Osama A. Badary

Thymoquinone is a potent superoxide anion scavenger.

Abstract The antioxidant and pro-oxidant effects of thymoquinone (TQ), a natural main constituent of the volatile oil of Nigella sativa seeds, and a synthetic structurally-related tert-butylhydroquinone (TBHQ), were examined in vitro. Both TQ and TBHQ efficiently inhibited iron-dependent microsomal lipid peroxidation in a concentration-dependent manner with median inhibitory concentration (IC50) values of 16.8 and 14.9 µM, respectively. TBHQ was stronger than TQ as a scavenger of 2,2′-diphenyl-p-picrylhydrazyl radical (DPPH) (IC50 = 5 µM, 200 times more active than TQ) and as a scavenger of hydroxyl radical (OH•) with an IC50 of 4.6 µM (approximately 10 times more active than TQ). TQ was more active than TBHQ as a superoxide anion scavenger with IC50 of 3.35 µM compared to 18.1 µM for TBHQ. Only TBHQ significantly promoted DNA damage in the bleomycin-Fe(III) system. The results suggest that both TQ and TBHQ have strong antioxidant potentials through scavenging ability of different free radicals. Moreover, the data indicate that TQ is acting mainly as a potent superoxide anion scavenger.

The influence of thymoquinone on doxorubicin-induced hyperlipidemic nephropathy in rats

The effect of thymoquinone (TQ), the main constituent of the volatile oil of Nigella sativa seeds, on the nephropathy and oxidative stress induced by doxorubicin (DOX) in rats was investigated. A single intravenous injection of DOX (6 mg/kg) induced a severe nephrotic syndrome (after 5 weeks) associated with hypoalbuminemia, hypoproteinemia, elevated serum urea, hyperlipidemia, and a high urinary excretion of protein, albumin and N-acetyl-beta-D-glucosaminidase (NAG). In the kidney, DOX induced a significant increase in total triglycerides (TG), total cholesterol (TC), and lipid peroxides and a significant decrease in non-protein sulfhydryl (NPSH) content and catalase (CAT) activity. Treatment of rats with TQ (10 mg/kg per day) supplemented with the drinking water for 5 days before DOX, and daily thereafter, significantly lowered serum urea, TG, and TC. Similarly, TG, TC and lipid peroxides in the kidneys of TQ-treated rats were decreased significantly compared with DOX alone. Moreover, NPSH content and CAT activity in the kidneys of TQ-treated DOX group were significantly elevated compared with DOX alone. Treatment with TQ significantly suppressed DOX-induced proteinuria, albuminuria, and urinary excretion of NAG. The results confirm the involvement of free radicals in the pathogenesis of nephropathy induced by DOX. Likewise, the study demonstrates the high antioxidant potential of TQ and its marked effect on the suppression of DOX-induced nephropathy. The data suggest that TQ might be applicable as a protective agent for proteinuria and hyperlipidemia associated with nephrotic syndrome.

Thymoquinone attenuates ifosfamide-induced Fanconi syndrome in rats and enhances its antitumor activity in mice

The effect of thymoquinone (TQ), the main constituent of the Nigella sativa L. oil, on ifosfamide (IFO)-induced Fanconi syndrome (FS) and its antitumor activity were investigated in rats and mice, respectively. In rats, a daily injection of IFO (50 mg/kg per day, i.p.) for 5 days induced a FS characterized by wasting off glucose, electrolytes and organic acids, along with elevated serum creatinine and urea, as well as decreased creatinine clearance rate. Administration of TQ with the drinking water of rats, (5 mg/kg per day) for 5 days before and during IFO treatment, ameliorated the severity of IFO-induced renal damage. TQ significantly improved IFO-induced phosphaturia, glucosuria, elevated serum creatinine and urea, and significantly normalized creatinine clearance rate. Moreover, TQ significantly prevented IFO-induced renal glutathione (GSH) depletion and lipid peroxide accumulation. In mice bearing Ehrlich ascites carcinoma (EAC) xenograft, TQ (10 mg/kg per day) administered in drinking water significantly enhanced the antitumor effect of IFO (50 mg/kg per day, i.p. on days 1-4 and 15-18). Furthermore, mice treated with IFO in combination with TQ showed less body weight loss and mortality rate compared to IFO single therapy. These observations demonstrate that TQ may improve the therapeutic efficacy of IFO by decreasing IFO-induced nephrotoxicity and improving its antitumor activity.

Frequent co-occurrence of the TATA box mutation associated with Gilbert's syndrome (UGT1A1*28) with other polymorphisms of the UDP-glucuronosyltransferase-1 locus (UGT1A6*2 and UGT1A7*3) in Caucasians and Egyptians.

Polymorphisms of drug metabolizing enzymes are frequently associated with diseases and side effects of drugs. Recently, a TATA box mutation of UGT1A1 (UGT1A1*28), a common genotype leading to Gilberts syndrome, and several missense mutations of other UDP-glucuronosyltransferase 1 (UGT1) family members have been described. Furthermore, co-occurrence of UGT1A1*28 and UGT1A6*2 has been observed. In order to elucidate the basis for co-occurrence of UGT1 mutations, fluorescence resonance energy transfer techniques were developed for rapid determination of polymorphisms of three UGT isoforms (UGT1A1*28, 1A6*2, and 1A7*2/*3). Hundred healthy Caucasians and 50 Egyptians were genotyped. All genotypes followed the Hardy-Weinberg equilibrium. Only three major haplotypes were found, including a haplotype consisting of allelic variants of all three isoforms (29% in Caucasians and 22% in Egyptians), all leading to reduced UGT activity. Frequent haplotypes containing several UGT1 allelic variants should be taken into account in studies on the association between diseases, abnormal drug reactions, and UGT1 family polymorphisms.

Acetyl-L-Carnitine Ameliorates Caerulein-induced Acute Pancreatitis in Rats

In the present study, we have addressed the possible protective role of acetyl-L-carnitine in caerulein-induced acute pancreatitis in male Swiss albino rats. Acute pancreatitis paradigm was developed by challenging animals with a supramaximal dose of caerulein (20 microg/kg, SC) four times at hourly intervals. Caerulein induced acute pancreatitis that was well-characterized morphologically and biochemically. Severe oedema with marked increased relative pancreatic weight, marked atrophy of acini with increased interacinar spaces, vacuolization, and extensive leucocytic infiltration were diagnostic fingerprints of the pancreatitis phenotype. A biochemical test battery that confirmed the model comprised increased plasma amylase and lipase activities, calcium levels as well as increased pancreatic enzymatic myeloperoxidase and glutathione-S-transferase activities, beside increased pancreatic contents of nitric oxide and malondialdehyde and reduced pancreatic glutathione level. Prior administration of acetyl-L-carnitine (200 mg/kg, IP) for seven consecutive days ahead of caerulein challenge alleviated all the histological and biochemical manifestations of acute pancreatitis. These results suggest a possible protective role of the carnitine ester in such a murine acute pancreatitis model probably via regulation of the oxidant/antioxidant balance, beside modulation of the myeloperoxidase and nitric oxide systems, which are involved in the inflammatory cascade that most often associate the disease.

L-Histidinol Attenuates Fanconi Syndrome Induced by Ifosfamide in Rats

The effect of L-histidinol (LHL), a structural analogue of the essential amino acid L-histidine, on ifosfamide (IFO) induced nephrotoxicity was investigated in the rat. The aim of this study was to assess whether oral supplementation of LHL could attenuate Fanconi syndrome (FS) induced by IFO. Male Wistar albino rats received daily injections of IFO (50 mg/kg) for 5 days with or without oral supplementation of 0.5% LHL in the drinking water. LHL was supplemented for 3 days before IFO administration and daily thereafter. Control rats were injected with saline with or without oral LHL. The results demonstrated that IFO induces a FS characterized by wasting of glucose, electrolytes, and organic acids, along with elevated serum creatinine and urea levels and decreased creatinine clearance. IFO-induced FS was associated with significant renal nonprotein sulfhydryl depletion and lipid peroxide (malondialdehyde) accumulation. LHL strongly ameliorated the severity of renal dysfunction induced by IFO, with significant decreases in total and fractional excretions of Na+, K+, PO43–, and glucose. Also, LHL significantly decreased the elevated serum creatinine and urea levels and significantly increased the creatinine clearance. Moreover, the beneficial effects of LHL were associated with a significant improvement of IFO-induced nonprotein sufhydry depletion and lipid peroxide accumulation. These results demonstrate that oral supplementation of LHL can partially protect against IFO-induced FS in rats.

Evaluation of cisplatin combined with ondansetron in Ehrlich ascites carcinoma in vitro and in vivo.

Aims and background Nausea and vomiting occur in the majority of patients receiving cisplatin (CDDP) chemotherapy. Ondansetron, a new 5-HT3 receptor antagonist, has been used effectively to control CDDP-induced nausea and vomiting. This study examined the potential of ondansetron to interfere with CDDP antitumor activity and toxicity in Ehrlich ascites carcinoma (EAC). Methods The influence of ondansetron on CDDP cytotoxicity was evaluated using EAC cells in culture. In addition, the influence of ondansetron pretreatment on CDDP-induced antitumor activity and host tissue toxicity was studied in EAC-bearing mice. Results Ondansetron (0.25 μM) enhanced CDDP (0–32 μM) cytotoxicity against EAC cells in vitro. In EAC-bearing mice ondansetron (0.2 mg/kg, ip) administered 1 h before CDDP (7 mg/kg, ip) did not modify the antitumor activity of CDDP. CDDP (7 mg/kg, ip) single treatment induced significant increases in blood urea nitrogen (2-fold) and serum creatinine (2.5-fold) and significant decreases in hematocrit (25%) and white blood cell count (39%) compared to saline treatment. Mice receiving ondansetron 1 h before CDDP showed no significant enhancement of CDDP-induced nephrotoxicity or myelosuppression compared to those pretreated with saline receiving the same dose of CDDP. Conclusions This study suggests that the use of ondansetron to control CDDP-induced nausea and vomiting does not affect CDDP antitumor efficacy.