Stimulatory effects on Na+ transport in renal epithelia induced by extracts of Nigella arvensis are caused by adenosine

Evaluation of antimicrobial and anti-inflammatory activities of seed extracts from six Nigella species

Seed extracts from six species of the genus Nigella (Family Ranunculaceae)-Nigella arvensis, Nigella damascena, Nigella hispanica, Nigella nigellastrum, Nigella orientalis, and Nigella sativa-obtained by successive extraction with n-hexane, chloroform, and methanol, were tested for their antimicrobial activity against 10 strains of pathogenic bacteria and yeast using the microdilution method as well as for anti-inflammatory properties by in vitro cyclooxygenase (COX)-1 and COX-2 assay. Chemical characterization of active extracts was carried out including free and fixed fatty acid analysis. Comparison of antimicrobial activity showed that N. arvensis chloroform extract was the most potent among all species tested, inhibiting Gram-positive bacterial and yeast strains with minimum inhibitory concentration (MIC) values ranging from 0.25 to 1 mg/mL. With the exception of selective inhibitory action of n-hexane extract of N. orientalis on growth of Bacteroides fragilis (MIC = 0.5 mg/mL), we observed no antimicrobial activity for other Nigella species. Anti-inflammatory screening revealed that N. sativa, N. orientalis, N. hispanica, N. arvensis n-hexane, and N. hispanica chloroform extracts had strong inhibitory activity (more than 80%) on COX-1 and N. orientalis, N. arvensis, and N. hispanica n-hexane extracts were most effective against COX-2, when the concentration of extracts was 100 microg/mL in both COX assays. In conclusion, N. arvensis, N. orientalis, and N. hispanica seeds, for the first time examined for antimicrobial and anti-inflammatory effects, revealed their significant activity in one or both assays.

Ancient nigella seeds from Boyali Höyük in north-central Turkey

AIM OF THE STUDY

The seeds of nigella (black cumin) (Nigella sativa L.) have been widely used as a natural remedy, either alone or in combination with bee products, for the treatment of many acute as well as chronic conditions for centuries, especially in the Middle East and Southeast Asia. In consideration of potential utilization, in recent years the seeds have been extensively studied in terms of pharmacological effects. It has been shown that the seeds have significant effects on multiple biological systems. In addition, the protective roles of the seeds with bee products (honey and wax) have been recently proved. This study reports the palaeoethnobotanical find of nigella seeds recovered in a pilgrim flask from the Old Hittite Period level of Boyali Höyük (Mound), dating from around 1650 BC, in north-central Turkey. The study also deals with a comparison between the chemical properties of the Boyali Höyük nigella seeds (ancient seeds) and those of modern nigella seeds. The results of chemical analysis of the debris found in the pilgrim flask to test the presence of bee product are also presented here.

MATERIALS AND METHODS

All macro-remains found in the pilgrim flask were first examined under a zoom stereomicroscope for specific determination and all were identified as nigella seeds using the reference collection of modern seeds. Ethyl alcohol and dichloromethane (Aldrich, Buch-Switzerland) were used for the extraction of the ancient seeds and modern nigella seeds to trace both polar and non-polar chemical compounds by a Gas Chromatography-Mass Spectrometer (GC-MS) system. Characterization of the chemical compounds in propolis extracts was also made by GC-MS.

RESULTS

The GC-MS chromatograms showed that the ancient and modern seed samples were similar in essential oil acids. Many organic compounds of bee products, such as wax and phenolic antioxidants, were also detected in the container.

CONCLUSION

The results of this study indicated that the Hittite pilgrim flask contained a pure cache of nigella seeds mixed with bee products, wax and propolis. There has been no direct archaeological evidence for medicinal use of nigella seeds with bee products by the inhabitants of Boyali Höyük or the Hittities so far. However, in view of the folkloric use of nigella seeds in combination with bee products for treatments of disorders and promotion of health, it is thought that the Boyali Höyük material would represent a remedy used by the Hittites in Anatolia about 3600 years ago.

Membrane cholesterol extraction decreases Na+transport in A6 renal epithelia

In this study, we have investigated the dependence of Na+transport regulation on membrane cholesterol content in A6 renal epithelia. We continuously monitored short-circuit current ( Isc), transepithelial conductance ( GT), and transepithelial capacitance ( CT) to evaluate the effects of cholesterol extraction from the apical and basolateral membranes in steady-state conditions and during activation with hyposmotic shock, oxytocin, and adenosine. Cholesterol extraction was achieved by perfusing the epithelia with methyl-β-cyclodextrin (mβCD) for 1 h. In steady-state conditions, apical membrane cholesterol extraction did not significantly affect the electrophysiological parameters; in contrast, marked reductions were observed during basolateral mβCD treatment. However, apical mβCD application hampered the responses of Iscand GTto hypotonicity, oxytocin, and adenosine. Analysis of the blocker-induced fluctuation in Iscdemonstrated that apical mβCD treatment decreased the epithelial Na+channel (ENaC) open probability ( Po) in the steady state as well as after activation of Na+transport by adenosine, whereas the density of conducting channels was not significantly changed as confirmed by CTmeasurements. Na+transport activation by hypotonicity was abolished during basolateral mβCD treatment as a result of reduced Na+/K+pump activity. On the basis of the findings in this study, we conclude that basolateral membrane cholesterol extraction reduces Na+/K+pump activity, whereas the reduced cholesterol content of the apical membranes affects the activation of Na+transport by reducing ENaC Po.

Sodium-sensitive and -insensitive copper accumulation by isolated intestinal cells of rainbow troutOncorhynchus mykiss

The pathway for copper (Cu) uptake across the mucosal membrane into intestinal cells has not been elucidated in fish. Copper accumulation in freshly isolated intestinal cells from rainbow trout Oncorhynchus mykiss was measured after exposure to 0–800 μmol l–1 CuSO4 for 15 min. With external Cu concentration (Cuo) of 800 μmol l–1, the rate of Cu accumulation by cells was 1.88±0.52 nmol Cu mg–1cell protein h–1 compared to 0.05±0.01 nmol Cu mg–1 cell protein h–1 with no added Cuo (means ± s.e.m., N=6). Deduction of a rapid Cu accumulation measured on/in cells at time zero (about 12% of the total Cu uptake when Cuo was 800 μmol l–1)revealed a saturable uptake curve, which reached a plateau at 400 μmol l–1 Cuo (Km=216 μmol l–1 Cuo; Vmax=1.09 nmol Cu mg–1 cell protein h–1; 140 mmol l–1 NaCl throughout). Incubation of cells at 4°C did not prevent Cu accumulation. Lowering external [Na+] to 11 mmol l–1 (low Na+o) generally did not alter the rate of Cu accumulation into the cells over a 15 min period. Under low Na+o conditions Cu accumulation was exponential(non-saturable). Na+-insensitive Cu accumulation dominated (59% of total Cu accumulation) when Cuo was 400 μmol l–1 or less. At high Cuo (800 μmol l–1), removal of Na+ caused a 45% increase in Cu accumulation. Pre-incubation of cells with blocking agents of epithelial Na+ channel (ENaC) for 15 min (normal [NaCl] throughout) caused Cu accumulation rates to increase by 40-fold (100 μmol l–1phenamil), 21-fold (10 μmol l–1 CDPC) or 12-fold (2 mmol l–1 amiloride) when Cuo was 800 μmol l–1 compared to those in drug-free controls. Lowering the external chloride concentration [Cl–]o from 131.6 to 6.6 mmol l–1 (replaced by sodium gluconate) caused the rate of Cu accumulation to increase 11-fold when Cuo was 800μmol l–1. Application of 0.1 mmol l–1DIDS (normal Cl–o) caused a similar effect. Lowering external pH from 7.4 to pH 5.5 produced a 17-fold, saturable,increase in Cu accumulation rate, which was not explained by increased instantaneous Cu accumulation on/in cells at low pH. We conclude that Cu accumulation by intestinal cells is mainly Na+-insensitive and more characteristic of a pH- and K+-sensitive Ctr1-like pathway than Cu uptake through ENaCs.

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes. Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates. Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself. The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system. Nevertheless, substantial questions about the evolution of these mechanisms and control remain.