Preventive effects of Salvia officinalis leaf extract on insulin resistance and inflammation in a model of high fat diet-induced obesity in mice that responds to rosiglitazone

Effect of Salvia officinalis aqueous infusion on copper sulfate-induced inflammatory response and oxidative stress imbalance in mice liver and kidney

Extracts of Salvia officinalis (S. officinalis) have been described to have many therapeutic properties. However, the effect of S. officinalis on copper sulfate toxicity has not been previously reported. The aim of this study was to investigate the toxicity of copper sulfate and the potential beneficial effects of S. officinalis aqueous infusion on proinflammatory response and antioxidant status. 56 male mice were used and equally divided into 6 groups: control group, copper sulfate treated group (40 mg/kg), S. officinalis aqueous infusion treated groups (200 mg/kg and 400 mg/kg) separately or in combination with copper. IL-6 (interleukine-6) and TNF-α (Tumor necrosis factor alpha) were assessed by Elisa. Catalase (CAT), superoxide dismutase (SOD) and acetylcholinesterase (AChE) activities, malondialdehyde (MDA) and oxygen peroxide levels were determined. Serum biochemical parameters were analyzed. Copper enhanced aspartate aminotransferase (AST), alanine aminotransferase (ALT) and Lactate dehydrogenase (LDH) (p < 0.05). Copper enhances significantly IL-6, TNF-α and MDA levels in liver and kidney and reduced CAT, SOD and AChE activities (p < 0.05). Aqueous infusion of S. officinalis at 400 mg/kg abolished copper-induced changes in AST and ALT activity. S. officinalis aqueous infusion at 200 mg/kg reversed copper-induced IL-6 in kidney and TNF-α in liver at both doses. S. officinalis aqueous infusion at 400 mg/kg restored SOD in kidney and CAT and AChE activities in both liver and kidney. S. officinalis aqueous infusion may be useful in partially ameliorating tissue disorders induced by copper exposure such as inflammatory response, oxidative stress imbalance and organ dysfunction through its phenolic compounds and higher antioxidant capacity.

Aqueous sage leave extract attenuates inflammation and oxidant-induced genotoxicity in human peripheral blood mononuclear cells

Traditional medicine has used sage (Salvia officinalis L.) preparations for centuries to prevent and treat various inflammatory and oxidative stress-induced conditions. The aim of this in vitro study was to determine the bioactive properties of a sage leave extract obtained with environmentally friendly aqueous extraction and lyophilisation in primary human peripheral blood cells. To that end we measured the total phenolic and flavonoid content (TPC and TFC, respectively) with gas chromatography-mass spectrometry (GC-MS). Non-cytotoxic concentrations determined with the trypan blue assay were used to assess the antioxidant (DPPH, ABTS, and PAB assay), antigenotoxic (CBMN assay), immunomodulatory (IL-1β and TNF-α), and neuroprotective effects (AChE inhibition). The extract contained high TPC (162 mg GAE/g of dry extract) and TFC (39.47 mg QE/g of dry extract) concentrations, while β-thujone content was unexpectedly low (below 0.9 %). Strong radical-scavenging activity combined with glutathione reductase activation led to a decrease in basal and H2O2-induced oxidative stress and DNA damage. A decrease in TNF-α and increase in IL-1β levels suggest complex immunomodulatory response that could contribute to antioxidant and, together with mild AChE inhibition, neuroprotective effects. Overall, this study has demonstrated that aqueous sage leave extract reduces the levels of thujone, 1,8-cineole, pinene, and terpene ketones that could be toxic in high concentrations, while maintaining high concentrations of biologically active protective compounds which have a potential to prevent and/or treat inflammatory and oxidative stress-related conditions.

The effect of Salvia officinalis on blood glycemic indexes and blood lipid profile in diabetic patients: a systematic review and meta-analysis

Diabetes is one of the most common endocrine disorders that increases the economic burden on the public health system. In this regard, understanding the effect of available herbs on diabetes can be useful. This systematic review was performed to determine the effect of Salvia officinalis on blood glycemic indexes and blood lipid profile (primary outcomes) and 2 h postprandial blood glucose (2HPPG), alanine transaminase (ALT) (U/L) and aspartate transaminase (AST) (U/L) and its side effects (secondary outcomes) in diabetic patients. A systematic search was conducted in the English (Cochrane Library, Medline (PubMed), Scopus, CINAHL, ProQuest and Persian databases since inception to March 2021, without publication time restriction. Two authors separately evaluated the quality of the articles using Cochrane Collaboration's tool for assessing the risk of bias in randomized trials and extracted the data. Heterogeneity of data was evaluated by squared I (I 2). Three studies included in the review and all of them included in meta-analysis. The results of meta-analysis showed that S. officinalis reduced fasting blood sugar (FBS) (mg/dL) (MD: -31.15; 95% CI: -37.56 to -24.73; p<0.00001). It also reduced HbA1c (%) (MD: -0.94; 95% CI: -1.25 to -0.63; p<0.00001) and total cholesterol (mg/dL) (MD: -43.64; 95% CI: -83.26 to -4.02; p=0.03) and reduction of low-density protein (LDL) (mg/dL) (MD: -19.23; 95% CI: -35.81 to -2.65; p=0.02) but it did not have a significant effect on triglyceride (mg/dL) (p=0.09), and high-density lipoprotein (HDL) (mg/dL) (p=0.18). Regarding the secondary outcomes, S. officinalis also had significant effect on 2HPPG, but it did not have a significant effect on ALT (U/L) and AST (U/L). No specific side effects for this plant were reported in these three studies. The results showed that S. officinalis has a positive effect on blood glycemic status and blood lipid profile in diabetes except for triglyceride and HDL. However, due to the small number of included articles, it is recommended that stronger clinical trials be conducted in this field.

Regulatory T cells differentiation in visceral adipose tissues contributes to insulin resistance by regulating JAZF-1/PPAR-γ pathway

Regulatory T cell (Treg) activity and differentiation in visceral adipose tissue (VAT) play an important role in inhibiting chronic inflammation and insulin resistance. Whether JAZF-1 and PPAR-γ mediate VAT Treg differentiation to promote the inhibition of chronic inflammation and insulin resistance remains unclear. Here, we investigated the roles of JAZF-1 and PPAR-γ in VAT Treg differentiation, inflammation and insulin resistance using a transgenic mouse model. First, we determined that the levels of glucose and insulin biochemical markers in the JAZF-1 transgenic general feeding or high-fat groups were lower than those in the wild-type general feeding or high-fat groups. Second, the levels of CD4⁺ , CD25⁺ , and FOXP3⁺ differentiation markers in the JAZF-1 transgenic general feeding or high-fat groups were significantly higher than those in the wild-type groups. PPAR-γ inhibition was associated with low levels of CD4⁺ , CD25⁺ and FOXP3⁺ differentiation markers. Third, the levels of TNF-α, IL-1β and IL-6 in the JAZF-1 transgenic groups were lower than those in the wild-type groups, whereas IL-10 and TGF-β levels were higher in the JAZF-1 transgenic groups than in the wild-type groups. After using the PPAR-γ inhibitor, we observed that TNF-α, IL-1β and IL-6 increased, while IL-10 and TGF-β decreased. We found that JAZF-1 and PPAR-γ could promote Tregs differentiation and regulate insulin resistance by synergistically decreasing the expression levels of TNF-α, IL-1β and IL-6 and increasing those of IL-10 and TGF-β.

Evaluation of antiobesity and hepatorenal protective activities of Salvia officinalis extracts pre-treatment in high-fat diet-induced obese rats

The present study evaluated the effects of Hail Salvia officinalis total extract (SOTE) and its high flavonoid fraction (SOHFF) on the high-fat diet (HFD)-induced obesity and hepatorenal damage in rats. Salvia officinalis plants were collected from Hail region, Saudi Arabia. Rats were fed HFD and supplemented orally with SOTE (250 mg kg^-1) or SOHFF (100 mg kg^-1) or simvastatin (SVS; 10 mg kg^-1) every day for 8 weeks. Compared to the controls, HFD-induced obesity led to significant increases in body weight, body weight gained, blood insulin, leptin, cardiac enzymes (LDH and CPK) activity, and atherogenic index (AI). HFD rats also showed higher levels of hepatic and renal function biomarkers (ALT, urea, and creatinine), as well as lower levels of PPARγ and Nrf2-gene expression and a disrupted lipid profile. Moreover, HFD rats had lower levels of hepatic and renal antioxidant biomarkers (CAT, GPx, SOD, GR, and GSH), accompanied by higher levels of hepatic and renal lipid peroxidation (LPO), nitric oxide (NO), and inflammatory mediators (interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)). In addition, histological examination of hepatic and renal tissues revealed histopathological changes that validated the biochemical findings. Compared to HFD group, SOTE and SOHFF treatment led to marked amelioration of all the aforementioned parameters. Collectively, supplementation with SOTE and SOHFF effectively reversed HFD-induced alterations through its antioxidant, hypolipidemic, and anti-inflammatory properties. Hence, SOTE and SOHFF have therapeutic potential in controlling obesity and related pathologies.

The Potential of Lamiaceae Herbs for Mitigation of Overweight, Obesity, and Fatty Liver: Studies and Perspectives

Numerous plants, plant extracts, and plant-derived compounds are being explored for their beneficial effects against overweight and liver diseases. Obesity is associated with the increased prevalence of non-alcoholic fatty liver disease (NAFLD), becoming the most common liver disease in Western countries. Obesity and NAFLD are closely associated with many other metabolic alternations such as insulin resistance, diabetes mellitus, and cardiovascular diseases. Many herbs of the Lamiaceae family are widely employed as food and spices in the Mediterranean area, but also in folk medicine, and their use for the management of metabolic disorders is well documented. Hereby, we summarized the scientific results of the medicinal and nutraceutical potential of plants from the Lamiaceae family for prevention and mitigation of overweight and fatty liver. The evidence indicates that Lamiaceae plants may be a cost-effective source of nutraceuticals and/or phytochemicals to be used in the management of metabolic-related conditions such as obesity and NAFLD. PubMed, Google Scholar, Scopus, and SciFinder were accessed to collect data on traditional medicinal plants, compounds derived from plants, their reported anti-obesity mechanisms, and therapeutic targets.

DMRT2 Interacts With FXR and Improves Insulin Resistance in Adipocytes and a Mouse Model

Insulin resistance (IR) plays a critical role in cardiovascular diseases and metabolic diseases. In this study, we identified the downregulation of DMRT2 in adipose tissues from insulin-resistant subjects through bioinformatics analysis and in an insulin-resistant mouse model through experimental analysis. DMRT2 overexpression significantly attenuated HDF-induced insulin resistance and inflammation in mice. Moreover, in control and insulin-resistant differentiated mouse 3T3-L1 adipocytes, DMRT2 overexpression attenuated but DMRT2 knockdown enhanced the insulin resistance of 3T3-L1 adipocytes. DMRT2 interacted with FXR and positively regulated FXR level and transcription activity. In both control and insulin-resistant differentiated mouse 3T3-L1 adipocytes, FXR knockdown enhanced the insulin resistance and attenuated the effects of DMRT2 overexpression upon 3T3-L1 adipocyte insulin resistance. In conclusion, we identify the downregulation of DMRT2 in the insulin-resistant mouse model and cell model. DMRT2 interacts with FXR and improves insulin resistance in adipocytes.

Preventive effects of polysaccharides from Physalis alkekengi L. on dietary advanced glycation end product-induced insulin resistance in mice associated with the modulation of gut microbiota

Advanced glycation end products (AGEs) are commonly found in thermally processed foods, and long-term high AGE feeding has been reported to have negative effects on body health. In the current study, the effect of Physalis alkekengi L. fruit polysaccharide (PFP) on preventing dietary AGE-induced insulin resistance (IR) in mice was investigated. The results showed that PFP administration can significantly ameliorate hyperglycemia, dyslipidemia, and insulin resistance induced by dietary AGEs in mice. Compared to AGE-treated mice, the homeostasis model assessment for insulin resistance (HOMA-IR) index and insulin sensitivity (HOMA-IS) index of PFP-treated mice were improved significantly (p < 0.05). The levels of endotoxin and inflammatory cytokines in the liver decreased, while the levels of insulin receptor substrate-1 and insulin receptor substrate-2 in the liver increased (p < 0.05). The 16S rRNA analysis showed that PFP administration reversed the Bacteroidetes/Firmicutes ratio and reduced lipopolysaccharide generation and inflammation-related bacteria, including Desulfovibrio and Acetatifactor. In addition, PFP administration also increased short-chain fatty acid levels in feces compared to dietary AGE-treated mice. Spearman's correlation analysis showed that certain specific genera, including Alistipes and Caproiciproducens, are closely related to IR-related parameters. These findings suggest that PFP can prevent dietary AGE-induced IR by modulating the gut microbiota and increasing microbial metabolites.

Salvia Officinalis Protects Pancreatic Beta-cells Against Streptozotocin-Induced Damage; A Stereological Study

Background: Diabetes mellitus (DM) is a chronic disease, progressing due to inadequate secretion of insulin by pancreas. Salvia officinalis (SVO) has anti-inflammatory and anti-oxidative potentials, which may be beneficial in regulating underlying causes of DM. Objectives: In this study, we aimed to estimate the protective effects of SVO against Streptozotocin (STZ)-induced pancreatic injury in rat models of DM. Methods: Forty-eight male Sprague-Dawley rats were randomly divided into four groups (n = 12); C1: normal group with no treatment, C2: diabetic group with no treatment, E1: diabetic group treated with 200 mg/kg of the SVO extract, and E2: diabetic group treated with 400 mg/kg of the SVO extract. All groups received a single dose of STZ on day 7 except C1. Pancreas volume, shrinkage, volume densities of the islets, numerical densities, and volume of the beta cells were measured using stereological methods. Results: Blood sugar (BS) levels were significantly lower in SVO-treated groups comparing to C2 group. Also, volume densities and total number of islets and beta cells in E1 and E2 groups were higher than C2 (P < 0.05), but lower than C1 (P < 0.05). Volume densities of the islets and beta cells, and total number of beta cells in E1, and volume densities of the islets and beta cells in E2 groups were considerably higher than C2 group (P < 0.05). Conclusions: Our result showed the beneficial effects of SVO extract regarding pancreatic damage. We concluded that SVO might be prescribed as a therapeutic food supplement for patients with diabetes.

Effect of Salvia officinalis and S. sclarea on rats with a high-fat hypercaloric diet

Phytotherapy for the correction of excess body weight is widely used. However, a comprehensive study of herbal preparations on the organism of model animals has been carried out only for a few plant species. Supplementing the diet of rats with closely related sage species (Salvia officinalis L. and S. sclarea L.) against the background of high-fat hypercaloric diet triggered multidirectional changes in their metabolism. The addition of crushed dry shoots of S. officinalis to the diet of animals led to a sharp increase in their body weight (up to 130.8% of the initial one in 30 days of the experiment). The body weight of the rats treated with S. sclarea for 30 days increased only up to 103.8% of their initial weight and was lower than in the control group. Addition of S. officinalis caused an increase in daily weight gain up to 253.1% of the control group, and S. sclarea – its decrease to 27.8% of the daily weight gain in the control group. In the S. officinalis group, the relative weight of the brain, spleen, and thymus decreased, while in the S. sclarea group, the relative weight of the thymus decreased and that of the colon increased. Under the influence of S. officinalis, the concentration of urea, total bilirubin, and triglycerides in the blood plasma of male rats decreased and the concentration of total protein and the activity of alkaline phosphatase increased. While consuming S. sclarea shoots, there was an increase of alkaline phosphatase activity in the rats’ blood, but atherogenic index (23.1% of the level of the control group) sharply dropped due to an increase in the concentration of high-density lipoprotein cholesterol (286.9% of the control) and a decrease in the concentration of low-density lipoprotein cholesterol (67.7% of control). In rats feeding on S. sclarea shoots, we observed a decrease in the concentration of triglycerides in the blood (39.9% of the control), a decrease in the activity of gamma-glutamyl transferase (62.8%), and an increase in the Ca/P ratio (132.5% of the control group). No significant changes were observed in CBC and WBC differential of male rats when eating S. officinalis and S. sclarea shoots. According to the results of the open field test, the physical and orientational activity of male rats under the influence of S. officinalis significantly decreased by the end of the experiment. Emotional status of rats, on the contrary, decreased when they ate dry crushed shoots of S. sclarea in the composition of the food. Thus, excess body weight of rats in the conditions of hypercaloric diet led to more pronounced deviations from the norm while consuming dry crushed shoots of S. officinalis. The addition of S. sclarea dry crushed shoots to the animals’ diet normalized the body weight in comparison with the control group, reduced the negative manifestations of obesity at the biochemical and organismal levels. In this regard, the substances that contains S. sclarea should be carefully studied for anti-atherosclerotic activity, and tea supplemented with S. sclarea shoots can be recommended as a corrective supplement in the diet of overweight people.

Inhibition of Protein Glycation by Combined Antioxidant and Antiglycation Constituents from a Phenolic Fraction of Sage (Salvia officinalis L.)

Disturbed advanced glycation end products (AGEs)-oxidative stress axis is strongly linked to vascular complications observed in diabetes and other metabolic conditions. Salvia officinalis L. (sage) is a medicinal plant used as an ingredient in foods and beverages and displays a wide range of biological and pharmacological activities including anti-diabetic effects. However, no study has assessed its anti-glycative potential. The aim of this study is to determine the phenolic compounds associated with the anti-glycation and antioxidant potential of sage methanol extract (SME). SME shows similar effects to aminoguanidine on fluorescent AGEs inhibition. It protects albumin damage from glycation (52.9 vs. 50.3%, respectively) by preventing the loss of protein thiol groups (50.0 vs. 44.3%, respectively) and by reducing protein carbonyl accumulation (67.4 vs. 70.5%, respectively). Moreover, linear regression and multivariate analysis support the efficient contribution of SME antioxidant capacity, as judged by DPPH, TBARS and iron chelating tests, in AGEs suppression. Furthermore, HPLC analysis revealed the presence of verbascoside as a novel phenolic constituent identified in sage leaves and suggests that the protective activity is mostly assigned to the presence of rosmarinic acid, resveratrol, quercetin, rutin and luteolin-7-O-glucoside. Likewise, the screening of SME phenolic content supports the contribution of various antioxidant substances to the observed effects. Therefore, a polyphenol enriched sage extract was able to inhibit the formation of AGEs and protein glycation. Our data unveils the promising properties of sage and its bioactive principles in the management of AGEs-mediated vascular complications observed in diabetes and other metabolic disorders.

Evaluation of in vitro α-amylase and α-glucosidase inhibitory potential and hemolytic effect of phenolic enriched fractions of the aerial part of Salvia officinalis L

BACKGROUND

The inhibition of α-amylase and α-glucosidase activities is one of the major practical strategies for the control of postprandial hyperglycemia. Salvia officinalis L. is known by its various bioactive compounds and its effective therapeutic properties towards illnesses including diabetes.

OBJECTIVE

The present study aimed to evaluate the in vitro inhibitory effect of S. officinalis on key digestive enzymes linked to type 2 diabetes and to identify its hemolytic effect.

METHODS

Hydro-methanol decoction extract and fractions of ethyl acetate and n-butanol were investigated for their in vitro α-amylase and α-glucosidase inhibitory activities, compared to acarbose as a standard. Furthermore, they were evaluated for their hemolytic effect.

RESULTS

Phytochemical composition demonstrated the richness of S. officinalis in secondary metabolites. Extract and fractions inhibited the activity of both enzymes. They showed weak hemolytic activity. Quantitative estimation of total phenolic and flavonoids revealed that ethyl acetate fraction contained the highest amount of these compounds (450.51 ± 0.6 μg GAE/mg DE and 352.01 ± 0.78 μg CE/mg of DE, respectively). It showed the best antidiabetic activity tested both by α-amylase and α-glucosidase assays (IC₅₀ = 46.52 ± 2.68 and 104.58 ± 0.06 μg/mL, respectively). Moreover, this fraction showed the least hemolytic effect (11.58 ± 0.1%).

CONCLUSIONS

S. officinalis extract and fractions are promising sources of α-amylase and α-glucosidase inhibitors.

Targeting obesity with plant-derived pancreatic lipase inhibitors: A comprehensive review

The prevalence of obesity is alarmingly increasing in the last few decades and leading to many serious public health concerns worldwide. The dysregulated lipid homeostasis due to various genetic, environmental and lifestyle factors is considered one of the critical putative pathways mediating obesity. Nonetheless, the scientific advancements unleashing the molecular dynamics of lipid metabolism have provided deeper insights on the emerging roles of lipid hydrolysing enzymes, including pancreatic lipase. It is hypothesized that inhibiting pancreatic lipase would prevent the breakdown of triglyceride and delays the absorption of fatty acids into the systemic circulation and adipocytes. Whilst, orlistat is the only conventional pancreatic lipase enzyme inhibitor available in clinics, identifying the safe clinical alternatives from plants to inhibit pancreatic lipase has been considered a significant advancement. Consequently, plants which have shown significant potential to combat obesity are now revisited for its abilities to inhibit pancreatic lipase. In this regard, our review surveyed the potential of medicinal plants and its phytoconstituents to inhibit pancreatic lipase and to elicit anti-obesity effects. Thus, the review collate and critically appraise the potential of medicinal plants and phyto-molecules inhibiting pancreatic lipase enzyme and consequently modulating triglyceride absorption in gut, and discuss its implications in the development of novel therapeutic strategies to combat obesity.

The protective effects of Salvia officinalis essential oil compared to simvastatin against hyperlipidemia, liver, and kidney injuries in mice submitted to a high-fat diet

The present study was undertaken to evaluate the effects of Salvia officinalis essential oil (SEO) and simvastatin in hyperlipidemic mice. Animals were randomly divided into four groups. The control group received a standard diet. The high-fat diet (HFD) group received HFD. The third and fourth groups received HFD associated either with simvastatin (2.5 mg/kg bw) or with SEO (4 mg/kg bw). All animals were sacrificed after 8 weeks of treatment. SEO and simvastatin reduced in HFD mice body weight gain, hyperlipidemia, disruption of liver and renal functions and reactive oxygen species production. In fact, total cholesterol, triglycerides, total lipids, and low-density lipoprotein cholesterol levels, as well as aspartate transaminase, alanine transaminase, gamma-glutamyltranspeptidase and lactate dehydrogenase activities were reduced, while fecal lipids increased compared to those of HFD mice. The lipid-lowering effect of SEO was more effective than that of simvastatin. PRACTICAL APPLICATIONS: High-fat diet provokes hyperlipidemia, atherosclerosis, and abnormal lipid metabolism leading to the development of hepatic and renal dysfunctions as well as perturbations of the antioxidant status in liver and kidney. The results of this research highlight the beneficial effects of SEO in the management of these disorders without inducing side effects; in fact, the plant essential oil decreased lipids and improved the antioxidant status more than did a synthetic drug.

Reduction of blood glucose by plant extracts and their use in the treatment of diabetes mellitus; discrepancies in effectiveness between animal and human studies

ETHNOPHARMACOLOGICAL RELEVANCE

The global problem of diabetes, together with the limited access of large numbers of patients to conventional antidiabetic medicines, continues to drive the search for new agents. Ancient Asian systems such as traditional Chinese medicine, Japanese Kampo medicine, and Indian Ayurvedic medicine, as well as African traditional medicine and many others have identified numerous plants reported anecdotally to treat diabetes; there are probably more than 800 such plants for which there is scientific evidence for their activity, mostly from studies using various models of diabetes in experimental animals.

AIM OF THE REVIEW

Rather than a comprehensive coverage of the literature, this article aims to identify discrepancies between findings in animal and human studies, and to highlight some of the problems in developing plant extract-based medicines that lower blood glucose in patients with diabetes, as well as to suggest potential ways forward.

METHODS

In addition to searching the 2018 PubMed literature using the terms 'extract AND blood glucose, a search of the whole literature was conducted using the terms 'plant extracts' AND 'blood glucose' AND 'diabetes' AND 'double blind' with 'clinical trials' as a filter. A third search using PubMed and Medline was undertaken for systematic reviews and meta-analyses investigating the effects of plant extracts on blood glucose/glycosylated haemoglobin in patients with relevant metabolic pathologies.

FINDINGS

Despite numerous animal studies demonstrating the effects of plant extracts on blood glucose, few randomised, double-blind, placebo-controlled trials have been conducted to confirm efficacy in treating humans with diabetes; there have been only a small number of systematic reviews with meta-analyses of clinical studies. Qualitative and quantitative discrepancies between animal and human clinical studies in some cases were marked; the factors contributing to this included variations in the products among different studies, the doses used, differences between animal models and the human disease, and the impact of concomitant therapy in patients, as well as differences in the duration of treatment, and the fact that treatment in animals may begin before or very soon after the induction of diabetes.

CONCLUSION

The potential afforded by natural products has not yet been realised in the context of treating diabetes mellitus. A systematic, coordinated, international effort is required to achieve the goal of providing anti-diabetic treatments derived from medicinal plants.

Moringa oleifera leaf extract ameliorated high-fat diet-induced obesity, oxidative stress and disrupted metabolic hormones

Background

Obesity is a health problem in many countries, and maintaining a perfect weight is challenging. Moringa oleifera leaf extract (ME) is rich in polyphenols with antioxidant and pharmaceutical potential. The present study investigated the potential protective effect of Moringa oleifera leaf extract against obesity induced from a high-fat diet (HFD), oxidative stress and disruption of metabolic hormones compared to simvastatin (SIM) or their combination.

Results

Rats fed a HFD for 6 weeks exhibited a significant increase in body weight and levels of serum glucose and lipid fractions, verifying an obesity state. There were also higher levels of insulin and leptin and lower gherlin in sera of HFD rats compared to the levels in control rats. Homeostasis model assessment for insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and the atherogenic index were elevated, indicating the development of insulin resistance and dyslipidaemia in these rats. These changes were accompanied with a significant increase in oxidative stress, as indicated by elevated lipid peroxidation and protein oxidation with low levels of antioxidants in liver. The activities of liver function enzymes, including aspartate amino transferase, alanine amino transferase, alkaline phosphatase and gamma glutamyltransferase, were also significantly increased in serum. Concurrent treatment with 300 mg/kg ME for 6 weeks ameliorated the increase in body weight and improved the levels of glucose, lipid fractions and metabolic hormones, indicating the anti-obesity effect and amelioration of tissue insulin resistance potential of ME. ME treatment also normalized oxidative stress and antioxidants in liver and improved liver function enzymes, indicating the antioxidant potential of ME. The effects of ME were similar to SIM, and the combination of these agents was better than each agent alone.

Conclusion

We propose that ME extract has anti-obesity and antioxidant potential and may be used as a lipid-lowering drug to control weight, obesity and its pathophysiological consequences.

Hypoglycemic and hypolipidemic activity of aqueous leaf extract of Passiflora suberosa L

Leaves of Passiflora suberosa L. (Family: Passifloraceae; common name: wild passion fruit, devil's pumpkin) are used in Sri Lankan traditional medicine for treating diabetes. The present study investigated the in vivo ability of P. suberosa leaves to manage blood sugar status and associated cholesterol levels. Mechanisms of action and toxicity were also determined. Phytochemical screening of aqueous extracts of P. suberosa leaves and carbohydrate content of the leaves were determined according to previously published methods. In two group of male mice (n = 9), effects on fasting and random blood glucose levels (BGLs) of different acute doses (0, 25, 50, 100 and 200 mg/kg) of the aqueous leaf extract (ALE) were evaluated at 1, 3, and 5 h post-treatment. In another set of mice, the fasting BGL was evaluated following treatment of 0 or 50 mg/kg ALE (dose prescribed in traditional medicine) for 30 consecutive days. The lipid profile, some mechanism of ALE action (diaphragm glucose uptake, glycogen content in the liver and skeletal muscles) and its toxicity (behavioural observation, food and water intake, hepatoxicity) were also assessed following 30-day treatment. However, sucrose and glucose tolerance tests and intestinal glucose uptake were conducted to determine portion of mechanisms of action following single dose of 50 mg/kg ALE. Phytochemical screening revealed the presence of alkaloids, unsaturated sterols, triterpenes, saponins, flavonoids, tannins and proanthocyanidins. Carbohydrate content of the leaves was 12.97%. The maximum hypoglycemic effect was observed after 4 h of 50 and 100 mg/kg ALE administration. The extract decreased fasting BGL (18%) following an oral sucrose challenge and inhibited (79%) glucose absorption from the intestine. Correspondingly, the levels of glycogen in the liver (61%) and in the skeletal muscles (57%) were found be higher than that of the control group. The levels of total cholesterol (17%) and tri-glyceraldehyde levels (12%) found to be reduced in treated groups. Furthermore, no significant toxic effects were observed in treated groups. The present results suggest that the leaves of P. suberosa can be used to manage blood glucose and cholesterol levels. Isolation of active compounds are recommended for further analysis.