An aqueous extract of Salacia oblonga root, a herb-derived peroxisome proliferator-activated receptor-alpha activator, by oral gavage over 28 days induces gender-dependent hepatic hypertrophy in rats

Adipose and non-adipose perspectives of plant derived natural compounds for mitigation of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Phyto-preparations and phyto-compounds, by their natural origin, easy availability, cost-effectiveness, and fruitful traditional uses based on accumulated experiences, have been extensively explored to mitigate the global burden of obesity.

AIM OF THIS REVIEW

The review aimed to analyse and critically summarize the prospect of future anti-obesity drug leads from the extant array of phytochemicals for mitigation of obesity, using adipose related targets (adipocyte formation, lipid metabolism, and thermogenesis) and non-adipose targets (hepatic lipid metabolism, appetite, satiety, and pancreatic lipase activity). Phytochemicals as inhibitors of adipocyte differentiation, modulators of lipid metabolism, and thermogenic activators of adipocytes are specifically discussed with their non-adipose anti-obesogenic targets.

MATERIALS AND METHODS

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. The taxonomically accepted name of each plant in this review has been vetted from "The Plant List" (www.theplantlist.org) or MPNS (http://mpns.kew.org).

RESULTS

Available knowledge of a large number of phytochemicals, across a range of adipose and non-adipose targets, has been critically analysed and delineated by graphical and tabular depictions, towards mitigation of obesity. Neuro-endocrinal modulation in non-adipose targets brought into sharp dual focus, both non-adipose and adipose targets as the future of anti-obesity research. Numerous phytochemicals (Berberine, Xanthohumol, Ursolic acid, Guggulsterone, Tannic acid, etc.) have been found to be effectively reducing weight through lowered adipocyte formation, increased lipolysis, decreased lipogenesis, and enhanced thermogenesis. They have been affirmed as potential anti-obesity drugs of future because of their effectiveness yet having no threat to adipose or systemic insulin sensitivity.

CONCLUSION

Due to high molecular diversity and a greater ratio of benefit to risk, plant derived compounds hold high therapeutic potential to tackle obesity and associated risks. This review has been able to generate fresh perspectives on the anti-diabetic/anti-hyperglycemic/anti-obesity effect of phytochemicals. It has also brought into the focus that many phytochemicals demonstrating in vitro anti-obesogenic effects are yet to undergo in vivo investigation which could lead to potential phyto-molecules for dedicated anti-obesity action.

Salacia chinensis exerts its antidiabetic effect by modulating glucose-regulated proteins and transcription factors in high-fat diet fed-streptozotocin-induced type 2 diabetic rats

This study aimed to investigate the properties of Salacia chinensis (Celastraceae, SC) and its molecular mechanism in the type 2 diabetic rats. Forty-two Wistar rats were divided into six groups (n = 7): control, SC (100 mg/kg, per os), high-fat diet (HFD), HFD + SC (100 mg/kg), HFD + streptozotocin (STZ, 40 mg/kg, i.p.), and HFD + STZ+SC. SC decreased serum glucose, insulin, triglycerides, free fatty acid, and malondialdehyde levels, but increased serum total antioxidant capacity (0.33 ± 0.02 versus. 0.79 ± 0.03), compared with the untreated group (p < .001). Additionally, SC elevated the expression of glucose-regulated proteins GLUT2, PPAR-ɣ, p-IRS, and Nrf2, but downregulated NF-κB in the liver and kidney (p < .001). In conclusion, SC could improve insulin resistance by modulation of glucose-regulated proteins and transcription factors in diabetic rats. PRACTICAL APPLICATIONS: Present data has contributed to the current ethnomedicinal benefits of SC, through which the SC intake regulated the carbohydrate metabolism and increased the antioxidant capacity. The balance of transcription factors can mediate these efficacies partially and various key proteins involved in energy metabolism, along with oxidative stress and insulin sensitivity.

In Vitro Antioxidant Properties of Dichloromethanolic Leaf Extract of Gnidia glauca (Fresen) as a Promising Antiobesity Drug

The acquisition of ethnobotanical information from traditional practitioners remains an empirical aspect of understanding the ethnopharmacology research. However, integration of information on chemical composition of plant extracts and their pharmacological activities forms a key resource for synthesis of new and effective therapeutics. In traditional African medicine, Gnidia glauca has folkloric remedies against obesity and its associated oxidative stress-mediated complications. However, the upsurge in its use has not been accompanied with scientific validations to support these claims. The present study aimed to determine the antioxidant potential of G glauca as a promising antiobesity agent. The antioxidant effects of the extract were assessed against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, hydrogen peroxide, nitric oxide, and superoxide radicals as well as lipid peroxidation, iron-chelating effect, and ferric-reducing power. Phytochemical analysis was conducted using gas chromatography linked to mass spectrophotometry. The results revealed that G glauca exhibited scavenging activities against all radicals formed. Besides, the extract showed iron chelation and ferric reducing abilities. The extract indicated a lower half maximal inhibitory concentration value than the standards used. For instance, the extract inhibited 50% of the formation of 2,2-diphenyl-1-picrylhydrazine at the concentration of 1.33 ± 0.03 mg/mL relative to 1.39 ± 0.06 mg/mL of the standard, vitamin C at 1% confidence limit. Similarly, the extract scavenged 50% of hydroxyl radical at 204.34 ± 10.64 μg/mL relative to 210.05 ± 8.80 μg/mL of gallic acid. The extract also contained various phytochemicals that have been associated with antiobesity effects. The synergistic effects of these phytocompounds increase their bioavailability and action on multiple molecular targets thereby correcting obesity-induced oxidative stress.

An Updated Review on the Phytochemistry, Pharmacology, and Clinical Trials of Salacia oblonga

Salacia oblonga (S. oblonga), a perennial herb, has been used for thousands of years in ayurvedic medicine and is closely associated with prevention, treatment, and cure of various human ailments such as obesity and diabetes. A vast and wide range of chemical compounds such as polyphenols, friedelane-type triterpenes, norfriedelane-type triterpenes, eudesmane-type sesquiterpenes including various glycosides had been isolated from this plant. This review is aimed to survey the literature covering the phytochemistry and pharmacology of S. oblonga and to review the scientific data including active components and their multi-targeted mechanisms of action against various metabolic syndromes. We also included clinical trials related to this plant in this review. The overview would assist researchers to gather scientific information related to S. oblonga in future.

A review on possible therapeutic targets to contain obesity: The role of phytochemicals

The prevalence and severity of obesity has increased markedly in recent decades making it a global public health concern. Since obesity is a potential risk factor in the development of hypertension, type-2 diabetes, cardiovascular diseases, infertility, etc., it is no more viewed as a cosmetic issue. Currently, only a few FDA-approved anti-obesity drugs like Orlistat, Lorcaserin and Phentermine-topiramate are available in the market, but they have considerable side effects. On the other hand, bariatric surgery as an alternative is associated with high risk and expensive. In view of these there is a growing trend towards natural product-based drug intervention as one of the crucial strategies for management of obesity and related ailments. In Asian traditional medicine and Ayurvedic literature a good number of plant species have been used and quoted for possible lipid-lowering and anti-obesity effects; however, many of them have not been evaluated rigorously for a definite recommendation and also lack adequate scientific validation. This review explores and updates on various plant species, their used parts, bioactive components and focuses multiple targets/pathways to contain obesity which may pave the way to develop novel and effective drugs. We also summarised different drugs in use to treat obesity and their current status. Nature is future promise of our wellbeing.

Anti-diabetic and Anti-hyperlipidemic Effects and Safety of Salacia reticulata and Related Species

Extracts of Salacia reticulata Wight (Hypocrataceae) roots, stems, and leaves have been used in Asia for hundreds of years for the folkloric treatment of diabetes and other health problems. Constituents that have been identified as exhibiting anti-diabetic effects include salacinol, kotalanol, ponkorinol, salaprinol, and their corresponding de-0-sulfonated compounds. Mangiferin, kotalagenin 16-acetate and various proanthocyanidin oligomers have also been isolated. Studies indicate that Salacia extracts modulate multiple targets that influence carbohydrate and lipid metabolism including α-glucosidase, aldose reductase, pancreatic lipase, peroxisomal proliferator-activated receptor-α, glucose transporter-4 mediated glucose uptake, and angiotensin II type 1 receptor. Furthermore, Salacia extracts exhibit free radical scavenging, antioxidant and hepatoprotectant activities. In human studies, Salacia extracts have been shown to decrease plasma glucose and insulin levels, decrease HbA1c, and modulate serum lipid levels with no adverse effects being reported. Similar results have been demonstrated in rat and mouse models as well as in vitro systems. Safety of S. reticulata and other Salacia species as S. oblonga and S. chinensis in rats and mice indicate that extracts are exceedingly safe. No clinical studies have examined the effects of Salacia extracts on human weight loss, although weight loss and decreases in weight gain have been demonstrated in animal models. Because of the large number of pharmacologically active compounds, it is difficult to establish standards for extracts.

Modulation of hepatic sterol regulatory element-binding protein-1c-mediated gene expression contributes to Salacia oblonga root-elicited improvement of fructose-induced fatty liver in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Salacia oblonga root (SOR) is a traditionally herbal medicine for obesity and diabetes, which are closely associated with fatty liver. To investigate the molecular mechanisms of SOR in the treatment of dietary-induced fatty liver.

MATERIALS AND METHODS

Male rats were co-administered with fructose in drinking water and vehicle or the aqueous-ethanolic extract of SOR (by gavage, once daily) for 10 weeks. Biochemical variables were determined enzymatically or by ELISA. Gene expression was analyzed by Real-Time PCR and/or Western blot.

RESULTS

SOR treatment (20mg/kg) diminished fructose-induced fatty liver indicated by decreases in excess triglyceride accumulation and the increased vacuolization and Oil Red O staining area in the livers of rats. Importantly, Hepatic gene expression profile revealed that SOR suppressed fructose-stimulated overexpression of sterol regulatory element-binding protein (SREBP)-1/1c mRNA and nuclear protein. In accord, overexpression of SREBP-1c-responsive genes, such as fatty acid synthase, acetyl-CoA carboxylase-1 and stearoyl-CoA desaturase-1, was also downregulated. In contrast, overexpressed nuclear protein of carbohydrate response element binding protein and mRNA of its target gene liver pyruvate kinase were not altered. Additionally, SOR also did not affect expression of peroxisome proliferator-activated receptor-gamma- and -alpha, as well as their target genes, such as carnitine palmitoyltransferase-1a, acyl-CoA oxidase and CD36.

CONCLUSIONS

These results suggest that modulation of hepatic sterol regulatory element-binding protein-1c-mediated gene expression contributes to SOR-elicited improvement of fructose-induced fatty liver in rats. Our findings provide a better understanding of SOR in the treatment of obesity and diabetes.

Screening of polyphenolic plant extracts for anti-obesity properties in Wistar rats

BACKGROUND

Polyphenols have been reported to prevent chronic diseases such as cardiovascular diseases, cancers, diabetes and neurodegenerative diseases. The objective of the study was to conduct a screening for potential anti-obesity polyphenolic plant extracts using a diet-induced animal model. Rats were fed a high-fat-sucrose (HFS) diet with or without supplementation of different polyphenolic plant extracts (almond, apple, cinnamon, orange blossom, hamamelis, lime blossom, grape vine, and birch) for 56-64 days.

RESULTS

Body weight gain was lower in rats supplemented with apple, cinnamon, hamamelis and birch extracts as compared to HFS non-supplemented group. Moreover, apple and cinnamon extracts prevented the increase in fat mass promoted by the HFS diet. Insulin resistance, estimated by the homostatic model assessment-insulin resistance (HOMA-IR) index, was reduced in rats fed apple, cinnamon, hamamelis and birch extracts. Apple extract also prevented the HFS-induced hyperglycaemia and hyperleptinaemia.

CONCLUSION

Only apple and cinnamon extracts were finally considered as potentially important anti-obesogenic extracts, due to their body fat-lowering effects, while the improvement of obesity-related metabolic complications by apple polyphenols highlights this extract as a promising functional food ingredient for the management of obesity and its metabolic complications.

Salacia oblonga ameliorates hypertriglyceridemia and excessive ectopic fat accumulation in laying hens

ETHNOPHARMACOLOGICAL RELEVANCE

Salacia oblonga root (SOR) is an Ayurvedic medicine for obesity and diabetes, those are associated with glucose and lipid metabolism.

AIM OF THE STUDY

SOR has been demonstrated previously to improve glucose and lipid metabolism in animal models of obesity and diabetes and to be a peroxisome proliferator-activated receptor-alpha activator. However, the anti-obesogenic and anti-diabetic mechanisms of SOR are still not largely understood. Here, we investigated the effects of SOR on lipid metabolism using laying hen, a unique animal model with a very high rate of triglyceride synthesis in the liver.

MATERIALS AND METHODS

Laying hens and preadolescent pullets were treated with the layer ration containing 0%, 0.5%, or 1% SOR water extract for 4 weeks. Biochemical variables were determined enzymatically.

RESULTS

Laying hens showed much higher fasted triglyceride concentrations (increased by 5-13 folds) in plasma, liver, skeletal muscle and heart than pullets. 1% SOR extract treatment inhibited body weight increase without affecting food intake. Importantly, this treatment substantially attenuated hypertriglyceridemia and inhibited increases in triglyceride contents in the non-adipose tissues. However, SOR extract did not induce change in plasma glucose concentration. Moreover, SOR extract did not alter all variables in pullets.

CONCLUSIONS

These results demonstrate that SOR ameliorates hypertriglyceridemia and excessive ectopic fat accumulation in laying hens. These findings suggest that the triglyceride-lowering property is one of the primary effects of SOR, possibly via hepatic mechanisms.

Effects of Lycium barbarum aqueous and ethanol extracts on high-fat-diet induced oxidative stress in rat liver tissue

This study evaluated the protective effects of aqueous extract of Lycium barbarum (LBAE) and ethanol extract of Lycium barbarum (LBEE) on blood lipid levels, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activities and liver tissue antioxidant enzyme activities in rats fed a high fat diet (HF). The rats were randomly divided into seven groups of ten rats each and fed a different diet for eight weeks as follows: One group (NC group) was fed a standard diet, one group was fed a high-fat diet (HF group), one group was fed a high-fat diet and orally fed with 20 mg/kg b.w. simvastatin (HF + simvastatin group), and the other group was fed the high fat diet and orally fed with 50 mg/kg b.w. or 100 mg/kg b.w. LBAE (HF + LBAE), or 50 mg/kg b.w. or 100 mg/kg b.w. LBEE (HF + LBEE), respectively. After eight weeks, the HF diet caused deleterious metabolic effects. Rats fed the HF diet alone showed increased hepatocellular enzyme activities in plasma, a significant decline in antioxidant enzyme activities, and elevated liver lipid peroxidation indices. LBAE and LBEE administration significantly reduced liver damage and oxidative changes, and brought back the antioxidants and lipids towards normal levels. These data suggest that these antioxidants protect against toxicity parameters in HF rats.

Nephroprotective and antioxidant activities of Salacia oblonga on acetaminophen-induced toxicity in rats

Salacia oblonga, a woody climbing plant belonging to the family Celastaceae, is widely distributed in India and other southeast Asian countries. The genus Salacia have been used particularly for the treatment of diabetes, obesity, gonorrhoea, rheumatism, pruritus and asthma. Acetaminophen (APAP), used as an analgesic drug, produces liver and kidney necrosis in mammals at high doses. The aim of this study was to investigate the nephroprotective and antioxidant activities of the ethanol extract of Salacia oblonga (EESO) at the two dose levels of 250 and 500 mg/kg bw on APAP-induced toxicity in rats. The results showed that APAP significantly increases the levels of serum urea, creatinine, and reduces levels of uric acid concentration. The EESO reduces these by increasing anti-oxidative responses as assessed by biochemical and histopathological parameters. In conclusion, our results suggest that the EESO possesses nephroprotective and antioxidant effects against APAP-induced nephrotoxicity in rats.

Sex differences in nuclear receptor-regulated liver metabolic pathways

Liver metabolism is markedly sex-dimorphic; accordingly, the prevalence of liver diseases is different between sexes. The superfamily of nuclear receptors (NRs) governs the proper expression of key liver metabolism genes by sensing lipid-soluble hormones and dietary lipids. When the expression of those genes is deregulated, disease development is favored. However, we lack a comprehensive picture of the differences between NR actions in males and females. Here, we reviewed explorative studies that assessed NR functions in both sexes, and we propose a first map of sex-dimorphic NR expression in the liver. Our analysis suggested that NRs in the female liver exhibited cross-talk with more liver-protective potential than NRs in male liver. This study provides empirical support to the hypothesis that women are more resilient to some liver diseases than men, based on a more compensative NR network. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.

Co-medications that modulate liver injury and repair influence clinical outcome of acetaminophen-associated liver injury

BACKGROUND & AIMS

Acetaminophen-induced liver injury is the most common cause of acute liver failure in the United States; it occurs inadvertently in approximately half of all cases. Concomitant use of other medications might impact susceptibility to acetaminophen hepatotoxicity. We investigated its association with administration of drugs that have been shown to modulate liver injury and/or repair in preclinical studies.

METHODS

We analyzed data from 6386 cases of acetaminophen-associated liver injury that were defined in the FDA database of reported adverse events. Data reported in the severe adverse event categories of "died" or "life-threatening" (defined as "fatal" cases, n = 2512) were compared with those of "non-fatal" cases (n = 3874). Potential associations between fatality and concomitant use of 9 drug classes were assessed using multiple logistic regression analyses after adjusting for other variables.

RESULTS

Among female subjects, concomitant use of statins, fibrates or nonsteroidal anti-inflammatory drugs was associated with decreased likelihood of fatality, whereas ethanol use was associated with increased likelihood. Among male subjects, concomitant use of statins was associated with decreased likelihood of fatality, whereas concomitant use of sympathetic stimulants or ethanol was associated with increased likelihood. Concomitant use of angiotensin converting enzyme inhibitors or angiotensin receptor II antagonists was associated with decreased likelihood of fatality among younger subjects.

CONCLUSIONS

Concomitant use of medications that have been shown in preclinical studies to modulate liver injury and/or repair influenced acetaminophen hepatotoxicity. Drugs that reduce injury or increase repair are protective, whereas those that exacerbate injury or reduce repair are detrimental.

Sulfonium-ion glycosidase inhibitors isolated from Salacia species used in traditional medicine, and related compounds

A novel class of naturally-occurring glycosidase inhibitors, having sulfonium sulfate structures, has been isolated as bioactive components from Indian plants, belonging to the Salacia genus in the family Celastraceae, and used in Ayurvedic medicine for the treatment of type-2 diabetes. Thus far, five such sulfonium salts, namely, salacinol, kotalanol, salaprinol, ponkoranol and de-O-sulfonated kotalanol, have been isolated from this plant species. These structurally unique zwitterionic glycosidase inhibitors have received much attention due to their therapeutic potential in the treatment of type-2 diabetes. We recently reported a review article which focused mainly on salacinol and related analogues. The present review presents an update on the remaining four compounds from this class of glycosidase inhibitors, with respect to their isolation, glucosidase inhibitory activities, and synthesis. In addition, progress towards the stereochemical structure elucidation of kotalanol, through synthesis of analogues, is described. Review with 42 references.