Evaluation of the in vitro anti-hyperglycemic effect of Cinnamomum cassia derived phenolic phytochemicals, via carbohydrate hydrolyzing enzyme inhibition

Suppression of the postprandial hyperglycemia in patients with type 2 diabetes by a raw medicinal herb powder is weakened when consumed in ordinary hard gelatin capsules: A randomized crossover clinical trial

INTRODUCTION

Contradictory claims about the efficacy of several medicinal plants to promote glycemic control in patients with type 2 diabetes mellitus (T2DM) have been explained by divergences in the administration form and by extrapolation of data obtained from healthy individuals. It is not known whether the antidiabetic effects of traditional herbal medicines are influenced by gelatin capsules. This randomized crossover trial aimed to evaluate the acute effect of a single dose of raw cinnamon consumed orally either dissolved in water as a beverage or as ordinary hard gelatin capsules on postprandial hyperglycemia (>140 mg/dL; >7.8 mmol/L) in T2DM patients elicited by a nutritionally-balanced meal providing 50 g of complex carbohydrates.

METHODS

Fasting T2DM patients (n = 19) randomly ingested a standardized meal in five experimental sessions, one alone (Control) and the other after prior intake of 3 or 6 g of crude cinnamon in the form of hard gelatin capsules or powder dissolved in water. Blood glucose was measured at fasting and at 0.25, 0.5, 0.75, 1, 1.5 and 2 hours postprandially. After each breakfast, its palatability scores for visual appeal, smell and pleasantness of taste were assessed, as well as the taste intensity sweetness, saltiness, bitterness, sourness and creaminess.

RESULTS

The intake of raw cinnamon dissolved in water, independently of the dose, decreased the meal-induced large glucose spike (peak-rise of +87 mg/dL and Δ1-hour glycemia of +79 mg/dL) and the hyperglycemic blood glucose peak. When cinnamon was taken as capsules, these anti-hyperglycemic effects were lost or significantly diminished. Raw cinnamon intake did not change time-to-peak or the 2-h post-meal glycaemia, but flattened the glycemic curve (lower iAUC) without changing the shape that is typical of T2DM patients.

CONCLUSIONS

This cinnamon's antihyperglycemic action confirms its acarbose-like property to inhibit the activities of the carbohydrate-digesting enzymes α-amylases/α-glucosidases, which is in accordance with its exceptionally high content of raw insoluble fiber. The efficacy of using raw cinnamon as a diabetes treatment strategy seems to require its intake at a specific time before/concomitantly the main hyperglycemic daily meals. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC), number RBR-98tx28b.

Ramulus Cinnamomi essential oil exerts an anti-inflammatory effect on RAW264.7 cells through N-acylethanolamine acid amidase inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Ramulus Cinnamomi, the dried twig of Cinnamomum cassia (L.) J.Presl., is a traditional Chinese medicine (TCM) with anti-inflammatory effects. The medicinal functions of Ramulus Cinnamomi essential oil (RCEO) have been confirmed, although the potential mechanisms by which RCEO exerts its anti-inflammatory effects have not been fully elucidated.

AIM OF THE STUDY

To investigate whether N-acylethanolamine acid amidase (NAAA) mediates the anti-inflammatory effects of RCEO.

MATERIALS AND METHODS

RCEO was extracted by steam distillation of Ramulus Cinnamomi, and NAAA activity was detected using HEK293 cells overexpressing NAAA. N-Palmitoylethanolamide (PEA) and N-oleoylethanolamide (OEA), both of which are NAAA endogenous substrates, were detected by liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). The anti-inflammatory effects of RCEO were analyzed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and the cell viability was measured with a Cell Counting Kit-8 (CCK-8) kit. The nitric oxide (NO) in the cell supernatant was measured using the Griess method. The level of tumor necrosis factor-α (TNF-α) in the RAW264.7 cell supernatant was determined using an enzyme-linked immunosorbent assay (ELISA) kit. The chemical composition of RCEO was assessed by gas chromatography-mass spectroscopy (GC-MS). The molecular docking study for (E)-cinnamaldehyde and NAAA was performed by using Discovery Studio 2019 software (DS2019).

RESULTS

We established a cell model for evaluating NAAA activity, and we found that RCEO inhibited the NAAA activity with an IC50 of 5.64 ± 0.62 μg/mL. RCEO significantly elevated PEA and OEA levels in NAAA-overexpressing HEK293 cells, suggesting that RCEO might prevent the degradation of cellular PEA and OEA by inhibiting the NAAA activity in NAAA-overexpressing HEK293 cells. In addition, RCEO also decreased NO and TNF-α cytokines in lipopolysaccharide (LPS)-stimulated macrophages. Interestingly, the GC-MS assay revealed that more than 93 components were identified in RCEO, of which (E)-cinnamaldehyde accounted for 64.88%. Further experiments showed that (E)-cinnamaldehyde and O-methoxycinnamaldehyde inhibited NAAA activity with an IC50 of 3.21 ± 0.03 and 9.62 ± 0.30 μg/mL, respectively, which may represent key components of RCEO that inhibit NAAA activity. Meanwhile, docking assays revealed that (E)-cinnamaldehyde occupies the catalytic cavity of NAAA and engages in a hydrogen bond interaction with the TRP181 and hydrophobic-related interactions with LEU152 of human NAAA.

CONCLUSIONS

RCEO showed anti-inflammatory effects by inhibiting NAAA activity and elevating cellular PEA and OEA levels in NAAA-overexpressing HEK293 cells. (E)-cinnamaldehyde and O-methoxycinnamaldehyde, two components in RCEO, were identified as the main contributors of the anti-inflammatory effects of RCEO by modulating cellular PEA levels through NAAA inhibition.

Two new meroterpenoids from the bark of Cinnamomum cassia and their antioxidant activity

Two new (1 and 2) meroterpenoids were isolated from the bark of Cinnamomum cassia. Their structures were determined by spectroscopic analyses and chemical methods. Antioxidant activities of 1 and 2 were evaluated by the ORAC and DPPH radical scavenging assays, and the results revealed that compound 2 displayed oxygen radical absorbance capacity. The discovery of compounds 1 and 2 added new members of this kind of natural product.

Stimulation of ACE inhibitory and improving α-amylase and α-glucosidase and antioxidant activities of semi-prepared and dry soup by incorporating with date kernel powder

Date kernel as a functional food component has a special importance due to its rich nutritional profile, low price, and ease of access. For this, in this research, the sub-product was used for formulation of semi-prepared dry soup (SPDS); the effect of adding 0 (S1 = control), 2 (S2), and 4 (S3) %w/w date kernel powder (DKP) on physicochemical, nutritional, and organoleptic properties and beneficial effects of SPDS samples were evaluated. The results revealed that S2 and S3 samples were different from the control sample in some physicochemical properties so that viscosity increased 1.27 and 1.52 times and a* raised 5.6 and 8.5 times, respectively, while L* decreased 0.94 and 0.88 times and b* reduced 0.92 and 0.8 times, respectively. The nutritional properties of S2 and S3 samples compared with the control sample improved. Also, differences were observed in the beneficial effects of S2 and S3 compared with the control sample as total polyphenol content (TPC) increased 1.06 and 1.11 times, respectively (p < .05); antioxidant activities (AA) of S2 and S3 samples were 8.04 and 6.01 mg/ml and angiotensin-converting enzyme (ACE) inhibitory activities were measured to be 8.2 and 7.86 mg/ml, respectively; also, α-amylase and α-glucosidase inhibitory activities of S2 and S3 samples were observed 4.48% and 5.70%, and 4.59% and 6.36%, respectively. From the organoleptic aspect, S3 had the highest acceptability. Generally, it is concluded that with the addition of DKP (maximally 4%w/w) to SPDS formulation, a functional soup could be produced considering the rich nutritional profile of DKP.

Urease Inhibitory Kinetic Studies of Various Extracts and Pure Compounds from Cinnamomum Genus

Urease is an enzyme that plays a significant role in the hydrolysis of urea into carbonic acid and ammonia via the carbamic acid formation. The resultant increase in pH leads to the onset of various pathologies such as gastric cancer, urolithiasis, hepatic coma, hepatic encephalopathy, duodenal ulcers and peptic ulcers. Urease inhibitors can reduce the urea hydrolysis rate and development of various diseases. The Cinnamomum genus is used in a large number of traditional medicines. It is well established that stem bark of Cinnamomum cassia exhibits antiulcerogenic potential. The present study evaluated the inhibitory effect of seven extracts of Cinnamomum camphora, Cinnamomum verum and two pure compounds Camphene and Cuminaldehyde on urease enzyme. Kinetic studies of potential inhibitors were carried out. Methanol extract (IC₅₀ 980 µg/mL) of C. camphora and a monoterpene Camphene (IC₅₀ 0.147 µg/mL) possess significant inhibitory activity. The Lineweaver Burk plot analysis suggested the competitive inhibition by methanol extract, hexane fraction and Camphene. The Gas Chromatography-Mass Spectroscopy (GC–MS) analysis of hexane fraction revealed the contribution of various terpenes. The present study targets terpenes as a new class of inhibitors that have potential therapeutic value for further development as novel drugs.

Cinnamomum Species: Bridging Phytochemistry Knowledge, Pharmacological Properties and Toxicological Safety for Health Benefits

The genus Cinnamomum includes a number of plant species largely used as food, food additives and spices for a long time. Different traditional healing systems have used these plants as herbal remedies to cure diverse ailments. The aim of this comprehensive and updated review is to summarize the biodiversity of the genus Cinnamomum, its bioactive compounds, the mechanisms that underlie the pharmacological activities and molecular targets and toxicological safety. All the data in this review have been collected from databases and recent scientific literature including Web of Science, PubMed, ScienceDirect etc. The results showed that the bioactive compounds of Cinnamomum species possess antimicrobial, antidiabetic, antioxidant, anti-inflammatory, anticancer and neuroprotective effects. The preclinical (in vitro/in vivo) studies provided the possible molecular mechanisms of these action. As a novelty, recent clinical studies and toxicological data described in this paper support and confirm the pharmacological importance of the genus Cinnamomum. In conclusion, the obtained results from preclinical studies and clinical trials, as well as reduced side effects provide insights into future research of new drugs based on extracts and bioactive compounds from Cinnamomum plants.

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.

Cytotoxic activity of the twigs of Cinnamomum cassia through the suppression of cell proliferation and the induction of apoptosis in human colorectal cancer cells

Background

Because twigs of Cinnamomum cassia (TC) have been reported to exert anti-cancer activity, the mechanistic study for TC’s anti-cancer activity is required. Thus, we elucidated the potential molecular mechanism of TC’s anti-proliferative effect and the induction of apoptosis in human colorectal cancer cells.

Methods

How water extracts form TC (TC-HW) was used in this study. Anti-cell proliferative effect of TC-HW was evaluated by MTT assay. The change of protein or mRNA level by TC-HW was evaluated by Western blot and RT-RCR, respectively. The promoter construct for ATF3, NF-κB, TOP-FLASH or FOP-FLASH was used for the investigation of the transcriptional activity for ATF3, NF-κB or Wnt. siRNA for ATF3 or p65 was used for the knockdown of ATF3 and p65.

Results

TC-HW reduced the cell viability in human colorectal cancer cells. TC-HW decreased cyclin D1 protein level through cyclin D1 degradation via GSK3β-dependent threonine-286 (T286) phosphorylation of cyclin D1, indicating that cyclin D1 degradation may contribute to TC-HW-mediated decrease of cyclin D1 protein level. TC-HW downregulated the expression of cyclin D1 mRNA level and inhibited Wnt activation through the downregulation of β-catenin and TCF4 expression, indicating that inhibition of cyclin D1 transcription may also result in TC-HW-mediated decrease of cyclin D1 protein level. In addition, TC-HW was observed to induce apoptosis through ROS-dependent DNA damage. TC-HW-induced ROS increased NF-κB and ATF3 activation, and inhibition of NF-κB and ATF3 activation attenuated TC-HW-mediated apoptosis.

Conclusions

Our results suggest that TC-HW may suppress cell proliferation through the downregulation of cyclin D1 via proteasomal degradation and transcriptional inhibition, and may induce apoptosis through ROS-dependent NF-κB and ATF3 activation. These effects of TC-HW may contribute to the reduction of cell viability in human colorectal cancer cells. From these findings, TC-HW has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

The essential oil from the twigs of Cinnamomum cassia Presl inhibits oxytocin-induced uterine contraction in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

The twigs and bark of Cinnamomum cassia Presl (Lauraceae) are widely used in traditional Chinese medicine in the treatment of tumor, abdominal pain, dysmenorrhea, digestive system disease and inflammatory diseases. The aim of this study was to determine the inhibitory effect of the essential oil from the twigs of Cinnamomum cassia Presl (EOCC) on uterine contraction in vitro and in vivo.

MATERIALS AND METHODS

The Institute of Cancer Research (ICR) mouse uterine contraction was induced by oxytocin (OT) exposure following estradiol benzoate pretreatment. Mice were given the EOCC (60, 30, and 15mg/kg) by gavage. The level of prostaglandin F_2α (PGF_2α) in uterine tissue were determined according to specification of enzyme linked immunosorbent assay (ELISA) kit. Uterine tissue was collected for histopathological analysis (H&E). Myosin light chain 20 (MLC20), phosphorylation of myosin light chain 20 (p-MLC20) and cyclooxygenase-2 (COX-2) proteins in uterine tissue were assessed by Western Blot. Mouse isolated uterus strips were mounted in tissue organ baths containing Locke's solution. The contractile responses were recorded with Power Lab recording system. The effect of the EOCC on uterine contraction induced by OT, PGF_2α, and acetylcholine (Ach) was observed. Myometrial cells were exposed to OT (7μM) to induce Ca²⁺ release, and the effect of the EOCC (100, 50, and 25μg/ml) on intracellular Ca²⁺ was analysed with fluorometry imaging.

RESULTS

In vivo study demonstrated that the EOCC significantly reduced OT-induced writhing responses with a maximal inhibition of 66.5%. It also decreased the level of PGF_2α in OT-induced mice uterine tissue. Moreover, Western blot analysis showed that COX-2 and p-MLC20 expressions in uterine tissue of dysmenorrhea mice were significantly reduced. EOCC inhibited spontaneous uterus contractions in a dose-dependent manner, and the concentration of the EOCC giving 50% of maximal contraction (IC₅₀) value was 61.3μg/ml. The IC₅₀ values of the EOCC on OT, PGF_2α, and Ach-induced contractions were 113.0μg/ml, 94.7μg/ml, and 61.5μg/ml, respectively. Further in vitro studies indicated that the EOCC could restrain intracellular Ca²⁺ levels in favour of uterine relaxation.

CONCLUSION

Both in vivo and in vitro results suggest that the EOCC possesses significant spasmolytic effect on uterine contraction. Thus, the EOCC yields a possible therapeutic choice for the prevention and treatment of primary dysmenorrhea.

The essential oil from the twigs of Cinnamomum cassia Presl alleviates pain and inflammation in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Cinnamomum cassia Presl (Lauraceae) can be found southern China and its bark is commonly used for centuries as ingredient in food and cosmetic industry. The twigs of Cinnamomum cassia Presl is popularly used in China to treat inflammatory processes, pain, menstrual disorders, hypertension, fever etc. The aim of this study is to evaluate the antinociceptive and anti-inflammatory properties of the essential oil (EO) from the twigs of Cinnamomum cassia Presl.

MATERIAL AND METHODS

The chemical characterization of the EO was performed by gas chromatography coupled with mass spectrometry (GC-MS). The EO doses of 15, 30, and 60mg/kg were employed in the biological assays. The antinociceptive effects of the EO were evaluated using the models of acetic acid-induced writhing, oxytocin-induced writhing, and formalin and complete Freund's adjuvant (CFA) -induced overt pain tests. we also investigated the effect of the EO in pain intensity to a mechanical stimulus (mechanical hyperalgesia) after carrageenan by using an electronic version of von Frey filaments. Evaluation of anti-inflammatory activity was based on paw edema induced by carrageenan (300µg/25µL/paw) in mice. The levels of cytokines, NO, and PGE2 in paw skin tissue were determined according to instructions. COX-2 and iNOS proteins in paw skin tissue were assessed by Western Blot.

RESULTS

The EO (15, 30, and 60mg/kg) reduced the number of abdominal writhings induced by acetic acid with inhibition of 38.0%, 55.4% and 58.7%, respectively. The EO (15, 30, and 60mg/kg) also reduced the number of abdominal writhings induced by oxytocin with inhibition of 27.3%, 51.7% and 69.0%, respectively. The EO significant inhibited the inflammatory (second phase: 10-30min) phase of the formalin-induced paw flinching and licking at the doses of 15, 30, and 60mg/kg. The EO at the tested doses of 15, 30, and 60mg/kg showed inhibited CFA-induced paw flinching and licking. The EO (15, 30, and 60mg/kg) also inhibited carrageenan-induced mechanical hyperalgesia and paw edema. It also decreased the levels of cytokines (TNF-α, and IL-1β), NO, and PGE2 in carrageenan-induced mice paw skin tissue. Moreover, Western blot analysis showed that COX-2 and iNOS expressions in paw skin tissue of mice were significantly reduced.

CONCLUSIONS

These results demonstrate that the antinociceptive and anti-inflammatory properties of the EO from the twigs of Cinnamomum cassia Presl, corroborating its use in folk medicine.

Screening of Phenolic Compounds Reveals Inhibitory Activity of Nordihydroguaiaretic Acid Against Three Enzymes Involved in the Regulation of Blood Glucose Level

In this work we have focused on the inhibition of three different enzymes with a role in postprandial glucose management: α-amylase, α-glucosidase and dipeptidyl peptidase 4. The assortment of 29 monomeric phenolic compounds was first screened at a single concentration. Next, the IC50 values of tested compounds were evaluated for compounds that considerably inhibited any of the enzymes. Nordihydroguaiaretic acid, a phenolic compound abundant in Creosote bush Larrea tridentata, possessed inhibitory activity for all tested enzymes. This in vitro mechanism of action supports traditional use of Creosote bush in diabetes treatment.

The Use of Green Leaf Membranes to Promote Appetite Control, Suppress Hedonic Hunger and Loose Body Weight

On-going research aims at answering the question, which satiety signal is the most potent or which combination of satiety signals is the most potent to stop eating. There is also an aim at finding certain food items or food additives that could be used to specifically reduce food intake therapeutically. Therapeutic attempts to normalize body weight and glycaemia with single agents alone have generally been disappointing. The success of bariatric surgery illustrates the rationale of using several hormones to treat obesity and type-2-diabetes. We have found that certain components from green leaves, the thylakoids, when given orally have a similar rationale in inducing the release of several gut hormones at the same time. In this way satiety is promoted and hunger suppressed, leading to loss of body weight and body fat. The mechanism is a reduced rate of intestinal lipid hydrolysis, allowing the lipolytic products to reach the distal intestine and release satiety hormones. The thylakoids also regulate glucose uptake in the intestine and influences microbiota composition in the intestine in a prebiotic direction. Using thylakoids is a novel strategy for treatment and prevention of obesity.

Relationship Between Metabolites Composition and Biological Activities of Phyllanthus niruri Extracts Prepared by Different Drying Methods and Solvents Extraction

The study investigated the changes in the metabolite, antioxidant and α-glucosidase inhibitory activities of Phyllanthus niruri after three drying treatments: air, freeze and oven dryings. Water extracts and extracts obtained using different solvent ratios of ethanol and methanol (50, 70, 80 and 100%) were compared. The relationships among the antioxidant, α-glucosidase inhibitory activity and metabolite levels of the extracts were evaluated using partial least-square analysis (PLS). The solvent selectivity was assessed based on the phytochemical constituents present in the extract and their concentrations quantitatively analyzed using high performance liquid chromatography. The freeze-dried P. niruri samples that were extracted with the mixture of ethanol or methanol with low ratio of water showed higher biological activity values compared with the other extracts. The PLS results for the ethanolic with different ratio and water extracts demonstrated that phenolic acids (chlorogenic acid and ellagic acid) and flavonoids were highly linked to strong α-glucosidase inhibitory and antioxidant activities.

Effect of Black Tea and Black Tea Pomace Polyphenols on α-Glucosidase and α-Amylase Inhibition, Relevant to Type 2 Diabetes Prevention

This study evaluates the potential mechanism of action and bioactivity of black tea and black tea pomace for type 2 diabetes prevention via inhibition of carbohydrate hydrolyzing enzymes. Black tea leaves were extracted in hot water and black tea pomace was extracted in 70% acetone. The phenolic content of the water extract (WBT) and pomace acetone extracts (AOBT) were 5.77 and 8.9 mg/mL, respectively, both based on the same concentration of solid tea in the extract. The water extract was subjected to C18 extraction and the resulting hydrophobic fraction (HBBT) was further subjected to LH-20 extraction to recover a low molecular weight phenolic enriched fraction (LMW) and a high molecular weight enriched fraction (HMW). The phenolic content of the LMW and HMW fraction were 1.42 and 2.66 mg/mL, respectively. Among water extracts the HMW fraction was most bioactive against α-glucosidase (IC50 = 8.97 μg/mL) followed by HBBT fraction (IC50 = 14.83 μg/mL). However, the HBBT fraction was the most bioactive fraction against α-amylase (IC50 = 0.049 mg/mL). The black tea pomace (AOBT) had significant α-glucosidase inhibitory activity (IC50 = 14.72 μg/mL) but lower α-amylase inhibitory activity (IC50 = 0.21 mg/mL). The phenolic profiles for LMW and HMW fractions were evaluated using HPLC and the differences between the two profiles were identified. Further research is underway to identify and evaluate the phenolic compounds that are present in the HMW fraction. Our findings suggest that black tea and black tea pomace has potential for carbohydrate hydrolyzing enzyme inhibition and this activity depends on high molecular weight phenolic compounds.