Effect of guarana on exercise in normal and epinephrine-induced glycogenolytic mice

Active transport of glucose across the jejunal epithelium decreases with age in broiler chickens

Intestinal glucose absorption varies with growth; however, the dynamics of these variations has not been yet fully elucidated in broiler chickens. The present study aimed to compare jejunal glucose uptake and maltose digestion in broilers of 2 different ages, i.e., 1- vs. 5 wk old. Oral D-maltose gavage, everted sac, and Ussing chamber experiments were carried out to investigate intestinal glucose absorption and mRNA expression of glucose-transport-related genes as well as jejunal maltase activity. Upon gavage, glucose concentrations peaked at 10 min post-administration in 1-wk-old chicks, while they peaked at 40 min in 5-wk-old chickens. Glucose concentrations at 10 min were significantly higher in the 1-wk-old chicks (P = 0.010). Using the everted sacs experimental setup, 5 intestinal regions i.e., duodenum, proximal jejunum, distal jejunum, proximal ileum, and distal ileum, were targeted to examine D-maltose digestion and glucose transport across the intestinal mucosa. In the distal and proximal ileum, glucose concentrations were found to be significantly higher in the serosal compartment of the 1-wk-old chicks upon incubation with D-maltose (25 mM) (P < 0.05), while in the mucosal compartment the levels were significantly higher in the 5-wk-old chickens (P < 0.05). An Ussing chamber setup was employed to measure glucose-induced short-circuit current (ΔIsc) in the mucosal epithelium of the jejunum. In response to the addition of D-maltose (10 mM) into the mucosal compartment, ΔIsc was significantly higher in the 1-wk-old chicks (P = 0.018). Furthermore, no variations in jejunal maltase activity were observed between the 2 age groups. While jejunal glucose absorption was lower in the 5-wk-old chickens, the mRNA expression levels of jejunal SGLT1, GLUT2, and Na+/K+-ATPase did not show any significant differences between the 2 age groups. Our results suggest that the active transport of glucose across the jejunal epithelium decreases upon growth in broiler chickens but is not accompanied by any variations in maltase activity or in the expression of glucose-absorption-related genes.

Guarana: revisiting a highly caffeinated plant from the Amazon

ETHNOPHARMACOLOGICAL RELEVANCE

Guarana (Paullinia cupana Kunth var. sorbilis (Mart.) Ducke) has been traditionally consumed by indigenous communities of the Amazon region. It is valued mainly for its stimulant property because of its high content of caffeine, which can be up to 6% in the seeds.

AIM OF THE REVIEW

The purpose of this review is to revisit this typically Brazilian plant, addressing economic considerations, the chemical makeup of the seeds and pharmacological properties so far investigated.

RESULTS

Guarana is primarily produced in the Brazilian states of Amazonas and Bahia, and approximately 70% of the production is used by the industry of soft and energy drinks. The other 30% becomes guarana powder for direct consumption in capsules or dilution in water, or it serves as a raw material for the pharmaceutical and cosmetics industries. In addition to its stimulant property, guarana has other therapeutic properties, which have aroused the interest of the scientific community.

CONCLUSION

This review shows that other guarana properties may be explored and how scarce are the studies regarding agronomic, plant pathology, physiology and breeding. So far, caffeine has been the main reason to study guarana and still will lead the researches because the demand for this alkaloid by food and pharmaceutical industry, and a strongly growing market related with beauty products. However, guarana has other components and there is great interest in studies designed to elucidate the effects of guarana's bioactive components and their potential pharmacological applications. Significant part of the guarana production in Brazil still comes from Indians tribes in the Amazon State, and any improvement in this plant, in any aspect, may propitiate a positive economic impact in their lives.

Guarana (Paullinia cupana var. sorbilis), an anciently consumed stimulant from the Amazon rain forest: the seeded-fruit transcriptome

Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.

Antibacterial and antioxidant activities of ethanol extract from Paullinia cupana Mart

The antibacterial and antioxidant activity of the ethanol extract from Paullinia cupana var. sorbilis Mart. (Sapindaceae) seeds, commonly called guarana, was assessed towards selected bacteria as well as in different antioxidant models. The extract, at a concentration between 16 and 128 microg/ml, showed a significant antibacterial effect expressed as minimum inhibitory concentration (MIC) against both Gram-negative and Gram-positive bacteria. In particular, Pseudomonas aeruginosa (MIC=16 microg/ml), Proteus mirabilis (MIC=32 microg/ml), Proteus vulgaris (MIC=32 microg/ml) and Escherichia coli (MIC=32 microg/ml) were the most inhibited. The antioxidant activity was determined by the malonyldialdehyde (MDA) test, measuring the MDA concentration in 3T3-L1 cells after induced cellular damage using ferric ammonium citrate (FAC). The reduction of lipid peroxidation was 62.5% using a guarana extract with a concentration of 2 microg/ml. This effect was dose/dependent. The ethanol extract from Paullinia cupana seeds was analysed by spectrophotometry to determine the concentration of catechol substances after treatment of the extract with p-aminophenol. The total phenolics content in the ethanol extract was also determined spectrophotometrically according to the Folin-Ciocalteu procedure and calculated as gallic acid equivalents (GAE). The concentration of catechol equivalent was 6.06+/-0.13 mg/g (mean+/-S.D.), while the total phenolic content was 8.43+/-0.21 mg/g (mean+/-S.D.). The correlation index between antioxidant activity and catechol content was 0.96.

Clinical toxicology study of an herbal medicinal extract of Paullinia cupana, Trichilia catigua, Ptychopetalum olacoides and Zingiber officinale (Catuama) in healthy volunteers

In Brazil, a herbal medicinal extract named Catuama containing a mixture of Paullinia cupana (guarana; Sapindaceae), Trichilia catigua (catuaba; Meliaceae), Ptychopetalum olacoides (muirapuama; Olacaceae) and Zingiber officinale (ginger; Zingiberaceae) is used as a body stimulant, energetic, tonic and aphrodisiac. The present study investigated the chronic administration of 25 mL Catuama twice a day during 28 days for any toxic effect on healthy human volunteers of both sexes. No severe adverse reactions or haematological and biochemical changes were reported.

Diabetic ketoacidosis associated with Metabolife: a report of two cases

AIM

To describe two cases of diabetic ketoacidosis in newly diagnosed type 1- and type-2-diabetic individuals associated with Metabolife-356.

METHODS

We report the acute hospitalizations and clinical courses of two individuals with diabetic ketoacidosis taking Metabolife-356.

RESULTS

Both patients presented without a previous diagnosis of diabetes mellitus. One patient clinically has type 1 diabetes (positive islet cell antibodies and subnormal pancreatic beta cell function to glucagon stimulation) and is treated with insulin. The second patient, after 5 days of treatment with intravenous insulin of up to 25 units per hour, is now treated with oral medications. Several possible mechanisms may exist, including the increases in catecholamines and in blood glucose after ingestion of the ingredients of these supplements. Recent clinical trial data shows an increase in blood glucose (in non-diabetics) with these supplements despite significant weight loss at 8 weeks, although no association with diabetes mellitus has been shown in these closely monitored studies.

CONCLUSIONS

Although no precipitating factor of diabetic ketoacidosis was found in these individuals, the dietary supplement Metabolife cannot be established as a precipitant. However, patients with diabetes should take this supplement only after consultation with their health care provider, as stated on the product label. Most individuals using this supplement meet the current criteria for screening to detect undiagnosed diabetes mellitus and should consider these tests.

The relaxation of isolated rabbit corpus cavernosum by the herbal medicine Catuama and its constituents

The effects of the Brazilian herbal medicine Catuama and each of its plant constituents (Paullinia cupana, Trichilia catigua, Zingiber officinalis and Ptychopetalum olacoides) were investigated on rabbit corpus cavernosum (RbCC) using a bioassay cascade. Catuama caused short-lived and dose-dependent relaxations (11% +/- 7%, 26% +/- 5% and 82% +/- 9%, at doses of 1, 3 and 10 mg, respectively). Neither the nitric oxide synthesis inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME; 10 microM) nor the soluble guanylate cyclase inhibitor ODQ (10 microM) significantly affected the Catuama-induced relaxations. Similarly, the selective ATP-dependent K(+) channel (K(ATP)) blocker glibenclamide (10 microM), the muscarinic receptor antagonist atropine (1 microM) and the voltage-dependent Na(+) channel blocker tetrodotoxin (1 microM) all failed to affect significantly the Catuama-induced relaxations. These results indicate that the relaxations induced by Catuama involve neither nitric oxide release nor K(ATP) channel activation. The extracts of P. cupana, Z. officinalis and P. olacoides caused short-lived and dose-dependent RbCC relaxations, whereas T. catigua evoked long-lasting relaxations which were occasionally preceded by a brief contractile effect. The extract of P. cupana was the most active in relaxing RbCC strips. The relaxations induced by all extracts were not significantly affected by L-NAME (10 microM). The infusion of ODQ (10 microM) had no significant effect on the P. cupana- and Z. officinalis-induced relaxations but reduced by >50% (p < 0.05) those evoked by P. olacoides and T. catigua. Incubations of RbCC with Catuama(10 mg/mL for 0.25 to 5 min) caused increases of cAMP levels (143% increase at 5 min of incubation). Incubations of RbCC with P. cupana extract (1 mg/mL) increased the cAMP levels by 200% whereas higher doses (10 and 100 mg/mL) caused smaller increases in the nucleotide levels (150% and 89%, respectively). The extracts of Z. officinalis and P. olacoides (same doses) caused smaller increases of the cAMP levels compared with the P. cupana extract, whereas T. catigua (1-100 mg) did not increase the levels of this nucleotide above the basal values. Our results show that of the four extracts assayed, P. cupana was the most effective, indicating that it is the main extract responsible for the relaxing effect of Catuama on rabbit cavernosal tissue.

An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial

OBJECTIVE

To examine in overweight humans the short-term safety and efficacy for weight loss of an herbal supplement containing Ma Huang, Guarana and other ingredients.

DESIGN

An 8 week randomized, double-blind placebo controlled study of a herbal dietary supplement (72 mg/day ephedrine alkaloids and 240 mg/day caffeine).

SUBJECTS

Overweight men and women (body mass index, > or =29 and < or =35 kg/m2).

MEASUREMENTS

The primary outcome variable was body weight change. Secondary variables included anthropometric, metabolic and cardiovascular changes.

RESULTS

Sixty-seven subjects were randomized to either placebo (n=32) or active Ma Huang/Guarana (n=35). Twenty-four subjects in each group completed the study. Active treatment produced significantly (P<0.006) greater loss of weight (X+/-s.d.,-4.0+/-3.4 kg) and fat (-2.1+/-3.0% fat) over the 8-week treatment period than did placebo (-0.8+/-2.4 kg and 0.2+/-2.3% fat). Active treatment also produced greater reductions in hip circumference and serum triglyceride levels. Eight of the 35 actively treated subjects (23%) and none of the 32 placebo-treated control subjects withdrew from the protocol because of potential treatment-related effects. Dry mouth, insomnia and headache were the adverse symptoms reported most frequently by the herbal vs placebo group at the final evaluation visit.

CONCLUSIONS

This herbal mixture of Ma Huang and Guarana effectively promoted short-term weight and fat loss. Safety with long-term use requires further investigation.