tannins and eckstolonol

In psychopharmacology, researchers have been interested in the hypnotic effects of terrestrial plant polyphenols and their synthetic derivatives. Phlorotannins, a marine plant polyphenol, could have potential as a source of novel hypnotic drugs.. The effects of phlorotannins and major phlorotannin constituent eckstolonol on sleep-wake profiles in mice were evaluated in comparison with diazepam, and their hypnotic mechanism was also investigated.. The effects of phlorotannin preparation (PRT) and eckstolonol orally given on sleep-wake profiles were measured by recording electroencephalograms (EEG) and electromyograms in C57BL/6N mice. Flumazenil, a GABAA-benzodiazepine (BZD) receptor antagonist, was injected 15 min before PRT and eckstolonol to reveal its hypnotic mechanism.. PRT administration (>250 mg/kg) produced a significant decrease in sleep latency and an increase in the amount of non-rapid eye movement sleep (NREMS). Eckstolonol significantly decreased sleep latency (>12.5 mg/kg) and increased the amount of NREMS (50 mg/kg). PRT and eckstolonol had no effect on EEG power density of NREMS. The hypnotic effects of PRT or eckstolonol were completely abolished by pretreatment with flumazenil.. We demonstrated that phlorotannins promote NREMS by modulating the BZD site of the GABAA receptor. These results suggest that phlorotannins can be potentially used as an herbal medicine for insomnia and as a promising structure for developing novel sedative-hypnotics.

Topics: Animals; Diazepam; Dioxanes; Dose-Response Relationship, Drug; Electroencephalography; Flumazenil; Heterocyclic Compounds, 4 or More Rings; Hypnotics and Sedatives; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Polyphenols; Receptors, GABA-A; Sleep; Tannins

In the present study, a methanolic extract of Ecklonia cava and its solvent-partitioned fractions were evaluated for their antiadipogenic effect in 3T3-L1 adipocytes. One of them, the n-BuOH fraction, effectively reduced lipid accumulation and glucose consumption. In addition, the presence of the n-BuOH fraction in adipocytes suppressed the regulations of adipogenic transcription factors, PPARγ and SREBP1c, and adipogenic specific genes, FABP4, FABP1, FAS, LPL, HSL, and ACS1. Further purification of n-BuOH fractions led to the isolation of six phlorotannins (1-6). The six phlorotannins effectively suppressed triglyceride accumulation. Comparative analysis showed that lipid accumulation in adipocytes was dramatically attenuated in the presence of eckstolonol (4).

Topics: 3T3-L1 Cells; Adipocytes; Adipogenesis; Animals; Dioxanes; Gene Expression; Glucose; Heterocyclic Compounds, 4 or More Rings; Mice; Phaeophyceae; Tannins; Triglycerides

In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with EC50 values of 62.0 and 79.2 microg/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an EC50 value of 50.0 microg/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.

Topics: Benzofurans; Cell Line, Tumor; Cell Survival; Chemical Fractionation; Dioxanes; Dioxins; Ethanol; Heterocyclic Compounds, 4 or More Rings; Humans; Inhibitory Concentration 50; Liver; Phaeophyceae; Phloroglucinol; Protective Agents; Silybin; Silymarin; Tacrine; Tannins