Enhanced anti-diabetic activity of polyphenol-rich de-coumarinated extracts of Cinnamomum cassia

Dietary Polyphenols and Obesity: A Review of Polyphenol Effects on Lipid and Glucose Metabolism, Mitochondrial Homeostasis, and Starch Digestibility and Absorption

Obesity is a major global public health concern, limiting socio-economic development and human productivity. As studies focus on finding sustainable solutions to this challenge, polyphenols have shown promising results and have become a research focus. This is mainly because of associated lower risks of side effects with their use, compared to synthetic pharmaceuticals. In this study, the anti-obesity potentials of dietary polyphenols have been reviewed. Using a narrative approach, the biological activities of polyphenols and their influence on energy metabolism and mechanisms are discussed. Specifically, their roles in insulin-dependent glucose uptake, insulin sensitivity, lipid metabolism and storage in adipocytes, starch digestibility, and regulation of mitophagy and mitogenesis in muscle cells and adipocytes, were considered. After considering the major findings of many related studies, it was confirmed that polyphenols can prevent and ameliorate obesity by fighting insulin resistance (IR) induced by pro-inflammatory cytokines, scavenging reactive oxygen species (ROS) and limiting their effects, and by regulating the expression and/or activity of key enzymes along relevant pathways. More human studies are needed to reveal more about the anti-obesity effects of dietary polyphenols and their effective doses in humans.

Cinnamon as a Complementary Therapeutic Approach for Dysglycemia and Dyslipidemia Control in Type 2 Diabetes Mellitus and Its Molecular Mechanism of Action: A Review

The scientific evidence that cinnamon may exert beneficial effects on type 2 diabetes mellitus due to the biological activity of its bioactive compounds has been increasing in recent years. This review provides an overview of the effects of cinnamon on clinical parameters of diabetes and summarizes the molecular mechanisms of action of cinnamon on glucose and lipid metabolism. Search criteria include an electronic search using PubMed, Medline, and Cochrane Library databases. English literature references from 2000 up to 2022 were included. Following title and abstract review, full articles that met the inclusion criteria were included. The results from the available evidence revealed that cinnamon improved glycemic and lipidemic indicators. Clinical trials clarified that cinnamon also possesses an anti-inflammatory effect, which may act beneficially in diabetes. Based on in vitro and in vivo studies, cinnamon seems to elicit the regulation of glucose metabolism in tissues by insulin-mimetic effect and enzyme activity improvement. Furthermore, cinnamon seems to decrease cholesterol and fatty acid absorption in the gut. The current literature search showed a considerable number of studies on diabetic subjects. Some limitations in comparing published data should be highlighted, including variability in doses, extracts and species of cinnamon, administration forms, and antidiabetic therapy.

Lipid Digestibility and Polyphenols Bioaccessibility of Oil-in-Water Emulsions Containing Avocado Peel and Seed Extracts as Affected by the Presence of Low Methoxyl Pectin

In this study, the digestibility of oil-in-water (O/W) emulsions using low methoxyl pectin (LMP) as surfactant and in combination with avocado peel (AP) or seed (AS) extracts was assessed, in terms of its free fatty acid (FFA) release and the phenolic compound (PC) bioaccessibility. With this purpose, AP and AS were characterized by UPLC-ESI-MS/MS before their incorporation into O/W emulsions stabilized using LMP. In that sense, AP extract had a higher content of PCs (6836.32 ± 64.66 mg/100 g of extract) compared to AS extract (1514.62 ± 578.33 mg/100 g of extract). Both extracts enhanced LMP's emulsifying properties, leading to narrower distributions and smaller particle sizes compared to those without extracts. Similarly, when both LMP and the extracts were present in the emulsions the FFA release significantly increased. Regarding bioaccessibility, the PCs from the AS extracts had a higher bioaccessibility than those from the AP extracts, regardless of the presence of LMP. However, the presence of LMP reduced the bioaccessibility of flavonoids from emulsions containing either AP or AS extracts. These results provide new insights regarding the use of PC extracts from avocado peel and seed residues, and the effect of LMP on emulsion digestibility, and its influence on flavonoids bioaccessibility.

Phenolic-Rich Extracts from Avocado Fruit Residues as Functional Food Ingredients with Antioxidant and Antiproliferative Properties

In this study, the total phenolic compounds content and profile, the nutritional value, the antioxidant and antiproliferative activities of avocado peel, seed coat, and seed extracts were characterized. Additionally, an in-silico analysis was performed to identify the phenolic compounds with the highest intestinal absorption and Caco-2 permeability. The avocado peel extract possessed the highest content of phenolic compounds (309.95 ± 25.33 mMol GA/100 g of extract) and the lowest effective concentration (EC₅₀) against DPPH and ABTS radicals (72.64 ± 10.70 and 181.68 ± 18.47, respectively). On the other hand, the peel and seed coat extracts had the lowest energy densities (226.06 ± 0.06 kcal/100 g and 219.62 ± 0.49 kcal/100 g, respectively). Regarding the antiproliferative activity, the avocado peel extract (180 ± 40 µg/mL) showed the lowest inhibitory concentration (IC₅₀), followed by the seed (200 ± 21 µg/mL) and seed coat (340 ± 32 µg/mL) extracts. The IC₅₀ of the extracts induced apoptosis in Caco-2 cells at the early and late stages. According to the in-silico analysis, these results could be related to the higher Caco-2 permeability to hydroxysalidroside, salidroside, sakuranetin, and luteolin. Therefore, this study provides new insights regarding the potential use of these extracts as functional ingredients with antioxidant and antiproliferative properties and as medicinal agents in diseases related to oxidative stress such as cancer.

What is the influence of cinnamon supplementation on liver enzymes? A systematic review and meta-analysis of randomized controlled trials

Existing evidence has uncovered the potential health benefits of cinnamon intake; however, its effect on liver function is unclear. Thus, the aim of this systematic review and meta-analysis was to examine the effect of cinnamon supplementation on liver enzymes. Relevant articles were identified through a systematic search in PubMed/Medline, Scopus, Web of Science, Cochrane Library, and Embase up to September 2020. All trials assessing the effect of oral cinnamon supplementation on serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in adults were included. The pooled effect sizes were obtained using the random-effects model and expressed as mean difference (MD) and 95% confidence intervals (CI). A total of seven original trials (nine treatment arms) involving a total of 256 subjects were included in the final analysis. The pooled analysis indicated that cinnamon supplementation had no significant effect on serum levels of ALT, AST, and ALP. However, there was a significant reduction in ALT levels in patients with type 2 diabetes (MD: -4.01 U/L; 95% CI: -6.86, -1.15) and in trials with low-dose supplementation (<1,500 mg/d), follow-up duration longer than 12 weeks, and in the elderly patients (aged>50 years). The beneficial effects of cinnamon intake were also shown in AST levels in patients with type 2 diabetes and trials with long-term follow-up (>12 weeks). Longer-term, oral cinnamon supplementation may improve serum levels of liver enzymes in patients with type 2 diabetes. Further high-quality studies are needed, especially in populations with abnormal liver enzyme levels, to firmly establish the clinical efficacy of cinnamon on liver function.

Bioactivity-Oriented Purification of Polyphenols from Cinnamomum cassia Presl. with Anti-Proliferation Effects on Colorectal Cancer Cells

Cinnamomum cassia Presl. (CCP) is a popular natural spice possessing various pharmacological properties. We obtained polyphenol-rich fraction (CCP-P) from CCP by bioactivity-oriented purification method and evaluated its Wnt signaling inhibition activity. Firstly, the phenolic components were identified as the main bioactive compounds with anti-colorectal cancer activity. Then, we compared the anti-colorectal cancer activity of CCP extract obtained from different solvent by cell morphology alteration and EdU assay. Ethanol extract showed higher antiproliferative activity compared to water extract on HCT116 cells, with proliferating cells reducing to 41.12 and 21.83% at 156.00 μg GAE/mL, respectively. Next, separation and enrichment of polyphenols from ethanol extract was performed on AB-8 macroporous resins under optimal conditions. Further evaluation of the CCP-P bioactivity revealed that it exerted more potent antiproliferative activity on RKO and HCT116 cells, showing higher selectivity for Wnt-dependent colorectal cancer cells (CRCs). Ten major polyphenols were identified in the CCP-P by UPLC-ESI-MS/MS. In summary, this study presents evidence that CCP-derived polyphenols are promising potential candidates as functional food ingredients against CRC.

Anti-hypertensive effects of cinnamon supplementation in adults: A systematic review and dose-response Meta-analysis of randomized controlled trials

Background & Objectives: Despite controversies, no earlier study has systematically summarized findings from earlier studies on the effect of cinnamon supplementation on blood pressure. Therefore, current systematic review and meta-analysis was done on the effect of cinnamon supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults.Methods: Relevant studies published up to July 2019 were searched through PubMed/Medline, Scopus, ISI Web of Science, Embase and Google Scholar. All randomized clinical trials investigating the impact of oral cinnamon supplementation on any of the blood pressure parameters including SBP or/and DBP were included.Results: Out of 469 citations, 9 trials that enrolled 641 subjects were included. Cinnamon supplementation resulted in significant reduction in SBP (Weighted Mean Differences (WMD): -6.23 mmHg, 95% CI: -10.69 to -1.77, P = 0.006) and DBP (WMD: -3.93 mmHg, 95% CI: -6.33 to -1.52, P = 0.001). Greater effects on SBP were detected in trials using ≤2 g cinnamon, lasted ≥12 weeks and participants aged <50 years' old. DBP was also reduced by using lower doses. However, no significant non-linear associations were found between cinnamon supplementation dosage and study duration with both SBP (For dosage: P_{non-linearity} = 0.35, for duration: P_{non-linearity} = 0.21) and DBP (For dosage: P_{non-linearity} = 0.27, for duration: P_{non-linearity} = 0.41).Conclusions: We found a significant reduction in both SBP and DBP following cinnamon supplementation in adults. It could be proposed as a hypotensive supplement in hypertension management.

Cinnamomum cassia Presl: A Review of Its Traditional Uses, Phytochemistry, Pharmacology and Toxicology

Cinnamomum cassia Presl is a tropical aromatic evergreen tree of the Lauraceae family, commonly used in traditional Chinese medicine. It is also a traditional spice, widely used around the world. This paper summarizes the achievements of modern research on C. cassia, including the traditional uses, phytochemistry, pharmacology and toxicology. In addition, this review also discusses some significant issues and the potential direction of future C. cassia research. More than 160 chemicals have been separated and identified from C. cassia. The main constituents of C. cassia are terpenoids, phenylpropanoids, glycosides, etc. Modern studies have confirmed that C. cassia has a wide range of pharmacological effects, including antitumour, anti-inflammatory and analgesic, anti-diabetic and anti-obesity, antibacterial and antiviral, cardiovascular protective, cytoprotective, neuroprotective, immunoregulatory effects, anti-tyrosinase activity and other effects. However, the modern studies of C. cassia are still not complete and more in-depth investigations need to be conducted in alimentotherapy, health product, toxicity and side effects, and more bioactive components and potential pharmacological effects need to be explored in the future.

Cinnamon supplementation positively affects obesity: A systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Data about the effects of cinnamon supplementation on obesity measures are conflicting. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to summarize the effects of cinnamon intake on body weight (BW), Body Mass Index (BMI), Waist Circumference (WC), and fat mass (FM) in adults.

METHODS

Online electronic search engines including PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to find pertinent articles until September 2018. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). The non-linear association was assessed using fractional polynomial modeling.

RESULTS

Out of 679 records, 12 trials that enrolled 786 subjects were included. The pooled results showed that cinnamon administration significantly decreased BW (WMD: -1.02 kg, 95% CI: -1.66 to -0.38, P = 0.002), BMI (WMD: -0.51 kg/m², 95% CI: -0.74, -0.28, P < 0.001), WC (WMD: -2.40 cm, 95% CI: -4.48, -0.33, P = 0.02), and FM (WMD: -1.02%, 95% CI: -1.80, -0.24, P = 0.01). Greater effects on BW were observed in subjects aged <50 years old and those with a baseline BMI of ≥30 kg/m². The cinnamon administrations significantly reduced FM at the dosages of ≥2 g/d, when administered for ≥12 weeks. Cinnamon administration resulted in BW and WC reduction in non-linear fashion (P = 0.04).

CONCLUSIONS

Cinnamon supplementation significantly affects obesity measures. It could be recommended as a weight-reducing supplement in obesity management.

Costus afer Protects Cardio-, Hepato-, and Reno-Antioxidant Status in Streptozotocin-Intoxicated Wistar Rats

Medicinal plants are efficient modulators of oxidative stress associated with diabetes mellitus. This study evaluated the cardio-, reno-, and hepato-antioxidant status of hydroethanolic extract of Costus afer on streptozotocin-intoxicated diabetic rats. Experimental animals were daily administered with hydroethanolic extract of C. afer by oral intubation for eight weeks (60 days), after which the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and lipid peroxidation marker (MDA) were evaluated in the heart, liver, and kidney homogenates. Plasma biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total protein, creatinine, and urea were determined. Meanwhile, parts of the heart, kidneys, and liver were histopathologically examined. Streptozotocin administration induced toxicity in the cardiac, hepatic, and renal tissues by stimulating significant increases (p<0.05) in the levels of CAT and SOD, GSH, and MDA. Similarly, significant increases (P<0.05) in the levels of ALT, AST, urea, and total protein were observed in streptozotocin treated rats, whereas decreases were observed in the levels of ALP, LDH, and creatinine. Following the treatments with C. afer hydroethanolic extract prevented the effect of streptozotocin by maintaining the tissue antioxidant status (CAT, SOD, GSH, and MDA) and the plasma biochemical parameters (AST, ALT, ALP, LDH, creatinine, and urea) towards the normal ranges. The histopathological examination revealed hepatovascular congestion and leucocyte infiltration as well as renovascular congestion, glomerulosclerosis, and tubular clarification in the untreated diabetic control and their absence in the group of animals treated with a high dose of C. afer extract. The findings of the present investigation suggest that C. afer possesses antioxidant activities capable of regulating drug induced tissue damage.

The Hypoglycemic and Antioxidant Activity of Cress Seed and Cinnamon on Streptozotocin Induced Diabetes in Male Rats

The present study aimed to estimate the stimulation of pancreas of rats with streptozotocin induced diabetes using 20% (w/w) garden cress seed (Lepidium sativum) and cinnamon methanol extracts. The positive control diabetic group showed a significant increase in fasting blood sugar, lipid peroxide, interleukin-6, carboxymethyl lysine, serum uric acid, urea, creatinine, immunoglobulins, and urine albumin and a significant decrease in antioxidant enzymes, sodium ions, potassium ions, and urine creatinine. Severe histopathological changes in the kidney and pancreas tissues in hyperglycemic rats were also shown in the positive control diabetic group. Meanwhile, the groups that were treated with 20% garden cress seed and cinnamon methanol extracts showed a significant decrease in fasting blood sugar and all elevated abovementioned biochemical parameters and an increase in the lowered ones restoring them nearly to the normal levels of G1. Kidney and pancreas tissues were also ameliorated and restored nearly to the normal status. Both garden cress seed and cinnamon methanol extracts succeeded in controlling hyperglycemia in rats with streptozotocin induced diabetes and ameliorated the biochemical and histopathological changes because of their antioxidant activity acquired by their possession of phenolic phytochemicals.

The effect of isorhamnetin glycosides extracted from Opuntia ficus-indica in a mouse model of diet induced obesity

A diet rich in polyphenols can ameliorate some metabolic alterations associated with obesity and type 2 diabetes. Opuntia ficus-indica (OFI) is a plant rich in isorhamnetin glycosides and is highly consumed in Mexico. The purpose of this research was to determine the metabolic effect of an OFI extract on a mouse model of diet-induced obesity and in isolated pancreatic islets. OFI extract was added to a high fat (HF) diet at a low (0.3%) or high (0.6%) dose and administered to C57BL/6 mice for 12 weeks. Mice fed the HF diet supplemented with the OFI extract gained less body weight and exhibited significantly lower circulating total cholesterol, LDL cholesterol and HDL cholesterol compared to those fed the HF diet alone. The HF-OFI diet fed mice presented lower glucose and insulin concentration than the HF diet fed mice. However, the HF-OFI diet fed mice tended to have higher insulin concentration than control mice. The OFI extract stimulated insulin secretion in vitro, associated with increased glucose transporter 2 (GLUT2) and peroxisome proliferator-activated receptor gamma (PPARγ) mRNA content. Furthermore, the OFI extract improved glucose tolerance, and additionally increased energy expenditure. These metabolic improvements were associated with reduced adipocyte size, increased hepatic IRS1 tyr-608 and S6 K thr-389 phosphorylation. OFI isorhamnetin glycosides also diminished the hepatic lipid content associated with reduced mRNA expression of the endoplasmic reticulum stress markers and lipogenic enzymes and increased mRNA expression of genes related to fatty acid oxidation. Overall, the OFI extract prevented the development of metabolic abnormalities associated with diet-induced obesity.

β-Caryophyllene, a natural sesquiterpene, modulates carbohydrate metabolism in streptozotocin-induced diabetic rats

The study was designed to evaluate the antihyperglycemic effects of β-caryophyllene (BCP), a natural sesquiterpene from spices on streptozotocin (STZ) induced diabetic rats. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (40 mg/kg b.w.) in adult male Wistar rats. Diabetic rats exhibited an increase in glucose and HbA1c with a significant fall in insulin and hemoglobin levels. Aberrations in carbohydrate metabolic enzymes were noticed in liver, kidney and skeletal muscle of diabetic rats. A fall in liver and skeletal muscle glycogen with alterations in glycogen synthase and phosphorylase activities was also observed. Oral administration of BCP in dose dependent manner and glibenclamide (600 μg/kg b.w.), a standard oral hypoglycemic drug to diabetic rats for 45 days significantly decreased glucose with increased plasma insulin levels and ameliorated the altered activities of carbohydrate metabolic enzymes to near normal. The insulinotropic effect of BCP was supported by immunohistochemical studies. BCP at a dose of 200mg/kg b.w. exerted significant antidiabetic effects than other two doses (100 and 400mg/kg b.w.). We conclude that administration of BCP has beneficial effects in glucose homeostasis in diabetic rats.