stevioside and isosteviol

The diterpenoids present highly varied oxidation patterns subjected to fascinating skeletal rearrangements, and possess antitumor, antibacterial, antihyperglycemic, anti-inflammatory activities and so on. While total synthesis is a possible solution to obtain required diterpenoid derivatives, the need for multisteps to build complex "privileged structures" is always prohibitive by semi-synthesis from naturally abundant related molecules. From this perspective, stevioside and its hydrolysis products steviol and isosteviol are good leads in the field of medicinal chemistry for diterpenoid drug discovery. Stevioside has a complex diterpenoid glycoside molecule comprised of an aglycone, steviol with the ent-kaurane skeleton and three molecules of glucose. Hydrolyzed under alkaline or acidic condition, stevioside generates ent-kaurane diterpenoid steviol or ent-beyerane diterpenoid isosteviol, respectively. Except for direct applications, they are widely used to provide ent-kaurane or ent-beyerane core structures for further medicinal chemistry study. Besides, these molecules also serve as model molecules, starting materials or catalysts in the field of synthetic chemistry. In this review, their biological activities and medicinal chemistry work are comprehensively summarized which are very helpful for diterpenoid drug exploration.

Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Chemistry Techniques, Synthetic; Diterpenes, Kaurane; Drug Discovery; Glucosides; Humans; Hydrolysis; Hypoglycemic Agents

Isosteviol, a prodrug used to be obtained via Wagner-Meerwein rearrangement from steviol with low yield and long reaction time. Herein, an in-situ separation-coupling-reaction is presented to prepare isosteviol from the natural sweetener stevioside. Simply with in-situ water-washing, the product containing 92.98% purity of isosteviol was obtained with a stevioside conversion of 97.23% from a packet bed reactor without further separation. Within the assayed inorganic acid, organic acids and acidic ionic liquids, the acidic ion-exchange resins provided higher product specificity towards isosteviol. Furthermore, comparing to 5-Fluorouracil, the product presented similar and even stronger inhibition on proliferation of the assayed human cancer cells in a time and dose-dependence by causing cell phase arrest. Isosteviol treatment caused G1 arrest on SGC-7901, HCT-8 and HCT-116 cells, S arrest on HepG2, Huh-7 and HepG3B cells, and G2 arrest on MGC-803 cells, respectively. Reaction coupling separation for isosteviol production catalyzed by acidic ion-exchange resin.

Topics: Antineoplastic Agents; Catalysis; Diterpenes, Kaurane; G2 Phase; Glucosides; HCT116 Cells; Hep G2 Cells; Humans; Ion Exchange Resins; Neoplasms; Prodrugs

Food products and botanicals on the global market need to be investigated in a more comprehensive way to detect effects, falsifications or adulterations. This is especially true for such ones containing Stevia leaves, Stevia extracts, or steviol glycosides. A multi-imaging profiling was developed exploiting hydrophilic interaction liquid chromatography (HILIC). A minimalistic sample preparation, different mixtures of acetonitrile and water/buffer on the silica gel phase as well as derivatization reagents and optional hyphenation with high-resolution mass spectrometry were exploited. The hydrophilic interaction high-performance thin-layer chromatography (HI-HPTLC) development took 10 min for 48 analyses. It was used to screen Stevia leaf extracts and 20 different food products. For the first time, the biological and biochemical profiling of Stevia leaf products by HI-HPTLC-UV/Vis/FLD-assay pointed to 19 different bioactive compound bands found in the more natural multicomponent Stevia leaf extracts, whereas most of these activities were not existent for the steviol glycosides. The chemically isolated, purified, and EU-regulated steviol glycosides ease risk assessment and food product development. However, multipotent botanicals may have subtle impact on homeostasis via several metabolic pathways, providing benefits for the consumer's health. Analyzed side by side by means of the effect-directed profiling, their individual activity profiles were visualized as image and individual substances of importance were pointed out. Multi-imaging (comprehensive detection) plus non-targeted bioprofiling (focus on known and unknown bioactivity) allows for a fast detection of questionable product changes that occur along the global food chain and are particularly related to food safety. Graphical abstract.

Topics: Chromatography, Thin Layer; Diterpenes, Kaurane; Food Analysis; Glucosides; Plant Leaves; Stevia

The concentrations of steviol and its derivatives stimulating the growth of wheat plants were measured: 10

Topics: Diterpenes; Diterpenes, Kaurane; Glucosides; Plant Leaves; Stevia; Triticum

Stevia rebaudiana extracts are used as sweeteners in several countries worldwide. Several extracts of diverse composition are available on the market, and their taste depends on the contents of the various steviol glycosides. This study presents an accurate method for the qualitative and quantitative determination of steviol glycosides in 40 Stevia extracts, 7 sweeteners and 3 Stevia-sweetened beverages by a UHPLC coupled to an Orbitrap mass spectrometer. The sub-2 μm amide column provided the separation of all the target analytes in a run time of 30 min with high resolution. The effect of different eluent compositions on the ionisation efficiency of the steviol glycosides was studied. The optimal ionisation conditions were achieved in negative mode using 0.05% formic acid. Under this condition, adducts were not found, [M-H]

Topics: Beverages; Chromatography, High Pressure Liquid; Diterpenes, Kaurane; Food Additives; Food Analysis; Glucosides; Glycosides; Mass Spectrometry; Plant Extracts; Stevia; Sweetening Agents

Cardiac hypertrophy is a thickening of the heart muscle that is associated with cardiovascular diseases such as hypertension and myocardial infarction. It occurs initially as an adaptive process against increased workloads and often leads to sudden arrhythmic deaths. Studies suggest that the lethal arrhythmia is attributed to hypertrophy-induced destabilization of cardiac electrical activity, especially the prolongation of the action potential. The reduced activity of I

Topics: Action Potentials; Animals; Arrhythmias, Cardiac; Calcium Channels, L-Type; Cardiomegaly; Diterpenes, Kaurane; Glucosides; Myocardium; Myocytes, Cardiac; Potassium; Potassium Channels; Rats; Rats, Sprague-Dawley; RNA, Messenger

This report describes a fragment-based approach to the examination of congeneric organic compounds by NMR spectroscopy. The method combines the classic interpretation of 1D- and 2D-NMR data sets with contemporary computer-assisted NMR analysis. Characteristic NMR profiles of key structural motifs were generated by (1)H iterative full spin analysis and then joined together as building blocks to recreate the (1)H NMR spectra of increasingly complex molecules. To illustrate the methodology described, a comprehensive analysis of steviol (1), seven steviol glycosides (2-8) and two structurally related isosteviol compounds (9, 10) was carried out. The study also assessed the potential impact of this method on relevant aspects of natural product research including structural verification, chemical dereplication, and mixture analysis.

Topics: Diterpenes, Kaurane; Glucosides; Glycosides; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Stevia

We have applied a diversity-oriented approach for the synthesis of skeletally diverse and stereochemically complex templates for small-molecule library production by performing Beckmann rearrangement and Beckmann fragmentation reactions on the bicyclo[3.2.1]octane rings of steviol and isosteviol, aglycones derived from the diterpene natural product stevioside. The optimization of these two reaction pathways is presented along with the successful application of a photo-Beckmann rearrangement. This work also led to the discovery of cyano-Prins-type and Thorpe-Ziegler-type cyclization reactions.

Topics: Biological Products; Combinatorial Chemistry Techniques; Cyclization; Diterpenes, Kaurane; Glucosides; Nuclear Magnetic Resonance, Biomolecular; Octanes

1. The aim of the present study was to investigate the mechanisms involved in the clearance of isosteviol using the rat isolated perfused liver. 2. Six livers from male Sprague-Dawley rats were perfused with 15.7 mumol isosteviol in a recirculating system. Perfusate and bile samples were collected for 60 min and the liver was collected at the end of the perfusion. All samples collected were incubated with alpha-glucuronidase. Isosteviol-glucuronide was determined as equivalent isosteviol. Isosteviol concentrations were determined using a previously developed liquid chromatography-tandem mass spectrometry method. The final isosteviol liver/perfusate (L/P), bile/liver (B/L) and isosteviol-glucuronide in bile/liver (B(G)/L(G)) ratios were determined. 3. Isosteviol has a high clearance (21.4 +/- 4.8 mL/min) from the perfusate, with a short half-life (13 +/- 4 min). alpha-Glucuronidase incubation revealed that isosteviol is conjugated in the liver and excreted into the bile. There was no isosteviol-glucuronide detected in perfusate samples. The total recovery of the rat isolated perfused liver system is 74 +/- 14% and glucuronidated isosteviol accounted for 23 +/- 4% of the administered dose. 4. In conclusion, we are the first to characterize the metabolism of isosteviol using rat isolated liver perfusion. Our results strongly suggest that the liver is the main organ of isosteviol elimination and that isosteviol is glucuronidated in the liver before it is excreted into the bile.

Topics: Animals; Bile; Chromatography, Liquid; Diterpenes, Kaurane; Glucosides; Glucuronides; Glycoside Hydrolases; In Vitro Techniques; Liver; Male; Metabolic Clearance Rate; Molecular Structure; Perfusion; Rats; Rats, Sprague-Dawley; Tandem Mass Spectrometry; Tissue Distribution

In a search for potential cancer chemopreventive agents from natural resources, stevioside (1), a sweetener, and six related compounds, including two aglycones steviol (6) and isosteviol (7), were screened in an in vitro assay for inhibitory effects on Epstein-Barr virus early antigen activation. Compounds 1, 6 and 7 showed significant activity in this assay and also exhibited strong inhibitory effects in a two-stage carcinogenesis test using mouse skin induced by 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA). The inhibitory effects of these three compounds were greater than that of glycyrrhizin. Furthermore, these three compounds significantly inhibited mouse skin carcinogenesis initiated by peroxynitrite and promoted by TPA. Their activities were comparable to that of curcumin. These results suggested that 1, as well as 6 and 7, could be valuable as chemopreventive agents for chemical carcinogenesis.

Topics: Animals; Antineoplastic Agents; Carcinogenicity Tests; Chemoprevention; Curcumin; Diterpenes, Kaurane; Glucosides; Glycyrrhizic Acid; Herpesvirus 4, Human; Mice; Skin Neoplasms