Hibiscus sabdariffa extract reduces serum cholesterol in men and women

Anti-metastasis effects of gallic acid on gastric cancer cells involves inhibition of NF-kappaB activity and downregulation of PI3K/AKT/small GTPase signals

Polyphenols are natural antioxidants that are thought to contribute to prevention of cardiovascular disease and malignancy. Although many studies have been carried out to investigate the chemopreventive role of flavonoids, less attention has been focused on phenolic acids. In this study, the aim was to investigate the effect of phenolic acids found abundantly in vegetables, i.e. gallic acid (GA), caffeic acid (CA) and protocatechuic acid (PCA), on the inhibition of gastric adenocarcinoma (AGS) cell metastasis. The results showed 0.01 mM GA induced the same level of cell toxicity as 4.0mM PCA. Using wound-healing assay and Boyden chamber assay, GA had potent inhibitory effects on AGS cell migration. The expression of MMP-2/9 of AGS cells was inhibited by 2.0 microM of GA. It is possible that the suppressive effect of GA on MMP-2/9 might involve the inhibition of NF-kappaB activity. Multiple proteins involved in metastasis and the cytoskeletal reorganization signal pathway, including Ras, Cdc42, Rac1, RhoA, RhoB, PI3K and p38MAPK, were also inhibited by GA. Furthermore, immunoreactivity assay of cytoskeletal F-actin demonstrated a significant inhibitory effect of GA treatment. In conclusion, GA may have the potential to be an effective agent for prevention and treatment of gastric cancer metastasis.

An evaluation of the hypolipidemic effect of an extract of Hibiscus Sabdariffa leaves in hyperlipidemic Indians: a double blind, placebo controlled trial

Background

Hibiscus sabdariffa is used regularly in folk medicine to treat various conditions.

Methods

The study was a double blind, placebo controlled, randomized trial. Sixty subjects with serum LDL values in the range of 130-190 mg/dl and with no history of coronary heart disease were randomized into experimental and placebo groups. The experimental group received 1 gm of the extract for 90 days while the placebo received a similar amount of maltodextrin in addition to dietary and physical activity advice for the control of their blood lipids. Anthropometry, blood biochemistry, dietary and physical activity were assessed at baseline, day 45 and day 90.

Results

While body weight, serum LDL cholesterol and triglyceride levels decreased in both groups, there were no significant differences between the experimental and placebo group.

Conclusions

It is likely that the observed effects were as a result of the patients following the standard dietary and physical activity advice. At a dose of 1 gm/day, hibiscus sabdariffa leaf extract did not appear to have a blood lipid lowering effect.

Trial Registration

REFCTRI2009000472

Effects of Hibiscus sabdariffa extract powder and preventive treatment (diet) on the lipid profiles of patients with metabolic syndrome (MeSy)

Insulin resistance, obesity, hypertension, and dyslipidemia are strongly associated with metabolic syndrome (MeSy), which is considered to be a reversible clinical stage before its evolution to coronary heart disease and diabetes. Currently, the antihypertensive and hypolipidemic properties of aqueous Hibiscus sabdariffa extracts (HSE) have been demonstrated in clinical trials and in vivo experiments. The aim of the present study was to evaluate the effects of a Hibiscus sabdariffa extract powder (HSEP) and a recognized preventive treatment (diet) on the lipid profiles of individuals with and without MeSy according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria. The protocol was a follow-up study carried out in a factorial, randomized design (T1=preventive treatment comprises Diet, T2=HSEP, T3=HSEP+preventive treatment (Diet) X MeSy, non-MeSy individuals). A total daily dose of 100 mg HSEP was orally administered in capsules for one month. The preventive treatment (diet) was selected according to NCEP-ATP III recommendations and adjusted individually. Total cholesterol, LDL-c, HDL-c, VLDL-c, triglycerides, glucose, urea, creatinine, AST, and ALT levels in the blood were determined in all individuals pre- and post-treatment. The MeSy patients treated with HSEP had significantly reduced glucose and total cholesterol levels, increased HDL-c levels, and an improved TAG/HDL-c ratio, a marker of insulin resistance (t-test p<0.05). Additionally, a triglyceride-lowering effect was observed in MeSy patients treated with HSEP plus diet, and in individuals without MeSy treated with HSEP. Significant differences in total cholesterol, HDL-c, and the TAG/HDL-c ratio were found when the means of absolute differences among treatments were compared (ANOVA p<0.02). Therefore, in addition to the well documented hypotensive effects of Hibiscus sabdariffa, we suggest the use of HSEP in individuals with dyslipidemia associated with MeSy.

Inhibition of angiotensin convertin enzyme (ACE) activity by the anthocyanins delphinidin- and cyanidin-3-O-sambubiosides from Hibiscus sabdariffa

ETHNOPHARMACOLOGICAL RELEVANCE

The beverages of Hibiscus sabdariffa calyces are widely used in Mexico as diuretic, for treating gastrointestinal disorders, liver diseases, fever, hypercholesterolemia and hypertension. Different works have demonstrated that Hibiscus sabdariffa extracts reduce blood pressure in humans, and recently, we demonstrated that this effect is due to angiotensin converting enzyme (ACE) inhibitor activity.

AIM OF THE STUDY

The aim of the current study was to isolate and characterizer the constituents responsible of the ACE activity of the aqueous extract of Hibiscus sabdariffa.

MATERIALS AND METHODS

Bioassay-guided fractionation of the aqueous extract of dried calyces of Hibiscus sabdariffa using preparative reversed-phase HPLC, and the in vitro ACE Inhibition assay, as biological monitor model, were used for the isolation. The isolated compounds were characterized by spectroscopic methods.

RESULTS

The anthocyanins delphinidin-3-O-sambubioside (1) and cyanidin-3-O-sambubioside (2) were isolated by bioassay-guided purification. These compounds showed IC(50) values (84.5 and 68.4 microg/mL, respectively), which are similar to those obtained by related flavonoid glycosides. Kinetic determinations suggested that these compounds inhibit the enzyme activity by competing with the substrate for the active site.

CONCLUSIONS

The competitive ACE inhibitor activity of the anthocyanins 1 and 2 is reported for the first time. This activity is in good agreement with the folk medicinal use of Hibiscus sabdariffa calyces as antihypertensive.

Effect of Hibiscus sabdariffa L. dried calyx ethanol extract on fat absorption-excretion, and body weight implication in rats

The effect of Hibiscus sabdariffa L. (Hs) calyx extract on fat absorption-excretion and body weight in rats, was investigated. Rats were fed with either a basal diet (SDC = Control diet) or the same diet supplemented with Hs extracts at 5%, 10% and 15% (SD₅, SD₁₀ and SD₁₅). Only SD₅ did not show significant increases in weight, food consumption and efficiency compared to SD_C. The opposite occurred in SD₁₅ group which showed a significant decrease for these three parameters. The SD₁₀ responses were similar to SD₁₅, with the exception of food consumption. In both SD_C and SD₅ groups, no body weight loss was observed; however, only in the latter group was there a significantly greater amount of fatty acids found in feces. A collateral effect emerging from the study is that components of Hs extract at the intermediate and greater concentrations used in this experiment could be considered possible antiobesity agents.

Chemistry and quality of Hibiscus (Hibiscus sabdariffa) for developing the natural-product industry in Senegal

The objectives of this study were to assess and improve the quality of the hibiscus calyces from Senegal over 2 production seasons (2004 to 2005), to develop and adapt new procedures for the determination of hibiscus anthocyanins and analysis of the 2 major ones, delphinidin-3-sambubioside and cyanidin-3-sambubioside. The foreign matter, total ashes, and acid insoluble ashes showed that the calyces harvested in 2005 were produced following hygienic practices, while the color assessment of the calyces and analysis of hibiscus active principles also showed higher amounts of anthocyanins in 2005. A protocol to measure anthocyanins by pH-differential UV-Vis spectrophotometry was adapted to measure the hibiscus anthocyanins from a water extract. The spectrophotometric method for quantitation of total anthocyanins showed a close correlation (r(2)= 0.82) when compared with the HPLC method, suggesting the use of the colorimetric method in quality control programs as an affordable alternative method to assess anthocyanin content in hibiscus. New and raised standards for the cleanliness and active principle content in hibiscus are also proposed. This study demonstrated that the implementation of a quality control program and the application of agricultural good practices in the production and processing of hibiscus calyces can lead to higher quality natural plant products.

Hibiscus sabdariffa inhibits vascular smooth muscle cell proliferation and migration induced by high glucose--a mechanism involves connective tissue growth factor signals

Recently, the herbal extract of Hibiscus sabdariffa was shown to have multiple bioactive effects, including anti-atherosclerosis. On the basis of this, we aimed to examine whether the polyphenolic isolate of H. sabdariffa (HPI) could protect high-glucose-treated vascular smooth muscle cell (VSMC) and its putative transduction signals. Results showed that HPI dose- and time-dependently reduced the high-glucose-stimulated cell proliferation and migration. HPI suppressed the proliferating cell nuclear antigen (PCNA) level and matrix metalloproteinase (MMP)-2 activation. In addition, the expressions of connective tissue growth factor (CTGF) and receptor of advanced glycation end product (RAGE) enhanced by high glucose were prominently suppressed by HPI. The proliferation signal mediated by high glucose was demonstrated via CTGF/RAGE, while MMP-2 was regulated by CTGF but not RAGE. Conclusively, the results suggest that HPI potentially can be a promising adjuvant herbal therapy for diabetic patients.