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To identify healthy, nutritious, and sustainable plant-based products rich in biologically active compounds, this present study was conducted, and the phytochemical composition and biological properties of the hydroethanolic ultrasound-assisted extract of the fruits of Cucumis metuliferus were investigated. Cucumis metuliferus is an unexplored fruit of a climbing plant in the Cucurbitaceae family, widely distributed in the tropical and subtropical regions of sub-Saharan Africa and whose nutritional and medicinal benefits are well known in African countries, especially. Therefore, its cultivation in other regions could influence chemical composition. The structural identification of the compounds from the hydroethanolic extract from Cucumis metuliferus fruits grown in Romania was carried out by chromatographic techniques (HPLC). The main compounds identified were catechin, oleanolic acid, ursolic acid, p-coumaric acid, and epicatechin. Subsequently, a method was proposed to isolate and characterize ursolic acid, one of the major compounds. The obtained results show that the hydroethanolic extract is rich in antioxidant compounds evaluated using the DPPH radical inhibition method (IC50 = 32.74 ± 0.02 µg/mL) and ABTS cation radical inhibition method (IC50 = 11.37 ± 0.07 µg/mL). It also demonstrate in vitro anti-inflammatory activities, such as anti-lipoxygenase (IC50 = 32.90 ± 0.05 µg/mL) and anti-proteinase (IC50 = 16.34 ± 0.07 µg/mL), and antidiabetic properties by inhibiting α-amylase (IC50 = 429.541 ± 0.25 µg/mL) and β-glucosidase activity (IC50 = 385.685 ± 0.76 µg/mL). Therefore, C. metuliferus fruits could be effectively used in the development of various health-promoting products, being not only appetizing, with spectacular appearance and with extended storage life, but also curative and healthy.

Four rotation sequences consisting of ungrafted tomato cv. Durinta – melon cv. Paloma or tomato grafted onto the resistant rootstock ‘Aligator’ – melon grafted onto the resistant Cucumis metuliferus accession BGV11135, and in reverse order, were conducted from 2015 to 2017 in a plastic greenhouse infested or not with Meloidogyne incognita to determine the plant tolerance (T), the minimum relative crop yield (m) and fruit quality. The relationship between M. incognita densities in soil at transplanting (Pi) of each crop and the crop yield was assessed and T and m were estimated by the Seinhorst’s damage model. In addition, the volume and the number of nuclei of single giant cells and the number of giant cells, its volume and the number of nuclei per feeding site in susceptible tomato and melon were compared to those in the resistant tomato and C. metuliferus 15 days after nematode inoculation in pot test. The relationship between the Pi and the relative crop yield fitted the Seinhorst’s damage model in both ungrafted and grafted tomato and melon, but not for all years and cropping seasons. The estimated T for ungrafted and grafted tomato did not differ but m was lower in the former (34%) than the latter (67%). Sodium concentration in fruits from ungrafted but not from grafted tomato increased with nematode densities in spring 2015 and 2016. The estimated ungrafted melon T did not differ from the grafted melon cultivated in spring, but it did when it was cultivated in summer. The relative crop yield of ungrafted melon was lower (2%) than the grafted cultivated in spring (62%) and summer (20%). Sodium concentration in melon fruits from ungrafted plants increased with nematode densities. No variations in fruit quality from grafted melon cultivated in spring were found, although less dry matter and soluble solid content at highest nematode densities were registered when it was cultivated in summer. Lower number of giant cells per feeding site was observed in both susceptible tomato germplasms compared to the resistant ones but they were more voluminous and held higher number of nuclei per giant cell and per feeding site.

Plant regeneration from C. anyuria var. longipes A. Meeuse and C. metuliferus Naud. leaf explants was investigated. It was found that embryoid-like structures were formed from C. anguria leaf explants cultured on media containing 0.3 mg dm-3 2,4-D and 0.8 mg dm-3 2iP. After being transferred to medium with 0.3 mg dm-3 2iP and 1 mg dm-3 GA3 they developed 187±49 shoots per explant. Further growth and root formation proceeded on hormone free medium.

Se evaluó la eficacia de C. metuliferus sobre las densidades de población de M. incognita, la producción y calidad de melón, y la potencial selección de poblaciones virulentas. El melón cv. Paloma, sin injertar o injertado sobre C. metuliferus, se cultivó en primavera y verano en invernadero en rotación con tomate susceptible cv. Durinta, sin injertar o injertado en el portainjerto resistente Aligator, en suelo sin infestar e infestado con M. incognita