Antidiabetic Activity of Cactus Acid Fruit Extracts: Simulated Intestinal Conditions of the Inhibitory Effects on α-amylase and α-glucosidase

Bioaccessibility of bioactive compounds from Pereskia aculeata and their cellular antioxidant effect

Ora-pro-nobis (Pereskia aculeata) is a Cactaceae plant with edible leaves and fruits whose extracts are consumed to promote health, albeit bioactive compounds' bioaccessibility was still not assessed. To address this, ora-pro-nobis fruits (FE) and leaf extracts (LE) were subjected to in vitro digestion to better understand how this process impacts the bioactivities of the extracts. The study investigated the composition of the extracts, their cytotoxicity, and their chemical, plasmatic, and cellular antioxidant capacity. The results revealed that total polyphenolics were about 70% bioaccessible in LE and FE, with phenylalanine being the most bioaccessible essential amino acid in leaves (42.7%) and fruits (83.6%). The samples' antioxidant activity (CUPRAC) was reduced by 25%. LE demonstrated antioxidant activity against human plasma oxidation and haemolysis (21.8%), but digestion mitigated these activities. FE diminished haemolysis (47.0%) and presented cytotoxicity (IC50 = 1086 μg/mL) to HUVEC cells, but these properties were lost following digestion. Ultimately, digestion partially degraded the samples' bioactive compounds, diminishing their cellular protection against oxidative stress.

Potential Antidiabetic Activity of Apis mellifera Propolis Extraction Obtained with Ultrasound

Recent studies have linked phenolic compounds to the inhibition of digestive enzymes. Propolis extract is consumed or applied as a traditional treatment for some diseases. More than 500 chemical compounds have been identified in propolis composition worldwide. This research aimed to determine Mexican propolis extracts' total phenolic content, total flavonoid content, antioxidant activity, and digestive enzyme inhibitory activity (ɑ-amylase and ɑ-glucosidase). In vitro assays measured the possible effect on bioactive compounds after digestion. Four samples of propolis from different regions of the state of Oaxaca (Mexico) were tested (Eloxochitlán (PE), Teotitlán (PT), San Pedro (PSP), and San Jerónimo (PSJ)). Ethanol extractions were performed using ultrasound. The extract with the highest phenolic content was PE with 15,362.4 ± 225 mg GAE/100 g. Regarding the flavonoid content, the highest amount was found in PT with 8084.6 ± 19 mg QE/100 g. ABTS•+ and DPPH• radicals were evaluated. The extract with the best inhibition concentration was PE with 33,307.1 ± 567 mg ET/100 g. After simulated digestion, phenolics, flavonoids, and antioxidant activity decreased by 96%. In contrast, antidiabetic activity, quantified as inhibition of ɑ-amylase and ɑ-glucosidase, showed a mean decrease in enzyme activity of approximately 50% after the intestinal phase. Therefore, it is concluded that propolis extracts could be a natural alternative for treating diabetes, and it would be necessary to develop a protective mechanism to incorporate them into foods.

Crotofoligandrin, a new endoperoxide crotofolane-type diterpenoid from the twigs of Croton oligandrus Pierre ex. Hutch (Euphorbiaceae)

Crotofoligandrin (1), a new endoperoxide crotofolane-type diterpenoid was isolated from the dichloromethane/methanol (1:1) extract of the twigs of Croton oligandrus Pierre Ex Hutch along with thirteen known secondary metabolites including 1-nonacosanol (2), lupenone (3), friedelin (4), β-sitosterol (5), taraxerol (6), (-)-hardwickiic acid (7), apigenin (8), acetyl aleuritolic acid (9), betulinic acid (10), fokihodgin C 3-acetate (11), D-mannitol (12), scopoletin (13) and quercetin (14). The structures of the isolated compounds were determined based on their spectroscopic data. The crude extract and the isolated compounds were assessed in vitro for their antioxidant, lipoxygenase, butyrylcholinesterase (BChE), urease and glucosidase inhibitory potentials. Compounds 1-3, and 10 displayed activities on all the performed bioassays. All the tested samples showed strong to significant antioxidant activity with compound 1 being the most potent (IC50 39.4 μM).

Screening strategy for predominant phenolic components of digestive enzyme inhibitors in passion fruit peel extracts on simulated gastrointestinal digestion

BACKGROUND

The targeted biological activity of a natural product is often the result of the combined action of multiple functional components. Screening for predominant contributing components of targeting activity is crucial for quality evaluation.

RESULTS

Thirteen and nine phenolic compounds inhibiting α-glucosidase and α-amylase, respectively, were identified in the ethanol extracts of passion fruit peel through liquid chromatography-tandem mass spectrometry and multivariate analysis. Considering the different concentrations of components and their interactions, the role of the semi-inhibitory concentration (IC₅₀ ) in the dose-effect relationship is limited. We proposed the active contribution rate (ACR), which is the ratio of a single component concentration to its IC₅₀ in the whole, to assess the relative activity of each compound. Luteolin, quercetin, and vitexin exhibited a minimum IC₅₀ . Before the simulation of gastrointestinal digestion, quercetin, salicylic acid, and luteolin were identified as the dominant contributors to α-glucosidase inhibition according to ACR, while salicylic acid, 2,3-dihydroxybenzoic acid, and quercetin were identified as dominant contributors to α-amylase inhibition. After simulated digestion, the contents of all polyphenolic compounds decreased by various degrees. Salicylic acid, gentisic acid, and vitexin became the dominant inhibitors of α-glucosidase based on ACR (cumulative 57.96%), while salicylic acid and 2,3-dihydroxybenzoic acid became the dominant inhibitors of α-amylase (cumulative 84.50%).

CONCLUSION

Therefore, the ACR evaluation strategy can provide a quantitative reference for screening the predominant contributor components of a specific activity in complex systems. © 2022 Society of Chemical Industry.

The Application of Ultrasound in Honey: Antioxidant Activity, Inhibitory Effect on α-amylase and α-glucosidase, and In Vitro Digestibility Assessment

In the present study, the effects of ultrasound (10, 20, and 30 min) on the bioactive compounds, antioxidant capacity, enzymatic inhibition, and in vitro digestion of six honey extracts from the Oaxaca state, Mexico, were analyzed. Significant differences were found in each honey extract with respect to the ultrasonic treatment applied (p < 0.05). In the honey extract P-A1 treated with 20 min of ultrasound, the phenols reached a maximum concentration of 29.91 ± 1.56 mg EQ/100 g, and the flavonoids of 1.92 ± 0.01 mg EQ/100 g; in addition, an inhibition of α-amylase of 37.14 ± 0.09% was noted. There were also differences in the phases of intestinal and gastric digestion, presenting a decrease in phenols (3.92 ± 0.042 mg EQ/100 g), flavonoids (0.61 ± 0.17 mg EAG/100 mg), antioxidant capacity (8.89 ± 0.56 mg EAG/100 mg), and amylase inhibition (9.59 ± 1.38%). The results obtained from this study indicate that, in some honeys, the processing method could increase the concentration of bioactive compounds, the antioxidant capacity, and the enzymatic inhibition; however, when subjected to in vitro digestion, the properties of honey are modified. The results obtained could aid in the development of these compounds for use in traditional medicine as a natural source of bioactive compounds.

Bioactive Compounds of Opuntia spp. Acid Fruits: Micro and Nano-Emulsified Extracts and Applications in Nutraceutical Foods

The acid fruit of the "xoconostle" cactus belongs to the genus Opuntia family of cacti. It is used as a functional food for its bioactive compounds. Several studies reported that xoconostle fruits have a high amount of ascorbic acid, betalains, phenols, tannins, and flavonoids. These compounds confer antioxidant, antibacterial, anti-inflammatory, and hepatoprotective gastroprotective activity. Xoconostle fruit extracts were tested by in vitro assays where the digestion conditions were simulated to measure their stability. At the same time, the extracts were protected by encapsulation (microencapsulation, multiple emulsions, and nanoemulsions). Applications of encapsulated extracts were probed in various food matrices (edible films, meat products, dairy, and fruit coatings). The xoconostle is a natural source of nutraceutical compounds, and the use of this fruit in the new food could help improve consumers' health.

Inhibitory Effect of Fisetin on α-Glucosidase Activity: Kinetic and Molecular Docking Studies

The inhibition of α-glucosidase is a clinical strategy for the treatment of type 2 diabetes mellitus (T2DM), and many natural plant ingredients have been reported to be effective in alleviating hyperglycemia by inhibiting α-glucosidase. In this study, the α-glucosidase inhibitory activity of fisetin extracted from Cotinus coggygria Scop. was evaluated in vitro. The results showed that fisetin exhibited strong inhibitory activity with an IC₅₀ value of 4.099 × 10⁻⁴ mM. Enzyme kinetic analysis revealed that fisetin is a non-competitive inhibitor of α-glucosidase, with an inhibition constant value of 0.01065 ± 0.003255 mM. Moreover, fluorescence spectrometric measurements indicated the presence of only one binding site between fisetin and α-glucosidase, with a binding constant (lgKa) of 5.896 L·mol⁻¹. Further molecular docking studies were performed to evaluate the interaction of fisetin with several residues close to the inactive site of α-glucosidase. These studies showed that the structure of the complex was maintained by Pi-Sigma and Pi-Pi stacked interactions. These findings illustrate that fisetin extracted from Cotinus coggygria Scop. is a promising therapeutic agent for the treatment of T2DM.

The Addition of Microencapsulated or Nanoemulsified Bioactive Compounds Influences the Antioxidant and Antimicrobial Activities of a Fresh Cheese

The objective of this study was to compare the effects of the incorporation of microcapsules or nanoemulsions with Opuntiaoligacantha on the quality of fresh cheese. Three treatments were established: Control, cheese with microcapsules (Micro), and cheese with nanoemulsion (Nano). The parameters evaluated were physicochemical (moisture, ash, fat, proteins, and pH), microbiological (mesophilic aerobic bacteria, mold-yeast, and total coliforms), functional (total phenols, flavonoids, and antioxidant capacity), and texture (hardness, elasticity, cohesion, and chewiness) during storage for 45 days at 4 °C. The results showed that adding microcapsules and nanoemulsion did not affect the physicochemical parameters of the cheese. Total coliforms decreased in all samples from the first days of storage (Control: 4.23 ± 0.12, Micro: 3.27 ± 0.02, and Nano: 2.68 ± 0.08 Log10 CFU), as well as aerobic mesophiles and mold-yeast counts. Regarding the functional properties, an increase in total phenols was observed in all treatments. The texture profile analysis showed that the addition of microcapsules and nanoemulsion influenced hardness (Control: 8.60 ± 1.12, Micro: 1.61 ± 0.31, and Nano: 3.27 ± 0.37 N). The antimicrobial effect was greater when nanoemulsions were added, while adding microcapsules influenced the antioxidant activity more positively.

Encapsulation Preserves Antioxidant and Antidiabetic Activities of Cactus Acid Fruit Bioactive Compounds under Simulated Digestion Conditions

Cactus acid fruit (Xoconostle) has been studied due its content of bioactive compounds. Traditional Mexican medicine attributes hypoglycemic, hypocholesterolemic, anti-inflammatory, antiulcerogenic and immunostimulant properties among others. The bioactive compounds contained in xoconostle have shown their ability to inhibit digestive enzymes such as α-amylase and α-glucosidase. Unfortunately, polyphenols and antioxidants in general are molecules susceptible to degradation due to storage conditions, (temperature, oxygen and light) or the gastrointestinal tract, which limits its activity and compromises its potential beneficial effect on health. The objectives of this work were to evaluate the stability, antioxidant and antidiabetic activity of encapsulated extract of xoconostle within double emulsions (water-in-oil-in-water) during storage conditions and simulated digestion. Total phenols, flavonoids, betalains, antioxidant activity, α-amylase and α-glucosidase inhibition were measured before and after the preparation of double emulsions and during the simulation of digestion. The ED40% (treatment with 40% of xoconostle extract) treatment showed the highest percentage of inhibition of α-glucosidase in all phases of digestion. The inhibitory activity of α-amylase and α-glucosidase related to antidiabetic activity was higher in microencapsulated extracts than the non-encapsulated extracts. These results confirm the viability of encapsulation systems based on double emulsions to encapsulate and protect natural antidiabetic compounds.

Cactus: Chemical, nutraceutical composition and potential bio-pharmacological properties

Cactus species are plants that grow in the arid and semiarid regions of the world. They have long fascinated the attention of the scientific community due to their unusual biology. Cactus species are used for a variety of purposes, such as food, fodder, ornamental, and as medicinal plants. In the last regard, they have been used in traditional medicine for eras by the ancient people to cure several diseases. Recent scientific investigations suggest that cactus materials may be used as a source of naturally-occurring products, such as mucilage, fiber, pigments, and antioxidants. For this reason, numerous species under this family are becoming endangered and extinct. This review provides an overview of the habitat, classification, phytochemistry, chemical constituents, extraction and isolation of bioactive compounds, nutritional and pharmacological potential with pre-clinical and clinical studies of different Cactus species. Furthermore, conservation strategies for the ornamental and endangered species have also been discussed.