Functionally active metabolites in two cultivars of chayote (Sechium edule(Jacq.) Swartz)

Abstract

Chayote fruits (Sechium edule (Jacq.) Swartz) is a vegetable widely consumed by the Asiatic and Latino-American population, but little is known about the nutraceutical potential of different varieties. This study aimed to determine the chemical compositions and antioxidant activities of fruits from two commercial varieties of chayote cultivated in Mexico. The physicochemical properties of juice from S. edule var. virens levis (VL) and var. nigrum spinosum (NS) were determined using standard methods. Dried fruits were extracted successively with methanol and ethanol for chemical analysis and assessment of antioxidant (2,2-diphenyl-β-picrylhydrazyl test and β-carotene-linoleic acid test) properties. The juice of the two genotypes differed significantly regarding the concentrations of total soluble solids, total sugars, chlorophyll a, pH and colour, but not vitamin C. The total concentration of phenolics in NS extracts was slightly higher than in VL (1005 and 856 mg 100 g‑1 dry-weight, respectively) but the total flavonoid contents were similar (27 and 26 mg 100 g(‑1) dry-weight, respectively). Cucurbitacin D was predominant in both genotypes, while cucurbitacin B was higher in NS than in VL. The radical scavenging capacities of VL and NS extracts varied slightly (IC50=0.45 to 0.65 mg mL(‑1)), while the antioxidant activities were similar (~80%). In conclusion the two cultivars of chayote are chemically distinct, and the NS cultivar is particularly promising regarding nutraceutical application.