Various beneficial properties has been attributed to Nigella sativa, including its antioxidant potential. Previously, it was reported that supercritical fluid extraction (SFE) could be used to obtain N. sativa extract rich in antioxidants. In the present study, N. sativa extracts prepared using the previously optimized SFE as well as the traditional Soxhlet extraction approaches were analyzed for various known antioxidants. N. sativa extracts were found to prevent protein carbonyl formation as well as depletion of intracellular glutathione (GSH) in fibroblasts exposed to toluene. Furthermore, partially purified SFE and Soxhlet fractions could prevent loss of hepatic GSH in toluene-induced oxidative stressed Wistar rats as well as in L929 fibroblasts. The results showed that SFE-produced N. sativa extract is richer in antioxidants than the Soxhlet approach. It was also shown using preparative silica gel and reverse phase chromatography that different fractions of SFE-extracted or Soxhlet-extracted N. sativa had different levels of protective effects with regards to GSH depletion in vivo as well as in cell culture. Although fractions rich in thymoquinone were found to be most potent in terms of antioxidant capacity, the data indicates that the protective effects of N. sativa may not only be due to thymoquinone, but perhaps other antioxidants.

Although medicinal plants are used as antispasmodic agents in folk medicine there have been no scientific studies of the phytochemical composition and usefulness of these plants for such treatment. Extracts of 23 plants used in the traditional medicine of the United Arab Emirates were tested for their effects on intestinal smooth muscle activity. Most of the plants tested caused stimulation followed by inhibition of the motility of the rabbit jejunum and guinea-pig ileum. The inhibitory effect of plants that had EC50 values < 1 mg was confirmed in-vivo using the gastrointestinal transit time test. These plants were phytochemically screened for their secondary constituents. The effect of Rhazya stricta was investigated, particularly in relation to acetylcholine effect. The results indicated the potential of some of the plants, especially Rhazya stricta, as a source of antispasmodic agents.

No abstract

Our objectives were to compare the levels of circulating electrolytes, hormones, and renal function during 20 days of dehydration in camels versus the level in non-dehydrated camels and to record the effect of blocking angiotensin II AT1 receptors with losartan during dehydration. Dehydration induced significant increments in serum sodium, creatinine, urea, a substantial fall in body weight, and a doubling in plasma arginine vasopressin (AVP) levels. Plasma aldosterone, however, was unaltered compared with time-matched controls. Losartan significantly enhanced the effect of dehydration to reduce body weight and increase serum levels of creatinine and urea, whilst also impairing the rise in plasma AVP and reducing aldosterone levels. We conclude that dehydration in the camel induces substantial increments in serum sodium, creatinine, urea and AVP levels; that aldosterone levels are altered little by dehydration; that blockade of angiotensin II type 1 receptors enhances the dehydration-induced fall in body weight and increase in serum creatinine and urea levels whilst reducing aldosterone and attenuating the rise in plasma AVP.

In the intestine glucose transport occurs via an apical Na-coupled glucose co-transporter (SGLTI) and a basolateral hcilitated glucose transporter GLUT 2. cDNA encoding rat, rabbit, human and lamb intestinal SGLTI have been cloned and amino acid sequences deduced. They all share an extraordinary degree of sequence homology [I]. Antibodies have been raised to synthetic peptides, derived from defined regions of the SGLTl amino acid sequences and have been used to study the distribution of these epitopes in ditbent species [2, 31. It is well established that in diabetes mellitus there is an increase in the capacity of the intestine to absorb glucose [4]. This increase has been proposed to be due to a) hypertrophy of the small intestinal villi, resulting in a greater sufice area for glucose absorption, andor b)increased activities of brush border SGLTl and the basolateral membrane GLUT2 [5].We have assessed the expression of the intestinal SGLTI and the structural protein d i n in brush-border membrane vesicles isolated from control and the diabetic rats. Our results indicate that in diabetes there is a specific increase in the abundance of SGLTI with no change in the levels of villin.Non-insulin dependent diabetes was induced in male Wistar rats, aged 10 weeks, by a single injection of streptozotocin (65 mglkg). Brush-border membrane vesicles (BBMV) were isolated from the small intestine, of both control and diabetic animals, using a method described previously [6] and applied to rat intestine. without modification. The Na*-dependent transport of D-glucose and SGLTl protein abundance were measured in BBMV prepared fiom rats I week, I month and 3 months fbllowing the onset of diabetes.As can be seen in Table 1, within I week following treatment with streptozotocin blood glucose levels have increased over 4fold. Mean body weight, however, remained constant throughopt the 3 month period. The initial rate of Na'-dependent glucose uptake was unchanged in the acute phase of diabetes, after 7 days, but increased over 2-fold within 4 weeks. Table I . Changes in blood ~lucom level. bodv . weiszht and Na'd -1 en e, (pmoi/s/mn protein) Control 58+2 254+ 11 I30 + 20 7 days 469 _+ 28 2 6 1 t 7 80 _+ 20 4weeks 438220 224 t 21 310 2 30 3 months 428 5 36 225 16 240 & 10 Vaiues are psentrrrlas man & S. E. M. h=3)Western blot analysis, using antibodies raised against SGLTI, was used to assess changes in the abundance of SGLTI protein in the intestinal BBMV samples. The results are shown in Fig. 1. The amount of SGLTI protein is 2-fold higher in the chronic diabetic rats (4 weeks and 3 months), than in the control animals.It has been reported that diabetes can induce hyperphagia, which in turn leads to mucosal hyperplasia [7] and the increased mucosal mass could be responsible for the enhanced capacity of the intestine to absorb glucose. In order to standardise our results for any changes in villus morphology we screened the samples with monoclonal antibodies against the structural protein villin.BBMV. SGLT1 abundance(pmol / mg protei...