Table 3.
Overview of studies reporting on the ameliorative effect of tea and fruits-rich in gallic acid against obesity-associated complications.
| Author, Year | Experimental Model, Dose Used, and Intervention Period | Comparative/Combination Therapy | Experimental Outcome and Proposed Mechanism |
|---|---|---|---|
| Ikeda et al., 2005 [15] | High fat diet fed male Sprague Dawley rats treated with tea catechins or heat-treated catechins extracts, which are rich in epigallocatechin gallate and epicatechin gallate at 1% in diet and fed for 23 days | None | Tea and the extracts markedly reduced visceral fat deposition and hepatic triglyceride levels. The activities of fatty acid synthase and malic enzyme were also decreased |
| Amin and Nagy, 2009 [119] | High fat diet fed male albino rats treated with herbal mixture extract rich in gallic acid at 790 mg/kg body weight for 4 weeks | l-carnitine was used at 250 mg/kg body weight for 4 weeks | The extract and carnitine improved disturbed lipid profile, defective antioxidant stability, and high values of insulin resistance parameters |
| Hogan et al., 2010 [120] | High fat diet fed male C57BLK/6J mice treated with Norton grape pomace extract rich in garlic acid at 2.4 g/kg of feed in order to dose each mouse at approximately 250 mg GPE/kg body weight for 12 weeks | None | The extract lowered plasma C-reactive protein levels. However, the extract did not improve oxidative stress as determined by plasma Oxygen Radical Absorbance Capacity (ORAC) assay, glutathione peroxidase, and liver lipid peroxidation |
| Cao et al., 2011 [121] | High fat diet fed male Sprague-Dawley rats treated with Pu-erh tea extract at 0.5 g, 2 g and 4 g/kg body weight for 8 weeks | None | The extract significantly lowered plasma total cholesterol, triglyceride concentrations and low-density lipoprotein-cholesterol levels. It further enhanced mRNA levels of hormone-sensitive lipase |
| Chang et al., 2011 [102] | In vitro molecular docking screening of traditional Chinese medicine, rich in gallic acid, for inhibition of fat mass and obesity-associated protein activity | (S)-tryptophan-betaxanthin, 3-methoxytyramine-betaxanthin, 4-O-methylgallic acid, syringic acid, ethacrynic acid, ferulic acid, caffeic acid, canavanine, and 3-methylthymidine | Gallic acid, together with (S)-tryptophan-betaxanthin, 3-methoxytyramine-betaxanthin and 4-O-methylgallic acid were among the leading compounds shown to inhibit fat mass and obesity-associated protein activity |
| Koh et al., 2011 [122] | High fat diet fed male Sprague Dawley rats treated with Chinese sweet leaf tea (Rubus suavissimus), rich in gallic acid, at 0.22 g/kg body weight for 9 weeks | None | Significantly reduced body weight gain and abdominal fat gain. Although food intake was not affected, blood glucose was lowered, serum triglycerides and cholesterol were significantly reduced |
| Peng et al., 2011 [123] | High fat diet fed male Syrian golden hamsters treated with mulberry water extracts, rich in gallic acid, at 0.5%, 1% and 2% of extract supplemented in diet for 12 weeks | None | The extracts lowered body weight and visceral fat, accompanied with hypolipidemic effects by reducing serum triacylglycerol, cholesterol, free fatty acid, and the low-density lipoprotein/high-density lipoprotein ratio |
| Makihara et al., 2012 [98] | Type 2 diabetic obese male TSOD mice treated with a hot water extract of Terminalia bellirica, rich in gallic acid, at 1% and 3% supplemented in diet for 8 weeks | None | The extract displayed preventive effect on obesity, insulin resistance, and hyperlipidemia. It suppressed absorption of triacylglycerol in an olive oil loading test (in vivo test) |
| In vitro pancreatic lipase activity inhibitory assay | Demonstrated inhibitory effect on pancreatic lipase activity | ||
| Yuda et al., 2012 [99] | In vitro pancreatic lipase inhibitory assay for black tea (Camellia sinensis) extracts rich in gallic acid | Theaflavin 3-O-gallate, theaflavin 3’-O-gallate, theaflavin 3,3’-O-gallate, epigallocatechin gallate, and epicatechin gallate | All extracts inhibited pancreatic lipase but extracts obtained at 100 to 140 °C showed the greatest lipase inhibition (IC50s of 0.9 to 1.3 μg/mL) |
| Esposito et al., 2015 [11] | High fat diet fed male C57BL/6J mice treated blackcurrant (Ribes nigrum L), rich in gallic acid, at 1% supplemented diet for 8 weeks | None | The extract reduced body weight gain and improved glucose metabolism |
| Monika and Geetha, 2015 [124] | High fat diet fed male Sprague Dawley rats treated with hydro-alcoholic fruit extract of avocado, rich in gallic acid, at 100 mg/kg body weight for 11 weeks | None | The extract reduced body mass index, adiposity index, total fat pad mass, blood cholesterol, triglycerides, and low-density lipoprotein. In addition, mRNA expression levels of fatty acid synthase, lipoprotein lipase, and leptin in adipose tissue was reduced |
| Colantuono et al., 2016 [125] | In vitro α-glucosidase, α-amylase and lipase inhibitory assays to assess pomegranate peels enriched cookies containing high levels of gallic acid and its derivatives | None | Showed inhibitory activity against α-glucosidase, α-amylase and α-lipase activities |
| De Camargo et al., 2016 [126] | In vitro antioxidant assays, as well as α-glucosidase and lipase inhibitory activities for phenolics from winemaking by-products rich in gallic acid | None | In addition to strong antioxidant potential, extracts showed inhibition of α-glucosidase and lipase activities |
| Park et al., 2016 [127] | High fat diet fed male C57BL/6 mice treated with an aqueous ethanol extraction of black tea, rich in gallic acid, at 100 and 300 mg/kg body weight for 8 weeks. 3T3-L1 adipocytes were exposed to 100 and 300 µg/mL during differentiation | None | Reduced body weight and body fat, improved fatty liver, regulated blood glucose, and decreased blood cholesterol. However, it did not have an effect on PPARγ protein expression |
| Septembre-Malaterre et al., 2016 [128] | 3T3-L1 pre-adipocytes treated with pineapple and mango extracts, rich in garlic acid, at 25 µM for 1 h | None | Inhibited hydrogen peroxide induced production of reactive oxygen species |
| Torabi and DiMarco, 2016 [129] | 3T3-F442A pre-adipocytes treated with grape powder extract, rich in gallic acid, at 125–500 mg GP/mL during differentiation period | None | The extract dose dependently induced adipocyte differentiation via upregulation of glucose transported (GLUT) 4, phosphatidylinositol-4,5- bisphosphate 3-kinase (PI3K) and adipogenic genes |
| Pascual-Serrano et al., 2017 [130] | High fat diet fed male Wistar rats treated with grape seed proanthocyanidin, rich in gallic acid, at 25 mg GSPE/kg body weight for 3 weeks | Gallic acid was used at 7 mg gallic acid/kg body weight for 3 weeks | Treatments did not reduce weight gain or reverse adiposity. However, the extract induced antihypertrophic and hyperplasic activities in white adipose tissue through enhancing perilipin-1 and fatty acid binding protein 4 expression and restoring adiponectin |
| Simao et al., 2017 [131] | In vitro α-amylase, α-glycosidase, lipase, and trypsin enzymes assays on aqueous extract from three cultivars of Psidium guajava L. (Pedro Sato, Paluma and Século XXI) rich in gallic acid | None | In presence of simulated gastric fluid, all cultivars showed increase in the inhibition of lipase and α-glycosidase, and decrease in inhibition of α-amylase and trypsin enzymes |
| Ge et al., 2018 [132] | The network-based pharmacological analysis was used to assess mulberry leaves rich in gallic acid | None | The extract regulated Tnf-α, PPARγ, glycogen synthase kinase-3 beta (GSK3B), insulin receptor substrate 1 (IRS1), interleukin 6 (IL-6) and other proteins involved in diabetes and obesity associated complications |
| Sandoval-Gallegos et al., 2018 [133] | High fat diet fed male Wistar rats treated with methanolic acid extract of Mangifera indica L. leaves, rich in gallic acid, at 100, 200 and 400 mg/kg for 32 days | None | In addition to increasing antioxidant capacity, the extract improved hyperlipidemic markers such as cholesterol, triglycerides, and atherogenic index |
| Wu and Tian, 2018 [134] | In vitro α-glucosidase, α-amylase and lipase inhibitory activity of flowers of pomegranate (Punica granatum) rich in gallic acid | Acarbose | The extract showed enhanced effect of suppress α-glucosidase, α-amylase, and lipase activities |