated versus the control ( P < 0.05). This study demonstrates for the first time the hypolipemic properties of CFE from the first administration, modifying postprandial lipemia by reducing the extents of fat digestion and absorption.