A review of the efficacy and safety of banaba (Lagerstroemia speciosa L.) and corosolic acid.
Banaba (Lagerstroemia speciosa L.) extracts have been used for many years in folk medicine to treat diabetes, with the first published research study being reported in 1940. This review summarizes the current literature regarding banaba and its constituents. The hypoglycemic effects of banaba have been attributed to both corosolic acid as well as ellagitannins. Studies have been conducted in various animal models, human subjects and in vitro systems using water soluble banaba leaf extracts, corosolic acid-standardized extracts, and purified corosolic acid and ellagitannins. Pure corosolic acid has been reported to decrease blood sugar levels within 60 min in human subjects. Corosolic acid also exhibits antihyperlipidemic, antioxidant, antiinflammatory, antifungal, antiviral, antineoplastic and osteoblastic activities. The beneficial effects of banaba and corosolic acid with respect to various aspects of glucose and lipid metabolism appear to involve multiple mechanisms, including enhanced cellular uptake of glucose, impaired hydrolysis of sucrose and starches, decreased gluconeogenesis and the regulation of lipid metabolism. These effects may be mediated by PPAR, MAP K, NF-κB and other signal transduction factors. No adverse effects have been observed or reported in animal studies or controlled human clinical trials. Banaba extract, corosolic acid and other constituents may be beneficial in addressing the symptoms associated with metabolic syndrome, as well as offering other health benefits.
Stohs SJ, Miller H, Kaats GR
Phytother Res Mar 2012
Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483.
Epidemiological studies suggest that the incidence of CVD and postmenopausal osteoporosis is low in the Mediterranean area, where herbs and nuts, among others, play an important role in nutrition. In the present study, we sought a role of walnuts (Juglans regia L.) in endothelial and bone-cell function. As the endothelial cell expression of adhesion molecules has been recognised as an early step in inflammation and atherogenesis, we examined the effect of walnut methanolic extract and ellagic acid, one of its major polyphenolic components (as shown by HPLC analysis), on the expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in human aortic endothelial cells. After incubating the cells with TNF-alpha (1 ng/ml) in the absence and in the presence of walnut extract (10-200 microg/ml) or ellagic acid (10- 7-10- 5 m), the VCAM-1 and ICAM-1 expression was quantified by cell-ELISA. We further evaluated the effect of walnut extract (10-50 microg/ml), in comparison with ellagic acid (10- 9-10- 6m), on nodule formation in the osteoblastic cell line KS483. Walnut extract and ellagic acid decreased significantly the TNF-alpha-induced endothelial expression of both VCAM-1 and ICAM-1 (P < 0.01; P < 0.001). Both walnut extract (at 10-25 microg/ml) and ellagic acid (at 10- 9-10- 8 m) induced nodule formation in KS483 osteoblasts. The present results suggest that the walnut extract has a high anti-atherogenic potential and a remarkable osteoblastic activity, an effect mediated, at least in part, by its major component ellagic acid. Such findings implicate the beneficial effect of a walnut-enriched diet on cardioprotection and bone loss.
Papoutsi Z, Kassi E, Chinou I, Halabalaki M…
Br. J. Nutr. Apr 2008
Anti-inflammatory Effects of Polyphenolic-Enriched Red Raspberry Extract in an Antigen-Induced Arthritis Rat Model.
The red raspberry ( Rubus idaeus ) fruit contains bioactive polyphenols including anthocyanins and ellagitannins with reported anti-inflammatory properties. This study sought to investigate the cartilage-protecting and anti-inflammatory effects of a polyphenolic-enriched red raspberry extract (RRE; standardized to total polyphenol, anthocyanin, and ellagitannin contents) using (1) an in vitro bovine nasal explant cell culture model and (2) an in vivo adjuvant-induced arthritis rat model. RRE contained 20% total polyphenols (as gallic acid equivalents), 5% anthocyanins (as cyanidin-3-glucoside equivalents), and 9.25% ellagitannins (as ellagic acid equivalents). In the in vitro studies, bovine nasal explants were stimulated with 10 ng/mL IL-1β to induce the release of proteoglycan and type II collagen. On treatment with RRE (50 μg/mL), there was a decrease in the rate of degradation of both proteoglycan and type II collagen. In the in vivo antigen-induced arthritis rat model, animals were gavaged daily with RRE (at doses of 30 and 120 mg/kg, respectively) for 30 days after adjuvant injection (750 μg of Mycobacterium tuberculosis suspension in squalene). At the higher dose, animals treated with RRE had a lower incidence and severity of arthritis compared to control animals. Also, histological analyses revealed significant inhibition of inflammation, pannus formation, cartilage damage, and bone resorption by RRE. This study suggests that red raspberry polyphenols may afford cartilage protection and/or modulate the onset and severity of arthritis.
Jean-Gilles D, Li L, Ma H, Yuan T…
J. Agric. Food Chem. Dec 2011
Furosin, an ellagitannin, suppresses RANKL-induced osteoclast differentiation and function through inhibition of MAP kinase activation and actin ring formation.
Phenolic compounds including tannins and flavonoids have been implicated in suppression of osteoclast differentiation/function and prevention of bone diseases. However, the effects of hydrolysable tannins on bone metabolism remain to be elucidated. In this study, we found that furosin, a hydrolysable tannin, markedly decreased the differentiation of both murine bone marrow mononuclear cells and Raw264.7 cells into osteoclasts, as revealed by the reduced number of tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells and decreased TRAP activity. Furosin appears to target at the early stage of osteoclastic differentiation while having no cytotoxic effect on osteoclast precursors. Analysis of the inhibitory mechanisms of furosin revealed that it inhibited the receptor activator of nuclear factor-kappaB ligand (RANKL)-induced activation of p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK)/activating protein-1 (AP-1). Furthermore, furosin reduced resorption pit formation in osteoclasts, which was accompanied by disruption of the actin rings. Taken together, these results demonstrate that naturally occurring furosin has an inhibitory activity on both osteoclast differentiation and function through mechanisms involving inhibition of the RANKL-induced p38MAPK and JNK/AP-1 activation as well as actin ring formation.
Park EK, Kim MS, Lee SH, Kim KH…
Biochem. Biophys. Res. Commun. Dec 2004
Evaluation of estrogenic/antiestrogenic activity of ellagic acid via the estrogen receptor subtypes ERalpha and ERbeta.
Ellagic acid is a plant-derived polyphenol, possessing antioxidant, antiproliferative, and antiatherogenic properties. Whether this compound has estrogenic/antiestrogenic activity, however, remains largely unknown. To answer this question, we first investigated the ability of ellagic acid to influence the activity of the estrogen receptor subtypes ERalpha and ERbeta in HeLa cells. Cells co-transfected with an estrogen response element (ERE)-driven luciferase (Luc) reporter gene and an ERalpha- or ERbeta-expression vector were exposed to graded concentrations of ellagic acid. At low concentrations (10(-7) to 10(-9) M), this compound displayed a small but significant estrogenic activity via ERalpha, whereas it was a complete estrogen antagonist via ERbeta. Further evaluation revealed that ellagic acid was a potent antiestrogen in MCF-7 breast cancer-derived cells, increasing, like the pure estrogen antagonist ICI182780, IGFBP-3 levels. Moreover, ellagic acid induced nodule mineralization in an osteoblastic cell line (KS483), an effect that was abolished by the estrogen antagonist. Endometrium-derived epithelial cells (Ishikawa) showed no response to the natural compound by using a cell viability assay (MTT). These findings suggest that ellagic acid may be a natural selective estrogen receptor modulator (SERM).
Papoutsi Z, Kassi E, Tsiapara A, Fokialakis N…
J. Agric. Food Chem. Oct 2005