Obesity is recognized as a major life style disorder especially in developing countries and it is prevailing at an alarming speed in new world countries due to fast food intake, industrialization, and reduction of physical activity. Furthermore, it is associated with a vast number of chronic diseases and disabilities. To date, relatively effective drugs, from either natural or synthetic sources, are generally associated with serious side effects, often leading to cessation of clinical trials or even withdrawal from the market. In order to find new compounds which are more effective or with less adverse effects compared to orlistat, the drug that has been approved for obesity, new compounds isolated from natural products are being identified and screened for antiobesity effects, in particular, for their pancreatic lipase inhibitory effect. Pancreatic lipase inhibitory activity has been extensively used for the determination of potential efficacy of natural products as antiobesity agents. In attempts to identify natural products for overcoming obesity, more researches have been focused on the identification of newer pancreatic lipase inhibitors with less unpleasant adverse effects. In this review, we consider the potential role of plants that have been investigated for their pancreatic lipase inhibitory activity.
Colorectal cancer (CRC) is the third most common type of cancer in the world, causing thousands of deaths annually. Although chemotherapy is known to be an effective treatment to combat colon cancer, it produces severe side effects. Natural products, on the other hand, appear to generate fewer side effects than do chemotherapeutic drugs. Flavonoids are polyphenolic compounds found in various fruits and vegetables known to possess antioxidant activities, and the literature shows that several of these flavonoids have anti-CRC propertiesFlavonoids are classified into five main subclasses: flavonols, flavanones, flavones, flavan-3-ols, and flavanonols. Of these subclasses, the flavanonols have a minimum effect against CRC, whereas the flavones play an important role. The main targets for the inhibitory effect of flavonoids on CRC signaling pathways are caspase; nuclear factor kappa B; mitogen-activated protein kinase/p38; matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9; p53; β-catenin; cyclin-dependent kinase (CDK)2 and CDK4; and cyclins A, B, D, and E.In this review article, we summarize the in vitro and in vivo studies that have been performed since 2000 on the anti-CRC properties of flavonoids. We also describe the signaling pathways affected by flavonoids that have been found to be involved in CRC. Some flavonoids have the potential to be an effective alternative to chemotherapeutic drugs in the treatment of colon cancer; well-controlled clinical studies should, however, be conducted to support this proposal.
The present study investigated the antiobesity and lipid lowering effects of an ethanolic extract of leaves obtained from (200 and 400 mg/kg) and its major compound (rosmarinic acid, 10 mg/kg) in obese mice (C57BL/6) induced by a high-fat diet. Continuous supplementation with extract (200 and 400 mg/kg) for 8 weeks significantly decreased body weight gain (p < 0.05). However, supplementation with rosmarinic acid, a constituent in the extract, produced only a slight reduction in body weight gain compared to the high-fat diet control group. Food intake between the treatment and the high-fat diet groups was similar, which suggested that the plant extract did not suppress food intake. Further, body weight reduction of the treatment groups was not due to a decreased reduction in energy intake. Compared to the high-fat diet-fed group, serum triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels were significantly reduced in the treated groups, while high-density lipoprotein cholesterol levels were not significantly altered. Accumulation of hepatic lipid droplets induced by a high-fat diet was markedly inhibited by extract. In addition, significantly diminished liver malondialdehyde production, and significantly elevated the activities of hepatic superoxidase dismutase. The present study showed that an ethanolic extract prepared from the leaves of can significantly reduce a gain in body weight, enhance antioxidant activity, and possess hypolipidemic and antiobesity effects, thereby protecting against the adverse effects of high-fat diet-induced obesity.
Background: Khat (Catha edulis) is a plant that is deeply rooted in the cultural life of East African and Southwestern Arabian populations. Prevalent traditional beliefs about khat are that the plant has an effect on appetite and body weight. Summary: This review assesses the accumulated evidences on the mutual influence of monoamines, hormones and neuropeptides that are linked to obesity. A few anti-obesity drugs that exert their mechanisms of action through monoamines are briefly discussed to support the notion of monoamines being a critical target of drug discovery for new anti-obesity drugs. Subsequently, the review provides a comprehensive overview of central dopamine and serotonin changes that are associated with the use of khat or its alkaloids. Then, all the studies on khat that describe physical, biochemical and hormonal changes are summarised and discussed in depth. Conclusion: The reviewed studies provide relatively acceptable evidence that different khat extracts or cathinone produces changes in terms of weight, fat mass, appetite, lipid biochemistry and hormonal levels. These changes are more pronounced at higher doses and long durations of intervention. The most suggested mechanism of these changes is the central action that produces changes in the physiology of dopamine and serotonin. Nonetheless, there are a number of variations in the study design, including species, doses and durations of intervention, which makes it difficult to arrive at a final conclusion about khat regarding obesity, and further studies are necessary in the future to overcome these limitations.
Non-alcoholic fatty liver disease (NAFLD) is the most prevalent form of liver disease. Orthosiphon aristatus (Blume) Miq, a traditional plant in South Asia, has previously been shown to attenuate obesity and hyperglycaemic conditions. Eight weeks of feeding C57BL/6 mice with the standardized O. aristatus extract (400 mg/kg) inhibited the progression of NAFLD. Liver enzymes including alanine aminotransferase and aspartate transaminase were significantly reduced in treated mice by 74.2% ± 7.69 and 52.8% ± 7.83, respectively. Furthermore, the treated mice showed a reduction in serum levels of glucose (50% ± 5.71), insulin (70.2% ± 12.09), total cholesterol (27.5% ± 15.93), triglycerides (63.2% ± 16.5), low-density lipoprotein (62.5% ± 4.93) and atherogenic risk index relative to the negative control. Histologically, O. aristatus reversed hepatic fat accumulation and reduced NAFLD severity. Notably, our results showed the antioxidant activity of O. aristatus via increased superoxide dismutase activity and a reduction of hepatic malondialdehyde levels. In addition, the levels of serum pro-inflammatory mediators (IL-6 and TNFα) decreased, indicating anti-inflammatory activity. The aqueous, hydroethanolic and ethanolic fractions of O. aristatus extract significantly reduced intracellular fat accumulation in HepG2 cells that were treated with palmitic–oleic acid. Together, these findings suggest that antioxidant activities are the primary mechanism of action of O. aristatus underlying the anti-NAFLD effects.
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