In vitro α-glucosidase inhibition by Brazilian medicinal plant extracts characterised by ultra-high performance liquid chromatography coupled to mass spectrometry

Qualitative chemical characterization of salva-de-marajó (Lippia origanoides, Verbenaceae) preparations

Lippia origanoides Kunth (LO, Verbenaceae), commonly known in Brazil as salva-de-marajó, is an aromatic plant native to the Americas. Quilombola women from Oriximiná (Pará State, Brazil) use decoctions and decoction vapors of LO aerial parts orally or in sitz baths to alleviate symptoms of dysmenorrhea. This study aimed to evaluate LO decoctions and essential oils through a chemo-qualitative approach. Aerial parts of LO were collected from two individuals, and other two commercial samples were acquired from a public market. Aqueous extract of each sample was obtained by decoction and spray drying. The spray-dried decoctions were chemically characterized using UPLC-APCI(-)-IT-MS2 and cluster heatmap analysis to discern compositional patterns. Essential oils were obtained through hydrodistillation and analyzed using GC-MS and GC-FID. In total, 12 compounds were tentatively identified from LO decoctions. Their product ion spectra were characteristic of flavonoid aglycones (5) and glycosides (4), and phenylpropanoids, including two stilbene glycosides and one hydroxycinnamic acid glycoside. Variations were noted in the chemical fingerprints of the decoctions, but the flavonoid glycosides orientin, isoorientin, and vitexin emerged as potential markers for the species. The essential oils of the samples contained high amounts of oxygenated monoterpenoids, with a predominance of the p-menthanes carvacrol (up to 61.9 %) and/or thymol (up to 17.0 %), and p-cymene (up to 24.9 %). This study was the first to explore the chemical composition of decoctions derived from LO, highlighting the species as an untapped source of phenolic glycosides, an aspect that has received limited discussion thus far.

In Vitro Hypoglycemic Activities of Lactobacilli and Bifidobacterium Strains from Healthy Children's Sources and Their Effect on Stimulating GLP-1 Secretion in STC-1 Cells

A long-term use of chemical drugs cannot cure type II diabetes mellitus (T2DM) and their numerous toxic side effects can be harmful to human health. In recent years, probiotics have emerged as a natural resource to replace chemical drugs in alleviating many human ailments. Healthy children's intestines have a lot of colonized Lactobacilli and Bifidobacterium, and these beneficial bacteria can help promote overall health. The objective of this study was to isolate potential antidiabetic probiotic strains from healthy children and evaluate their application prospects. Firstly, Lactobacillus and Bifidobacterium strains were isolated from healthy children's feces and identified by the pheS or clpC genes with their respective 16S rRNA genes. Then, hydrophobicity, artificial gastrointestinal fluid tolerance, α-Glucosidase and Dipeptidyl peptidase IV (DPP-IV) inhibitory activities of isolated strains were determined, and antioxidant activities and promoting secretion of GLP-1 in STC-1 cells of candidate strains were tested. Results showed that 6 strains of Lactobacillus and Bifidobacterium were obtained from the feces of healthy children aged 3 years, respectively, including Lacticaseibacillus paracasei L-21 and L-25, Levilactobacillus brevis L-16, Lentilactobacillus buchneri L-9, Lactiplantibacillus plantarum L-8 and L-3, Bifidobacterium bifidum 11-1 and B-84, Bifidobacterium longum subsp. longum 6-1, 6-2, B42 and B53. The hydrophobicity and auto-aggregation levels of all these strains were higher than 30% and 50%, respectively, and the decrease in the number of colonies of all strains in the artificial gastrointestinal fluid was less than 2 log CFU/mL. Strains L-3, L-8, L-9, L-21, 6-1, 11-1, B53 and B84 were selected based on their high α-glucosidase inhibitory activity and DPP-IV inhibitory activity, and results of the antioxidant capacity assay showed that the remaining strains all had intense comprehensive antioxidant activity. Additionally, Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 had the most substantial prompting effect on GLP-1 secretion in the STC-1 cell line. These results indicated that Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 could be used as a potential antidiabetic strain; thus, its application as a food supplement and drug ingredient could be recommended after in vivo mitigation of type II diabetes test.

Nourishing Yin traditional Chinese medicine: potential role in the prevention and treatment of type 2 diabetes

Type 2 diabetes mellitus (T2DM), a common and frequently occurring disease in contemporary society, has become a global health threat. However, current mainstream methods of prevention and treatment, mainly including oral hypoglycemic drugs and insulin injections, do not fundamentally block the progression of T2DM. Therefore, it is imperative to find new ways to prevent and treat diabetes. Traditional Chinese medicine is characterized by multiple components, pathways, and targets with mild and long-lasting effects. Pharmacological studies have shown that nourishing yin traditional Chinese medicine (NYTCM) can play a positive role in the treatment of T2DM by regulating pathways such as the phosphatidylinositol 3-kinase/serine-threonine kinase, mitogen-activated protein kinase, nuclear factor-kappa B, and other pathways to stimulate insulin secretion, protect and repair pancreatic β cells, alleviate insulin resistance, ameliorate disordered glucose and lipid metabolism, mitigate oxidative stress, inhibit inflammatory responses, and regulate the intestinal flora. The pharmacologic activity, mechanisms, safety, and toxicity of NYTCM in the treatment of T2DM are also reviewed in this manuscript.

Identification and Isolation of α-Glucosidase Inhibitors from Siraitia grosvenorii Roots Using Bio-Affinity Ultrafiltration and Comprehensive Chromatography

The discovery of bioactive compounds from medicinal plants has played a crucial role in drug discovery. In this study, a simple and efficient method utilizing affinity-based ultrafiltration (UF) coupled with high-performance liquid chromatography (HPLC) was developed for the rapid screening and targeted separation of α-glucosidase inhibitors from Siraitia grosvenorii roots. First, an active fraction of S. grosvenorii roots (SGR2) was prepared, and 17 potential α-glucosidase inhibitors were identified based on UF-HPLC analysis. Second, guided by UF-HPLC, a combination of MCI gel CHP-20P column chromatography, high-speed counter-current countercurrent chromatography, and preparative HPLC were conducted to isolate the compounds producing active peaks. Sixteen compounds were successfully isolated from SGR2, including two lignans and fourteen cucurbitane-type triterpenoids. The structures of the novel compounds (4, 6, 7, 8, 9, and 11) were elucidated using spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. Finally, the α-glucosidase inhibitory activities of the isolated compounds were verified via enzyme inhibition assays and molecular docking analysis, all of which were found to exhibit certain inhibitory activity. Compound 14 exhibited the strongest inhibitory activity, with an IC₅₀ value of 430.13 ± 13.33 μM, which was superior to that of acarbose (1332.50 ± 58.53 μM). The relationships between the structures of the compounds and their inhibitory activities were also investigated. Molecular docking showed that the highly active inhibitors interacted with α-glucosidase through hydrogen bonds and hydrophobic interactions. Our results demonstrate the beneficial effects of S. grosvenorii roots and their constituents on α-glucosidase inhibition.