Hibiscus sabdariffa polyphenolic extract inhibits hyperglycemia, hyperlipidemia, and glycation-oxidative stress while improving insulin resistance

H. sabdariffa polyphenolic extract (HPE) was demonstrated to inhibit high glucose-stimulated cellular changes. In this study, we analyzed the composition of HPE and used a type 2 diabetic rat model to test its protective effect. At least 18 phenolic compounds were found in HPE. Treatment with HPE reduced hyperglycemia and hyperinsulinemia, especially at the dose of 200 mg/kg. HPE decreased serum triacylglycerol, cholesterol, and the ratio of low density lipoprotein/high density lipoprotein (LDL/HDL). Diabetes promoted plasma advanced glycation end product (AGE) formation and lipid peroxidation, while HPE significantly reduced these elevations. Immunohistological observation revealed that HPE inhibited the expression of connective tissue growth factor (CTGF) and receptor of AGE (RAGE), which was increased in type 2 diabetic aortic regions. Furthermore, HPE recovered the weight loss found in type 2 diabetic rats. In conclusion, we demonstrated the anti-insulin resistance properties of HPE and its effect on hypoglycemia, hypolipidemia, and antioxidation. HPE has the potential to be an adjuvant for diabetic therapy.     

Thermal stability of anthocyanin extract of Hibiscus sabdariffa L. in the presence of beta-cyclodextrin

The thermal stability of anthocyanin extract isolated from the dry calyces of Hibiscus sabdariffa L. was studied over the temperature range 60-90 degrees C in aqueous solutions in the presence or absence of beta-cyclodextrin (beta-CD). The results indicated that the thermal degradation of anthocyanins followed first-order reaction kinetics. The temperature-dependent degradation was adequately modeled by the Arrhenius equation, and the activation energy for the degradation of H. sabdariffa L. anthocyanins during heating was found to be approximately 54 kJ/mol. In the presence of beta-CD, anthocyanins degraded at a decreased rate, evidently due to their complexation with beta-CD, having the same activation energy. The formation of complexes in solution was confirmed by nuclear magnetic resonance studies of beta-CD solutions in the presence of the extract. Moreover, differential scanning calorimetry revealed that the inclusion complex of H. sabdariffa L. extract with beta-CD in the solid state was more stable against oxidation as compared to the free extract, as the complex remained intact at temperatures 100-250 degrees C where the free extract was oxidized. The results obtained clearly indicated that the presence of beta-CD improved the thermal stability of nutraceutical antioxidants present in H. sabdariffa L. extract, both in solution and in solid state.     

Adsorption and desorption properties of macroporous resins for anthocyanins from the calyx extract of roselle (Hibiscus sabdariffa L.)

Adsorption of roselle anthocynins, a natural pigment, onto various macroporous resins was optimized to develop a simple and efficient process for industrial separation and purification of roselle anthocyanins. Nine different macroporous resins (AB-8, X-5, HPD-100, SP-207, XAD-4, LS-305A, DM-21, LS-610B, and LS-305) were evaluated for the adsorption properties of the anthocyanins extracted from the calyx extract of Hibiscus sabdariffa L. The influences of phase contact time, solution pH, initial anthocyanin concentration, and ethanol concentration with different citric acid amounts were studied by the static adsorption/desorption method. The adsorption isotherm data were fitted well to the Langmuir isotherm, and according to this model, LS-610B and LS-305 exhibited the highest monolayer sorption capacities of 31.95 and 38.16 mg/g, respectively. The kinetic data were modeled using pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations. The experimental data were well described by the pseudo-second-order kinetic model. Continuous column adsorption-regeneration cycles indicated negligible capacity loss of LS-305 during operation. The overall yield of pigment product was 49.6 mg/g dried calyces. The content of roselle anthocynins in the pigment product was 4.85%.     

Dietary fiber content and associated antioxidant compounds in Roselle flower (Hibiscus sabdariffa L.) beverage

The beverage of Hibiscus sabdariffa flowers is widely consumed in Mexico. Polyphenols contained in plant foods are frequently associated with dietary fiber. The aim of this work is to quantify the dietary fiber, associated polyphenols, and antioxidant capacity of the Roselle flower and the beverage traditionally prepared from it and its contribution to the Mexican diet. Roselle flower contained dietary fiber as the largest component (33.9%) and was rich in phenolic compounds (6.13%). Soluble dietary fiber was 0.66 g/L in beverage, and 66% of total extractable polyphenols contained in Roselle flower passed to the beverage and showed an antioxidant capacity of 335 micromoL trolox equivalents/100 mL beverage measured by ABTS. These data suggest that Roselle flower beverage intake in the Mexican diet may contribute around 166 and 165 mg/per serving to the intake of dietary fiber and polyphenols, respectively. The health benefits from consumption of Hibiscus beverage could be of considerable benefit to the whole population.     

3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, an active principle of kimchi, inhibits development of atherosclerosis in rabbits

The effects of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA) originating from Korean cabbage kimchi were investigated, showing an antioxidant effect on the prevention of atherosclerosis in hypercholesterolemic rabbits. Twenty-one 3-month-old rabbits were fed an atherogenic diet containing 0.5% (w/w) cholesterol and 10% (w/w) coconut oil, whereas another two groups were given an atherogenic diet with intravenous injection of either HDMPPA or simvastatin (0.33 mg/kg/day) for 4 weeks. HDMPPA inhibited the oxidative modification of low-density lipoprotein (IC 50 = 1.4 microg/mL) and increased 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activity (IC 50 = 0.78 microg/mL) in a dose-dependent manner. In hypercholesterolemic rabbits, the thickness of intima of aorta of the HDMPPA group was significantly reduced (control versus HDMPPA, 42%; simvastatin, 38%) without a plasma cholesterol-lowering effect. Thiobarbituric acid reactive substance formation in the plasma of the HDMPPA group was significantly decreased compared to that of the control group. Furthermore, the generation of vascular reactive oxygen species in HDMPPA group was suppressed as the cyclooxygenase-2 protein level decreased. These findings suggest that HDMPPA prevents the development of aortic atherosclerosis in high-cholesterol-fed rabbits. The antiatherosclerotic effect of HDMPPA may be due to an antioxidative effect at a low dose without cholesterol-lowering effects.     

Influence of weather on the fibre yield of mesta (Hibiscus sabdariffa) in the north coastal zone of Andhra Pradesh,India

Mesta (Hibiscus sabdariffa) is an important fibre crop in the north coastal zone of Andhra Pradesh which accounts for 59% of India's total production of mesta. The area under this crop has reduced dramatically in recent years and in order to understand the contribution of weather to this decline, long-term experimental data (14 years) on mesta cv. AMV-4 and regional crop yields were analysed. Crop yields decreased in seasons when rainfall exceeded 900 mm and maximum temperature remained below 32.0°C during 10–16 weeks after sowing (WAS), which coincided with the active vegetative stage. The average yields of the region were high when seasonal rainfall ranged between 600 and 725 mm. Increased fibre yields were observed when increasing seasonal rainfall coincided with maximum temperatures exceeding 33.5°C. Fibre yields from a long-term experiment showed strong positive correlations with maximum temperature during 6–16 WAS (r = 0.79) and with mean diurnal temperature range (8.6–10.7°C) during 11–19 WAS (r = 0.66). Step-wise regression showed that maximum variability in fibre yield was explained by maximum temperature which could be used to develop models to predict yield at least one month in advance with acceptable accuracy. This prediction could then be used as an input for crop planning and market intelligence.     

Antioxidant and antimutagenic properties of Hibiscus tiliaceus L. methanolic extract

The genus Hibiscus thrives in a variety of climates and produces a diversity of natural compounds with bioactive properties. We have studied the chemical composition and the in vivo antioxidant properties of Hibiscus tiliaceus L. methanolic flower extract, as well as its mutagenic/antimutagenic effects. Vitamin E and some stigmasterol derivatives that might confer an antioxidant effect to the extract were present. Treatment with this extract protected several Saccharomyces cerevisiae strains defective in antioxidant defenses against H2O2 and t-BOOH cytotoxicities, showing a clear antioxidant activity. The effect is the same for all strains used, independent of the antioxidant defense disrupted, suggesting that protection may be due to molecules that act as versatile and wide spectrum nonenzymatic antioxidants, such as vitamins or phytosterols. The extract was not mutagenic in either Salmonella typhimurium or S. cerevisiae and showed a significant antimutagenic action against oxidative mutagens in S. cerevisiae.     

Buckwheat extract inhibits progression of renal failure

Rats subjected to partial resection of the parenchyma showed reduced radical-scavenging activity in the remaining kidney and increased severity of renal tissue lesions. However, in similarly nephrectomized rats given buckwheat extract, the state of oxidative stress improved by restoring the decreased activities of reactive oxygen species-scavenging enzymes such as superoxide dismutase and catalase. The degree of mesangial proliferation, severity of extratubular lesions such as crescents and adhesions, glomerulosclerosis index, and severity of tubular interstitial lesions also improved. In addition, nephrectomized rats given buckwheat extract showed improvement in renal function, as indicated by decreased serum level of creatinine, with a significant decrease in the level of methylguanidine, a uremic toxin produced from creatinine in the presence of hydroxyl radical.     

Study on furundu, a traditional Sudanese fermented roselle (Hibiscus sabdariffa L.) seed: effect on in vitro protein digestibility, chemical composition, and functional properties of the total proteins

Furundu, a meat substitute, is traditionally prepared by cooking the karkade (Hibiscus sabdariffa L.) seed and then fermenting it for 9 days. Physicochemical and functional properties of raw and cooked seed and of furundu ferments were analyzed. Furundu preparation resulted in significant changes in karkade seed major nutrients. Total polyphenols and phytic acid were also reduced. The increase in total acidity and fat acidity coupled with a decrease in pH indicates microbial hydrolysis of the major nutrients; proteins, carbohydrates, and fats. In vitro digestibility of the seed proteins reached the maximum value (82.7%) at the sixth day of fermentation, but thereafter it significantly decreased. The effect of furundu preparation on N solubility profiles and functional properties, such as emulsification and foaming properties and other related parameters, is investigated in water and in 1 M NaCl extracts from defatted flour samples. The results show that cooking followed by fermentation affects proteins solubility in water and 1 M NaCl. The foaming capacity (FC) from the flour of raw seed decreased as a result of cooking. Fermentation for 9 days significantly increased the FC of the cooked seed, restoring the inherent value. Foam from fermented samples collapsed more rapidly during a period of 120 min as compared to the foam from raw and cooked karkade seeds; stability in 1 M NaCl was lower as compared to those in water. In water, the emulsion stability (ES) from the fermented samples was significantly higher than that of the raw seed flour. Addition of 1 M NaCl significantly decreased the ES of the fermented samples.     

Antioxidative activity of green tea polyphenol in cholesterol-fed rats

This study investigated the effects of green tea polyphenol on the serum antioxidative activity and cholesterol levels of cholesterol-fed rats and compared them with those of probucol, an antioxidant hypocholesterolemic agent. To evaluate the antioxidative activity, the susceptibility to oxidative modification of low-density lipoprotein (LDL) isolated from the serum of cholesterol-fed rats was measured, as was the serum antioxidative activity using the spontaneous autoxidation system of brain homogenate. Administration of green tea polyphenol effectively inhibited LDL oxidation and elevated serum antioxidative activity to the same degree as probucol. However, higher amounts of polyphenol than probucol needed to be administered to reduce the total, free, and LDL cholesterol levels. Furthermore, green tea polyphenol increased the levels of high-density lipoprotein (HDL) cholesterol, leading to dose-dependent improvement of the atherogenic index, an effect that was not seen with probucol. Thus, green tea polyphenol may exert an antiatherosclerotic action by virtue of its antioxidant properties and by increasing HDL cholesterol levels.     

Solanum nigrum Linn. water extract inhibits metastasis in mouse melanoma cells in vitro and in vivo

Metastatic melanoma is an aggressive skin cancer notoriously resistant to current cancer therapies. Thus, new treatment strategies are urgently needed. Solanum nigrum Linn., commonly used in Oriental medicine, has showed antineoplastic activity in human cancer cell lines. The aim of this study was to evaluate the inhibitive effect of S. nigrum Linn. water extract (SNWE) on melanoma metastasis and dissect the underlying mechanisms of SNWE actions. B16-F1 cells were analyzed for migrating and invasive abilities with SNWE treatment, and several putative targets involved in metastatic melanoma were examined. In parallel, primary mouse xenograft and lung metastasis of melanoma models were established to examine the therapeutic potential of SNWE. The results indicated SNWE significantly inhibited B16-F1 cell migration and invasion. Meanwhile, decreased Akt activity and PKCα, Ras, and NF-κB protein expressions were detected in dose-dependent manners. In line with this notion, >50% reduced tumor weight and lung metastatic nodules were observed in 1% SNWE fed mice. This was associated with reduced serum MMP-9 as well as Akt activity and PKCα, Ras, and NF-κB protein expressions. Thus, this work indicates SNWE has potential application for treating metastatic melanoma.     

Protocatechuic acid, a metabolite of anthocyanins, inhibits monocyte adhesion and reduces atherosclerosis in apolipoprotein E-deficient mice

Polyphenols, including anthocyanins, from various plant foods are effective in the prevention of atherosclerosis in animal and human studies. Protocatechuic acid (PCA), a major metabolite of anthocyanins, has been found to possess the anti-carcinogenic effect, whereas the in vivo effect of PCA as an anti-atherosclerotic agent remains unknown. We demonstrated herein that PCA inhibited monocyte adhesion to tumor necrosis factor-α (TNF-α)-activated mouse aortic endothelial cells, associated with the inhibition of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) expression. Furthermore, PCA inhibited the nuclear content of p65, a subunit of nuclear factor-κB (NF-κB), along with reduced NF-κB binding activity. Finally, PCA administration in the apolipoprotein E (ApoE)-deficient mouse model reduced aortic VCAM-1 and ICAM-1 expression, NF-κB activity, and plasma-soluble VCAM-1 and ICAM-1 levels, with inhibiting atherosclerosis development. We suggest that PCA possesses the anti-atherogenic effect at least partially via its anti-inflammatory activity.     

Cataract development in sand and galactosemic rats fed a natural tomato extract

This study investigated the effect of a natural tomato extract (TE) on cataract formation in two animal models. A TE containing 5% lycopene was included in the diet of diabetic sand rats at 0.2%, and Sprague Dawley rats were fed a high-galactose diet (30 g/100 g of diet), supplemented with either the lycopene-rich extract at concentrations of 0.2, 0.4, and 0.8% or BHT (0.2%). TE had no significant effect on plasma glucose levels or cataract development in sand rats; however, in rats maintained on a diet rich in galactose, both BHT and TE decreased cataract incidence, and grades were lower than in control animals. In addition, lens protein and reduced glutathione levels were higher and aldose reductase activity was lower than in the control group. The results suggest that antioxidants act as protective agents when oxidative stress is a primary cause of cataract formation but may be less effective in preventing cataracts in hyperglycemic animals.     

Crude extract of Astragalus mongholicus root inhibits crop seed germination and soil nitrifying activity

Astragalus mongholicus has been of medicinal use within the traditional Chinese system for centuries. However, little information is available on its allelopathic effects on other crop plants and soil biochemical properties. Field experiment showed that the extracted residues of A. mongholicus root inhibited seed germination of wheat. Inhibition of seed germination was further confirmed in laboratory using the same crude extract. When the crude extract was applied to soil at various rates and incubated for 30 days, soil urease activity and denitrifying enzyme activity were significantly increased while soil nitrification rate was significantly decreased at 10% amendment rate as compared to the control. Soil respiration rate was significantly increased by the crude extract when measured at the start of incubation but returned to basal levels after 30 days of incubation. The crude extract supplemented to NB medium significantly decreased the colony numbers of Agrobacterium tumefaciens C58, Paraccocus denitrificans and soil bacteria. The stimulating effects of crude extract observed in the amended soil was attributed to the easily-available carbohydrates in the extract, which might served as external energy sources for heterotrophic microbial activities. It was concluded that A. mongholicus contained some compounds that inhibited seed germination, soil nitrification and bacterial growth in general. Possible links between allelochemicals responsible for the inhibitory effects observed in the present study and the medically bioactive compounds are discussed based on information reported in other fields. Further work is needed to specify and verify the allelochemicals produced by this herbal plant.     

Dietary anthocyanin-rich tart cherry extract inhibits intestinal tumorigenesis in APC(Min) mice fed suboptimal levels of sulindac

A promising approach for cancer chemoprevention might be a combination therapy utilizing dietary phytochemicals and anticarcinogenic pharmaceuticals at a suboptimal dosage to minimize any potential adverse side effects. To test this hypothesis, various dosages of anthocyanin-rich tart cherry extract were fed in combination with suboptimal levels of the nonsteroidal anti-inflammatory drug sulindac to APCMin mice for 19 weeks. By the end of the feeding period, fewer mice that were fed the anthocyanin-rich extract in combination with sulindac lost more than 10% of body weight than mice fed sulindac alone. Mice that were fed anthocyanin-rich extract (at any dose) in combination with sulindac had fewer tumors and a smaller total tumor burden (total tumor area per mouse) in the small intestine when compared to mice fed sulindac alone. These results suggest that a dietary combination of tart cherry anthocyanins and sulindac is more protective against colon cancer than sulindac alone.     

Effect of red wine consumption on low-density lipoprotein oxidation and atherosclerosis in aorta and coronary artery in Watanabe heritable hyperlipidemic rabbits.

Red wine was given to Watanabe heritable hyperlipidemic (WHHL) rabbits (7 mL/kg/day, approximately 23 mg total polyphenol/kg/day) from the age of 4 months for 14 months. With WHHL rabbits given a comparable dose of alcohol used as references, the effect of wine phenolics on the morphology of atherosclerotic lesions in the coronary artery and aorta was investigated in light of the susceptibility of plasma intermediate and low-density protein (ILDL) to oxidation. ILDL of animals consuming red wine showed reduced susceptibility to oxidation, but atherosclerotic lesion progression was not prevented. In WHHL rabbits, a dose of wine phenolics sufficient to inhibit ILDL oxidation might not be adequate to prevent the progression of atherosclerosis morphologically.     

Potential Use of Hibiscus Rosa-Sinensis Leaf Extract for the Destabilization of Turbid Water

In the present study, the ability of Hibiscus rosa-sinensis leaf extract (HLE) to act as a natural coagulant for the water treatment was tested. Synthetic turbid solutions were prepared using kaolinite, and the efficiency of HLE was examined for low and high turbid solutions. HLE was very effective in high turbid solutions than in low turbid water and follows enmeshment mechanism of destabilization. An insignificant effect of alkalinity on the performance of HLE was observed. The addition of NaCl increased the dissolution of coagulation active species and enhanced the efficiency of HLE, significantly. Hydroxyl and carboxyl groups present in HLE were the major functional groups responsible for the bonding between coagulant and kaolinite. The efficiency of alum was very high compared to that of HLE in both turbid solutions. But the optimal dosages of HLE were lesser than that of alum. Thus, HLE can be used as a coagulant aid for the effective treatment of water.     

Hypolipidemic effect in cholesterol-fed rats of a soluble fiber-rich product obtained from cocoa husks

A new soluble cocoa fiber product (SCFP), obtained after enzymatic treatment of cocoa husks, was characterized and its potential health effects studied in an animal model of dietary-induced hypercholesterolemia. The SCFP was rich in soluble dietary fiber (DF) and antioxidant polyphenols. Consumption of a cholesterol-rich diet containing the SCFP as a source of DF resulted in lower food intake and body weight gain in comparison with control groups consuming cholesterol-free or cholesterol-rich diets with cellulose as DF. The cholesterol-rich diet caused remarkable hypercholesterolemia. However, the SCFP diminished the negative impact of the cholesterol-rich diet, buffering the decrease of high density lipoprotein-cholesterol, and the increase of total and low density lipoprotein-cholesterol levels, and lipid peroxidation (malondialdehyde levels) induced by the fatty diet. The SCFP also decreased triglyceride levels to values lower than those in the group fed the cholesterol-free diet. These results put forward the potential application of the SCFP as a dietary supplement or functional food ingredient.     

Effect of fly ash extract on growth and development of corn and soybean seedlings

Different concentrations of aqueous extract of fly ash were prepared by soaking air dried fly ash and mixing thoroughly with an electric blender. Extracts were then applied to the seeds of corn (Zea mays L.) and soybean (Glycine max L.) after being filtered through a Whatman No. 42 filter paper. Fly ash extract in the lower concentration range of 0.5 to 1.0% (W/V) had no significant effect on germination and seedling growth of each of the two crops. Higher concentrations of fly ash extracts, however, had deleterious effects on the percentage of germination, viability, number of roots, shoot and root length, fresh weight and dry weight of seedlings of both the crops. The elemental concentrations in shoot and root systems of control seedlings of corn and soybean were found to be the same, whereas in the extract treated corn and soybean seedlings, a relatively high elemental concentration was found in roots as compared to shoots.