Exploring non-cytotoxic, antioxidant, and anti-inflammatory properties of selenium nanoparticles synthesized from Gymnema sylvestre and Cinnamon cassia extracts for herbal nanomedicine.

The increasing need for pharmaceutical agents that possess attributes such as safety, cost-effectiveness, environmental sustainability, and absence of side effects has driven the advancement of nanomedicine research, which lies at the convergence of nanotechnology and medicine. AIMS AND OBJECTIVES: The study aimed to synthesize non-toxic selenium nanoparticles (SeNPs) using Gymnema sylvestre (G. sylvestre) and Cinnamon cassia (C. cassia) extracts. It also sought to develop and evaluate versatile nanomedicine formulations i.e. selenium nanoparticles of G. sylvestre and C. cassia (SeNPs), drug (lupeol) loaded SeNPs (DLSeNPs), drug-loaded and coated (PEG) SeNPs (DLCSeNPs) without side effects. METHODS: The SeNPs formulations were hydrothermally synthesized, loaded with lupeol to improve efficacy, coated with polyethylene glycol (PEG) for targeted delivery, and characterized using UV-Vis spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), zeta potential analysis, size distribution analysis, and X-ray diffraction (XRD). Hemolytic cytotoxicity, 2,2-Diphenyl-1-picrylhydzayl (DPPH), total Reducing power, and total antioxidant capacity (TAC) antioxidant assays, carrageenan-induced paw edema, and histological studies were used to estimate the acute anti-inflammatory activity of the synthesized SeNPs. RESULTS: The final form of PEGylated and drug (lupeol)-loaded selenium nanoparticles (DLCSeNPs) exhibited an average particle size ranging from 100 to 500 nm as evidenced by SEM, and Zeta potential results. These nanoparticles demonstrated no cytotoxic effects and displayed remarkable antioxidant (IC50 values 19.29) and anti-inflammatory capabilities. These results were fed into Graph-pad Prism 5 software and analyzed by one-way ANOVA, followed by Tukey's post hoc test (p < 0.001). All nano-formulations exhibited significant overall antioxidant activity, with IC50 values ≤ 386 (p < 0.05) as analyzed by ANOVA. The study's results suggest that G. sylvestre outperformed C. cassia in terms of reducing 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical, potassium ferricyanide, and ammonium molybdate in respective antioxidant assays. As far as anti-inflammatory activities are concerned drug (lupeol)-loaded and PEG-coated G. sylvestre SeNPs exhibited the highest anti-inflammatory potential from all other nano-formulations including drug (lupeol)-loaded and PEG-coated C. cassia SeNPs, as exhibited to reduce the release of pro-inflammatory signals i.e. cytokines and NF-kB, making them innovative anti-inflammatory nanomedicine. CONCLUSION: The study synthesized lupeol-loaded and PEG-coated SeNPs, showcasing the potential for biocompatible, cost-effective anti-inflammatory nanomedicines. G. Sylvester's superior antioxidant and anti-inflammatory performance than Cinnamon cassia emphasizes medicinal plant versatility.

Novel gurmarin-like peptides from Gymnema sylvestre and their interactions with the sweet taste receptor T1R2/T1R3.

Gymnema sylvestre (GS) is a traditional medicinal plant known for its hypoglycemic and hypolipidemic effects. Gurmarin (hereafter Gur-1) is the only known active peptide in GS. Gur-1 has a suppressive sweet taste effect in rodents but no or only a very weak effect in humans. Here, 8 gurmarin-like peptides (Gur-2 to Gur-9) and their isoforms are reported in the GS transcriptome. The molecular mechanism of sweet taste suppression by Gur-1 is still largely unknown. Therefore, the complete architecture of human and mouse sweet taste receptors T1R2/T1R3 and their interaction with Gur-1 to Gur-9 were predicted by AlphaFold-Multimer (AF-M) and validated. Only Gur-1 and Gur-2 interact with the T1R2/T1R3 receptor. Indeed, Gur-1 and Gur-2 bind to the region of the cysteine-rich domain (CRD) and the transmembrane domain (TMD) of the mouse T1R2 subunit. In contrast, only Gur-2 binds to the TMD of the human T1R2 subunit. This result suggests that Gur-2 may have a suppressive sweet taste effect in humans. Furthermore, AF-M predicted that Gα-gustducin, a protein involved in sweet taste transduction, interacts with the intracellular domain of the T1R2 subunit. These results highlight an unexpected diversity of gurmarin-like peptides in GS and provide the complete predicted architecture of the human and mouse sweet taste receptor with the putative binding sites of Gur-1, Gur-2, and Gα-gustducin. In addition, gurmarin-like peptides may serve as promising drug scaffolds for the development of antidiabetic molecules.

Phytofabrication of biocompatible zinc oxide nanoparticle using Gymnema sylvestre and its potent in vitro antibacterial, antibiofilm, and cytotoxicity against human breast cancer cells (MDA-MB-231).

The increasing incidence of breast cancer and bacterial biofilm in medical devices significantly heightens global mortality and morbidity, challenging synthetic drugs. Consequently, greener-synthesized nanomaterials have emerged as a versatile alternative for various biomedical applications, offering new therapeutic avenues. This study explores the synthesis of biocompatible zinc oxide (ZnONPs) nanoparticles using Gymnema sylvestre and its antibacterial, antibiofilm, and cytotoxic properties. Characterization of ZnONPs inferred that UV-Vis spectra exhibited a sharp peak at 370 nm. Fourier transform infrared spectroscopical analysis revealed the presence of active functional groups such as aldehyde, alkyne, cyclic alkene, sulfate, alkyl aryl ether, and Zn-O bonds. X-ray diffraction analysis results confirmed the crystalline nature of the nanoparticle. Scanning electron microscope analysis evidenced hexagonal morphology, and energy-dispersive X-ray analysis confirmed zinc content. High-resolution transmission electron microscope analysis showed hexagonal and rod-shaped ZnONPs with a size of 5 nm. Zeta potential results affirmed the stability of nanoparticles. The ZnONPs effectively inhibited gram-positive (18-20 mm) than gram-negative (12-18 mm) bacterial pathogens with lower bacteriostatic and higher bactericidal values. Biofilm inhibitory property inferred ZnONPs were more effective against gram-positive (38-94%) than gram-negative bacteria (27-86%). The concentration of ZnONPs to exert 50% biofilm-inhibitory is lower against gram-positive bacteria (179.26-203.95 µg/mL) than gram-negative bacteria (201.46-236.19 µg/mL). Microscopic visualization inferred that at 250 µg/mL, ZnONPs strongly disrupted biofilm formation, as evidenced by decreased biofilm density and altered architecture. The cytotoxicity of ZnONPs against breast cancer cells showed a dose-dependent reduction in cell viability with an IC50 value of 19.4 µg/mL. AO/EB staining indicated early and late apoptotic cell death of breast cancer cells under fluorescence microscopy. The results of hemolytic activity validated the biocompatibility of the ZnONPs. Thus, the unique properties of the green-synthesized ZnONPs suggest their potential as effective drug carriers for targeted delivery in cancer therapy and the treatment of biofilm-related infections.

Identification of a putative novel cholivirus in the transcriptome of Gymnema sylvestre R. Br.

Gymnema sylvestre is a tropical climber species that is widely used in traditional medicine since ages. In the present study, the transcriptome datasets of G. sylvestre available in public domain were screened for the presence of novel plant viral sequences and a putative novel virus tentatively named as Gymnema sylvestre virus 1 (GysV1) was identified. Coding-complete genome segments of GysV1 that are 6.35 kb (RNA1) and 3.98 kb (RNA2) long possessed a single large open reading frame coding for a polyprotein. BLASTp, sequence identity and phylogenetic analyses revealed the relatedness of GysV1 to the members of the subgenus Cholivirus (genus Sadwavirus; family Secoviridae; order Picornavirales). Based on the species demarcation criteria of the family Secoviridae, GysV1 can be regarded as a new cholivirus member.

Biotechnological approaches for the production of gymnemic acid from Gymnema sylvestre R. Br.

Diabetes is a chronic disease that affects several organs and can be treated using phytochemicals found in medicinal plants. Gymnema sylvestre (Asclepiadaceae) is one such medicinal plant rich in anti-diabetic properties. The plant is commonly known as madhunashini in Sanskrit because of its ability to cure diabetes (sugar). Gymnemic acid (GA) is a phytochemical (a triterpenoid saponin) responsible for the herb's main pharmacological activity. This secondary metabolite has a lot of potential as a phytochemical with pharmacological properties including nephroprotection, hypoglycemia, antioxidant, antimicrobial, and anti-inflammatory. Gymnema has acquired a lot of popularity in recent years due to its low side effects and high efficacy in healing diabetes, which has led to overexploitation by pharmaceutical enterprises for its biomass in the wild for the purification of gymnemic acid. Modern biotechnological techniques involving the establishment of cell and organ cultures from G. sylvestre will assist us in fulfilling the need for gymnemic acid production. The present review provides insights on the establishment of cell and organ cultures for the production of a potent antidiabetic molecule gymnemic acid. Further, the review also delves into the intricacies of the different strategies for improved production of gymnemic acid using various elicitors. There is huge potential for sustainable production of gymnemic acid which could be met by establishment of bioreactor scale production. Understanding and engineering the biosynthetic pathway could also lead to improved GA production. KEY POINTS: • Gymnemic acid is one of the potential anti-diabetic molecules from madhunashini • Cell and organ culture offers potential approach for gymnemic acid production • Elicitation strategies have improved the gymnemic acid production.

The effects of Gymnema Sylvestre supplementation on lipid profile, glycemic control, blood pressure, and anthropometric indices in adults: A systematic review and meta-analysis.

There is a growing interest in the considerable health benefits of Gymnema Sylvestre (GS) supplementation, as some studies have reported that it may improve cardiometabolic risk factors. However, the widespread impact of GS supplementation on the parameters mentioned above is not fully resolved. Consequently, this study aimed to examine the effects of GS supplementation on lipid profile, glycemic control, blood pressure, and anthropometric indices in adults. Eligible randomized controlled trials (RCT), published up to November 2021, were identified through PubMed, Scopus, and ISI Web of Science databases. Six studies were included and analyzed using a random-effects model to calculate weighted mean differences (WMDs) with 95% confidence intervals (CI). All studies were conducted in adults that used a GC supplement (>1 week) and assessed our selected cardiovascular risk factors. Outcomes revealed that GS supplementation significantly decreased triglyceride (p < .001), total cholesterol (p < .001), low-density lipoprotein (p < .001), fasting blood sugar (p < .001), and diastolic blood pressure (p = .003). Some limitations, including notable heterogeneity, low quality of studies, and lack of diversity among research participants, should be considered when interpreting our results. Our outcomes suggest that GS supplementation may improve cardiovascular risk factors. Future large-high-quality RCTs with longer duration and various populations are needed to firmly establish the clinical efficacy of the plant.

Anti-inflammatory and antioxidant activities of Gymnema Sylvestre extract rescue acute respiratory distress syndrome in rats via modulating the NF-κB/MAPK pathway.

Acute respiratory distress syndrome (ARDS) is one of the major causes of mortality in COVID-19 patients, due to limited therapeutic options. This prompted us to explore natural sources to mitigate this condition. Gymnema Sylvestre (GS) is an ancient medicinal plant known to have various therapeutic effects. This investigation examined the therapeutic effect of hydroalcoholic extract of Gymnema Sylvestre (HAEGS) against lipopolysaccharide (LPS)-induced lung injury and ARDS in in vitro and in vivo models. UHPLC-HRMS/GC-MS was employed for characterizing the HAEGS and identified several active derivatives including gymnemic acid, gymnemasaponins, gymnemoside, gymnemasin, quercetin, and long fatty acids. Gene expression by RT-qPCR and DCFDA analysis by flow cytometry revealed that several inflammatory cytokine/chemokine, cell injury markers, and reactive oxygen species (ROS) levels were highly upregulated in LPS control and were significantly reduced upon HAEGS treatment. Consistent with the in vitro studies, we found that in LPS-induced ARDS model, pre-treatment with HAEGS significantly suppressed the LPS-induced elevation of inflammatory cell infiltrations, cytokine/chemokine marker expression, ROS levels, and lung injury in a dose-dependent manner. Further mechanistic studies demonstrated that HAEGS suppressed oxidative stress by modulating the NRF2 pathway and ameliorated the ARDS through the NF-κB/MAPK signalling pathway. Additional fractionation results revealed that fraction 6 which has the exclusive composition of gymnemic acid derivatives showed better anti-inflammatory effects (inhibition of IL-6 and IL-1ß) at lower concentrations compared to HAEGS. Overall, HAEGS significantly mitigated LPS-induced lung injury and ARDS by targeting the NF-κB/MAPK signalling pathway. Thus, our work unravels the protective role of HAEGS for the first time in managing ARDS.

Identification of Potential Plant-Derived Pancreatic Beta-Cell-Directed Agents Using New Custom-Designed Screening Method: Gymnema sylvestre as an Example.

BACKGROUND: Folk medicines are attractive therapeutic agents for treating type 2 diabetes mellitus (T2DM). Most plant extracts that have been suggested to restore ß-cells function were tested in vivo. Some only have been tested in vitro to determine whether they have a direct effect on ß-cells islets of Langerhans. Currently, there are no defined criteria for screening of ß-cell-directed plant-based remedies as potential antidiabetic agents. SUMMARY: In this review, we have identified certain criteria/characteristics that can be used to generate a "screening portfolio" to identify plant extracts as potential ß-cell-directed agents for the treatment of T2DM. To validate our screening method, we studied the potential therapeutic efficacy of a Gymnema sylvestre (GS) extract using the screening criteria detailed in the review. Six criteria have been identified and validated using OSA®, a GS extract. By using this screening method, we show that OSA® fulfilled most of the criteria identified for an effective ß-cell-directed antidiabetic therapy, being an effective insulin-releasing agent at nontoxic concentrations; maintaining ß-cell insulin content by stimulating a concomitant increase in insulin gene transcription; maintaining ß-cell mass by protecting against apoptosis; and being effective at maintaining normoglycemia in vivo in a mouse model and a human cohort with T2DM. KEY MESSAGES: The present review has highlighted the importance of having a screening portfolio for plant extracts that have potential antidiabetic effects in the treatment of T2DM. We propose that this screening method should be adopted for future studies to identify new ß-cell-directed antidiabetic plant derived agents.

Optimisation and evaluation of Gymnema sylvestre extract loaded polymeric nanoparticles for enhancement of in vivo efficacy and reduction of toxicity.

AIM: This work studies the development and evaluation of Gymnema sylvestre (GYM) extract loaded sustained release polymeric nanoparticles (PNPs) for enhanced bioavailability and reduced nephrotoxicity. The current therapy is associated with the drawbacks of addiction and repeated administration. METHOD: The sustained release PNPs were developed and evaluated for toxicity. PNPs of GYM were prepared by double emulsion solvent evaporation technique utilising Taguchi model and evaluated for physicochemical properties (particle size, zeta potential, entrapment efficiency), in vitro drug release, compatibility, and stability. Further, the bioavailability and in vivo nephrotoxicity studies in diabetic rat model were also carried out. RESULT: The developed optimised nanoparticles were 205.7 ± 1.20 nm in size, -40.68 mV zeta potential, compatible, and stable in nature with improved entrapment efficiency (67.1 ± 0.2%) and sustained release. Moreover, nanoparticles were found to lower the blood glucose level in single as well as multiple doses. Results of in vivo study indicated that GYM-NPs increased the phosphorylase activity and thus enhanced insulin secretion. Furthermore, the nanoparticles were free from toxicity, which was confirmed by the estimation of kidney biomarker. CONCLUSION: The nanoparticles increased the bioavailability of GYM extract and have a great potential for the treatment of diabetes in reduced dose, and so these can be potential candidates for treating diabetes.

The effect of Gymnema sylvestre supplementation on glycemic control in type 2 diabetes patients: A systematic review and meta-analysis.

This systematic review and meta-analysis aims to find the effect of Gymnema sylvestre (GS) supplementation on glycemic control in type-2 diabetes mellitus (T2DM). PubMed, Cochrane library, Google Scholar, and Science Direct were searched from inception to June 2020 to identify the studies that reported GS supplementation on glycemic parameters. Standardized mean difference (SMD) was calculated by comparing the post-intervention data with baseline data. SMDs with 95% confidence intervals (CIs) were pooled using a random-effects model. Our meta-analysis consisting of 10 studies with a total of 419 participants showed that GS supplementation significantly reduces fasting blood glucose (FBG) (SMD 1.57 mg/dl, 95% CI 2.22 to -0.93, p < .0001, I2 90%), postprandial blood glucose (PPBG) (SMD 1.04 mg/dl, 95% CI 1.53 to -0.54, p < .0001, I2 80%), and glycated haemoglobin (HbA1c) (SMD 3.91, 95% CI 7.35 to -0.16%, p < .0001, I2 99%) compared to baseline. Further, our study also found that GS significantly reduces triglycerides (SMD 1.81 mg/dl, 95% CI 2.95 to -0.66, p < .0001, I2 : 96%), and total cholesterol (SMD 4.10 mg/dl, 95% CI 7.21 to -0.99, p < .0001, I2 : 98%) compared to baseline. Our study shows that GS supplementation is effective in improving glycemic control and reducing lipid levels in T2DM patients and suggests that such supplementation might be used as an effective therapy for the management of T2DM and its associated complications to an extent.

Identification of C21 Steroidal Glycosides from Gymnema sylvestre (Retz.) and Evaluation of Their Glucose Uptake Activities.

Gymnema sylvestre (Retz.) Schult is a multi-purpose traditional medicine that has long been used for the treatment of various diseases. To discover the potential bioactive composition of G. sylvestre, a chemical investigation was thus performed. In this research, four new C21 steroidal glycosides sylvepregosides A-D (1-4) were isolated along with four known compounds, gymnepregoside H (5), deacetylkidjoladinin (6), gymnepregoside G (7) and gymnepregoside I (8), from the ethyl acetate fraction of G. sylvestre. The structures of the new compounds were established by extensive 1D and 2D nuclear magnetic resonance (NMR) spectra with mass spectroscopy data. Compounds 1-6 promoted glucose uptake by the range of 1.10- to 2.37-fold, respectively. Compound 1 showed the most potent glucose uptake, with 1.37-fold enhancement. Further study showed that compounds 1 and 5 could promote GLUT-4 fusion with the plasma membrane in L6 cells. The result attained in this study indicated that the separation and characterization of these compounds play an important role in the research and development of new anti-diabetic drugs and pharmaceutical industry.

Hepatoprotective and hypolipidemic activities of Caesalpinia bonduc seed kernels and Gymnema sylvestre leaves extracts in alloxan-induced diabetic rats.

The objective of the current research was to validate the hepatoprotective and anti-hyperlipidemic activities of C. bonduc seed kernels (CBSK) and G. sylvestre leaves (GSL) hydro-methanolic extracts, separately and in combination (CBSKE+GSLE) in alloxan-induced diabetic rat model for 28 days. Diabetes was induced by i.p. injection of alloxan monohydrate (140 mg/kg body weight) to albino Wistar rats. Six groups of rats (n=9) were used. Group 1 was the normal control; group 2 was diabetic control. After induction of diabetes metformin (150mg/kg), CBSKE (400mg/kg), GSLE (400 mg/kg) and CBSKE+GSLE (400mg/kg) were administered to diabetic rat groups 3, 4, 5 and 6 respectively for a period of 28 days. Diabetic rats exhibited an increase in serum blood glucose, liver function markers and lipid profile. Treatment of diabetic rats with metformin, CBSKE, GSLE and CBSKE+GSLE for 4 weeks significantly produced hepatoprotective and hypolipidemic effect via amelioration of raised serum glucose, liver profile, and lipid profile. The outcomes of this study suggest that G. sylvestre leaves and C. bonduc seed kernels have hepatoprotective and hypolipidemic potential which possibly help in managing diabetes-induced liver injury and hyperlipidemia.

A novel Gymnema sylvestre extract protects pancreatic beta-cells from cytokine-induced apoptosis.

Inflammatory cytokines such as interleukin-1ß, TNF-α, and interferon-γ are known to be involved in mediating ß-cells death in diabetes mellitus (DM). Thus, protecting from ß-cells death in patients with DM may be a useful target in alleviating symptoms of hyperglycemia. Traditional plant-based remedies have been used to treat DM for many centuries and may play a role in protecting ß-cell from death. An example of these remedies is Gymnema sylvestre (GS) extract. In this study, we investigated the effect of this plant extract on ß-cells apoptosis. Om Santal Adivasi (OSA®) maintained cell membrane integrity in MIN6 cells and mouse islets. Om Santal Adivasi significantly protected MIN6 cells and mouse islets from cytokine-induced apoptosis. In the presence of cytokines, OSA® significantly reduced the expression and activity of caspase-3. The antiapoptotic effect of OSA® as shown by microarray analysis is largely mediated by activating pathways involved in cell survival (mainly casein kinase II pathway) and the free radical scavenger system (specifically superoxide dismutase and catalase). This study indicates that the GS isolate OSA® protects against cytokine-induced apoptosis of ß-cells by increasing the expression of cell survival pathways and free radical scavenger system.

Metabolic differentiation and quantification of gymnemic acid in Gymnema sylvestre (Retz.) R.Br. ex Sm. leaf extract and its fermented products.

INTRODUCTION: Gymnemagenin is the bioactive metabolite found in Gymnema sylvestre leaves and possesses different therapeutic potential. Due to its lower abundance and higher market potential, gymnemagenin was obtained from chemical conversion and bacterial biotransformation. OBJECTIVE: To obtain the probiotic-based fermentative conversion of gymnemic acid-enriched G. sylvestre leaf extract to gymnemagenin-containing nutraceuticals and its metabolites based chromatographic comparison. MATERIAL AND METHODS: Gymnema sylvestre leaves were extracted through soxhalation, and the extract was prepared and characterised. Gymnemic acid was fermented, separately, by Lactobacillus casei, Lactobacillus rhamnosus, Bifidobacterium bifidum, and by their mix co-culture. The fermented materials were analysed for their gymnemagenin content, antioxidant potential, antidiabetic potential, and metabolomics analysis. RESULTS: Extraction yielded about 35% w/w of raw plant material, and 8.5% was found to be as total saponin content. Extract at higher concentration (≥ 5%, w/v) significantly altered the growth behaviour of probiotics. High-performance thin-layer chromatography (HPTLC) based quantification of gymnemagenin revealed that a maximum increase of 95.5% gymnemagenin was found in extract incubated with B. bifidum followed by mix co-culture containing (B. bifidum, L. casei, and L. rhamnosus), L. casei, and L. rhamnosus. However, liquid chromatography mass spectrometry (LC-MS) analysis resulted in the identification of a total of 56 metabolites. CONCLUSION: Chromatographically profiled, and probiotic-based fermented G. sylvestre leaves can be used as a potent nutraceutical for diabetes and other metabolic disorders.

Five New Pregnane Glycosides from Gymnema sylvestre and Their α-Glucosidase and α-Amylase Inhibitory Activities.

Gymnema sylvestre, a medicinal plant, has been used in Indian ayurvedic traditional medicine for the treatment of diabetes. Phytochemical investigation of Gymnema sylvestre led to the isolation of five new pregnane glycosides, gymsylosides A-E (1-5) and four known oleanane saponins, 3ß-O-ß-D-glucopyranosyl (1→6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-glucopyranosyl ester (6), gymnemoside-W1 (7), 3ß-O-ß-D-xylopyranosyl-(1→6)-ß-D- glucopyranosyl-(1→6)-ß-D-glucopyranosyl oleanolic acid 28-O-ß-D-glucopyranosyl ester (8), and alternoside XIX (9). Their structures were identified based on spectroscopic evidence and comparison with those reported in the literature. All compounds were evaluated for their α-glucosidase and α-amylase inhibitory activities. Compounds 2-4 showed significant α-amylase inhibitory activity, with IC50 values ranging from 113.0 to 176.2 µM.

Development of a Building Block Strategy to Target the Classification, Identification, and Metabolite Profiling of Oleanane Triterpenoids in Gymnema sylvestre Using UHPLC-qTOF/MS.

The major class of bioactive metabolites in Gymnema sylvestre, a popular Ayurvedic medicinal plant for the treatment of diabetes mellitus, is oleanane triterpenoids. In this study, a targeted, biosynthesis-inspired approach using UHPLC-qTOF/MS was implemented to elucidate the whole chemical profile of this plant for the standardization of the Vietnamese G. sylvestre variety. The known compounds were first determined to identify the building blocks of the biosynthetic intermediates and the construction rules for synthesizing oleanane triterpenoids in the plant. These blocks were recombined to build a virtual library of all reasonable compounds consistent with the deduced construction rules. Various techniques, including relative mass defect filtering, multiple key ion analysis, mass fragmentation analysis, and comparison with standard references, were applied to determine the presence of these predicted compounds. Conventional isolation and structure elucidation of six of the new compounds were carried out to identify the new building blocks and validate the assignments. Consequently, 119 peaks were quickly assigned to oleanane triterpenoids, and among them, 77 peaks were predicted to be new compounds based on their molecular formulas and mass fragmentation patterns. All the identified metabolites were then classified into different layers to analyze their logical relationships, and a multilayered chemical profile of the oleanane triterpenoids was constructed. This new approach is expected to be practical for characterizing structures of modular secondary metabolites, such as triterpenoid saponins, and for proposing biosynthetic relationships among compounds of the same class of metabolites in medicinal plants.

De novo in vitro shoot morphogenesis from shoot tip-induced callus cultures of Gymnema sylvestre (Retz.) R.Br. ex Sm.

BACKGROUND: Gymnema sylvestre is a medicinal woody perennial vine known for its sweetening properties and anti-diabetic therapeutic uses in the modern and traditional medicines. Its over-exploitation for the therapeutic uses and to meet the demand of pharmaceutical industry in raw materials supply for the production of anti-diabetic drugs has led to considerable decline in its natural population. RESULTS: An efficient system of shoot bud sprouting from nodal segment explants and indirect plant regeneration from apical meristem-induced callus cultures of G. sylvestre have been developed on Murashige and Skoog (MS) medium amended with concentrations of cytokinins. Of the three growth regulators tested, N6-benzylaminopurine (BAP) was the most efficient and 2.0 mg L-1 gave the best shoot formation efficiency. This was followed by thidiazuron (TDZ) and kinetin (Kin) but, most of the TDZ-induced micro shoots showed stunted growth. Multiple shoot formation was observed on medium amended with BAP or TDZ at higher concentrations. The produced micro shoots were rooted on half strength MS medium amended with auxins and rooted plantlets acclimatized with 87% survival of the regenerates. CONCLUSIONS: The developed regeneration system can be exploited for genetic transformation studies, particularly when aimed at producing its high yielding cell lines for the anti-diabetic phytochemicals. It also offers opportunities for exploring the expression of totipotency in the anti-diabetic perennial vine.

Flavor Alterations Associated with Miracle Fruit and Gymnema sylvestre.

Taste and flavor (retronasal olfaction) interact in the brain. The rules of that interaction are not well understood. This study uses 2 taste modifiers that alter sweet to examine the effects on flavors. Subjects used the Global Sensory Intensity Scale to assess the aroma, sweetness, sourness, and flavor of 10 foods. As previous work had shown, miracle fruit added sweetness to acids, which secondarily reduced sourness (mixture suppression) and Gymnema sylvestre reduced sweetness in sweet foods as well as the sweetness induced by miracle fruit. In this study, multiple regression showed that both sweet and sour contribute to flavor. Gymnema sylvestre reduced the perceived sweet of predominantly sweet foods (chocolate and maple syrup) as expected; reducing the sweet, reduced the flavor. The effects of miracle fruit were complicated by its dual action: intensification of sweet and reduction of sour. Predominantly sour foods (vinegar, lemon, mustard, pickle) were sweetened by miracle fruit but any flavor enhancement associated with the added sweet appears to have been countered by the flavor reduction associated with reduced sourness. Moderately sour foods that are also sweet (tomatoes, strawberries) were sweetened by miracle fruit and thus flavor was enhanced; flavor loss through sour reduction was apparently not sufficient to counter the flavor enhancement due to increased sweet so the net result was that tomato and strawberry flavors were enhanced. The flavors of control foods (not predominantly sweet or sour [sausage, peanuts]) showed only small changes.

Radio-protective dosimetry of Pangasius sutchi as a biomarker, against gamma radiation dosages perceived by genotoxic assays.

Exposure to ionizing radiation is harmful to any living organism. It may cause varying levels of genetic mutation or ultimately death. Synthetic compounds have been used to counteract the hazardous effect of radiation on the live cells, but the possibility of these synthetic compounds being harmful to the organism being treated also exists. Herbal formulations are thus being explored as a possible alternative for the synthetic radioprotectant. Induction of DNA damage in fishes caused by ionizing radiation and its protection by phytocompounds is a hardly studied topic. In this study, we analyzed the radioprotective effect of Gymnema sylvestre leaves extract (GS) and its active compound gymnemagenin (GG) against different doses of gamma radiation (60Co) on the freshwater fish Pangasius sutchi. The radioprotective efficacy was assessed by micronuclei and alkaline comet assays. The freshwater fish P. sutchi was pre-treated with intramuscular injection (IM) of amifostine (83.3 mg/kg of B.W.), GS (25 mg/kg of B.W.) and GG (0.3 mg/kg of B.W.), 1 h prior to the gamma radiation. The fishes were exposed to LD30, LD50 and LD70 of gamma radiation and the protection activities were assessed by analyzing the number of micronuclei (MN) and erythrocytic abnormalities in the blood after 2, 4, 8, 16 and 32 days after exposure. Compared to the irradiated fishes, frequency of erythrocytic abnormalities were decreased in response to the radio-protection in the amifostine treated groups for all three doses of gamma radiation (LD70 - 77.62%), (LD50 - 80.11%) and (LD30 - 82.30%); GS (LD70 - 62.66%), (LD50 - 69.74%) and (LD30 - 70.81%); and GG (LD70 - 49.42%), (LD50 - 53.43%) and (LD30 - 58.42%). Similarly, a significant radio-protective effect in terms of decremented DNA damage was observed using the comet assay after post exposure. The percentage of protection noted for amifostine was (LD70 - 58.68%), (LD50 - 64.52%) and (LD30 - 74.40%); GS (LD70 - 53.84%), (LD50 - 59.02%) and (LD30 - 65.97%); GG (LD70 - 49.85%), (LD50 - 52.56%) and (LD30 - 64.30%). From the current study, we can conclude that the radioprotective efficacy of the GS is similar to the synthetic compound (amifostine) and also greater than the bioactive compound (GG). The synergetic effect of the plant extract which leads to a better protection than the bioactive compound must be further studied. MN and Comet assays can easily identify the damage due to radiation exposure and thus can be used as predictive biomarkers for aquatic organisms exposed to radiation.

Suppression of Oral Sweet Taste Sensation with Gymnema sylvestre Affects Postprandial Gastrointestinal Blood Flow and Gastric Emptying in Humans.

An oral sweet taste sensation (OSTS) exaggerates digestive activation transiently, but whether it has a role after swallowing a meal is not known. Gymnema sylvestre (GS) can inhibit the OSTS in humans. We explored the effect of the OSTS of glucose intake on gastrointestinal blood flow, gastric emptying, blood-glucose, and plasma-insulin responses during the postprandial phase. Eight participants ingested 200 g (50 g × 4 times) of 15% glucose solution containing 100 mg of 13C-sodium acetate after rinsing with 25 mL of 2.5% roasted green tea (control) or 2.5% GS solution. During each protocol, gastrointestinal blood flow and gastric emptying were measured by ultrasonography and 13C-sodium acetate breath test, respectively. Decreased subjective sweet taste intensity was observed in all participants in the GS group. The time to attain a peak value of blood flow in the celiac artery and gastric emptying were delayed in the GS group compared with the control group. At the initial phase after glucose intake, blood-glucose and plasma-insulin responses were lower in the GS group than those for the control group. These results suggest that the OSTS itself has a substantial role in controlling postprandial gastrointestinal activities, which may affect subsequent glycemic metabolism.