Cornus mas L. is indigenous to Europe and parts of Asia. Although Cornus is widely considered to be an iridoid rich genera, only two iridoids have been previously found in this plant. The lack of information on taxonomically and biologically active iridoids prompted us to develop and optimize an analytical method for characterization of additional phytochemicals in C. mas fruit. An ultra performance liquid chromatography (UPLC) coupled with photodiode array spectrophotometry (PDA) and electrospray time-of-flight mass spectrometry (ESI-TOF-MS) was employed and mass parameters were optimized. Identification was made by elucidating the mass spectral data and further confirmed by comparing retention times and UV spectra of target peaks with those of reference compounds. Primary DNA damage and antigenotoxicity tests in E. coli PQ37 were used to screen the iridoids for biological activity. As a result, ten phytochemicals were identified, including iridoids loganic acid, loganin, sweroside, and cornuside. Nine of these were reported for the first time from C. mas fruit. The iridoids did not induce SOS repair of DNA, indicating a lack of genotoxic activity in E. coli PQ37. However, loganin, sweroside, and cornuside did reduce the amount of DNA damage caused by 4-nitroquinoline 1-oxide, suggesting potential antigenotoxic activity.
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In 2012, Nature journal published an ariticle entitled ”An alternative route to cyclic terpenes by reductive cyclization in iridoid biosynthesis” by Fernando Geu-Flores et al. The publication reported the discovery of iridoid synthase, a plant-derived enzyme that generates the iridoid ring scaffold, as evidenced by biochemical assays, gene silencing, co-expression analysis and localization studies. Iridoid synthase uses the linear monoterpene 10-oxogeranial as substrate and probably couples an initial NAD(P)H-dependent reduction step with a subsequent cyclization step via a Diels–Alder cycloaddition or a Michael addition. The authors anticipate that their work will enable the large-scale heterologous production of iridoids in plants and microorganisms for agricultural and pharmaceutical applications.
Inflammation is a manifestation of a wide range of disorders which include; arthritis, atherosclerosis, Alzheimer’s disease, inflammatory bowel syndrome, physical injury and infection amongst many others. Common treatment modalities are usually nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, paracetamol, indomethacin and ibuprofen as well as corticosteroids such as prednisone. These however, may be associated with a host of side effects due to non-selectivity for cyclooxygenase (COX) enzymes involved in inflammation and those with selectivity may be highly priced. Thus, there is a continuing search for safe and effective antiinflammatory molecules from natural sources. Research has confirmed that iridoids exhibit promising anti-inflammatory activity which may be beneficial in the treatment of inflammation. Iridoids are secondary metabolites present in various plants, especially in species belonging to the Apocynaceae, Lamiaceae, Loganiaceae, Rubiaceae, Scrophulariaceae and Verbenaceae families. Many of these ethnobotanicals have an illustrious history of traditional use alluding to their use to treat inflammation. Although iridoids exhibit a wide range of pharmacological activities such as cardiovascular, hepatoprotection, hypoglycaemic, antimutagenic, antispasmodic, anti-tumour, antiviral, immunomodulation and purgative effects this review will acutely focus on their anti-inflammatory properties. The paper aims to present a summary for the most prominent iridoid-containing plants for which anti-inflammatory activity has been demonstrated in vitro and / or in vivo.
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Corni Fructus (Cornus officinalis SIEB. et ZUCC.) was fractionated and evaluated for the effects against diabetes by Yamabe et al. They used one iridoid glycoside and three polyphenol fractions from Corni Fructus to administer orally at a dose of 20 mg/kg body weight/d for 10 d in streptozotocin-induced diabetic rats, respectively. As a result, iridoid glycosides and low molecular weight polyphenol fractions could reduce the pathogenesis of diabetic renal damage, each having different mechanisms, i.e., iridoid glycosides successfully decreased the hyperglycemic state and affected renal advanced glycation end-product (AGE) accumulation, such as N(epsilon)-(carboxyethyl)lysine and N(epsilon)-(carboxymethyl)lysine, while low molecular weight polyphenol fractions could reduce renal lipid peroxidation, the receptor for AGE, and inducible nitric oxide synthase. Overall, these data suggest that iridoid glycosides and low molecular weight polyphenols purified from Corni Fructus improve metabolic parameters associated with the development of diabetic renal damage. Iridoid is one of the main active principles.
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A scientific study was conducted to evaluate the in vitro and in vivo bioactivities of a beverage containing noni fruit, Cornelian cherries, and olive leaf extract (Thrive Adaptogenics Max). The major iridoids present were identified as asperulosidic acid, deacetylasperulosidic acid, oleuropein, morroniside, loganic acid, and loganin. In the 2, 2- diphenylpicrylhydrazyl (DPPH) radical scavenging assay, remarkably high in vitro antioxidant activity was observed, with an IC50 of 3.8 µL/mL. In vivo bioactivities were evaluated in type 2 diabetic Sprague Dawley rats. In a dose-dependent manner, Thrive Adaptogenics Max reduced abnormal weight gain, blood glucose levels, and serum Advanced Glycation End products (AGEs). These results suggest that this blend of ingredients is beneficial for improving and maintaining health in the general population, as well as among those with metabolic imbalance.
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A recent publication in the Journal of Natural Products by Liu et al reported the identification of 31 iridoids from the roots of Rehmannia glutinosa. Among these, 11 iridoids (rehmaglutosides A–K) were identified as new compounds, which were found for the first time in the world. Further in vitro bioassay tests indicated that five iridoids have moderate hepatoprotective activities against D-galactosamine-induced HL-7702 cell damage at a concentration of 10 μM.
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In a recent publication, West et al reported that an iridoid rich extract prepared from Morinda citrifolia (noni) fruit exhibited antimicrobial activity. The study incubated the iridoid rich extract with aliquots of twenty-four hour cultures of Candida albicans, Escherichia coli and Staphylococcus aureus at total iridoid concentrations of 0.096, 0.19, 0.45, 0.82 and 1.41 mg/mL. As a result, the effect of iridoid concentration on the growth of E. coli, S. aureus, and C. albicans cultures is demonstrated in a dose-dependent manner. Chemically, asperulosidic acid and deacetylasperulosidic acid were determined to be the major iridoids in the extract, which account for 10.4% of total extract. The results of the investigation suggests that the antimicrobial activity of noni fruit is due to the presence of iridoids, as iridoid concentration dependent decreases in cell culture growth were evident. Further, iridoids from noni fruit appear to be active against yeasts, Gram negative, and Gram positive bacteria. The study also provides additional corroboration to the traditional use of noni fruit as an anti-infective agent. It is of interest to note, however, that the anti-microbial properties do not appear to pose any safety risks to humans or animals. Multiple toxicity tests and human trials have revealed that noni fruit juice is safe to consume, even in large quantities and over extended periods of time.
The study also justifies that the absence of preservatives in most commercial noni juices.
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Determination and comparative analysis of major iridoids in different parts and cultivation sources of Morinda citrifolia
Introduction – Noni is a medicinal plant with a long history of use as a folk remedy in many tropical areas, and is attracting more attention worldwide. A comprehensive study on the major phytochemicals in different plant parts (fruit, leaf, seed, root and flower) and sources is of great value for fully understanding their diverse medicinal benefits.
Objective – To quantitatively determine the major iridoid components in different parts of noni plants, and compare iridoids in noni fruits collected from different tropical areas worldwide.
Methodology – The optimal chromatographic conditions were achieved on a C18 column with gradient elution using 0.1% formic acid aqueous formic acid and acetonitrile at 235 nm. The selective HPLC method was validated for precision, linearity, limit of detection, limit of quantitation and accuracy.
Results – Deacetylasperulosidic acid (DAA) was found to be the major iridoid in noni fruit. In order of predominance, DAA concentrations in different parts of the noni plant were dried noni fruit > fruit juice > seed > flower > leaf > root. The order of predominance for asperulosidic acid (AA) concentration was dried noni fruit > leaf > flower > root > fruit juice > seed. DAA and AA contents of methanolic extracts of noni fruits collected from different tropical regions were 13.8–42.9 and 0.7–8.9 mg/g, respectively, with French Polynesia containing the highest total iridoids and the Dominican Republic containing the lowest.
Conclusion – Iridoids DAA and AA are found to be present in leaf, root, seed and flower of noni plants, and were identified as the major components in noni fruit. Given the great variation of iridoid contents in noni fruit grown in different tropical areas worldwide, geographical factors appear to have significant effects on fruit composition. The iridoids in noni fruit were stable at the temperatures used during pasteurisation and, therefore, may be useful marker compounds for identity and quality testing of commercial noni products.
Oleuropein, a non-toxic secoiridoid derived from the olive tree, is a powerful antioxidant and anti-angiogenic agent. Now, it is found to be a potent anti-cancer compound, directly disrupting actin filaments in cells and in a cell-free assay. Oleuropein inhibited the proliferation and migration of advanced-grade tumor cell lines in a dose-responsive manner. In a novel tube-disruption assay, Oleuropein irreversibly rounded cancer cells, preventing their replication, motility, and invasiveness; these effects were reversible in normal cells. When administered orally to mice that developed spontaneous tumors, Oleuropein completely regressed tumors in 9–12 days. When tumors were resected prior to complete regression, they lacked cohesiveness and had a crumbly consistency. No viable cells could be recovered from these tumors. These observations elevate Oleuropein from a non-toxic antioxidant into a potent anti-tumor agent with direct effects against tumor cells. Our data may also explain the cancer-protective effects of the olive-rich Mediterranean diet.
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As we all know, herbs, medicinal plants, foods, and dietary supplements are very complicated natural matrix, and may consist of hundreds of compounds and components. As such, biologically active compounds (biomarkers) in these materials are needed to be clarified, in order to better understand their safety, efficacy, and daily usage. In Asia and Europe, some countries are enforcing legal requirements to clarify biomarkers in the commercial products. This not only benefits consumers, but also manufacturers. Consumers will know what in the products, and manufactuerers can justify what they claim for the products. Most importantly, biomarkers can be used for quality control purpose during production, and standardize raw materials, intermediates, semi-products and final products.
What kinds of compounds can be used for biomarkers then? Here’s a list you may consider: major components, bioactive compounds, unique constituents, and those with potential safety concerns.
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Clarity Needed in Use of Biomarkers to Substantiate Food, Supplement Health Claims
Many drugs made by pharmaceuticals are nitrogen-containing compounds, such as alkaloids. Iridoid may serve as an intermediate for alkaloids. Iridoid can be converted into alkaloids under certain conditions, such as with the presence of enzymes and amino acids. Check this reference out
Seven new iridoid glucosides, two new monoterpenoids, and three known ones were isolated from the fruit of Gardenia jasminoides. Short-term memory assays on an Aβ transgenic drosophila model showed that some compounds can improve the short-term memory capacity to varying degrees.
Bioactive iridoids in some popular commercial fruit juice products were compared by using an analytical HPLC method. The experimental results indicate that Tahitian Noni® Original Bioactive Beverage has the highest amount of iridoids, much higher than other fruit juice products, including the ones claimed to contain noni juice. The acai juice blend and mangosteen juice blend contain only very little amount of iridoids, which are from their minor ingredient, blueberry juice. No iridoids are found in any other juice products originating from other fruits.
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