Aqueous extract of Hibiscus sabdariffa L. decelerates acetaminophen‐induced acute liver damage by reducing cell death and oxidative stress in mouse experimental models

BACKGROUND: Acetaminophen (AAP)‐induced oxidative stress can cause cell death to induce liver damage. The antioxidant effect of Hibiscus sabdariffa L. (HS) was shown in previous studies. In this study the effect of HS extract (HSE) on AAP‐induced liver injury in BALB/c mice was investigated. RESULTS: In vivo, BALB/c mice were fed orally with 200, 400 or 600 mg kg⁻¹ HSE for 2 weeks and then injected with 1000 mg kg⁻¹ AAP. Pretreatment with HSE decreased lipid peroxidation and increased catalase activity and glutathione level. It also decreased AAP‐induced liver injury, accompanied by decreased expression of pJNK, Bax and tBid in the liver. Additionally, HSE protected BALB/c normal liver cells from AAP‐induced damage in vitro. CONCLUSION: It has been demonstrated that HSE can protect the mouse liver from AAP‐induced injury and that the protective mechanism might involve decreasing oxidative stress and reducing cell death. Copyright © 2009 Society of Chemical Industry     

Bioavailability study of a polyphenol‐enriched extract from Hibiscus sabdariffa in rats and associated antioxidant status

The aqueous extracts of Hibiscus sabdariffa have been commonly used in folk medicine. Nevertheless, the compounds or metabolites responsible for its healthy effects have not yet been identified. The major metabolites present in rat plasma after acute ingestion of a polyphenol‐enriched Hibiscus sabdariffa extract were characterized and quantified in order to study their bioavailability. The antioxidant status of the plasma samples was also measured through several complementary antioxidant techniques. High‐performance liquid chromatography coupled to time‐of‐flight mass spectrometry (HPLC‐ESI‐TOF‐MS) was used for the bioavailability study. The antioxidant status was measured by ferric reducing ability of plasma method, thiobarbituric acid reactive substances assay, and superoxide dismutase activity assay. Seventeen polyphenols and metabolites have been detected and quantified. Eleven of these compounds were metabolites. Although phenolic acids were found in plasma without any modification in their structures, most flavonols were found as quercetin or kaempferol glucuronide conjugates. Flavonol glucuronide conjugates, which show longer half‐life elimination values, are proposed to contribute to the observed lipid peroxidation inhibitory activity in the cellular membranes. By contrast, phenolic acids appear to exert their antioxidant activity through ferric ion reduction and superoxide scavenging at shorter times. We propose that flavonol‐conjugated forms (quercetin and kaempferol) may be the compounds responsible for the observed antioxidant effects and contribute to the healthy effects of H. sabdariffa polyphenolic extract.     

Consumption of Hibiscus sabdariffa L. aqueous extract and its impact on systemic antioxidant potential in healthy subjects

BACKGROUND: To evaluate health benefits attributed to Hibiscus sabdariffa L. a randomized, open‐label, two‐way crossover study was undertaken to compare the impact of an aqueous H. sabdariffa L. extract (HSE) on the systemic antioxidant potential (AOP; assayed by ferric reducing antioxidant power (FRAP)) with a reference treatment (water) in eight healthy volunteers. The biokinetic variables were the areas under the curve (AUC) of plasma FRAP, ascorbic acid and urate that are above the pre‐dose concentration, and the amounts excreted into urine within 24 h (Ae_0–24) of antioxidants as assayed by FRAP, ascorbic acid, uric acid, malondialdehyde (biomarker for oxidative stress), and hippuric acid (metabolite and potential biomarker for total polyphenol intake). RESULTS: HSE caused significantly higher plasma AUC of FRAP, an increase in Ae_0–24 of FRAP, ascorbic acid and hippuric acid, whereas malondialdehyde excretion was reduced. Furthermore, the main hibiscus anthocyanins as well as one glucuronide conjugate could be quantified in the volunteers' urine (0.02% of the administered dose). CONCLUSION: The aqueous HSE investigated in this study enhanced the systemic AOP and reduced the oxidative stress in humans. Furthermore, the increased urinary hippuric acid excretion after HSE consumption indicates a high biotransformation of the ingested HSE polyphenols, most likely caused by the colonic microbiota. Copyright © 2012 Society of Chemical Industry     

玫瑰茄栽培及其在食品工业应用研究进展

玫瑰茄是一种热带、亚热带经济作物,天然的药食两用营养保健植物。玫瑰茄含有的木槿酸、花青素、还原糖等,对人体具有重要的保健作用,花萼富含天然色素,又是色、香、味俱佳的食用材料。该文阐述了玫瑰茄的栽培技术及玫瑰茄花萼的有关产量,并对其各器官的化学成份进行了分类总结,综述了玫瑰茄在食品工业开发应用的最新研究进展,以期为更好地栽培利用玫瑰茄提供技术参考。     

Hibiscus sabdariffa L. extracts inhibit the mutagenicity in microsuspension assay and the proliferation of HeLa cells

ABSTRACT:  Hibiscus sabdariffa L. is used as a refreshing beverage and as a traditional medicine. The objective of this study was to determine the in vitro effect of phenolic compounds present in aqueous, ethyl acetate, and chloroform extracts of H. sabdariffa against mutagenicity of 1-nitropyrene (1-NP), and also the antiproliferative effect of these extracts. Inhibition of cell proliferation and DNA fragmentation were tested on transformed human HeLa cells. The hot aqueous extract (HAE) contained 22.27 ± 2.52 mg of protocatechuic acid (PCA) per gram of lyophilized dried extract, and was not statistically different from the cold aqueous or chloroform extracts; the ethyl acetate extract produced the least amount of PCA. The H. sabdariffa extracts inhibited mutagenicity of 1-NP in a dose-response manner. The inhibition rate on HeLa cells of HAE was also dose-dependent. The HAE did not induce DNA fragmentation. The results suggest that H. sabdariffa L. extracts have antimutagenic activity against 1-NP and decrease the proliferation of HeLa cells, probably due to phenolic acid composition.     

Release kinetics of antioxidant compounds from Hibiscus sabdariffa L. encapsulated in gelatin beads and coated with sodium alginate

Gelatin beads containing a concentrated extract of Roselle (Hibiscus sabdariffa L.) calyx rich in polyphenolic compounds were coated with sodium alginate and ionotropically gelled using CaCl₂. Single‐coated beads and double‐coated beads were obtained by this technique, and the release pattern of the loaded extract was evaluated. As a result, release pattern of these compounds fits properly to a first–order Weibull distribution equation. The release rate constant decreased linearly with the number of alginate coats and with the increase in immersion time in CaCl₂ and the Lag period increased significantly with the number of alginate coats. The release of H. sabdariffa's polyphenols can be well controlled manipulating the number of alginate coats and the immersion time in a CaCl₂ solution, allowing not only to control the gastrointestinal segment where they could be released but also to control the release rate with the certainty that the initial concentration will be completely released showing a highly significant antioxidant activity as well.     

Physicochemical and sensory quality of wines from red sorrel/roselle (Hibiscus sabdariffa L.) calyces: effects of pretreatments of pectolase and temperature/time

The effects of pretreating red sorrel (Hibiscus sabdariffa L.) calyces on the physicochemical and sensory quality of wines were investigated. Sorrel calyces were processed at 60 °C for 3.5 h or 90 °C for 30 min at 0%, 0.5% and 1.0% w/w pectolase addition in fermentation of wines. Significant changes (P < 0.01) in all physicochemical parameters of sorrel wines were found during fermentation, but not (P > 0.05) because of temperature/time effects. Colour (P < 0.01) became redder with pectolase and on storage at 23 °C for 2 months. Significant differences (P < 0.01) were noted in sensory quality for taste and flavour, balance, duration and overall quality. Higher (P < 0.01) overall sensory quality scores were obtained for wines by pretreatment at 90 °C for 30 min (10.44–11.06/20) when compared with wines at 60 °C for 3.5 h (6.88–9.06/20). Colour of wines from 90 °C/30 min was most saturated and red than all wines and had pH 2.57 ± 0.01, 0.43 ± 0.07% citric acid, 10.53 ± 0.53 °Bx and 15.29 ± 0.71% alcohol.     

Anti‐obesity effect of Liupao tea extract by modulating lipid metabolism and oxidative stress in high‐fat‐diet‐induced obese mice

Liupao tea (LPT) is traditional dark Chinese tea. The effect of LPT extract on high‐fat‐diet‐induced obese mice was investigated systematically. The results showed that LPT extract could reduce body weight and significantly alleviate liver damage and fat accumulation. LPT could also decrease the levels of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (AKP), total cholesterol (TC), triglycerides (TG), and low‐density lipoprotein cholesterol (LDL‐C) and increase the level of high‐density lipoprotein cholesterol (HDL‐C) in the liver. It also decreased the serum levels of inflammatory cytokines, including tumor necrosis factor alpha (TNF‐α), interferon gamma (IFN‐γ), interleukin (IL)‐1β, and IL‐6 and increased the serum levels of anti‐inflammatory cytokines, including IL‐10 and IL‐4. Moreover, LPT improved the levels of total superoxide dismutase (T‐SOD), glutathione peroxidase (GSH‐Px), and catalase (CAT) and reduced the level of malondialdehyde (MDA) in the liver. Moreover, LPT could upregulate the mRNA and protein expressions of peroxisome proliferator‐activated receptor alpha (PPAR‐α), lipoprotein lipase (LPL), carnitine palmitoyltransferase 1(CPT1), and cholesterol 7 alpha‐hydroxylase (CYP7A1) and downregulate those of PPAR‐γ and CCAAT/enhancer‐binding protein alpha (C/EBP‐α) in the liver. It also increased the mRNA expression of copper/zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), CAT, gamma‐glutamylcysteine synthetase 1 (GSH1), and GSH‐Px. The components of LPT extract include catechin, rutin, taxifolin, and astragalin, which possibly have a wide range of biological activities. In conclusion, our work verified that LPT extract possessed an anti‐obesity effect and alleviated obesity‐related symptoms, including lipid metabolism disorder, chronic low‐grade inflammation, and liver damage, by modulating lipid metabolism and oxidative stress.     

Hypolipidaemic and hepatoprotective effects of ethanolic and aqueous extracts from Asparagus officinalis L. by‐products in mice fed a high‐fat diet

BACKGROUND: Asparagus (Asparagus officinalis L.) by‐products, i.e. the parts of the spears discarded during industrial processing, might have potential use as food supplements for their therapeutic effects. In this study the hypolipidaemic and hepatoprotective effects of ethanolic (EEA) and aqueous (AEA) extracts from asparagus by‐products were evaluated in mice fed a high‐fat diet (HFD). RESULTS: Continuous HFD feeding caused obvious hyperlipidaemia and liver damage in mice. However, both EEA and AEA significantly decreased the levels of body weight gain, serum total cholesterol and serum low‐density lipoprotein cholesterol in hyperlipidaemic mice when administered at a daily dose of 200 mg kg^?1 for 8 weeks. Also, serum high‐density lipoprotein cholesterol levels were evidently increased in the AEA‐treated group. Moreover, both EEA and AEA dramatically decreased the activities of alanine and aspartate transaminases in serum. Finally, superoxide dismutase activity and total antioxidant capacity were increased and malondialdehyde level and the distribution of lipid droplets decreased in liver cells of both EEA‐ and AEA‐treated mice. CONCLUSION: The findings of this study suggest that both EEA and AEA have strong hypolipidaemic and hepatoprotective properties and could be used as supplements in healthcare foods and drugs or in combination with other hypolipidaemic drugs. Copyright © 2010 Society of Chemical Industry