Comparisons of antioxidant activities of two varieties of pumpkin (Cucurbita moschata and Cucurbita maxima) extracts

The Antioxidant Properties of Selected Varieties of Pumpkin Fortified with Iodine in the Form of Potassium Iodide and Potassium Iodate

This study aimed to investigate the use of selected pumpkin varieties as carriers of potassium iodide (KI) and potassium iodate (KIO₃) at different concentrations (2.3, 0.23, and 0.023 mg/100 g). It was hypothesized that the concentrations and form of iodine fortification in pumpkins affect the antioxidant activity of pumpkins. The results showed a high recovery of the introduced iodine in all pumpkin varieties after drying, as well as high iodine stability during storage, especially for KIO₃. However, statistical analysis confirmed a relationship between the forms and concentration of iodine and the ABTS cation radical and the DPPH radical test results. In the systems with iodine concentration at 0.023 and 0.23 mg/100 g, the antioxidant activity did not change. However, for all pumpkin varieties fortified with a KIO₃ concentration at 3.9 mg/100 g (2.3 mg/100 g of iodine), a statistically significant decrease in free-radical scavenging was confirmed. Therefore, for maximum effectiveness in pumpkin's free-radical scavenging indices, it is suggested to introduce iodine in the form of KI and KIO₃, but in controlled concentrations. However, KIO₃ should be added at a maximum amount of 0.39 mg/100 g.

Evaluation of Antidiabetic and Antioxidant Activities of Fruit Pulp Extracts of Cucurbita moschata Duchesne and Cucurbita maxima Duchesne

Objective

To evaluate and compare the antidiabetic and antioxidant activities of fruit pulp extracts from Cucurbita moschata (PCMOS) and Cucurbita maxima (PCMAX).

Methods

The antidiabetic activity was carried out in vivo by orally and daily giving the extracts at a dose of 500 mg/kg·b.w. to the streptozotocin-induced diabetic male albino Wistar rats for six weeks. After the period of administration, blood glucose levels, body weight, serum insulin, morphology of islets of Langerhans, biochemical parameters, and haematological values of the rats were determined. Meanwhile, the antioxidant activity was carried out in vitro by determination of total phenolic and flavonoid contents, DPPH radical scavenging activity, and ferric reducing antioxidant power.

Results

PCMAX significantly (p < 0.05) reduced blood glucose levels but increased the body weight, serum insulin levels, size and number of islets of Langerhans, and β-cell number of the treated diabetic rats more than PCMOS did. However, they did not alter biochemical parameters and haematological values of the treated diabetic rats. PCMAX possessed total phenolic and flavonoid contents and showed DPPH scavenging and FRAP reducing antioxidant power more significantly (p < 0.05) than PCMOS.

Conclusions

According to the obtained results, it is indicated that PCMOS and PCMAX possess antidiabetic and antioxidant activities. PCMAX possesses more potent antidiabetic and antioxidant activities than PCMOS. These are probably due to PCMAX providing polysaccharide and total phenolic and flavonoid contents more than PCMOS.

Nutritional characterization and antioxidant properties of various edible portions of Cucurbita maxima: A potential source of nutraceuticals

Pumpkin (Cucurbita maxima) is a widely grown vegetable in Bangladesh and is known as the sole supplier of various nutrients. Many studies evidence the nutritional value of flesh and seed while peel, flower, and leaves were reported scarcely with limited information. Therefore, the study aimed to investigate the nutritional composition and antioxidant properties of flesh, peel, seed, leaves, and flowers of Cucurbita maxima. The seed had a remarkable composition of nutrients and amino acids. Flowers and leaves possessed higher content of minerals, phenols, flavonoids, carotenes, and total antioxidant activity. The order of IC₅₀ value (peel > seed > leaves > flesh > flower) indicates higher DPPH radicals scavenging activity of the flower. Moreover, a significant positive relationship was observed among these phytochemical constituents (TPC, TFC, TCC, TAA) and DPPH radicals scavenging activity. It could be concluded that these five parts of the pumpkin plant have an intense potency to be an exigent component of functional food or medicinal herbs.

Physicochemical, nutritional and functional properties of Cucurbita moschata

Cucurbita moschata is widely planted in most parts of the world, and is rich in carotenoids, vitamins, dietary fiber, minerals, and phenolic compounds. It also has important medicinal value. Some related research has proven that Cucurbita moschata has the potential ability to induce anti-obesity, anti-diabetic, antibacterial, and anticancer effects. At the same time, it has attracted more attention in the medical field. These nutrients and bioactive compounds in Cucurbita moschata have important effects on human health. In order to make better use of this crop, it still needs further study. Therefore, the purpose of this article is to summarize the physicochemical properties and nutritional components of Cucurbita moschata, and to provide a reference for further research on the benefits of on human health.

Characterization of partially purified alkaloids from Cucurbita maxima seed and evaluation of their antioxidant activity in human erythrocytes and leukocytes

Cucurbita maxima, is a therapeutic plant spread all over the world. The seed of C. maxima constitutes a large amount of alkaloids, phenolic compounds, Vitamin E, and other secondary metabolites. The experiment was performed in four setups (Control, Only H₂ O₂ , H₂ O₂  + 25 mg of alkaloid, H₂ O₂  + 50 mg of alkaloids). The enzymatic and nonenzymatic antioxidants and lipid peroxidation (LPO) were determined to analyze the antioxidant effect of partially purified alkaloids. The results showed that partially purified alkaloids from C. maxima seed reacts effectively on the erythrocytes and leukocytes antioxidant enzyme system when compared to the hydrogen peroxide group. The present results indicate that the alkaloids present in this plant can be used as a natural antioxidant for the pharmacological purposes. PRACTICAL APPLICATIONS: The C. maxima seed constitutes rich source of alkaloids, phenolic compounds, Vitamin E, and other secondary metabolites. The results obtained revealed that the purified alkaloids from C. maxima seed acts as natural antioxidants, which enhanced the potential to scavenge H₂ O₂ and aids in protecting the RBC and WBC cells. The presence of 27 alkaloids of which seven major alkaloids possessing higher medicinal properties like antioxidant, antimicrobial, anti-inflammatory, antitumor, anti-aging, anti-diabetic, anticancer, anti-malarial, analgesic, nematicide, pesticide, and hemolytic activity were determined from the GC-MS analysis of the extract. Alkaloids acts as major constituent in phytotheraphy and has wide range of clinical application in humans and animals. In conclusion, alkaloids from C. maxima seed may have several properties that leading to the opening of new avenues in the natural product for the therapeutic purpose.