Stimulatory effects on Na+ transport in renal epithelia induced by extracts of Nigella arvensis are caused by adenosine. (1/12)

Effects of the extract of Nigella arvensis (NA) seeds on transepithelial Na(+) transport were studied in cultured A6 toad kidney cells by recording short-circuit current (I(sc)), transepithelial conductance (G(T)), transepithelial capacitance (C(T)) and fluctuation in I(sc). Apical application of NA extract had merely a small stimulatory effect on Na(+) transport, whereas basolateral administration markedly increased I(sc), G(T) and C(T). A maximal effect was obtained at 500 microll(-1) of lyophilized NA extract. The increase in C(T) suggests that the activation of I(sc) occurs through the insertion of transport sites in the apical membrane. In experiments performed in the absence of Na(+) transport [apical Na(+) was replaced by N-methyl-D-glucamine (NMDG(+))], basolateral NA extract did not affect I(sc) and G(T), indicating that Cl(-) conductance was not influenced. Noise analysis of I(sc) using 6-chloro-3,5-diaminopyrazine-2-carboxamide (CDPC) showed that NA extract reduced single-channel current (i(Na)) and decreased channel open probability (P(o)) but evoked a threefold increase in channel density (N(T)), which confirms the insertion of Na(+) channels. The separation of the compounds in the crude extract of NA was performed by fast protein liquid chromatography (FPLC) on a Superdex 200 gel-filtration column and by reverse-phase high-pressure liquid chromatography (RPHPLC) on an micro RPC C2/C18 SC2.1/10 column connected to a SMART system. Analysis of the purified active fraction by mass spectrometry demonstrated the presence of adenosine as the single organic compound in the extract that had a stimulatory effect on Na(+) transport. In a separate series of experiments, we confirmed that 1 micromol l(-1) adenosine had similar effects on the parameters of Na(+) transport as did the NA extract. The action of adenosine was further identified by experiments in which NA extract was added after adenosine. In these experiments, NA extract did not affect I(sc), G(T) or C(T). These results clearly demonstrate an essential role of adenosine in the stimulatory action of NA extract.  (+info)

A new alkaloid and its artificial derivative with an indazole ring from Nigella glandulifera. (2/12)

A new compound, nigeglanine (1), and its new artificial derivative (1a), were isolated from the seeds of Nigella glandulifera, together with a known aporphine alkaloid, fuzitine (2). Their structures were established by spectral analysis, including two-dimensional (2D)-NMR spectroscopy. Nigeglanine (1) is the third natural product determined to contain an indazole nucleus.  (+info)

Sativa seeds against Schistosoma mansoni different stages. (3/12)

The schistosomicidal properties of Nigella sativa seeds were tested in vitro against Schistosoma mansoni miracidia, cercariae, and adult worms. Results indicate its strong biocidal effects against all stages of the parasite and also showed an inhibitory effect on egg-laying of adult female worms. In the present work we also studied the effects of crushed seeds on some antioxidant enzymes; which have a role in protection of adult worms against host oxidant killing; as well as some enzymes of glucose metabolism; which have a crucial role in the survival of adult worms inside their hosts. The data revealed that the used drug induce an oxidative stress against adult worms which indicated by a decrease in the activities of both antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and glutathione reductase and enzymes of glucose metabolism, hexokinase and glucose-6-phosphate dehydrogenase. Disturbing of such enzymes of adult worms using N. sativa seeds could in turn render the parasite vulnerable to damage by the host and may play a role in the antischistosomal potency of the used drug.  (+info)

The genetic basis of naturally occurring pollen color dimorphisms in Nigella degenii (Ranunculaceae). (4/12)

Nigella degenii ssp. barbro and ssp. jenny differ from related taxa in being dimorphic for pollen color, with some plants having dark pollen and others light pollen. In this study we performed experimental crosses to determine whether the difference in pollen color is governed by few or many loci and whether the two subspecies utilize the same gene to control pollen color. Patterns of segregation in crosses between morphs show that dark pollen is dominant over light pollen and that a single major gene is responsible for most of the variation in pollen color. Consequently it should be relatively easy for pollen color dimorphisms to establish and spread in these subspecies. Aberrant segregation ratios were attributed to genetic factors that reduced the expression of the allele conferring dark pollen or processes that sorted between color morphs during seed development. Crosses between dark pollen plants from different subspecies showed signs of complementation in the F2 generation, but the frequency of the light morph was too low to support a model involving complementary action of recessive alleles at two separate loci. Based on this and other observations, we hypothesize that the pollen color difference is controlled by the same major locus in the two subspecies.  (+info)

Gastroprotective activity of Nigella sativa L oil and its constituent, thymoquinone against acute alcohol-induced gastric mucosal injury in rats. (5/12)

AIM: To evaluate the role of reactive oxygen species in the pathogenesis of acute ethanol-induced gastric mucosal lesions and the effect of Nigella sativa L oil (NS) and its constituent thymoquinone (TQ) in an experimental model. METHODS: Male Wistar albino rats were assigned into 4 groups. Control group was given physiologic saline orally (10 mL/kg body weight) as the vehicle (gavage); ethanol group was administrated 1 mL (per rat) absolute alcohol by gavage; the third and fourth groups were given NS (10 mL/kg body weight) and TQ (10 mg/kg body weight p.o) respectively 1 h prior to alcohol intake. One hour after ethanol administration, stomach tissues were excised for macroscopic examination and biochemical analysis. RESULTS: NS and TQ could protect gastric mucosa against the injurious effect of absolute alcohol and promote ulcer healing as evidenced from the ulcer index (UI) values. NS prevented alcohol-induced increase in thiobarbituric acid-reactive substances (TBARS), an index of lipid peroxidation. NS also increased gastric glutathione content (GSH), enzymatic activities of gastric superoxide dismutase (SOD) and glutathione-S-transferase (GST). Likewise, TQ protected against the ulcerating effect of alcohol and mitigated most of the biochemical adverse effects induced by alcohol in gastric mucosa, but to a lesser extent than NS. Neither NS nor TQ affected catalase activity in gastric tissue. CONCLUSION: Both NS and TQ, particularly NS can partly protect gastric mucosa from acute alcohol-induced mucosal injury, and these gastroprotective effects might be induced, at least partly by their radical scavenging activity.  (+info)

Cytotoxicity of two triterpenoids from Nigella glandulifera. (6/12)

During an investigation of antitumor substances from Nigella glandulifera Freyn et Sint. (Ranunculaceae) the cytotoxicity of two oleanane triterpene saponins isolated from the seeds of this species, kalopanaxsaponins A and I, was evaluated against HepG2, drug resistant HepG2 (R-HepG2) (two hepatocyte cell lines) and primary cultured normal mouse hepatocytes. Evident cytotoxic activities were observed. Morphological observations and cell cycle analysis suggest that these compounds inhibit the proliferation of hepatoma by inducing apoptosis and consequently kalopanaxsaponins A and I may be potential therapeutic agents for the treatment of parental and drug resistant hepatoma.  (+info)

Inhibition of melanogenesis by dioctyl phthalate isolated from Nigella glandulifera Freyn. (7/12)

Although a number of melanogenesis inhibitors have recently been reported and used as cosmetic additives, none is completely satisfactory, leaving a need for novel skin-depigmenting agents. Thus, to develop a novel skin-depigmenting agent from natural sources, the inhibition of melanogenesis by Chinese plants was evaluated. A methanolic extract of Nigella glandulifera Freyn was found to inhibit the melanin synthesis of murine B16F10 melanoma cells by 43.7% and exhibited a low cytotoxicity (8.1 %) at a concentration of 100 microg/ml. Thus, to identify the melanogenesis-inhibiting mechanism, the inhibitory activity towards tyrosinase, the key enzyme of melanogenesis, was further evaluated, and the results showed inhibitory effects on the activity of intracellular tyrosinase yet not on mushroom tyrosinase. Finally, to isolate the compounds with a hypopigmenting capability, activity-guided isolation was performed, and Dioctyl phthalate identified as inhibiting melanogenesis.  (+info)

Plant speciation in continental island floras as exemplified by Nigella in the Aegean Archipelago. (8/12)

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