The role of calcium in intracellular pathways of rutin in rat pancreatic islets: potential insulin secretagogue effect.

Rutin is a flavonol glycoside with multiple biological activities and it has been demonstrated that rutin modulates glucose homeostasis. In pancreatic ß-cell, an increase in intracellular calcium concentration triggers exocytosis and thus insulin secretion. The aim of the study reported herein was to investigate the effect of rutin associated intracellular pathways on Ca(2+) uptake in isolated rat pancreatic islets. We focused on the acute effects of rutin on in vivo insulin secretion and the in vitro cellular signaling of pancreatic islets related to this effect. The results show that rutin significantly increased glucose-induced insulin secretion in an in vivo treatment. Moreover, it was demonstrated that rutin stimulated Ca(2+) uptake after 10 min of incubation compared with the respective control group. The involvement of L-type voltage-dependent Ca(2+) channels (L-VDCCs) was evidenced using nifedipine, while the use of glibenclamide and diazoxide demonstrated that the ATP-sensitive potassium (KATP) channels are not involved in the rutin action in pancreatic islets. In conclusion, rutin diminish glycemia, potentiate insulin secretion in vivo and significantly stimulates Ca(2+) uptake in rat pancreatic islets. A novel cellular mechanism of action of rutin in Ca(2+) uptake on pancreatic ß-cells was elucidated. Rutin modulates Ca(2+) uptake in pancreatic islets by opening L-VDCCs, alter intracellular Ca(2+), PLC and PKC signaling pathways, characterizing KATP channel-independent pathways. These findings highlight rutin, a dietary adjuvant, as a potential insulin secretagogue contributing to glucose homeostasis.

Short and long-term effects of Baccharis articulata on glucose homeostasis.

In this study, the in vivo effect of the crude extract and n-butanol and aqueous residual fractions of Baccharis articulata (Lam.) Pers. on serum glucose levels, insulin secretion and liver and muscle glycogen content, as well as in vitro action on serum intestinal disaccharidase activity and albumin glycation were investigated. Oral administration of the extract and fractions reduced glycemia in hyperglycemic rats. Additionally, the n-butanol fraction, which has high flavonoids content, stimulated insulin secretion, exhibiting an insulinogenic index similar to that of glipizide. Also, the n-butanol fraction treatment significantly increased glycogen content in both liver and muscle tissue. In vitro incubation with the crude extract and n-butanol and aqueous residual fractions inhibited maltase activity and the formation of advanced glycation end-products (AGEs). Thus, the results demonstrated that B. articulata exhibits a significant antihyperglycemic and insulin-secretagogue role. These effects on the regulation of glucose homeostasis observed for B. articulata indicate potential anti-diabetic properties.

Phenolic content and antioxidant and antimicrobial properties of fruits of Capsicum baccatum L. var. pendulum at different maturity stages.

The phenolic content, antioxidant potential, and antimicrobial activity of extracts of different parts of the fruit from Capsicum baccatum L. var. pendulum were investigated. The analysis of phenolic content was performed by the Folin-Ciocalteu method and reversed-phase high-performance liquid chromatography. The in vitro antioxidant activity was assessed by the total reactive antioxidant potential and total antioxidant reactivity index. The antioxidant activity was positively correlated with the amount of phenolics found in each sample. The ex vivo antioxidant potential was assessed using the rat liver slice model. The antimicrobial activity was screened using Gram-positive and Gram-negative bacteria and fungi. All the extracts revealed antioxidant activity and a weak antimicrobial activity.

The aqueous extracts of Passiflora alata and Passiflora edulis reduce anxiety-related behaviors without affecting memory process in rats.

Several species of Passiflora have been employed widely as a folk medicine because of sedative and tranquillizer activities. In this study, we evaluate the effects on anxiety and memory process of two popularly used Passiflora species. To this aim, male Wistar rats (weighing 250-300 g) were intraperitoneally injected with the aqueous extract of Passiflora alata or Passiflora edulis (25, 50, 100, or 150 mg/kg; single injection) 30 minutes prior to the elevated plus-maze test, inhibitory avoidance test, or habituation to an open-field apparatus. The effects of both species of Passiflora were compared with that of diazepam (1 mg/kg), a standard anxiolytic drug. Our findings revealed that, similar to diazepam, the treatment with P. alata (100 and 150 mg/kg) and P. edulis (50, 100, and 150 mg/kg) induced anxiolytic-like effects in rats. Memory was not affected by the treatment with any dose of P. alata or P. edulis, but diazepam disrupted memory process in rats. Phytochemical analysis showed that the content of flavonoids of the aqueous extract of P. edulis is almost twice that of P. alata. These differences in contents of flavonoids could explain the lower active doses of the aqueous extract of P. edulis in inducing anxiolytic-like effects compared to P. alata. In conclusion, our findings suggest that, distinct from diazepam, the aqueous extract of both species of Passiflora induced anxiolytic-like effects in rats without disrupting memory process.