NMR-based metabolomics to determine the fluctuation of metabolites in hydroponic purslane crops at different harvesting times.

Purslane (Portulaca oleracea L.) has a high content of nutrients and medicinal effects that depend on the genotype, harvesting time, and production system. The objective of the present research work was to elucidate the NMR-based metabolomics profiling of three native purslane cultivars from Mexico (Xochimilco, Mixquic, and Cuautla) grown under hydroponic conditions and harvested in three different times (32, 39, and 46 days after emergence). Thirty-nine metabolites identified in the 1H NMR spectra of aerial parts of purslane, 5 sugars, 15 amino acids, 8 organic acids, 3 caffeoylquinic acids, as well as 2 alcohols and 3 nucleosides, choline, O-phosphocholine and trigonelline were also detected. A total of 37 compounds were detected in native purslane from Xochimilco and Cuautla, whereas 39 compounds were detected in purslane from Mixquic. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) separated the cultivars into three clusters. Mixquic cultivar had the highest number of differential compounds (amino acids and carbohydrates), followed by Xochimilco and Cuautla cultivars, respectively. Changes in the metabolome were observed in latest times of harvest for all the cultivars studied. The differential compounds were glucose, fructose, galactose, pyruvate, choline, and 2-hydroxysobutyrate. The results obtained in this investigation may contribute to selecting the best cultivar of purslane and the best time in which the levels of nutrients are optimal.

Fatty Acid Profile, Total Carotenoids, and Free Radical-Scavenging from the Lipophilic Fractions of 12 Native Mexican Avocado Accessions.

Mexico is the world's largest producer, exporter, and consumer of avocados. "Hass" avocado is the most commercialized cultivar, while the native Mexican avocado varieties have been displaced. Thus, studies regarding their chemical and nutraceutical characterization are scarce. We studied the total lipid content, fatty acid profile, carotenoid content, and free radical-scavenging activity of the fruit pulp from 12 accessions of the native Mexican avocado (Persea americana var. drymifolia). The results show that the chemical and nutraceutical characteristics depend on the accession type. The total lipid content ranged from 13.22 to 23.41%. The major saturated fatty acid in all the avocado accessions was palmitic acid (15.54-22.68%). Monounsaturated fatty acids, like oleic (56.58-74.19%), linoleic (5.62-16.85%) and linolenic (0.63-2.85%) acids were the most abundant unsaturated fatty acids in all the native Mexican avocado accessions. The total carotenoid content (1.57 to 7.83 mg eq. of ß-carotene 100 g-1 fresh weight) and the free radical-scavenging activity (7.58-88.62 mMol trolox equivalent 100 g-1 fresh weight) also varied significantly (p < 0.05) among accessions. Native Mexican avocados have a great nutraceutical potential due to their high content of omega-9, omega-6, and omega-3 fatty acids and carotenoids. These compounds have been reported to display antioxidant activities and protect against cardiovascular diseases.

Flavonoids and antioxidant activity of flowers of Mexican Crataegus spp.

Flavonoids and antioxidant activity of extracts of flowers from some Mexican accessions of Crataegus were studied using six accessions with the purpose of contributing to the knowledge of the nutraceutical properties of the accessions of the Germplasm Bank of the Universidad Autonoma Chapingo. Flavonoids were identified by HPLC-MS. Among the flavonoids, the quercetin 3-O-glucoside (3), quercetin 3-O-rhamnoside (4), quercetin 3-O-rhamnosyl-(1 → 6)-glucoside (2) and quercetin 3-O-rhamnosyl-(1 → 2)-[rhamnosyl-(1 → 6)]-glucoside (1) were assigned. Flavonoid content and radical scavenging activity explain some of the medicinal properties attributed to flowers of Mexican hawthorns.

Bactericidal and fungicidal activities of Calia secundiflora (Ort.) Yakovlev.

Calia secundiflora (Ortega) Yakovlev (Fabaceae) is considered a medicinal plant in Mexico but has scarcely been used because of the toxicity of its quinolizidine alkaloids. Several quinolizidine alkaloids have shown bactericidal, nematicidal, and fungicidal activities. The purpose of this study was to identify the alkaloids in the seeds and evaluate the activity of the organic extract on several phytopathogenic fungi and bacteria. An in vitro bioassay was conducted with species of the following phytopathogenic fungi: Alternaria solani, Fusarium oxysporum and Monilia fructicola; and of the following bacteria Pseudomonas sp., Xanthomonas campestris and Erwinia carotovora. Cytisine, lupinine, anagyrine, sparteine, N-methylcytisine, 5,6-dehydrolupanine, and lupanine were identified by liquid chromatography-mass spectrometry in the extract of seeds; the most abundant compound of the extract was cytisine. It was observed that the crude extract of Calia secundiflora was moderately active on bacteria and more potent on phytopathogenic fungi. In contrast cytisine showed the opposite effects.

Phytochemical differences between Calia secundiflora (Leguminosae) growing at two sites in Mexico.

The ecology and quinolizidine alkaloid chemistry of Calia secundiflora (Ortega) Yakovlev growing at two sites in Mexico were compared. At one site (Hidalgo) the vegetation was dominated by Flourensia resinosa and C. secundiflora, at the other site (Queretaro) C. secundiflora and Dodanaea viscosa were dominant. The Hidalgo site had shallower soils with less organic matter, N, P, and CaCO3. Seeds of C. secundiflora from each site accumulated a similar range of quinolizidine alkaloids, but the profile of alkaloids in the leaves and roots were different. The leaves and roots of plants at Hidalgo accumulated a similar range of alkaloids to the seeds with cytisine and/or N-methylcytisine being most abundant, whereas at Queretaro the leaves and roots accumulated lupinine, with other alkaloids being relatively minor constituents. The latter profile has not been reported previously for C. secundiflora.