Antidiabetic activity and phytochemical screening of crude extract of Stevia rebaudiana in alloxan-induced diabetic rats

Neuronal activity in the anterior paraventricular nucleus of thalamus positively correlated with sweetener consumption in mice

Although the brain can discriminate between various sweet substances, the underlying neural mechanisms of this complex behavior remain elusive. This study examines the role of the anterior paraventricular nucleus of the thalamus (aPVT) in governing sweet preference in mice. We fed the mice six different diets with equal sweetness for six weeks: control diet (CD), high sucrose diet (HSD), high stevioside diet (HSSD), high xylitol diet (HXD), high glycyrrhizin diet (HGD), and high mogroside diet (HMD). The mice exhibited a marked preference specifically for the HSD and HSSD. Following consumption of these diets, c-Fos expression levels in the aPVT were significantly higher in these two groups compared to the others. Utilizing fiber photometry calcium imaging, we observed rapid activation of aPVT neurons in response to sucrose and stevioside intake, but not to xylitol or water. Our findings suggest that aPVT activity aligns with sweet preference in mice, and notably, stevioside is the sole plant-based sweetener that elicits an aPVT response comparable to that of sucrose.

The Natural Sweetener Stevia: An Updated Review on its Phytochemistry, Health Benefits, and Anti-diabetic Study

Stevia rebaudiana Bertoni is one of the significant high qualities of non-caloric sugar substitute sweetener plants against diabetes disease. Diabetes mellitus is one of the most common metabolic diseases caused by insulin secretion defects, insulin resistance in peripheral tissues, or both. Stevia rebaudiana is a perennial shrub of the Compositae family that is grown in several places around the world. It contains a plethora of different bioactive constituents which are responsible for several activities and sweetness. This sweetness is due to the presence of steviol glycosides which is 100-300 times sweeter than sucrose. Furthermore, stevia reduces oxidative stress, lowering the risk of diabetes. Its leaves have been used to control and treat diabetes and a variety of other metabolic diseases. This review summarizes the history, bioactive constituents of S. rebaudiana extract, pharmacology, anti-diabetic activity, and its application, especially in food supplements.

The role of natural products from medicinal plants against COVID-19: traditional medicine practice in Tanzania

Background

Pandemic COVID-19 is a dangerous disease caused by a new coronavirus known as severe acute respiratory syndrome (SARS-CoV-2). There is non-reliable drug or vaccine available to combat for SARS-CoV-2. More efforts to search for antiviral agents against COVID-19 are obligatory, whereas phytochemicals are potent solution. Thus, this study involved phytochemical screening and examining medicinal plants used to combat COVID-19 in Tanzania.

Methods

The plant materials were collected from practitioners. The plant extracts were then subjected for qualitative phytochemical screening so as to identify the nature of secondary metabolites.

Results

Eucalyptus species, pepper, berries, ginger, garlic, onions and lemon were identified as commonly plants used. The flavonoids, tannins, fatty acids, steroids, terpenoids, and saponins were identified through phytochemical screening. Identified natural phytocompounds revealed to be potential in exhibiting antiviral activities by disrupting the viral life cycle including viral entrance, replication, assembly, and discharge, as well as virus-specific host targets. Thus, this prompt increasing of pharmaceutical industry focused on phytochemical extracts from medicinal plants, and aromatic herbs in the hopes of discovering lead compounds, with purposeful to antiviral medications.

Conclusion

The medicinal plants and phytocompounds revealed to have significant role due to their substantial antiviral activity against SARS-CoV-2 and other coronaviruses. The noted natural products inspire collective efforts in determination and gathering funds to support scientific researchers to investigate more phytochemicals from medicinal plants for development of antiviral drug against COVID-19.

Effect of stevia leaves ( Stevia rebaudiana Bertoni) on diabetes: A systematic review and meta‐analysis of preclinical studies

Stevia (Stevia rebaudiana Bertoni) is a natural herb with biological activities such as anticancer, antidiabetic, anticardiovascular disease, anti‐inflammatory, and antimicrobial. The current systematic review and meta‐analysis of previously published data were performed to assess the antidiabetic effect of stevia leaves. Three electronic databases (PubMed, CENTRAL, and DOAJ) had been used for searching articles published before September 2020. Meta‐analysis via random‐effect model had been performed to assess the effects of different doses of stevia on blood glucose level (BGL) and studies were weighted according to an estimate of the standard mean difference (SMD). Overall, 16 eligible studies were selected for qualitative analysis and 9 were included for quantitative analysis. The results of the meta‐analysis for BGL showed that at the doses of 200, 300, and 400 mg/kg of stevia leaves there was a significant difference in means of BGL between the intervention and control group and the dose of 500 mg/kg showed no significance (Standard mean difference (SMD): −3.84 (−9.96, 2.27); p = .22). Based on the duration of intervention, subgroup analysis of articles showed a significant difference between the groups (p < .001). The results of the meta‐analysis support the hypothesis that stevia leaf has an antihyperglycemic effect and reduces the blood glucose level at doses of 200, 300, and 400 mg/kg. Therefore, more clinical trials on animals and humans have to be done to investigate the antidiabetic and antihyperglycemic effects along with the efficacy and safety of these medicinal leaves.

Anthelmintic activity of Stevia multiaristata extract against Echinococcus granulosus sensu stricto

Cystic echinococcosis is a zoonotic disease caused by the larval stage of the parasite Echinococcus granulosus sensu lato. The available anti-parasitic treatment is mostly limited to a continuous administration of albendazole. However, due to its numerous side-effects and efficacy of around 50%, there is a need to find new drugs to improve the treatment for this disease. In the current study, the in vitro and in vivo efficacy of a Stevia multiaristata extract against E. granulosus sensu stricto (s.s.) was demonstrated. Stevia multiaristata extract (100 and 50 μg mL−1) caused a quick viability decrease on protoscoleces which was consistent with the observed tegumental alterations. Loss of turgidity was detected in 95 ± 3.4% of cysts incubated with S. multiaristata extract during 2 days (100 μg mL−1) and the collapse of the germinal layer was observed in 60 ± 9.3% of cysts treated with 100 μg mL−1 of the S. multiaristata extract during 4 days. The half maximal effective concentration value was 69.6 μg mL−1 and the selectivity index for E. granulosus s.s. cysts was 1.9. In this clinical efficacy study, the treatment of infected mice with the S. multiaristata extract (50 mg kg−1) caused a significant decrease in the weight of the cysts compared with the control group. These results coincided with the tissue damage observed in the cysts at the ultrastructural level. In conclusion, we observed high protoscolicidal and cysticidal effects, and significant reduction in the weight of the cysts in experimentally infected mice following treatment with the S. multiaristata extract.

Protective effects of Stevia rebaudiana extracts on beta cells in lipotoxic conditions

AIMS

Stevia rebaudiana Bertoni leaf extracts have gained increasing attention for their potential protection against type 2 diabetes. In this study, we have evaluated the possible beneficial effects of Stevia rebaudiana leaf extracts on beta-cells exposed to lipotoxicity and explored some of the possible mechanisms involved.

METHODS

Extracts, deriving from six different chemotypes (ST1 to ST6), were characterized in terms of steviol glycosides, total phenols, flavonoids, and antioxidant activity. INS-1E beta cells and human pancreatic islets were incubated 24 h with 0.5 mM palmitate with or without varying concentrations of extracts. Beta-cell/islet cell features were analyzed by MTT assay, activated caspase 3/7 measurement, and/or nucleosome quantification. In addition, the proteome of INS-1E cells was assessed by bi-dimensional electrophoresis (2-DE).

RESULTS

The extracts differed in terms of antioxidant activity and stevioside content. As expected, 24 h exposure to palmitate resulted in a significant decrease of INS-1E cell metabolic activity, which was counteracted by all the Stevia extracts at 200 μg/ml. However, varying stevioside only concentrations were not able to protect palmitate-exposed cells. ST3 extract was also tested with human islets, showing an anti-apoptotic effect. Proteome analysis showed several changes in INS-1E beta-cells exposed to ST3, mainly at the endoplasmic reticulum and mitochondrial levels.

CONCLUSIONS

Stevia rebaudiana leaf extracts have beneficial effects on beta cells exposed to lipotoxicity; this effect does not seem to be mediated by stevioside alone (suggesting a major role of the leaf phytocomplex as a whole) and might be due to actions on the endoplasmic reticulum and the mitochondrion.

Natural sweetener Stevia rebaudiana: Functionalities, health benefits and potential risks

Stevia rebaudiana is a South American plant, the cultivation of which is increasing worldwide due to its high content of sweet compounds. Stevia sweetness is mainly due to steviol glycosides, that are ~250-300 times sweeter than sucrose. Many studies have suggested the benefits of Stevia extract over sugar and artificial sweeteners, but it is still not a very popular sugar substitute. This review summarizes current data on the biological activities of S. rebaudiana extract and its individual glycosides, including anti-hypertensive, anti-obesity, anti-diabetic, antioxidant, anti-cancer, anti-inflammatory, and antimicrobial effects and improvement of kidney function. Possible side effects and toxicity of Stevia extract are also discussed.

Medicinal plants resources of Western Himalayan Palas Valley, Indus Kohistan, Pakistan: Their uses and degrees of risk of extinction

Present study was intended with the aim to document the pre-existence traditional knowledge and ethnomedicinal uses of plant species in the Palas valley. Data were collected during 2015–2016 to explore plants resource, their utilization and documentation of the indigenous knowledge. The current study reported a total of 65 medicinal plant species of 57 genera belonging to 40 families. Among 65 species, the leading parts were leaves (15) followed by fruits (12), stem (6) and berries (1), medicinally significant while, 13 plant species are medicinally important for rhizome, 4 for root, 4 for seed, 4 for bark and 1 each for resin. Similarly, thirteen species were used as a whole while twelve species as partial for medicinal purpose. Further, it is concluded that every part of plants such as bulb, rhizome, roots, barks, leaves, flowers, fruit and seed were used for various ailments. Moreover, among 65 plants species, 09 species are threatened and placed into Endangered (EN) and Least Concern (LC) categories of IUCN. The recorded data are very useful and reflects the significance of the Palas valley as medicinal plants resource area.

Ethnomedicinal Value of Antidiabetic Plants in Bangladesh: A Comprehensive Review

The use of conventional drugs to treat metabolic disorders and the pathological consequences of diabetes further increases the complications because of the side effects, and is sometimes burdensome due to relatively higher costs and occasionally painful route of administration of these drugs. Therefore, shifting to herbal medicine may be more effective, economical, have fewer side effects and might have minimal toxicity. The present review amasses a list of ethnomedicinal plants of 143 species belonging to 61 families, from distinctive domestic survey literature, reported to have been used to treat diabetes by the ethnic and local people of Bangladesh. Leaves of the medicinal plants were found leading in terms of their use, followed by fruits, whole plants, roots, seeds, bark, stems, flowers, and rhizomes. This review provides starting information leading to the search for and use of indigenous botanical resources to discover bioactive compounds for novel hypoglycemic drug development.

Steviol Glycosides Supplementation Affects Lipid Metabolism in High-Fat Fed STZ-Induced Diabetic Rats

A number of health-promoting properties of Stevia rebaudiana Bertoni and its glycosides, including the antihyperglycemic activity, have been found. The mechanisms of the antidiabetic action of stevia have not been fully understood. The aim of this study was to evaluate the effects of supplementary steviol glycosides on high-fat fed streptozotocin-induced diabetic rats with particular attention to lipid metabolism. The experiment was conducted on 70 male Wistar rats, of which 60 were fed a high-fat diet for 8 weeks followed by intraperitoneal injection of streptozotocin, to induce type 2 diabetes. Afterwards, rats were divided into six groups and fed a high-fat diet supplemented with pure stevioside or rebaudioside A, at two levels (500 or 2500 mg/kg body weight (b.w.)) for 5 weeks. Three additional groups: diabetic untreated, diabetic treated with metformin, and healthy, served as respective controls. Blood and dissected internal organs were collected for hematological, biochemical, and histopathological tests. It was found that dietary supplementation with steviol glycosides did not affect blood glucose, insulin, and insulin resistance indices, antioxidant biomarkers, but normalized hyperlipidemia and affected the appetite, as well as attenuated blood liver and kidney function indices, and reduced tissular damage in diabetic rats. Steviol glycosides normalize lipid metabolism and attenuate internal organs damage in diabetes.

Effect of stevia on the gut microbiota and glucose tolerance in a murine model of diet-induced obesity

Artificial sweeteners have been shown to induce glucose intolerance by altering the gut microbiota; however, little is known about the effect of stevia. Here, we investigate whether stevia supplementation induces glucose intolerance by altering the gut microbiota in mice, hypothesizing that stevia would correct high fat diet-induced glucose intolerance and alter the gut microbiota. Mice were split into four treatment groups: low fat, high fat, high fat + saccharin and high fat + stevia. After 10 weeks of treatment, mice consuming a high fat diet (60% kcal from fat) developed glucose intolerance and gained more weight than mice consuming a low fat diet. Stevia supplementation did not impact body weight or glucose intolerance. Differences in species richness and relative abundances of several phyla were observed in low fat groups compared to high fat, stevia and saccharin. We identified two operational taxonomic groups that contributed to differences in beta-diversity between the stevia and saccharin groups: Lactococcus and Akkermansia in females and Lactococcus in males. Our results demonstrate that stevia does not rescue high fat diet-induced changes in glucose tolerance or the microbiota, and that stevia results in similar alterations to the gut microbiota as saccharin when administered in concordance with a high fat diet.

Anthraquinone: a promising scaffold for the discovery and development of therapeutic agents in cancer therapy

Cancer, characterized by uncontrolled malignant neoplasm, is a leading cause of death in both advanced and emerging countries. Although, ample drugs are accessible in the market to intervene with tumor progression, none are totally effective and safe. Natural anthraquinone (AQ) equivalents such as emodin, aloe-emodin, alchemix and many synthetic analogs extend their antitumor activity on different targets including telomerase, topoisomerases, kinases, matrix metalloproteinases, DNA and different phases of cell lines. Nano drug delivery strategies are advanced tools which deliver drugs into tumor cells with minimum drug leakage to normal cells. This review delineates the way AQ derivatives are binding on these targets by abolishing tumor cells to produce anticancer activity and purview of nanoformulations related to AQ analogs.

Effects of Stevia Rebaudiana on Glucose Homeostasis, Blood Pressure and Inflammation: A Critical Review of Past and Current Research Evidence

The prevalence of obesity and its related comorbidities continues to rise in the United States and worldwide. Insulin resistance, increased inflammation and oxidative stress are the major pathogenic mechanisms involved in obesity-associated co-morbid conditions. Major efforts to curb the rising tide of obesity, including lifestyle modifications, anti-obesity medications and surgical interventions have shown minimal success. Therefore, introducing new methods to combat obesity, diabetes and associated disorders are desperately needed. Stevia rebaudiana, a natural, non-caloric sweetener has generated significant interest in the scientific community due to its effects on glucose homeostasis, blood pressure and inflammation, all known consequences of obesity. In this review, we assess the effects of Stevia on these parameters in humans as well as in animal models, highlighting its potential role as an effective intervention for the major cardiovascular risk factors associated with obesity.

A Newly Discovered Phenylethanoid Glycoside from Stevia rebaudiana Bertoni Affects Insulin Secretion in Rat INS-1 Islet β Cells

The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside (1), cuchiloside (2), salidroside (3), icariside D (4), and tyrosol (5). Of them, compound 1 is a novel compound. Mass spectrometry and NMR spectroscopy were employed to confirm the absolute configuration. A hydrolytic step with 4 N TFA at 95 °C for 4 h was used to confirm the monosaccharides. In addition, Discovery Studio 4.0 was used to predict the ADME and toxicity activity of compound 1. The results suggested that compound 1 was biocompatible and had poor toxicity, which was verified by rat INS-1 islet β cells through an MTT assay. Meanwhile, a significant stimulatory effect on INS-1 cells was observed, which indicated a hypoglycemic effect of compound 1. This is the first report that describes a natural, novel, and hypoglycemic phenylethanoid glycoside in Stevia.

Nanoformulations of natural products for management of metabolic syndrome

Metabolic syndrome is a common metabolic disorder which has become a public health challenge worldwide. There has been growing interest in medications including natural products as complementary or alternative choices for common chemical therapeutics regarding their limited side effects and ease of access. Nanosizing these compounds may help to increase their solubility, bioavailability, and promisingly enhance their efficacy. This study, for the first time, provides a comprehensive overview of the application of natural-products-based nanoformulations in the management of metabolic syndrome. Different phytochemicals including curcumin, berberine, Capsicum oleoresin, naringenin, emodin, gymnemic acid, resveratrol, quercetin, scutellarin, stevioside, silybin, baicalin, and others have been nanosized hitherto, and their nanosizing method and effect in treatment and alleviating metabolic syndrome have been reviewed and discussed in this study. It has been discovered that there are several pathways or molecular targets relevant to metabolic disorders which are affected by these compounds. Various natural-based nanoformulations have shown promising effect in treatment of metabolic syndrome, and therefore can be considered as future candidates instead of or in conjunction with pharmaceutical drugs if they pass clinical trials successfully.

Antihyperlipidemic efficacy of aqueous extract of Stevia rebaudiana Bertoni in albino rats

BACKGROUND

Stevia (Stevia rebaudiana Bertoni) natural, safe, non-toxic, non-caloric sugar substitute is rich source of pharmacologically important glycoside stevioside that is linked to the pathology and complications of hyperlipidemia.

METHODS

The present research was carried out to explore the anti-hyperlipidemic effect of aqueous extract of Stevia rebaudiana Bertoni leaves in albino rats. For this purpose, hyperlipidemia was induced by administration of Cholesterol (90% E, Appli Chem, Darmstadt, Germany) mixed at dose of 400 mg/kg body weight of rats in their daily routine feed. The hyperlipidemic rats were administered with aqueous stevia extract at different dose levels (200, 300, 400 and 500 ppm/kg b.w.) for 8 weeks; the control rats were fed basal diet during this period. Ethical approval for the current research was obtained from Institutional Review Board Faculty of Science & Technology Government College University, Faisalabad, Pakistan.

RESULTS

Stevia aqueous extract decreased the body weight gain by lowering the feed intake of hyperlipidemic rats. Furthermore, administration of stevia extract at different levels significantly (P < 0.05) lowered the TC (125.22 ± 5.91 to 110.56 ± 5.81 mg/dL), TG (102.13 ± 6.89 to 98.62 ± 7.22 mg/dL), LDL (33.02 ± 4.79 to 22.77 ± 4.36 mg/dL), VLDL (21.22 ± 5.79 to 19.33 ± 5.95 mg/dL) levels and LDL/HDL ratios (0.83 ± 1.22 to 0.54 ± 1.66 mg/dL) from H1 to H4. Conversely, it improved the HDL (39.76 ± 4.34 to l42.02 ± 4.39 mg/dL) level in hyperlipidemic rats compared with untreated rats after eight weeks study period.

CONCLUSION

It is concluded that aqueous extract of stevia has anti-hyperlipidemic effects in albino rats, and therefore could be a promising nutraceutical therapy for the management of hyperlipidemia and its associated complications.

Anti diabetic property of aqueous extract of Stevia rebaudiana Bertoni leaves in Streptozotocin-induced diabetes in albino rats

BACKGROUND

Stevia (Stevia rebaudiana) natural, non-caloric sugar substitute is rich source of pharmacologically important glycoside stevioside that is linked to the pathology and complications of diabetes.

METHODS

The current research was carried out to explore the anti-diabetic effect of aqueous extract of Stevia rebaudiana leaves in albino rats. For this purpose, diabetes was induced by administration of streptozotocin (40 mg/kg body weight, intraperitoneally). The diabetic rats were administered with aqueous stevia extract at different dose levels (200, 300, 400 and 500 ppm/kg b.w) for 8 weeks; the control rats were fed basal diet during this period.

RESULTS

Stevia aqueous extract improved caloric management and weight control by decreasing the feed intake and body weight gain. Furthermore, intake of stevia extract resulted in significant (P < 0.05) decrease in the random blood glucose level (- 73.24%) and fasting blood glucose (- 66.09%) and glycosylated (HbA1c) hemoglobin (5.32%) while insulin (17.82 μIU/mL) and liver glycogen (45.02 mg/g) levels significantly improved in the diabetic rats, compared with the diabetic and non-diabetic control rats after 8 weeks study period.

CONCLUSIONS

It is concluded that aqueous extact of stevia has anti-diabetic effects in albino rats, and therefore could be promising nutraceutical therapy for the management of diabetes and its associated complications.

Stevia rebaudiana Bertoni: A Natural Alternative for Treating Diseases Associated with Metabolic Syndrome

Stevia rebaudiana (SR) is often used by the food industry due to its steviol glycoside content, which is a suitable calorie-free sweetener. Further, both in vitro and in vivo studies indicate that these glycosides and the extracts from SR have pharmacological and therapeutic properties, including antioxidant, antimicrobial, antihypertensive, antidiabetic, and anticancer. This work reviews the antiobesity, antihyperglycemic, antihypertensive, and antihyperlipidemic effects of the majority of glycosides and aqueous/alcoholic extracts from the leaves, flowers, and roots of the SR. These compounds can serve as a natural and alternative treatment for diseases that are associated with metabolic syndrome, thus contributing to health promotion.

Improvement of Insulin Secretion and Pancreatic β-cell Function in Streptozotocin-induced Diabetic Rats Treated with Aloe vera Extract

Background:

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia. Plant extracts and their products are being used as an alternative system of medicine for the treatment of diabetes. Aloe vera has been traditionally used to treat several diseases and it exhibits antioxidant, anti-inflammatory, and wound-healing effects. Streptozotocin (STZ)-induced Wistar diabetic rats were used in this study to understand the potential protective effect of A. vera extract on the pancreatic islets.

Objective:

The aim of the present study was to evaluate the A. vera extract on improvement of insulin secretion and pancreatic β-cell function by morphometric analysis of pancreatic islets in STZ-induced diabetic Wistar rats.

Materials and Methods:

After acclimatization, male Wistar rats, maintained as per the Committee for the Purpose of Control and Supervision of Experiments on Animals guidelines, were randomly divided into four groups of six rats each. Fasting plasma glucose and insulin levels were assessed. The effect of A. vera extract in STZ-induced diabetic rats on the pancreatic islets by morphometric analysis was evaluated.

Results:

Oral administration of A. vera extract (300 mg/kg) daily to diabetic rats for 3 weeks showed restoration of blood glucose levels to normal levels with a concomitant increase in insulin levels upon feeding with A. vera extract in STZ-induced diabetic rats. Morphometric analysis of pancreatic sections revealed quantitative and qualitative gain in terms of number, diameter, volume, and area of the pancreatic islets of diabetic rats treated with A. vera extract when compared to the untreated diabetic rats.

Conclusion:

A. vera extract exerts antidiabetic effects by improving insulin secretion and pancreatic β-cell function by restoring pancreatic islet mass in STZ-induced diabetic Wistar rats.

SUMMARY

Fasting plasma glucose (FPG) and insulin levels were restored to normal levels in diabetic rats treated with Aloe vera extract

Islets of pancreas were qualitatively and quantitatively restored to normalcy leading to restoration of FPG and insulin levels of diabetic rats treated with Aloe vera extract

Morphometric analysis of pancreatic sections revealed quantitative and qualitative gain in terms of number, diameter, volume, and area of the pancreatic islets of diabetic rats treated with Aloe vera extract when compared to the untreated diabetic rats.

Abbreviations Used:A. vera, FPG: Fasting plasma glucose, STZ: Streptozotocin, BW: Body weight

Stevia rebaudiana ethanolic extract exerts better antioxidant properties and antiproliferative effects in tumour cells than its diterpene glycoside stevioside

Steviol glycosides are currently being used as natural sweeteners by the food industry and Stevia rebaudiana has long been used as a sweet plant in South America for patients suffering from diabetes. In this study, a Stevia rebaudiana ethanolic extract (SREE) was prepared, analysed and tested for antioxidant activity in terms of free radical scavenging properties and antiproliferative effects in cervix (HeLa), pancreatic (MiaPaCa-2) and colonic (HCT116) cancer cells. The antiproliferative mechanism was confirmed by testing the effects on cyclin D1-CDK4. Bioassays were also performed for the diterpene glycoside stevioside. Our results demonstrate that the extract acts as an antioxidant being able to scavenge free radicals, but this activity was not due to stevioside. The extract also induced cell death in the three cell lines, being more active against cervix cancer cells (HeLa); however, the concentration of stevioside needed to produce antiproliferative effects was higher than the amount of steviol glycosides found in a lower dose of extract inducing cell death. In addition, the extract clearly inhibited CDK4 whereas stevioside did not, concluding that the antiproliferative activity of stevia may be due to inhibition of cyclin-dependent kinases performed by other compounds of the extract.

Anti-inflammatory effect of Heliotropium indicum Linn on lipopolysaccharide-induced uveitis in New Zealand white rabbits

AIM

To investigate the anti-inflammatory effect of an aqueous whole plant extract of Heliotropium indicum (HIE) on endotoxin-induced uveitis in New Zealand white rabbits.

METHODS

Clinical signs of uveitis including flares, iris hyperemia and miosis, were sought for and scored in 1.0 mg/kg lipopolysaccharide (LPS) -induced uveitic rabbits treated orally with HIE (30-300 mg/kg), prednisolone (30 mg/kg), or normal saline (10 mL/kg). The number of polymorphonuclear neutrophils infiltrating, the protein concentration, as well as levels of tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), and monocyte chemmoattrant protein-1 (MCP-1) in the aqueous humor after the various treatments were also determined. A histopathological study of the anterior uveal was performed.

RESULTS

The extract and prednisolone-treatment significantly reduced (P≤0.001) both the clinical scores of inflammation (1.0-1.8 compared to 4.40±0.40 in the normal saline-treated rabbits) and inflammatory cells infiltration. The level of protein, and the concentrations of TNF-α, PGE2 and MCP-1 in the aqueous humor were also significantly reduced (P≤0.001). Histopathological studies showed normal uveal morphology in the HIE and prednisolone-treated rabbits while normal saline-treated rabbits showed marked infiltration of inflammatory cells.

CONCLUSION

The HIE exhibits anti-inflammatory effect on LPS-induced uveitis possibly by reducing the production of pro-inflammatory mediators.

Synthesis of rebaudioside-A by enzymatic transglycosylation of stevioside present in the leaves of Stevia rebaudiana Bertoni

Rebaudioside-A is the second most abundant sweet diterpene glycoside (1-3%) present in the leaves of Stevia rebaudiana Bertoni, and is now being considered as a possible sucrose substitute due to its pleasant organoleptic properties and associated health benefits. In the present study, a novel in situ enzymatic transglycosylation of stevioside has been developed by pre-treating the stevia leaves with cellulase and adding soluble starch as the glucosyl donor. The results confirm that the transglycosylation of stevioside led to an enrichment in the rebaudioside-A content from 4% to 66%. This was further purified by multiple column chromatography to obtain 95% pure rebaudioside-A. The isolated rebaudioside-A showed concentration-dependent α-glucosidase inhibitory activity with IC50=35.01 μg/ml. Thus the study highlights the biotransformation of stevioside present in stevia leaves to rebaudioside-A by a simple, inexpensive and eco-friendly process that has commercial potential.

A systematic review of medicinal plants used for weight loss in Brazil: Is there potential for obesity treatment?

ETHNOPHARMACOLOGICAL RELEVANCE

Obesity is a pandemic disease and its prevalence is still increasing. Moreover, it has important costs to public health. In Brazil, many plants are used for weight loss by overweight or obese people, but there is a lack of scientific basis for this practice. Many ethnobotanical studies aiming to characterize this usage have been published, but they are still limited by the region considered and the diversity of the popular knowledge.

AIM OF THE STUDY

The present study was undertaken to systematically review the ethnobotanical surveys regarding the species utilized to reduce body weight in overweight or obese people in Brazil.

METHODS

Ethnobotanical surveys related to this usage and performed in Brazilian regions were systematically found in MEDLINE, LILACS and Scopus.

RESULTS

Thirty-three studies were included in this review. Fifty species were popularly utilized to lose weight. The most cited species were Baccharis trimera (Less.) DC, Annona muricata L. and Hancornia speciosa Gomes. Camellia sinensis (L.) Kuntze and Hibiscus sabdariffa L. were also cited and are supported by either animal or human investigations that indicate some beneficial activity against obesity. However, for the majority of species cited in the included studies, there is no scientific basis that assures the biological effects of this usage. Many studies have demonstrated important effects of these plants on glycemia, serum lipid levels or body weight control in non-obese conditions, which is not sufficient to recommend the use of these plants to reduce body weight in overweight or obese people.

CONCLUSIONS

Although many plants are popularly used to reduce weight in overweight or obese people in Brazil, there is little scientific evidence corroborating its usage. Based on the ethnobotanical data presented, this review indicates the plants that should be considered for scientifically controlled studies devoted to investigating their effects on obesity.

Possible Mechanism of Action of the Antiallergic Effect of an Aqueous Extract of Heliotropium indicum L. in Ovalbumin-Induced Allergic Conjunctivitis

Heliotropium indicum is used traditionally as a remedy for conjunctivitis in Ghana. This study therefore evaluated the antiallergic potential of an aqueous whole plant extract of Heliotropium indicum (HIE) in ovalbumin-induced allergic conjunctivitis and attempted to predict its mode of action. Clinical scores for allergic conjunctivitis induced by intraperitoneal ovalbumin sensitization (100 : 10 μg OVA/Al(OH)3 in phosphate-buffered saline [PBS]) and topical conjunctival challenge (1.5 mg OVA in 10 μL PBS) in Dunkin-Hartley guinea pigs were estimated after a week's daily treatment with 30-300 mg kg(-1) HIE, 30 mg kg(-1) prednisolone, 10 mg kg(-1) chlorpheniramine, or 10 mL kg(-1) PBS. Ovalbumin-specific IgG and IgE and total IgE in serum were estimated using Enzyme-Linked Immunosorbent Assay. Histopathological assessment of the exenterated conjunctivae was also performed. The 30 and 300 mg kg(-1) HIE treatment resulted in a significantly (p ≤ 0.001) low clinical score of allergic conjunctivitis. Ovalbumin-specific IgG and IgE as well as total serum IgE also decreased significantly (p ≤ 0.01-0.001). The conjunctival tissue in HIE treated guinea pigs had mild mononuclear infiltration compared to the PBS-treated ones, which had intense conjunctival tissue inflammatory infiltration. HIE exhibited antiallergic effect possibly by immunomodulation or immunosuppression.

Anti-glaucoma potential of Heliotropium indicum Linn in experimentally-induced glaucoma

Background

Heliotropium indicum is used as a traditional remedy for hypertension in Ghana. The aim of the study was to evaluate the anti-glaucoma potential of an aqueous whole plant extract of H. indicum to manage experimentally-induced glaucoma.

Methods

The percentage change in intraocular pressure (IOP), after inducing acute glaucoma (15 mLkg⁻¹ of 5 % dextrose, i.v.), in New Zealand White rabbits pretreated with Heliotropium indicum aqueous extract (HIE) (30–300 mgkg⁻¹), acetazolamide (5 mgkg⁻¹), and normal saline (10 mLkg⁻¹) per os were measured. IOPs were also monitored in chronic glaucoma in rabbits (induced by 1 % prednisolone acetate drops, 12 hourly for 21 days) after treatments with the same doses of HIE, acetazolamide, and normal saline for 2 weeks. The anti-oxidant property of the extract was assessed by assaying for glutathione levels in the aqueous humour. Glutamate concentration in the vitreous humour was also determined using ELISA technique. Histopathological assessment of the ciliary bodies was made.

Results

The extract significantly reduced intraocular pressure (p ≤ 0.05–0.001) in acute and chronic glaucoma, preserved glutathione levels and glutamate concentration (p ≤ 0.01–0.001). Histological assessment of the ciliary body showed a decrease in inflammatory infiltration in the extract and acetazolamide-treated group compared with the normal saline-treated group.

Conclusion

The aqueous whole plant extract of Heliotropium indicum has ocular hypotensive, anti-oxidant and possible neuro-protective effects, which therefore underscore its plausible utility as an anti-glaucoma drug with further investigation.

The Claim of Anti-Cataract Potential of Heliotropium indicum: A Myth or Reality?

Introduction

Heliotropium indicum has several uses in traditional medicine attributable to its numerous bioactive compounds. It is used as a traditional remedy for cataracts in Ghana without any scientific verification. This study aimed at verifying the anti-cataract properties of an aqueous whole plant extract of H. indicum.

Methods

The effect (cataract score) of 30, 100, and 300 mg kg⁻¹ extract (bid for 21 days, per os) on the development of 30 µmol kg⁻¹ sodium selenite-induced cataract in 10-day-old rat pups was investigated. Soluble lens proteins alpha A and alpha B crystallins, total lens protein, total lens glutathione, and aquaporin 0 in enucleated lens homogenates were determined spectrophotometrically using commercially available kits. Histopathological studies on the lenses were also performed. The 2,2-diphenyl-1-picrylhydrazyl scavenging effect and linoleic acid autoxidation (antioxidant properties) of the extract (0.1–3.0 mg ml⁻¹), compared to n-propyl gallate, were ascertained using standard procedures.

Results

Cataract scores showed that the extract, at all dose levels, significantly alleviated selenite-induced cataracts (P ≤ 0.001). Markers of lens transparency (aquaporin 0, alpha A and B crystallins), as well as total lens proteins and lens glutathione levels, were significantly preserved (P ≤ 0.01–0.001). The extract exhibited activity relevant for scavenging free radicals and inhibition of lipid peroxidation. Epithelial and lens fiber integrity in the histopathological assessment were maintained with HIE treatment.

Conclusion

The aqueous whole plant extract of H. indicum significantly inhibited the development of cataracts in rats via multiple mechanisms.

Self-nanoemulsifying drug delivery system of trans-cinnamic acid: formulation development and pharmacodynamic evaluation in alloxan-induced type 2 diabetic rat model

The objective of this study was to formulate a self-nanoemulsifying oral drug delivery system (SNEDDS) for the poorly water-soluble trans-Cinnamic acid (t-CA SNEDDS) that could be evaluated for its antihyperglycemic efficacy in comparison to the parent t-CA in an alloxan-induced diabetic rat model. A SNEDDS formulation consisting of 60% surfactant (Kolliphor EL), 10% co-surfactant (PEG 400) and 30% oil (isopropyl myristate) proved to be optimal. t-CA SNEDDS (80 mg/kg, p.o.), t-CA suspension (80 mg/kg, p.o.), and Metformin Hydrochloride Tablets (230 mg/kg, p.o.) were administer qdfor 30 days to diabetic rats. After treatment the body weight of diabetic rats was increased, blood glucose levels, total cholesterol, and triglyceride in the serum tended to be normalized, while the levels of alanine aminotransferase and aspartate aminotransferase were markedly decreased. The effects of t-CA SNEDDS were superior to that of the t-CA suspension. The present study demonstrated that t-CA was effective in attenuating the effects of alloxan treatment and that t-CA SNEDDS with a more favorable absorption and enhanced bioavailability is more effective than t-CA.

In vitro α-amylase inhibitory activity and in vivo hypoglycemic effect of methanol extract of Citrus macroptera Montr. fruit

OBJECTIVE

To investigate the therapeutic effects of methanol extract of Citrus macroptera Montr.fruit in α-amylase inhibitory activity (in vitro) and hypoglycemic activity in normal and glucose induced hyperglycemic rats (in vivo).

METHODS

Fruits of Citrus macroptera without rind was extracted with pure methanol following cold extraction and tested for presence of phytochemical constituents, α-amylase inhibitory activity, and hypoglycemic effect in normal rats and glucose induced hyperglycemic rats.

RESULTS

Presence of saponin, steroid and terpenoid were identified in the extract. The results showed that fruit extract had moderate α-amylase inhibitory activity [IC50 value=(3.638±0.190) mg/mL] as compared to acarbose. Moreover at 500 mg/kg and 1 000 mg/kg doses fruit extract significantly (P<0.05 and P<0.01 respectively) reduced fasting blood glucose level in normal rats as compared to glibenclamide (5 mg/kg). In oral glucose tolerance test, 500 mg/kg dose significantly reduced blood glucose level (P<0.05) at 2 h but 1 000 mg/kg dose significantly reduced blood glucose level at 2 h and 3 h (P<0.05 and P<0.01 respectively) whereas glibenclamide (5 mg/kg) significantly reduced glucose level at every hour after administration. Overall time effect is also considered extremely significant with F value=23.83 and P value=0.0001 in oral glucose tolerance test.

CONCLUSION

These findings suggest that the plant may be a potential source for the development of new oral hypoglycemic agent.

Insulin secretion enhancing activity of roselle calyx extract in normal and streptozotocin-induced diabetic rats

Background and Objective:

Our recent study revealed the antihyperglycemic activity of an ethanolic extract of roselle calyxes (Hibiscus sabdariffa) in diabetic rats. The present study had, therefore, an objective to investigate the mechanism underlying this activity.

Materials and Methods:

Male Sprague Dawley rats were induced to be diabetes by intraperitoneal injection of 45 mg/kg streptozotocin (STZ). Normal rats as well as diabetic rats were administered with the ethanolic extract of H. sabdariffa calyxes (HS-EE) at 0.1 and 1.0 g/kg/day, respectively, for 6 weeks. Then, blood glucose and insulin levels, at basal and glucose-stimulated secretions, were measured. The pancreas was dissected to examine histologically.

Results:

HS-EE 1.0 g/kg/day significantly decreased the blood glucose level by 38 ± 12% in diabetic rats but not in normal rats. In normal rats, treatment with 1.0 g/kg HS-EE increased the basal insulin level significantly as compared with control normal rats (1.28 ± 0.25 and 0.55 ± 0.05 ng/ml, respectively). Interestingly, diabetic rats treated with 1.0 g/kg HS-EE also showed a significant increase in basal insulin level as compared with the control diabetic rats (0.30 ± 0.05 and 0.15 ± 0.01 ng/ml, respectively). Concerning microscopic histological examination, HS-EE 1.0 g/kg significantly increased the number of islets of Langerhans in both normal rats (1.2 ± 0.1 and 2.0 ± 0.1 islet number/10 low-power fields (LPF) for control and HS-EE treated group, respectively) and diabetic rats (1.0 ± 0.3 and 3.9 ± 0.6 islet number/10 LPF for control and HS-EE treated group, respectively).

Conclusion:

The antidiabetic activity of HS-EE may be partially mediated via the stimulating effect on insulin secretion.

Development of stevioside Pluronic-F-68 copolymer based PLA-nanoparticles as an antidiabetic nanomedicine

Stevioside (FDA approved nontoxic natural non-caloric sweetener) has been reported to have very good antidiabetic potential but its use as therapeutic drug is restricted in human due to its deprived intestinal absorption and poor bioavailability. We have nano-bioconjugated this molecule on biodegradable Pluronic-F-68 copolymer based PLA nanoparticles by nanoprecipitation method (spherical, size range 110-130 nm) to overcome deprived intestinal absorption and to enhance the bioavailability. The drug loading calculated by the standard calibrated HPLC was 16.32±4% (w/w). The in vitro release study showed the initial burst followed by the sustained release. The half release and complete release were observed on 25±4 h and 200±10 h respectively. This newly formulated nanostevioside showed very high potential to be used as antidiabetic nanomedicine for safe and effective use in vivo.

Antiarthritic effect of aqueous and ethanolic leaf extracts of Pistia stratiotes in adjuvant-induced arthritis in Sprague-Dawley rats

BACKGROUND

Pistia stratiotes has been used effectively to treat a number of inflammatory conditions. This study aims to determine the antiarthritic effect of aqueous and ethanolic leaf extracts of P. stratiotes.

METHODS

Arthritis was induced in Sprague-Dawley rats, paw swelling was measured, and arthritis indices were estimated in rats treated with aqueous and ethanolic leaf extracts of P. stratiotes (AQ PSE and ET PSE, respectively), methotrexate, diclofenac, dexamethasone, and normal saline-treated rats. Radiologic imaging, hematological assessment of red and white blood cells, C-reactive protein and erythrocyte sedimentation rate, as well as histopathological studies were also done. The data were analyzed using GraphPad Prism 5.

RESULTS

The 30, 100, and 300 mg/kg doses of AQ PSE and the 30 and 100 mg/kg doses of ET PSE caused a significant (P ≤ 0.05-0.001) reduction in ipsilateral paw swelling, similar to the effects of methotrexate, dexamethasone, and diclofenac. Only the 30 mg/kg dose of AQ PSE caused a significant (P ≤ 0.01) reduction in contralateral paw swelling. Arthritic indices reduced significantly (P ≤ 0.05-0.001) at all drug doses, except for the 100 and 300 mg/kg doses of ET PSE. White blood cell levels decreased significantly (P ≤ 0.05-0.01) in arthritic rats treated with the 30 mg/kg dose of AQ PSE and those treated with methotrexate. Erythrocyte sedimentation rate and C-reactive protein levels were significantly (P ≤ 0.01-0.001) lower in all the treatment groups except for the rats treated with AQ PSE 300 mg/kg and ET PSE 100 and 300 mg/kg doses. The arthritic animals treated with 30 mg/kg of the aqueous extract showed no inflammatory changes in the ipsilateral paw, while the contralateral paw showed only foci of mild chronic inflammatory changes, as seen with the reference drug treatment in histopathological studies.

CONCLUSION

This study establishes that aqueous and ethanolic extracts of P. stratiotes have antiarthritic activity in Sprague-Dawley rats with induced arthritis. The aqueous extract had better activity than the ethanolic extract.

Antihyperglycemic and antioxidative effects of the hydro-methanolic extract of the seeds of Caesalpinia bonduc on streptozotocin-induced diabetes in male albino rats

BACKGROUND

No satisfactory effective treatment is available yet to cure diabetes mellitus. Though, synthetic drugs are used but there are several drawbacks. The attributed antihyperglycemic effects of many traditional plants are due to their ability for the management of diabetes mellitus.

MATERIALS AND METHODS

A hydromethanolic extract was administered orally at a dose of 250 mg/kg of body weight per day for 21 days. Its effects on the fasting blood glucose (FBG) level, activities of key carbohydrate metabolic enzymes like hexokinase, glucose-6-phosphatase, and glucose-6-phosphate dehydrogenase, and antioxidant enzymes like catalase and superoxide dismutase along with the effect on the lipid peroxidation level in hepatic tissues were measured. Glycogen levels were also assessed in hepatic and skeletal muscles and some toxicity parameters, such as serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and alkaline phosphates activities were measured.

RESULTS

Treatment of the hydromethanolic extract of the seeds of Caesalpinia bonduc resulted in a significant (P < 0.05) recovery in the activities of carbohydrate metabolic enzymes along with correction in FBG and glycogen levels as compared with the untreated diabetic group. The extract also resulted in a significant (P < 0.05) recovery in the activities of toxicity assessment enzyme parameters. Activities of antioxidant enzymes like catalase and superoxide dismutase along with the lipid peroxidation levels were also recovered significantly (P < 0.05) after the treatment of the extract. The corrective effects produced by the extract were compared with the standard antidiabetic drug, glibenclamide.

CONCLUSION

Our findings provide that the extract shows possible antihyperglycemic and antioxidative activities.