Yanangdaengin, a dihydrochalcone glucoside galloyl ester as active antioxidative agent from leaves of Lysiphyllum strychnifolium (syn. Bauhinia strychnifolia)

Antihyperglycemic effects of Lysiphyllum strychnifolium leaf extract in vitro and in vivo

CONTEXT

Lysiphyllum strychnifolium (Craib) A. Schmitz (LS) (Fabaceae) has traditionally been used to treat diabetes mellitus.

OBJECTIVE

This study demonstrates the antidiabetic and antioxidant effects of aqueous extract of LS leaves in vivo and in vitro.

MATERIALS AND METHODS

The effects of aqueous LS leaf extract on glucose uptake, sodium-dependent glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2) mRNA expression in Caco-2 cells, α-glucosidase, and lipid peroxidation were evaluated in vitro. The antidiabetic effects were evaluated using an oral glucose tolerance test (OGTT) and a 28-day consecutive administration to streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic mice.

RESULTS

The extract significantly inhibited glucose uptake (IC₅₀: 236.2 ± 36.05 µg/mL) and downregulated SGLT1 and GLUT2 mRNA expression by approximately 90% in Caco-2 cells. Furthermore, it non-competitively inhibited α-glucosidase in a concentration-dependent manner with the IC₅₀ and K_i of 6.52 ± 0.42 and 1.32 µg/mL, respectively. The extract at 1000 mg/kg significantly reduced fasting blood glucose levels in both the OGTT and 28-day consecutive administration models as compared with untreated STZ-NA-induced diabetic mice (p < 0.05). Significant improvements of serum insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and GLUT4 levels were observed. Furthermore, the extract markedly decreased oxidative stress markers by 37-53% reduction of superoxide dismutase 1 (SOD1) in muscle and malondialdehyde (MDA) in muscle and pancreas, which correlated with the reduction of MDA production in vitro (IC₅₀: 24.80 ± 7.24 µg/mL).

CONCLUSION

The LS extract has potent antihyperglycemic activity to be used as alternative medicine to treat diabetes mellitus.

Lysiphyllum strychnifolium (Craib) A. Schmitz Extracts Moderate the Expression of Drug-Metabolizing Enzymes: In Vivo Study to Clinical Propose

Lysiphyllum strychnifolium (Craib) A. Schmitz (LS) has been traditionally used as a medicinal herb by folk healers in Thailand with rare evidence-based support. Hepatic cytochrome P450s (CYPs450) are well known as the drug-metabolizing enzymes that catalyze all drugs and toxicants. In this study, we investigated the mRNA levels of six clinically important CYPs450, i.e., CYP1A2, 3A2, 2C11, 2D1, 2D2, and 2E1, in rats given LS extracts. Seventy Wistar rats were randomized into seven groups (n = 10). Each group was given LS stem ethanol (SE) and leaf water (LW) extracts orally at doses of 300, 2000, and 5000 mg/kg body weight (mg/kg.bw) for twenty-eight consecutive days. After treatment, the expression of CYPs450 genes was measured using quantitative real-time PCR. The results revealed that SE and LW, which contained quercetin and gallic acid, promoted the upregulation of all CYPs450. Almost all CYPs450 genes were downregulated in all male LW-treated rats but upregulated in female-treated groups, suggesting that CYP gene expressions in LS-treated rats were influenced by gender. Moderate and high doses of the LS extracts had a tendency to induce six CYP450s’ transcription levels in both rat genders. CYP2E1 gene showed a unique expression level in male rats receiving SE at a dose of 2000 mg/kg.bw, whereas a low dose of 300 mg/kg.bw was found in the LW-treated female group. As a result, our findings suggest that different doses of LS extracts can moderate the varying mRNA expression of clinically relevant CYP genes. In this study, we provide information about CYP induction and inhibition in vivo, which could be a desirable condition for furthering the practical use of LS extracts in humans.

Research progress of chinese herbal medicine compounds and their bioactivities: Fruitful 2020

Traditional Chinese medicines (TCMs) have continued to be a treasure trove. The study of chemodiversity and versatility of bioactivities has always been an important content of pharmacophylogeny. There is amazing progress in the discovery and research of natural components with novel structures and significant bioactivities in 2020. In this paper we review 271 valuable natural products, including terpenoids, steroids, flavonoids, phenylpropanoids, phenolics, nitrogen containing compounds and essential oil, etc., isolated and identified from TCMs published in journals of Chinese Traditional and Herbal Drugs (Zhong Cao Yao) and Chinese Herbal Medicines (CHMs), and focus on their structures, source organisms, and relevant bioactivities, paying special attention to structural characteristics of novel compounds and newly revealed pharmacological properties of known compounds. It is worth noting that natural products with antitumor activity still constitute the primary object of research. Among the reported compounds, two new triterpenoids, i.e., ursolic acid 3-O-β-cis-caffeate and mollugoside E, display remarkable cytotoxicity against PC-9 and HL-60 cell lines, respectively. Three known phenolic compounds, i.e., pyoluteorin, 4-hydroxy-3-methoxy cinnamaldehyde and 3,7-dimethoxy-5-hydroxy-1,4-phenanthrenequinone, exhibit significant cytotoxicity against multiple cell lines. Numerous studies on the free radical scavenging activity of reported compounds are currently underway. In vitro, three known phenolic compounds, i.e., 3,4-O-dicaffeoylquinic acid methyl ester, 3,4,5-O-tricaffeoylquinic acid methyl ester and arbutin, had more considerable antioxidant activities than vitamin C. The anti-inflammatory, anti-diabetic, hypolipidemic, neuroprotective and antimicrobial activities of isolated compounds are also encouraging. The structural characteristics and bioactivities of TCM compounds highlighted here reflect the enormous progress of CHM research in 2020 and will play a positive role in the future drug discovery and development. According to pharmacophylogeny, the phylogenetic distribution of compounds with different natures and flavors can be explored, with view to better mining TCM resources.

Inhibition of α-glucosidase by trilobatin and its mechanism: kinetics, interaction mechanism and molecular docking

α-Glucosidase is related to the increase in postprandial blood glucose in vivo. Inhibition of α-glucosidase is supposed to be an effective approach to treat type 2 diabetes mellitus (T2DM). Trilobatin, a member of the dihydrochalcone family, shows anti-oxidant, anti-inflammatory and anti-diabetic activities. In this study, the inhibitory activity and mechanism of trilobatin on α-glucosidase were investigated using multispectroscopic and molecular docking techniques. The kinetic analysis showed that trilobatin reversibly inhibited α-glucosidase in a noncompetitive-type manner and the value of IC₅₀ was 0.24 ± 0.02 mM. The analysis of fluorescence spectra demonstrated that the formation of the trilobatin-α-glucosidase complex was driven mainly by hydrogen bonding and van der Waals forces, resulting in the conformational changes of α-glucosidase. Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) measurements suggested that the interaction could change the micro-environment and conformation of α-glucosidase affected by trilobatin. Molecular docking analysis determined the exact binding sites of trilobatin on α-glucosidase. These results indicated that trilobatin is a strong α-glucosidase inhibitor, thus it could be conducive to ameliorate T2DM.