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Qualitative Screening of Phytocompounds and Spectrophotometric Investigations of two Pumpkin Species
* 1 , 2 , 2
1  National Research & Development Institute for Chemistry and Petrochemistry - ICECHIM
2  The National Research&Development Institute for Chemistry and Petrochemistry


Pumpkin (Cucurbita maxima) is a fruit packed with vitamins and nutrients beneficial to human health with numerous therapeutic uses: antiparasitic, antioxidant, helps lower the bad cholesterol, adjuvant in weight loss, improves cancer prevention, etc. Pumpkin is rich in beta-carotene, contains important amounts of lutein and zeaxanthin, antioxidants that can considerable prevent cataracts and macular degeneration. Worldwide, five pumpkin species are grown for their edible fruit and seeds. This paper describes the qualitative screening of phytocompounds and the quantitative determination of main bioactive compounds found in two pumpkin species: Valenciano and Waltham Butternut. The qualitative screening of phytochemicals is based on the visual change in color of the aqueous extracts upon adding known reactants. This allows a preliminary evaluation regarding the presence of different bioactive compounds such as saponins, alkaloids, tannins, flavonoids, etc. In order to determine the specific amount of different phytocompounds (e.g.: total content of polyphenols, total content of flavonoids, etc.) UV - Vis spectra are recorded, in triplicate, at well - established wavelenghts, thus obtaining an average absorbance. For example, a method widely applied for the determination of total polyphenolic content is the Folin - Ciocalteu (FC) reaction, which is basically an antioxidant analyse that relies on electron transfer, therefore measuring the reductive ability of a specific antioxidant. Briefly, FC reaction involved mixing 1 mL diluted aqueous extract with 5 mL FC reagent and adding, after 8 minutes, 4 mL Na2CO3. After 60 minutes incubation at room temperature, we recordec the absorptions at 765 nm, which corresponds to gallic acid curve calibration standard. Also, the antioxidant activity using the DPPH method was recorded for both aqueous extracts.

Keywords: phytocompounds, qualitative screening, pumpkin, quantitative determination