Maize is part of the traditional diet of Mexico and other Latin American countries. The diverse varieties of maize produced by adaptation to different regions and climates are known as creole or native maize. The characteristics and nutritional contributions of each of these native maize are relatively diverse areas of study. This work specifically analyzes the nutritional aspects of creole maize grown in the Sierra Gorda in Querétaro. For this, a proximal chemical analysis was carried out, with a quantification of polyphenolic compounds and antioxidant capacities using the ABTS (2,20-azinobis (3-ethyl-benzothiazolin,6-sulfonic acid) and DPPH (2,2-difenil-1-picrilhidrazilo) methods to examine four landraces and one commercial hybrid control. The results indicate that, in general, the landraces present similar—and, in some cases, higher—nutritional indices than the commercial hybrid. With regard to polyphenolic compounds, the Elotes Occidentales and Tuxpeño varieties present greater amounts of total phenols and antiradical activity (ARA), as well as a higher concentration of flavonoids and percentage inhibition, respectively. Condensed tannins are identified both in the creole varieties and in the commercial hybrid. Creole maize presents important nutritional characteristics and can be a good source of antioxidant compounds, which can help the population as a source of food and in the prevention of chronic diseases.

C. berlandieri ssp. berlandieri (C. berlandieri) is one of the most common members of the group of plants known as quelites, which are dark leafy greens widely consumed in Mexico. This study aimed to evaluate the impact of two drying procedures (oven drying and freeze-drying/lyophilization) on the polyphenolic composition, antioxidant capacity, and proximal chemical analysis of C. berlandieri leaves and inflorescences (raw or boiled). The results indicated that the raw freeze-dried samples had higher amounts (p < 0.05) of total phenolic compounds, total flavonoids, and antioxidant capacity, mainly in the inflorescence. The oven-dried samples showed an increased concentration of polyphenols after boiling, while the lyophilized samples showed a slightly decreased concentration. The drying process was observed to have little impact on the proximal chemical composition. Quantification by UPLC-DAD-ESI-QToF/MS identified up to 23 individual phenolic compounds, with freeze-dried samples showing higher amounts of individual compounds compared with oven-dried. Procyanidin B2 was found exclusively in the inflorescences. The inflorescences have a higher content of phenolic compounds and greater antioxidant capacity than the leaves. Regardless of the drying process, the leaves and inflorescences of C. berlandieri contain an interesting variety of phenolic compounds that may have beneficial effects on health.

Cnidoscolus aconitifolius (CA) and Porophyllum ruderale (PR) are representative edible plants that are a traditional food source in Mexico. This research aimed to analyze the phytochemical composition and untargeted metabolomics analysis of CA and PR and evaluate their antiproliferative effect in vitro. The phytochemical composition (UPLC-DAD-QToF/MS-ESI) identified up to 38 polyphenols and selected organic acids that were clustered by the untargeted metabolomics in functional activities linked to indolizidines, pyridines, and organic acids. Compared with PR, CA displayed a higher reduction in the metabolic activity of human SW480 colon adenocarcinoma cells (LC₅₀: 10.65 mg/mL), and both extracts increased the total apoptotic cells and arrested cell cycle at G0/G1 phase. PR increased mRNA Apc gene expression, whereas both extracts reduced mRNA Kras expression. Rutin/epigallocatechin gallate displayed the highest affinity to APC and K-RAS proteins in silico. Further research is needed to experiment on other cell lines. Results suggested that CA and PR are polyphenol-rich plant sources exhibiting antiproliferative effects in vitro.

The fruit of Averrhoa carambola L. (A. carambola L.) belongs to the Oxalidaceae family, is probably native to Ceylon and Moluccas, and is commonly known in various places as “star-fruit” or “carambola.” This fruit is used as traditional medicine for a variety of diseases. The phenolic compounds that the fruit contains are thought to be responsible for its many benefits. Currently there is extensive research on the content of phenolic compounds and the antioxidant capacity of the fruit of A. carambola L. Most authors report total phenolic content (TPC) and total flavonoid content (TFC); while antioxidant capacity has been analyzed using different techniques such as: 1,1-diphenyl-2-picrylhydrazyl assay (DPPH), ferric reducing antioxidant power assay (FRAP), and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). HPLC analysis has resulted in the identification of phenolic compounds in the fruit. However, each of the authors use different methodologies in the various stages of the analysis, from obtaining the sample to the form of analysis, and this may explain the differences in their results. This paper offers a review of existing research on the phenolic profile and antioxidant capacity of the A. carambola L. fruit, with special attention to the methodologies used.

Porophyllum ruderale (P. ruderale) is a well-known Mexican plant from the group of “Quelites”, widely consumed plant species used for several food and medicinal purposes. As the production is very heterogeneous and the diverse agroclimatic conditions significantly impact the plant’s phytochemical composition, this research aimed to compare the phenolic compound composition and the antioxidant capacity of the P. ruderale plant from three different collection sites (Queretaro, Landa de Matamoros, and Arroyo Seco) in the State of Queretaro (Mexico). Plants collected from Queretaro displayed the lowest total phenolic compounds, flavonoids, and condensed tannins, reflected in a lower antioxidant capacity (DPPH, FRAP, ABTS), compared to the other collection places. Flavones (epicatechin and epigallocatechin gallate) were the most abundant (36.1–195.2 μg equivalents/g) phenolics quantified by HPLC-DAD, while 31 compounds were identified by UHPLC-DAD-QToF/MS-ESI. Most compounds were linked to biological mechanisms related to the antioxidant properties of the leaves. A PCA analysis clustered Landa de Matamoros and Arroyo Seco into two groups based on flavones, hydroxybenzoic acids, the antioxidant capacity (ABTS and DPPH), and total phenolic compounds, the main contributors to its variation. The results indicated contrasting differences in the polyphenolic composition of collected P. ruderale in Queretaro, suggesting the need to standardize and select plants with favorable agroclimatic conditions to obtain desirable polyphenolic compositions while displaying potential health benefits.

Pithecellobium dulce (P. dulce) is a Mexican plant that is consumed raw or in different preparations, and its anti-inflammatory and antioxidant properties have traditionally been useful in treating several conditions. However, the post-harvest drying process can alter the content of bioactive compounds in P. dulce. This study aims to evaluate the impact of different drying methods on the phenolic profile and antioxidant capacity of this plant, as well as its inhibitory effect on human SW480 colon adenocarcinoma cells. After oven drying, the samples showed a higher amount (p < 0.05) of phenolic compounds, up to 1149.45 ± 69.27 mg GAE/100 g LE, which is 80% more than the freeze-dried samples. Also, the antioxidant capacity was higher in oven-dried samples, with 44.63 ± 2.00 µmol Trolox equivalents/g LE, 108% more than the freeze-dried method. Methanolic extraction, in turn, yielded better results than aqueous and ethanolic extractions. Up to 14 polyphenolic compounds were detected in oven-dried samples. For in vitro assays in SW480 cells, the 50% v/v methanolic extract was used. From this extract, the median lethal concentration (LC₅₀) was determined to be 13.76 mg/mL, which represents the concentration necessary to inhibit the growth of half of the cancer cells of this cell line. The extract led to cell cycle arrest in the G1 phase and an increase in apoptosis-induced cell death. The P. dulce extract augmented p53 and decreased KRAS gene expressions. Results suggested pro-apoptotic mechanisms in colon cancer cells in vitro linked to P. dulce bioactive compounds, which are better preserved when oven-dried plants are subjected to methanolic extraction.