Development and validation of an UHPLC-DAD method for oleandrin content determination in dried leaves of Nerium oleander from Eastern Algeria

This study aimed to develop and validate an UHPLC-DAD method for quantifying oleandrin in dried leaves and assessing its concentrations in samples from Eastern Algeria. For this purpose, a total of 100 leaf samples were collected from wild and cultivated shrubs across five provinces in Eastern Algeria during the flowering period. The UHPLC-DAD system was used to identify and quantify oleandrin. Chromatographic separation was performed using a Kinetex C18 Polar column (100 x 2.1 mm, 2.6 mu m) from Phenomenex (R). The flow rate was of 0.6 mL/min, and the detection wavelength was set at 220 nm. The mean oleandrin amount in dried leaf samples collected from the entire region was found to be 0.12 +/- 0.12 mg/g. The analysis revealed statistically significant differences among the provinces and between wild and cultivated plants. These differences highlight potential disparities in the risk of acute poisoning in case of ingestion. However, no significant differences were observed among plants with different flower colors. Furthermore, no correlation was observed between the mean oleandrin levels and the meteorological parameters recorded during the annual survey of the harvest year, including temperature, humidity, sunshine, and cumulative rainfall. There was also no correlation between the mean, median, and 90th percentile oleandrin levels and the elevation of the collection sites.