Phenolic profile and antioxidant activity from peels and seeds of melon (Cucumis melo L. var. reticulatus) and their antiproliferative effect in cancer cells

Abstract

Melon (Cucumis melo L.) has high economic value and in recent years, its production has increased; however, part of the fruit is wasted. Usually, inedible parts such as peel and seeds are discarded during processing and consumption. Extracts of melon residues were prepared and their phenolic compounds, antioxidants and antiproliferative activities were evaluated. Total phenolic compounds were found in hydroethanolic, hydromethanolic, and aqueous extracts, especially for melon peel (1.016 mg gallic acid equivalent/100 g). Flavonoids total content found for melon peel aqueous extract was 262 µg of catechin equivalent (CA)/100 g. In all extracts of melon peel significant amounts of gallic acid, catechin, and eugenol were found. For total antioxidant capacity, reported as ascorbic acid equivalent, the hydroethanolic and hydromethanolic extracts in peels and hydromethanolic in seeds were 89, 74, and 83 mg/g, respectively. Different extracts of melon showed iron and copper ions chelating activity at different concentrations, especially melon peel aqueous extract, reaching values of 61% for iron and 84% for copper. The hydroethanolic extract of melon peel presented a significant ability for hydroxyl radicals scavenging (68%). To assess the antiproliferative potential in human cancer cell lines, such as kidney carcinoma, colorectal carcinoma, cervical adenocarcinoma and cervical carcinoma, MTT assay was performed. The proliferation was inhibited by 20–85% at extracts concentrations of 0.1–1.0 mg/mL in all cancer cell lines. The results suggest that melon residues extracts display a high antioxidant activity in in vitro assays and have effective biological activity against the growth of human tumor cells.

From seed to flour: Sowing sustainability in the use of cantaloupe melon residue (Cucumis melo L. var. reticulatus)

“…Melon seeds contain high percentages of lipids, proteins, and fibres. They present antiproliferative activity and antioxidant properties, in addition to their prebiotic potential [10,11]. In addition, the presence of flavonoids and phenolic compounds reaffirms that the melon seed flour Cucumis melo L. has high antioxidant properties [12].…”

Characterization of apple, pineapple, and melon by‐products and their application in cookie formulations as an alternative to enhance the antioxidant capacity

“…Other compounds, such as vanillic acid and catechin, were also identified, but in lower amounts. Rolim et al (2018) demonstrated that there are differences among melon by-products, with higher occurrence of phenolics in the peels than in the seeds, with a prevalence of gallic acid, salicylic acid and catechin in the first, whereas in the seeds, higher concentrations of vanillic acid, salicylic acid, and catechin were observed.…”

Phenolic Content and Antioxidant Activity of Extracts of 12 Melon (Cucumis melo) Peel Powders Prepared from Commercial Melons

“…Finally, Rolim et al. () showed that melon peel and seed extracts inhibited the growth of cancer cells. These observations imply that melon peels have the potential to ameliorate (mitigate) the adverse effects of animal and human diseases and further investigations would be beneficial.…”

“…Bidkar, Ghanwat, Bhujbal, and Dama (2012) showed that the observed anticholesterol activity of methanolic melon peel extracts in rats on a high-fat diet was equivalent to that observed with the drug atorvastatin. Finally, Rolim et al (2018) showed that melon peel and seed extracts inhibited the growth of cancer cells. These observations imply that melon peels have the potential to ameliorate (mitigate) the adverse effects of animal and human diseases and further investigations would be beneficial.…”