Chemical characterization, antioxidant capacity, and anti-hyperglycemic effect of Stenocereus stellatus fruits from the arid Mixteca Baja region of Mexico

Phytochemicals and Functional Properties of Pitaya Juice Powders

BACKGROUND

Crassulacean acid metabolism plants, such as Stenocereus spp., are climate warming-resilient crops used as food and for by-products elaboration in arid and semi-arid agroecosystems. A few studies on secondary metabolites have been conducted in pitayo fruit (PF), but there are no reports of these compounds in juice powders (JP) with (JPS) or without seeds (JPWS). This study was devoted to characterizing the juice powders (JPS and JPWS) of five pitayas with different flesh colors with regard to some phytochemical and functional attributes.

METHODS

The study was conducted with a completely random design with factorial arrangement in treatments (PF × JP).

RESULTS

Differences among pitayas were related to peel and flesh color attributes. Except for soluble dietary fiber, the remainder of the non-digestible carbohydrates were greater in JPS than in JPWS of all pitayas. Phenols and flavonoids were found to be the highest in the JPWS of all pitayas, whereas total saponins were the highest in JPS of the 'Pink' pitaya. The JPWS of the 'Yellow' and 'Reddish-Purple' pitayas had the highest content of betaxanthins and indicaxanthins, respectively. Antioxidant capacity was the highest in JPS of 'Reddish-Purple' and 'Pink' pitayas.

CONCLUSIONS

Except for some phenolic compounds, the study suggests that pitayas' JPS would benefit human health when freshly consumed or as elaborated by-products.

Chemical analysis of freeze-dried seeds of Stenocereus stellatus (white tunillo) components and evaluation of their effect on prediabetes reversion in an experimental model in female Wistar rats

Prediabetes is defined as a state of moderate hyperglycemia. Here, we used freeze-dried seeds of Stenocereus stellatus (white tunillo) as a possible therapeutic strategy for the treatment of prediabetes. In the aqueous extract of freeze-dried seeds of white tunillo, polyphenols were identified using the Folin-Ciocalteu technique, separated by UPLC and analyzed by infrared spectrophotometry. Five well-defined peaks with good resolution were observed in the chromatogram of the aqueous extract obtained by UPLC. Two of these peaks corresponded to polyphenols with similarity to quercetin and rutin. The subchronic oral administration of freeze-dried seeds of white tunillo for 14 days in a prediabetes model in female Wistar rats reversed hyperglycemia and glucose intolerance. Treatment with the freeze-dried seeds reversed the decrease in the hepatic expression of Akt, eNOS, and p-eNOSSer1177 but did not reverse the decrease in MnSOD, catalase, and GPx1. No changes in the expression of GPx4 and p-AktSer473 were observed in the pathological state or with the treatment but there was an increase in the expression and activity of eNOS. The bioactive compounds present in the freeze-dried seeds of Stenocereus stellatus could provide guidelines for studying the mechanisms of action through which they reverse signs of prediabetes.

Cactaceae plants as sources of active bioavailable phytochemicals

Arid-land plants from the Cactaceae family are endemic to the Americas and cultivated worldwide. Cactaceous plants and their fruits contain phenolic compounds, betalains, vitamins, carotenoids, minerals, and soluble fiber. Edible cactaceous matrices can be considered functional foods since their consumption may confer health benefits. These plants could be a source of novel bioactive compounds relevant to the area of phytomedicine. However, consumption of high concentrations of active molecules is not necessarily correlated to beneficial physiological effects because phytochemicals must be released from the food matrices under physiological conditions, resist digestion-associated chemical transformations, and remain in their active state in systemic circulation until the target tissues are reached. Notably, although digestion may either increase or decrease the bioactive phytochemicals' activity and stability, non-absorbed compounds may also be relevant for human health. Additionally, food matrices' type and composition and their technological processing operations may influence the compounds' release, stability, and accessibility. Thus, this review provides insights on the feasibility of using Cactaceae plants as sources of functional compounds. It is focused on compounds' bioactivity, bioaccessibility, and overall bioavailability after their metabolic transformation. Also, it addresses the influence of food processing on bioactive compounds. Many Cactaceae species are unexplored, and our understanding of how they confer health benefits is limited. To better understand the physiological relevance, nutraceutical potential, and therapeutic feasibility of cactaceous bioactive phytochemicals, future research should focus on the metabolic stability and safety of these compounds, as well as their assimilation mechanisms (absorption, distribution, and metabolic fate).

Chemical Characterization and Evaluation of the Antihyperglycemic Effect of Lychee (Litchi chinensis Sonn.) cv. Brewster

Lychee is a fruit of Asian origin with an exquisite flavor and an attractive reddish color. However, according to recent reports, the consumption of this fruit reduces the levels of blood glucose with adverse effects on human health such as encephalopathy and hypoglycemic. The objective of this work was to determine if the peel, pulp, and seed of "Brewster" lychee fruits harvested at two stages of maturity had antihyperglycemic effect. This effect was determined by an oral glucose tolerance test using Wistar rats. In addition, ultraviolet-visible spectrophotometry and high-resolution liquid chromatography were used to quantify phenolic compounds, flavonoids, organic acids (OAs), sugars, and antioxidant activity. Results indicated that stage I pulp (immature fruits) and stage II peel and seed (export mature fruits) reduced blood glucose levels, and the effects of the former two were synergistic with metformin. The pulp of mature fruits (stage II), however, lacked a hypoglycemic effect. Additionally, the peel and the seeds of these fruits presented a high antioxidant activity (as determined by DPPH [2,2-diphenyl-2-picryl-hydracyl] and ABTS⁺ [2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid] methods), which correlated well with the total content of phenolic compounds. The highest content of polyphenolics, flavonoids, and OAs was found in the extracts of the peel and seeds of both stages of maturity. It was therefore concluded that "Brewster" mature lychees are safe for human consumption, and both the seed and the peel can be useful sources for obtaining new compounds with antihyperglycemic activity.

Phenolic Compounds in Mesoamerican Fruits-Characterization, Health Potential and Processing with Innovative Technologies

Diets rich in phenolic compounds have been associated to reducing the risk of metabolic syndrome and its derived disorders. Fruits are healthy components of the human diet because of their vitamin, mineral, fiber and phenolic profile. However, they have a short shelf-life which is limited by microbiological growth and enzymatic activity. Innovative preservation methods such as high hydrostatic pressure, pulsed electric fields, ultrasound, microwave, cold plasma and ultraviolet light have become popular for the processing of fruits because they can preserve nutritional quality. In this review, the phenolic profile and health potential of 38 Mesoamerican fruits were assessed. Phenolic compounds were classified based on their contribution to the diet as flavonoids, phenolic acids, tannin, lignins and stilbenoids. Due to this composition, fruits showed a wide range of bioactivities which included anti-inflammatory, anti-diabetic, anti-hypertensive and anti-obesity activities, among others. Phenolic content in fruits submitted to innovative food processing technologies depended on parameters such as enzymatic activity, antioxidant capacity, microstructure integrity and cell viability. Innovative technologies could increase phenolic content while assuring microbiological safety by (i) promoting the release of bound phenolic compounds during processing and (ii) inducing the synthesis of phenolic compounds by activation of phenylpropanoid pathway during storage.