Safety assessment and behavioral effects of Solanum guaraniticum leaf extract in rats

ABSTRACT Solanum guaraniticum is a medicinal plant traditionally used to treat gastric and liver diseases. However, there is no documented evidence corroborating its safety. The present study evaluated the potential toxicity of S. guaraniticum leaf extract after acute administration in rats. Single doses of the extract (1.250, 2.500, and 5.000 mg/kg) were administered by gavage, and the rats were then monitored for 48 h and/or 14 days. Mortality, acute signs of toxicity, and general activity in the open field test were assessed as well as hematological and biochemical parameters, enzymatic activity (δ-aminolevulinate dehydratase and acetylcholinesterase), and oxidative stress parameters (lipid peroxidation level, non-protein thiol content, tissue catalase activity, and serum ferrous reducing power). Phytochemical analysis was also performed by HPLC. The results showed that extract administration produced no deaths (LD50 > 5,000 mg/kg), and no significant adverse effects regarding food consumption, body weight gain, gross pathology, or other parameters. However, the open field tests showed a decrease in spontaneous activity (crossing and rearing) mainly at 48 h after treatment. The results suggest that S. guaraniticum extract is not acutely toxic, but causes alterations in central nervous system activity

Economic valuation of preventing beach erosion: comparing existing and non-existing beach markets with stated and revealed preferences

Altres ajuts: CSO2013-42513-PPredicted climate change is likely to increase beach erosion in the future, inducing higher costs of beach maintenance. Hence, additional funds for their protection will be required. We examine the willingness to pay (WTP) of beach visitors for preventing beach erosion in the form of daily beach entrance fees in Crikvenica, Croatia, by applying the contingent valuation method. This is the first beach valuation study for this country in transition which has emerged as an important Mediterranean tourist destination. The novelty of our study is that it compares WTP estimates for an existing and a non-existing beach market. This is done by conducting a survey at the beach where an entrance fee is already levied and at the nearest open-access beach. Based on the initial (follow-up) valuation question the stated WTP per adult per day for avoiding beach erosion equals €1.69 (€1.26) for the paid beach and €2.08 (€1.84) for the free beach. In addition, the travel cost method is employed. It reveals that consumer surpluses for visiting the paid and the free beach amount to €2.57 and €1.74, respectively