BackgroundIn traditional medicine Cinnamon is considered a remedy for respiratory, digestive and gynaecological ailments. In-vitro and in-vivo studies from different parts of the world have demonstrated numerous beneficial medicinal effects of Cinnamomum zeylanicum (CZ). This paper aims to systematically review the scientific literature and provide a comprehensive summary on the potential medicinal benefits of CZ.MethodsA comprehensive systematic review was conducted in the following databases; PubMed, Web of Science, SciVerse Scopus for studies published before 31st December 2012. The following keywords were used: “Cinnamomum zeylanicum”, “Ceylon cinnamon”, “True cinnamon” and “Sri Lankan cinnamon”. To obtain additional data a manual search was performed using the reference lists of included articles.ResultsThe literature search identified the following number of articles in the respective databases; PubMed=54, Web of Science=76 and SciVerse Scopus=591. Thirteen additional articles were identified by searching reference lists. After removing duplicates the total number of articles included in the present review is 70. The beneficial health effects of CZ identified were; a) anti-microbial and anti-parasitic activity, b) lowering of blood glucose, blood pressure and serum cholesterol, c) anti-oxidant and free-radical scavenging properties, d) inhibition of tau aggregation and filament formation (hallmarks of Alzheimer’s disease), e) inhibitory effects on osteoclastogenesis, f) anti-secretagogue and anti-gastric ulcer effects, g) anti-nociceptive and anti-inflammatory activity, h) wound healing properties and i) hepato-protective effects. The studies reported minimal toxic and adverse effects.ConclusionsThe available in-vitro and in-vivo evidence suggests that CZ has many beneficial health effects. However, since data on humans are sparse, randomized controlled trials in humans will be necessary to determine whether these effects have public health implications.

Aims Diabetes is a leading cause of morbidity and mortality worldwide. Studies have frequently looked at dietary components beneficial in treatment and prevention. We aim to systematically evaluate the literature on the safety and efficacy of Cinnamomum zeylanicum on diabetes.Methods A comprehensive search of the literature was conducted in the following databases; PubMed, Web of Science, Biological Abstracts, SciVerse Scopus, SciVerse ScienceDierect, CINAHL and The Cochrane Library. A meta-analysis of studies examining the effect of C. zeylanicum extracts on clinical and biochemical parameters was conducted. Data were analysed using RevMan v5.1.2.Results The literature search identified 16 studies on C. zeylanicum (five in-vitro, six in-vivo and five in-vivo ⁄ in-vitro). However, there were no human studies. In-vitro C. zeylanicum demonstrated a potential for reducing post-prandial intestinal glucose absorption by inhibiting pancreatic a-amylase and a-glucosidase, stimulating cellular glucose uptake by membrane translocation of glucose transporter-4, stimulating glucose metabolism and glycogen synthesis, inhibiting gluconeogenesis and stimulating insulin release and potentiating insulin receptor activity. The beneficial effects of C. zeylanicum in animals include attenuation of diabetes associated weight loss, reduction of fasting blood glucose, LDL and HbA 1c , increasing HDL cholesterol and increasing circulating insulin levels. Cinnamomum zeylanicum also significantly improved metabolic derangements associated with insulin resistance. It also showed beneficial effects against diabetic neuropathy and nephropathy, with no significant toxic effects on liver and kidney and a significantly high therapeutic window.Conclusion Cinnamomum zeylanicum demonstrates numerous beneficial effects both in vitro and in vivo as a potential therapeutic agent for diabetes. However, further randomized clinical trials are required to establish therapeutic safety and efficacy.

BackgroundCinnamon is considered as a treatment for many ailments in native medicine. Evidence suggests that Cinnamomum zeylanicum (CZ) has anti-microbial, anti-parasitic, anti-oxidant, blood glucose lowering properties and beneficial cardiovascular effects. The present study aims to evaluate Pharmacodynamic properties and safety of CZ in healthy adults using a Phase I Clinical Trial.MethodsThis phase I clinical trial was conducted at the Department of Pharmacology, Faculty of Medicine, University of Colombo, Sri Lanka. Thirty healthy adults were recruited for the study, conducted for a period of 3 months, with the dose of CZ (water extract) increased at monthly intervals (85 mg, 250 mg and 500 mg). Data collection was carried out at baseline and during each monthly follow up visit. Anthropometric, clinical and biochemical assessments were done at baseline and during follow up. Adverse effects and drug compliance was also evaluated.ResultsTwenty eight subjects completed the three months follow up. Mean age was 38.8 ± 10.4 years and 50% were males. There were no significant changes in the anthropometric parameters during the three months follow up. Both systolic and diastolic blood pressure reduced significant during the 1st month and this reduction was sustained throughout follow up. Full blood count, renal function tests, liver function tests, fasting blood glucose, HDL-c, VLDL-d and triglycerides remained within the normal range without any significant alteration during the 3 months. A significant reduction in the TC (p < 0.05) and LDL-c (p < 0.001) was noted at the end of the 3 months follow up period. There were no serious adverse effects (including hypersensitivity) noted. In two participants dyspepsia necessitated the discontinuation of study participation. Drug compliance was between 85 and 95% during the study period.ConclusionsThis is the first phase I clinical trial in health adults evaluating efficacy and safety of CZ. Our results demonstrate no significant side effects and toxicity of CZ, including hepatotoxicity and anti-coagulation properties. CZ demonstrated beneficial anti-hyperlipidaemic and blood pressure lowering effects among healthy adults. Further studies with larger samples and longer durations may be able to elucidate other side effects and better describe the pharmacodynamic properties.Trial registrationSLCTR/2013/001 (Sri Lanka Clinical Trials Registry: http://www.slctr.lk/trials/106) (Date of Registration: 01/01/2013).

BackgroundPrevious studies have explored the anti-diabetic effects of Cinnamomum cassia extract in vivo and in vitro. However, there are no studies at present exploring the effects of the indigenous species of Sri Lankan cinnamon (Cinnamomum zeylanicum) in patients with diabetes mellitus. The present study aims to evaluate the potential effects of Cinnamomum zeylanicum extract as a pharmaceutical agent in patients with type-2 diabetes mellitus.Methods/designThe study will be conducted as a randomized, double-blind, placebo-controlled clinical trial for a period of 4 months at the Medical Clinic, University Medical Unit, National Hospital of Sri Lanka. A total of 210 subjects with diabetes, in three equal groups, will be recruited for the study. The patients will be randomized in a 1:1:1 ratio according to the method of block randomization and the subjects will be randomly and equally assigned into two test groups (n = 70 each) and one placebo group (n = 70). The population will be stratified at randomization based on age, gender and disease severity. The treatment drug is a capsule containing Cinnamomum zeylanicum extract as the active ingredient and the placebo capsule will contain lactose monohydrate. Two doses of Cinnamomum zeylanicum extracts (250 mg and 500 mg of the cinnamon extract) will be used. The study drugs will be double blinded to both investigators and participants. The visits and the evaluations will be done as follows: screening (visit 0), 1 month (visit 1), 2 months (visit 2), 3 months (visit 3) and 4 months (visit 4). The following primary outcome measures will be evaluated: glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG) and serum insulin. Secondary outcome measures include: Body Mass Index (BMI) and other anthropometric parameters, blood pressure, total cholesterol, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL) and triglycerides (TAG). Data will be analyzed using SPSS version 14.DiscussionWe describe the protocol for a clinical trial design evaluating the effects of Cinnamomum zeylanicum (Ceylon cinnamon) in patients with type-2 diabetes mellitus. The result of the present study, positive or negative, should provide a step change in the evidence guiding current and future policies regarding the use of cinnamon dietary supplementation in patients with diabetes.Trial registrationSri Lanka Clinical Trials Registry (SLCTR), identifier: SLCTR/2017/010 (http://slctr.lk/trials/714). Registered on 5 April 2017; study protocol version 3.1 21 March 2017.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-017-2192-0) contains supplementary material, which is available to authorized users.

BackgroundThe number of people with diabetes is increasing worldwide, especially in developing South Asian countries. Therefore, preventing diabetes at the early stages has become an important issue. Recent clinical trials, systematic reviews, and meta-analysis have shown that zinc has beneficial effects on glycemic and metabolic control in those with diabetes. The present study is designed to evaluate the effects of zinc supplementation on glycemic control and other metabolic parameters in those with pre-diabetes.Methods/designThe study will be conducted as a randomized, double-blind, placebo-controlled clinical trial for a period of 12 months at the Faculty of Medicine, University of Colombo, Sri Lanka. The study has been approved by the Ethics Review Committee of Faculty of Medicine, University of Colombo (EC/11/189). A total of 200 adults (age 18–60 years) with pre-diabetes will be recruited for the study. They will be stratified according to age, gender, and body mass index and randomly assigned into the test and placebo groups on a 1:1 ratio. The zinc capsules, each weighing 456 mg, will contain the following ingredients:zinc sulfate monohydrate 55.096 mg (elemental zinc 20 mg), lactose monohydrate 399.504 mg, and stearic acid 1.400 mg. The placebo capsule with the same weight will be comprised of lactose monohydrate 454.600 mg and stearic acid 1.400 mg. The subjects will receive either zinc 20 mg capsules or placebo daily for a period of 12 months. The study drugs will be double blinded to both investigators and subjects. The visits and the evaluations will be done as follows: screening (visit 0), 1 month (visit 1), 3 month (visit 2), 6 month (visit 3), and 12 month (visit 4). The following primary outcome measures will be evaluated:fasting plasma glucose (FPG), post oral glucose tolerance test (OGTT), serum insulin, HbA1c, total/low-density lipoprotein (LDL)/high-density lipoprotein (HDL) cholesterol, triglycerides, serum zinc, and appetite using a visual analog scale. Secondary outcome measures include: blood pressure, anthropometry, and dietary assessment using a validated food frequency questionnaire. Data will be analyzed using SPSS v16.DiscussionThe present protocol will aim to establish the beneficial effects of zinc supplementation on disease progression in those with pre-diabetes and also establish its effectiveness in the prevention of diabetes mellitus.Trial registrationSri Lanka Clinical Trial Registry: SLCTR/2012/010