Oral and intraperitoneal LD50 of thymoquinone, an active principle of Nigella sativa, in mice and rats.

BACKGROUND: Thymoquinone is the major active principle of Nigella sativa (N. sativa) and constitutes about 30% of its volatile oil or ether extract. N. sativa oil and seed are commonly used as a natural remedy for many ailments. Using modern scientific techniques, a number of pharmacological actions of N. sativa have been investigated including immunostimulant, anti-inflammatory, anticancer, antioxidant, antihistaminic, antiasthmatic, hypoglycemic, antimicrobial and antiparasitic. There are only few reports regarding the toxicity of thymoquinone. METHODS: The present study was carried out to determine LD50 of thymoquinone both in mice and rats, orally as well as intraperitoneall, by the method of Miller and Tainter. Autopsy and histopathology of liver, kidney, heart and lungs were also determined. RESULTS: The LD50 in mice after intraperitoneal injection was determined to be 104.7 mg/kg (89.7-119.7, 95% confidence interval) and after oral ingestion was 870.9 mg/kg (647.1-1094.8, 95% confidence interval). Whereas, LD50 in rats after intraperitoneal injection was determined to be 57.5 mg/kg (45.6-69.4, 95% confidence intervals) and after oral ingestion was 794.3 mg/kg (469.8-1118.8, 95% confidence intervals). The LD50 values presented here after intraperitoneal injection and oral gavages are 10-15 times and 100-150 times greater than doses of thymoquinone reported for its anti-inflammatory, anti-oxidant and anti-cancer effects. CONCLUSION: Thymoquinone is a relatively safe compound, particularly when given orally to experimental animals.

Vitamin D deficiency and rickets in the Eastern Province of Saudi Arabia.

BACKGROUND: Nutritional rickets remains prevalent in many developing countries, despite the availability of ample sunlight. The aim of this study was to investigate the clinical features and chemical pathology in a group of children with rickets and to compare them with a control group. SUBJECTS AND METHODS: In a case-control study over a 1-year period (March 2004 to February 2005), children clinically diagnosed with rickets (n=61) were age- and sex-matched with controls (n=58). In addition to routine chemical pathology, 25 (OH) vitamin D3 and parathormone (PTH) were determined. Controls were children without clinical rickets attending hospital for other blood investigations. RESULTS: The mean age of children with rickets was 14.8 mths and of controls was 16.5 mths. Mean (SD) body mass index of the children with rickets [16.8 (1.86)] was not significantly different from that of the controls [17.02 (3.16)]. Mean (SD) head circumference of rachitic children [45.41 (3.64) cm] was greater than that of controls [44.39 (5.07) cm, p=0.03]. Eighty per cent of the children with rickets were breastfed compared with 67% of controls. Thirty per cent of children with rickets were hypocalcaemic vs <7% of controls, 89% had phosphorus values <1.5 mmol/L vs 34.5% of controls and 75% had alkaline phosphatise levels >500 IU/L vs 28% of controls. Seventy-five per cent of children with rickets had serum 25 (OH) D3 <20 nmol/L vs 25% of controls. Mean (SD) PTH level was 23.59 (19.03) pmol/L in the rachitic group and 1.9 (1.05) pmol/L in controls (p<0.05). Lack of exposure to sunlight was recorded in 90% of the children with rickets and in 37% of the controls. CONCLUSION: Apparently healthy children living in areas where rickets is prevalent have risk factors for rickets and a small proportion will have evidence of biochemical rickets.