Antioxidant and α-Glucosidase Inhibitory Activities Guided Isolation and Identification of Components from Mango Seed Kernel

Mango (Mangifera indica L.) seed kernel extract suppresses hyperglycemia by modulating pancreatic β cell apoptosis and dysfunction and hepatic glucose metabolism in diabetic rats

This study investigated the anti-hyperglycemic action of mango seed kernel extract (MKE) and various mechanisms involved in its actions to improve pancreatic β cells and hepatic carbohydrate metabolism in diabetic rats. An intraperitoneal injection of 60 mg/kg of streptozotocin (STZ) followed by 30 consecutive days of treatment with MKE (250, 500, and 1000 mg/kg body weight) was used to establish a study group of diabetic rats. Using liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS) for identification, 26 chemical compounds were found in MKE and the high-performance liquid chromatography (HPLC) analysis of the MKE also revealed the existence of mangiferin, gallic acid, and quercetin. The results confirmed that in each diabetes-affected rat, MKE mitigated the heightened levels of fasting blood glucose, diabetic symptoms, glucose intolerance, total cholesterol (TC), and low-density lipoprotein-cholesterol (LDL-C). As demonstrated by a remarkable increment in serum and pancreatic insulin, the diabetic pancreatic β cell function was potentiated by treating with MKE. The effect of MKE on diabetic pancreatic apoptosis clearly reduced the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells, which was related to diminished levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and Bax and an increase in Bcl-xL protein expression. Furthermore, diabetes-induced liver damage was clearly ameliorated along with a notable reduction in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and abnormal liver histology. By enhancing anti-oxidant superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, MKE alleviated diabetes-induced pancreatic and liver oxidative damage, as demonstrated by diminished levels of malondialdehyde. In minimizing the expression levels of glucose 6-phosphatase and phosphoenolpyruvate carboxykinase-1 proteins in the diabetic liver, MKE also enhanced glycogen content and hexokinase activity. Collectively, these findings indicate that by suppressing oxidative and inflammatory processes, MKE exerts a potent anti-hyperglycemic activity in diabetic rats which serve to protect pancreatic β cell apoptosis, enhance their function, and improve hepatic glucose metabolism.

Antidiabetic properties of mango in animal models and humans: A systematic review

Mango has long been an attractive source of nutrition and pharmacological therapeutics. The mango plant (Mangifera indica L.) contains bioactive compounds that may have antidiabetic properties. This systematic review investigated the evidence for antidiabetic properties of the different parts of the mango plant in managing type 2 diabetes mellitus in animal models and humans. The electronic databases PubMed, FSTA, Web of Science, CINAHL, MEDLINE, and Cochrane Library were systematically searched to identify articles with clear objectives and methodologies available in the English language with publication date limits up to December 2020. Twenty-eight of 1001 animal and human studies met the inclusion criteria that investigated antidiabetic properties of mango from leaf (31%), flesh (38%), seed-kernel (7%), peel (14%), stem-bark (7%), and by-product (3%). Results support the glucose-lowering properties of mango in both animals and human. Proposed antidiabetic mechanisms of action include inhibition of α-amylase and α-glucosidase, improved antioxidant status, improved insulin sensitivity, facilitated glucose uptake, and gene regulation of glucose transporter type 4, insulin receptor substrate 1, and phosphoinositide 3-kinase. The animal and randomized control trial findings suggest that mango may be beneficial as an antidiabetic agent. Although these studies hold promise, additional observational studies and randomized control trials are required because human studies are significantly fewer in number, use mango flesh almost exclusively, and had modest blood glucose effects. Additional research gaps include identifying the mechanisms of action for the different components of the mango plant.

Composition and Functional Effect of Mango (Mangifera indica L.) Almond Flours on Wheat Dough Rheology

Composition and technofunctional properties of the almond flours of 12 mango varieties from savannah zones of Cameroon (Central Africa) are assessed in order to highlight their potential use in breadmaking, through their effect on dough rheology. The compositions of almonds display starch as the major constituent (60-65%) with more than 80% of amylopectin and a significant presence of phenolic compounds (1-7%), lipids (7-13%), and proteins (4-7%), depending on mango varieties, with local varieties showing the highest polyphenol and lipid contents. Almond flours are characterized by high WAC (water absorption capacity) and OAC (oil absorption capacity) and pasting properties influenced by starch lipid and starch protein complexes. In wheat-mango almond composite flours, the pasting properties are mango variety and almond flour treatment (native or delipidated) dependent, with a substitution threshold effect variable from one variety to another. Alveographic profiles of the composite flours result in dough characterized by high tenacity (P) but low swelling index (G) and baking strength (W). These effects are intensified with increasing substitution of wheat. However, up to 10% wheat substitution, the composite flours seem acceptable in breadmaking, with 9 mango varieties hypothetically convenient for the reduction of bread staling.

Characterization of Fatty Acids, Polysaccharides, Amino Acids, and Minerals in Marine Macroalga Chaetomorpha crassa and Evaluation of Their Potentials in Skin Cosmetics

Cosmetic industries are highly committed to finding natural sources of functional active constituents preferable to safer materials to meet consumers' demands. Marine macroalgae have diversified bioactive constituents and possess potential benefits in beauty care products. Hence, the present study was carried out to characterize the biochemical profile of marine macroalga Chaetomorpha crassa by using different techniques for revealing its cosmetic potentials. In results, the FTIR study characterized the presence of different bioactive functional groups that are responsible for many skin-beneficial compounds whereas six and fifteen different important phycocompounds were found in GCMS analysis of ethanolic and methanolic extracts, respectively. In the saccharide profile of C. crassa, a total of eight different carbohydrate derivatives were determined by the HRLCMS Q-TOF technique, which showed wide varieties of cosmetic interest. In ICP AES analysis, Si was found to be highest whereas Cu was found to be lowest among other elements. A total of twenty-one amino acids were measured by the HRLCMS-QTOF technique, which revealed the highest amount of the amino acid, Aspartic acid (1207.45 nmol/mL) and tyrosine (106.77 nmol/mL) was found to be the lowest in amount among other amino acids. Their cosmetic potentials have been studied based on previous research studies. The incorporation of seaweed-based bioactive components in cosmetics has been extensively growing due to its skin health-promoting effects.

Antidiabetic Medicinal Plants Used in Democratic Republic of Congo: A Critical Review of Ethnopharmacology and Bioactivity Data

Several studies have been conducted and published on medicinal plants used to manage Diabetes Mellitus worldwide. It is of great interest to review available studies from a country or a region to resort to similarities/discrepancies and data quality. Here, we examined data related to ethnopharmacology and bioactivity of antidiabetic plants used in the Democratic Republic of Congo. Data were extracted from Google Scholar, Medline/PubMed, Scopus, ScienceDirect, the Wiley Online Library, Web of Science, and other documents focusing on ethnopharmacology, pharmacology, and phytochemistry antidiabetic plants used in the Democratic Republic of Congo from 2005 to September 2021. The Kew Botanic Royal Garden and Plants of the World Online web databases were consulted to verify the taxonomic information. CAMARADES checklist was used to assess the quality of animal studies and Jadad scores for clinical trials. In total, 213 plant species belonging to 72 botanical families were reported. Only one plant, Droogmansia munamensis, is typically native to the DRC flora; 117 species are growing in the DRC and neighboring countries; 31 species are either introduced from other regions, and 64 are not specified. Alongside the treatment of Diabetes, about 78.13% of plants have multiple therapeutic uses, depending on the study sites. Experimental studies explored the antidiabetic activity of 133 plants, mainly in mice, rats, guinea pigs, and rabbits. Several chemical classes of antidiabetic compounds isolated from 67 plant species have been documented. Rare phase II clinical trials have been conducted. Critical issues included poor quality methodological protocols, author name incorrectly written (16.16%) or absent (14.25%) or confused with a synonym (4.69%), family name revised (17.26%) or missing (1.10%), voucher number not available 336(92.05%), ecological information not reported (49.59%). Most plant species have been identified and authenticated (89.32%). Hundreds of plants are used to treat Diabetes by traditional healers in DRC. However, most plants are not exclusively native to the local flora and have multiple therapeutic uses. The analysis showed the scarcity or absence of high-quality, in-depth pharmacological studies. There is a need to conduct further studies of locally specific species to fill the gap before their introduction into the national pharmacopeia.

In Vitro α-Amylase and α-Glucosidase Inhibitory and Antioxidant Activities of the Crude Extract and Solvent Fractions of Hagenia abyssinica Leaves

BACKGROUND

The leaves of Hagenia abyssinica have been used in the management of diabetes mellitus in Ethiopian folk medicine. Thus, this study is aimed at investigating the in vitro α-amylase and α-glucosidase inhibitory and antioxidant activities of the crude extract and solvent fractions of H. abyssinica leaves.

METHODS

The in vitro α-amylase and α-glucosidase inhibitory and antioxidant activities of the plant extract were assessed using 3,5-dinitrosalicylic acid (DNSA), p-nitro-phenyl-a-D glucopyranoside (p-NPG), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, respectively. Each value of percent inhibition of α-amylase, α-glucosidase, and DPPH scavenging effect was presented as means ± SEM (n = 3).

RESULTS

The α-amylase inhibitory activity of the crude extract and solvent fractions was found to be concentration-dependent. The strongest activity was exhibited by the crude extract at the highest concentration with a percentage inhibition of 74.52% (IC50, 14.52 μg/ml) followed by water fraction 68.24% (IC50, 16.31 μg/ml), ethyl acetate fraction 61.57% (IC50, 18.73 μg/ml), and chloroform fraction 56.87% (IC50, 21.57 μg/ml) of H. abyssinica leaves. In the α-glucosidase inhibition assay, the maximum activity was exhibited by the aqueous fraction 62.54% (IC50, 11.67 μg/ml) followed by ethyl acetate fraction 54.97% (IC50, 15.89 μg/ml), crude extract 46.79% (IC50, >16.5 μg/ml), and chloroform fraction 36.44% (IC50, >16.5 μg/ml). In the antioxidant assay, the crude extract exhibited the highest antioxidant activity 86.36% (IC50, 10.25 μg/ml) followed by water fraction 78.59% (IC50, 13.86 μg/ml), ethyl acetate fraction 71.58% (IC50, 16.34 μg/ml), and chloroform fraction 63.65% (IC50, 18.83 μg/ml).

CONCLUSION

This study has revealed that H. abyssinica leaves possess noticeable in vitro α-amylase and α-glucosidase inhibitory and antioxidant activities.