Chemical Profile and Phytotoxic Action of Hibiscus trionum Essential Oil.

The chemical profile and phytotoxic action of Hibiscus trionum essential oil (EO) was studied. In total 17 compounds were identified via GC/MS, representing 94.18 % of the entire oil, with phytol (40.37 %) being the dominant constituent. Bioassay revealed that the EO inhibited root elongation of Medicago sativa and Amaranthus retroflexus by 32.66 % and 61.86 % at 5 mg/mL, respectively; meanwhile, the major component phytol also exhibited significant phytotoxic activity, suppressing radical elongation of Pennisetum alopecuroides, M. sativa and A. retroflexus by 26.08 %, 27.55 % and 43.96 % at 1 mg/mL, respectively. The fact that the EO showed weaker activity than phytol implied that some constituents might trigger antagonistic action to decrease the oil's activity. Our study is the first on the chemical profile and phytotoxic effect of H. trionum EO.

Toxic effects of oral administration of extracts of dried calyx of Hibiscus sabdariffa Linn. (Malvaceae).

The effects of a 90-day oral administration of water and alcohol extracts of dried calyx of Hibiscus sabdariffa were evaluated in albino rats. Haematological, biochemical and histopathological changes were monitored every 30 days.The death of the animals was preceded by a severe loss in weight, accompanied with diarrhoea in animals on the 2000 mg/kg dose. There was an increase in food intake (g) per kg body weight per day in the aqueous (A) and ethanol (E) 300 mg/kg extract groups. Significant reductions in the erythrocyte count with no difference in total leucocyte count were observed. The activity of aspartate aminotransferase (AST) was enhanced by the administration of aqueous and 50% ethanol extract with a significant increase in its level at higher doses (p < 0.05). Alanine aminotransferase (ALT) and creatinine levels were significantly affected by all the extracts at the different dose levels. However, aqueous extracts exhibited a significant increase in creatinine levels (p < 0.05) at higher doses. The cholesterol levels were generally not significantly affected by the extracts. No significant histopathological changes were observed, although there was a significant reduction in the weight of the spleen of the animals administered with ethanol and water extracts when compared with the control (p < 0.01). Other organs were of the same relative weight.