New flavonoids from the roots of Sophora davidii (Franch.) Skeels and their glucose transporter 4 translocation activities

Effects of acid and aluminum stress on seed germination and physiological characteristics of seedling growth in Sophora davidii

Sophora davidii, a vital forage species, predominantly thrives in the subtropical karst mountains of Southwest China. Its resilience to poor soil conditions and arid environments renders it an ideal pioneer species for ecological restoration in these regions. This study investigates the influence of acidic, aluminum-rich local soil on the germination and seedling growth physiology of S. davidii. Experiments were conducted under varying degrees of acidity and aluminum stress, employing three pH levels (3.5 to 5.5) and four aluminum concentrations (0.5 to 2.0 mmol·L-1). The results showed that germination rate, germination index, and vigor index of S. davidii seeds were decreased but not significantly under slightly acidic conditions (pH 4.5-5.5), while strong acid (pH = 3.5) significantly inhibited the germination rate, germination index, and vigor index of white spurge seeds compared with the control group. Aluminum stress (≥0.5 mmol·L-1) significantly inhibited the germination rate, germination index, and vigor index of S. davidii seed. Moreover, the seedlings' root systems were sensitive to the changes of aluminum concentration, evident from significant root growth inhibition, characterized by root shortening and color deepening. Notably, under aluminum stress (pH = 4.3), the levels of malondialdehyde and proline in S. davidii escalated with increasing aluminum concentration, while antioxidant enzyme activities demonstrated an initial increase followed by a decline. The study underscores the pivotal role of cellular osmoregulatory substances and protective enzymes in combating aluminum toxicity in S. davidii, a key factor exacerbating growth inhibition in acidic environments. These findings offer preliminary theoretical insights for the practical agricultural utilization of S. davidii in challenging soil conditions.

Bioassay-guided isolation of antibacterial and anti-inflammatory components from Atractylodes lancea

A bioassay-guided isolation from Atractylodes lancea (Thunb.) DC. obtained 22 compounds, including eight previously undescribed sesquiterpenoids and polyacetylenes (1, 3 and 12-17), as well as fourteen known analogues, and their structures were confirmed by extensive spectroscopic methods. This study evaluated their antibacterial activity against methicillin resistant Staphylococcus aureus (MRSA) for the first time, as well as anti-inflammatory activity. Most of them, including new compounds, showed varying degrees of antibacterial activity against S. aureus and MRSA. Notably, compound 21 exhibited significant antibacterial activity against four different bacteria (MIC 6.25-20.00 μg/mL). This suggested that 21 may have the potential to be developed into a broad-spectrum antibacterial agent. Moreover, except for 9 and 11, most compounds exhibited great anti-inflammatory activity (IC50 1.92-37.91 μM), and iNOS might be a potential target of these compounds according to the molecular docking analysis.

Phenolic Constituents with Glucose Uptake and GLUT4 Translocation Bioactivities from the Fruits of Cordia dichotoma

From the fruits of Cordia dichotoma, 11 new phenolic compounds, dichotomins A-K, were isolated, together with 19 known compounds. Through the analysis of detailed NMR data and HRESIMS data, the planar structures of all compounds were confirmed. Using NMR calculations, the absolute configuration of dichotomins A-K was elucidated by comparing their observed and computed electronic circular dichroism (ECD) spectra. Dichotomin H (8) and dichotomin I (9) were determined as two pairs of enantiomers. The enantiomers of compounds 8 and 9 were separated using chiral-phase high-performance liquid chromatography (HPLC), and the stereostructure of each enantiomer was determined by similarly calculating the ECD. Compounds 3, 5, 7, 17, 18, 23-25, and 27-30 increased glucose uptake by 1.04- to 2.85-folds at concentrations of 30 μg/mL. Further studies revealed that compounds 3 and 5 had a moderate effect on glucose transporter 4 (GLUT4) translocation activity in L6 cells. At 30 μg/mL, compound 3 significantly enhanced AMPK phosphorylation and GLUT4 expression. As a whole, compound 3 has the potential to be a drug candidate for the treatment of type 2 diabetes mellitus (T2DM).

Natural products with potential hypoglycemic activity in T2DM: 2019-2023

As currently the most common metabolic disease, type 2 diabetes mellitus (T2DM) has shown a continuous increase in the number of patients in recent decades. Most anti-T2DM drugs tend to cause some side effects. Given the pathogenesis of T2DM, natural products have emerged as an important source of anti-T2DM drugs. This article reviews natural products with potential hypoglycemic activity from 2019 to 2023. A total of 200 previously natural products were discovered on SciFinder, PubMed and Web of Science. These products were categorized based on their structural frameworks and their biological activities were summarized. Although the mechanisms of action of most compounds are unclear, these compounds could still serve as candidates for the development of lead compounds. Therefore, further structure and activity research of natural products will significantly contribute to the development of potential anti-T2DM drugs.

Isoprenoid flavonoids isolated from Sophora davidii and their activities induces apoptosis and autophagy in HT29 cells

Four previously undescribed isoprenoid flavonoids (2-5) were isolated from Sophora davidii, along with five known analogues. The structures of the compounds were established through comprehensive analysis of spectroscopic data, including HRESIMS, 1D and 2D NMR, and absolute configurations determined by theoretical calculations, including ECD and NMR calculation. The cytotoxic effects of the isolated compounds on human HT29 colon cancer cells were evaluated using the MTT assay, compound 1 exhibited cytotoxicity against human HT29 colon cancer cells with an IC50 value of 8.39 ± 0.09 μM. Studies conducted with compound 1 in HT29 cells demonstrated that it may induce apoptosis and autophagy in HT29 by promoting the phosphorylation of P38 MAPK and inhibiting the phosphorylation of Erk MAPK.

Neolignans with anti-inflammatory activity from Piper kadsura (Choisy) Ohwi

Two novel neolignans, piperkadsurenin A (1) and kadsurenin N (2), along with six known neolignans (3-8) and two lignans (9-10) were isolated from the stems of Piper kadsura (Choisy) Ohwi. Extensive spectroscopic data interpretation and ECD calculations were used to identify the structures of the new compounds 1 and 2. Especially, compound 1 represents the first example of neolignan with cyclopenta[b]pyran framework. The anti-inflammatory efficacy of compounds 1-10 in vitro was systematically assessed through NO production inhibitory assay. Compounds 3 and 7 significantly inhibited LPS-induced NO generation in RAW 264.7 cells, with IC50 values of 34.29 ± 0.82 and 47.5 ± 5.81 μM, respectively.

Assessment of the dual role of Lyonia ovalifolia (Wall.) Drude in inhibiting AGEs and enhancing GLUT4 translocation through LC-ESI-QTOF-MS/MS determination and in silico studies

Introduction: Diabetes mellitus (DM) is a metabolic disorder that results in glucose accumulation in the blood, accompanied by the production of advanced glycation end products (AGEs) through glycation of cellular proteins. These AGEs interfere with insulin signaling and prevent GLUT4 membrane translocation, thereby promoting the accumulation of more glucose in the blood and causing post-diabetic complications.

Methods: In this study, we examine the anti-diabetic potential of Lyonia ovalifolia (Wall.) Drude, a well-known ethnomedicinal plant of the Indian Himalayas. Considering its various medicinal properties, we analyzed its ethanolic extract and various solvent fractions for in vitro antiglycation activity and antidiabetic potential, i.e., stimulation of GLUT4 translocation.

Result and Discussions: The results showed that the extract and fractions exhibited increased antiglycation activity and an increased level of GLUT4 translocation. Analysis of a further 12 bioactive compounds of ethanolic extract, identified through LC-ESI-QTOF-MS/MS, revealed the presence of three new compounds: leucothol B, rhodoterpenoids A, and leucothol A. Moreover, we performed molecular docking of identified compounds against key proteins of diabetes mellitus: the sirtuin family of NAD (+)-dependent protein deacetylases 6 (SIRT6), aldose reductase (AR), and tyrosine kinase (TK). The results showed that flavonoid luteolin showed the best binding affinity ((−12.3 kcal/mol), followed by eriodictyol, astilbin, and syringaresinol. An ADMET study showed that luteolin, eriodictyol, astilbin, and syringaresinol may be promising drug candidates belonging to the flavonoid class of compounds, with no harmful effects and complying with all the drug-likeness guidelines. Furthermore, molecular dynamics (MD) simulations on a 50 ns timescale revealed that AR protein was most stable with luteolin throughout the simulation period. Therefore, this study reveals for the first time that L. ovalifolia plays an important role in insulin homeostasis, as shown in in vitro and in silico studies.

Triterpenoid saponins and C21 steroidal glycosides from Gymnema tingens and their glucose uptake activities

Four new triterpenoid saponins, tigensides A-D (1-4), and one new C21 steroid, tipregnane A(9), together with six known compounds were isolated from the EtOAc fraction of the roots and stems of Gymnema tingens. The chemical structures of the new compounds were determined based on their spectroscopic data, including IR, UV, NMR, and mass spectrometric analysis. All compounds were isolated for the first time. Compounds 1-11 promoted glucose uptake in the range of 1.12 to 2.52 fold, respectively. Compound 2 showed the most potent glucose uptake, with 2.52 fold enhancement. Additionally, compound 2 showed a medium effect on the GLUT4 translocation activity in L6 cells in further study.

Discovery of bicyclic polyprenylated acylphloroglucinols from Hypericum himalaicum with glucose transporter 4 translocation activity

Hyperhimatins A-P (1-16), sixteen new bicyclic polyprenylated acylphloroglucinols (BPAPs), were isolated and identified from Hypericum himalaicum. The planner structures of hyperhimatins A-P were confirmed via extensive NMR and careful HRESIMS data analysis. The absolute configurations of the new compounds were mainly determined by electronic circular dichroism (ECD) calculation, NMR calculation, and the circular dichroism data of the in situ formed [Rh₂(OCOCF₃)₄] complexes. All compounds were assessed for the glucose transporter 4 (GLUT-4) translocation and expression enhancing effects in L6 myotubes. Compounds 1-16 could promote the GLUT-4 expression by the range of 1.95-6.04 folds, and accelerate the GLUT-4 fusion with the plasma membrane ranged from 53.56% to 76.97% at a consistence of 30 μg/mL, among compound 10 displayed the strongest GLUT-4 translocation effect.

Environmental filtering drives the establishment of the distinctive rhizosphere, bulk, and root nodule bacterial communities of Sophora davidii in hilly and gully regions of the Loess Plateau of China

In addition to the rhizobia, other non-rhizobial endophytes (NREs) have been simultaneously isolated from the root nodules. The existence of NREs in leguminous root nodules is a universal phenomenon, and they have the potential to enhance legume survival, especially under conditions of environmental stress. However, the diversity and biogeographic patterns of microbial communities inhabiting root nodules are not well studied or understood. Here, we explored and characterized the diversity of NRE bacteria by using 16S rRNA gene high-throughput amplicon sequencing. Additionally, we compared the biogeography and co-occurrence patterns in review of the bacterial microbiota inhabiting the rhizosphere, the bulk soil and the root nodule bacterial communities associated with Sophora davidii, a native N-fixing wild leguminous shrub in hilly and gully regions of the Loess Plateau of China. The results showed the presence of a large diversity of bacteria belonging to 81 phyla, 154 classes, 333 orders, 463 families, and 732 genera inside the nodules. Proteobacteria were dominant in the nodule and rhizosphere soil samples, and Actinomycetes were dominant in the bulk soil samples. Mesorhizobium was the dominant genus in the nodules, accounting for between 60.15 and 83.74% of the bacteria. The microbial community composition of the NRE in the root nodules differed from that in the rhizosphere soil and the bulk soil of S. davidii. Moreover, we found that the biogeographic patterns and assembly process of the rhizobia and non-rhizobia communities differed in the root nodule, the rhizosphere soil and the bulk soil. Furthermore, the correlation analysis between the soil’s physical and chemical properties and the bacteria showed that available phosphorus was the predominant factor affecting the bacterial diversity within the rhizosphere soil. Finally, our results revealed that the microbial network diagram of co-occurrence patterns showed more complexes in the soil than in the root nodules. This indicates that only specific microorganisms could colonize and thrive in the rhizosphere through the selection and filtering effects of roots. In conclusion, there are significant differences in bacterial community composition in the nodules, rhizosphere and bulk soil in the hilly and gully region of the Loess Plateau, which is the result of environmental filtration. Our study improves the understanding of the biogeographic patterns and diversity of bacterial microbiota inhabiting root nodules and can help quantify and define the root nodule assemblage process of S. davidii.

Morphological, transcriptomic and metabolomic analyses of Sophora davidii mutants for plant height

Sophora davidii is an important plant resource in the karst region of Southwest China, but S. davidii plant-height mutants are rarely reported. Therefore, we performed phenotypic, anatomic structural, transcriptomic and metabolomic analyses to study the mechanisms responsible for S. davidii plant-height mutants. Phenotypic and anatomical observations showed that compared to the wild type, the dwarf mutant displayed a significant decrease in plant height, while the tall mutant displayed a significant increase in plant height. The dwarf mutant cells were smaller and more densely arranged, while those of the wild type and the tall mutant were larger and loosely arranged. Transcriptomic analysis revealed that differentially expressed genes (DEGs) involved in cell wall biosynthesis, expansion, phytohormone biosynthesis, signal transduction pathways, flavonoid biosynthesis and phenylpropanoid biosynthesis were significantly enriched in the S. davidii plant-height mutants. Metabolomic analysis revealed 57 significantly differential metabolites screened from both the dwarf and tall mutants. A total of 8 significantly different flavonoid compounds were annotated to LIPID MAPS, and three metabolites (chlorogenic acid, kaempferol and scopoletin) were involved in phenylpropanoid biosynthesis and flavonoid biosynthesis. These results shed light on the molecular mechanisms of plant height in S. davidii mutants and provide insight for further molecular breeding programs.

Transcriptomic and Metabolomic Analyses Reveal Key Metabolites, Pathways and Candidate Genes in Sophora davidii (Franch.) Skeels Seedlings Under Drought Stress

Soil aridification and desertification are particularly prominent in China's karst areas, severely limiting crop yields and vegetation restoration. Therefore, it is very important to identify naturally drought-tolerant plant species. Sophora davidii (Franch.) Skeels is resistant to drought and soil infertility, is deeply rooted and is an excellent plant material for soil and water conservation. We studied the transcriptomic and metabolomic changes in S. davidii in response to drought stress (CK, control; LD, mild drought stress; MD, moderate drought stress; and SD, severe drought stress). Sophora davidii grew normally under LD and MD stress but was inhibited under SD stress; the malondialdehyde (MDA), hydrogen peroxide (H₂O₂), soluble sugar, proline, chlorophyll a, chlorophyll b and carotenoid contents and ascorbate peroxidase (APX) activity significantly increased, while the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and soluble protein content significantly decreased. In the LD/CK, MD/CK and SD/CK comparison groups, there were 318, 734 and 1779 DEGs, respectively, and 100, 168 and 281 differentially accumulated metabolites, respectively. Combined analysis of the transcriptomic and metabolomic data revealed the metabolic regulation of S. davidii in response to drought stress. First, key candidate genes such as PRR7, PRR5, GI, ELF3, PsbQ, PsaK, INV, AMY, E2.4.1.13, E3.2.1.2, NCED, PP2C, PYL, ABF, WRKY33, P5CS, PRODH, AOC3, HPD, GPX, GST, CAT and SOD1 may govern the drought resistance of S. davidii. Second, three metabolites (oxidised glutathione, abscisic acid and phenylalanine) were found to be related to drought tolerance. Third, several key candidate genes and metabolites involved in 10 metabolic pathways were identified, indicating that these metabolic pathways play an important role in the response to drought in S. davidii and possibly other plant species.

Genus Sophora: a comprehensive review on secondary chemical metabolites and their biological aspects from past achievements to future perspectives

Sophora is deemed as one of the most remarkable genera of Fabaceae, and the third largest family of flowering plants. The genus Sophora comprises approximately 52 species, 19 varieties, and 7 forms that are widely distributed in Asia and mildly in Africa. Sophora species are recognized to be substantial sources of broad spectrum biopertinent secondary metabolites namely flavonoids, isoflavonoids, chalcones, chromones, pterocarpans, coumarins, benzofuran derivatives, sterols, saponins (mainly triterpene glycosides), oligostilbenes, and mainly alkaloids. Meanwhile, extracts and isolated compounds from Sophora have been identified to possess several health-promising effects including anti-inflammatory, anti-arthritic, antiplatelets, antipyretic, anticancer, antiviral, antimicrobial, antioxidant, anti-osteoporosis, anti-ulcerative colitis, antidiabetic, anti-obesity, antidiarrheal, and insecticidal activities. Herein, the present review aims to provide comprehensive details about the phytochemicals and biological effects of Sophora species. The review spotlighted on the promising phytonutrients extracted from Sophora and their plethora of bioactivities. The review also clarifies the remaining gaps and thus qualifies and supplies a platform for further investigations of these compounds.

Do Uncommon Plant Phenolic Compounds Have Uncommon Properties? A Mini Review on Novel Flavonoids

Unique plants and their properties, once considered synonymous to medicine, remain a potent source for new compounds in modern science. Plant polyphenols and natural products continue to be investigated for effective treatments for the most persistent of human ailments. In this review, fifty novel plant phenolic compounds have been compiled and briefly described from the previous five years. Select compounds and notable plant species from genus Morinda and Sophora are further expanded on. Traditional medicine plants often contain rich and diverse mixtures of flavonoids, from which rare compounds should receive attention. The bioactivity of crude plant extracts, purified compounds and mixtures can differ greatly, requiring that these interactions and mechanisms of action be investigated in greater detail. Novel applications of uncommon natural products, namely mimosine and juglone, are explored within this review. The 2019 coronavirus pandemic has resulted in abrupt spike of related scientific publications: speculation is made regarding plant natural products and future of antiviral drug discovery.

Davidone C Induces the Death of Hepatocellular Carcinoma Cells by Promoting Apoptosis and Autophagy

Davidone C is a newly discovered flavonoid compound purified from the ethyl acetate-soluble fraction of Sophora davidii (Franch.) Skeels. This study explored the anti-tumor activity of davidone C on hepatocellular carcinoma HepG2 and Bel-7402 cells and its mechanism through MTT method, morphological observation, flow cytometry and Western blotting. The results showed that davidone C significantly inhibited the proliferation of HepG2 and Bel-7402 cells in a time- and dose-dependent manner. The morphological changes of apoptotic cells can be observed under an inverted microscope, such as cell floating, chromosome condensation, apoptotic bodies, and other phenomena. The expressions of Bax, cleaved caspase-9, cleaved caspase-3 and cleaved PARP increased with the increase of dosage while Bcl-2 decreased, suggesting that the apoptotic mechanism might be related to the mitochondrial apoptotic pathway. Moreover, davidone C administration can down-regulate the expression of Grp78, and simultaneously up-regulate the expression of caspase-7 and caspase-12, indicating that the apoptotic mechanism might be related to the ERS pathway. In addition, davidone C can down-regulate the expression of p62, and simultaneously up-regulate the expression of LC3-I and LC3-II with a quantitative dependence, suggesting that the mechanism of apoptosis may be related to the autophagy signal pathway. All these results showed davidone C has potential effects on hepatocellular carcinoma.

Davidones F and G, Two Novel Flavonoids from Sophora davidii (Franch.) Skeels

An unprecedented novel flavanone davidone F (1) with a seven-membered ring side chain, and a novel flavanonol davidone G (2), along with 11 known flavonoids, were isolated from the ethyl acetate fraction of Sophora davidii (Franch.) Skeels. Their planar structures were established by UV, IR, HRESIMS, 1D and 2D NMR data. The relative configurations of 1 and 2 were determined by calculation of NMR chemical shift values, the absolute configuration of 1 and 2 were assigned by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. Moreover, compounds 1–13 were screened for the translocation activity of glucose transporter 4 (GLUT-4), and the fluorescence intensity was increased to the range of 1.56 and 2.79 folds. Compounds 1 and 2 showed moderate GLUT-4 translocation activity with 1.64 and 1.79 folds enhancement, respectively, at a concentration of 20 μg/mL.

Bioactive sesquiterpenes from Inula helenium

Twenty-one eudesmane-type sesquiterpenes, including five new compounds, were isolated from the roots of Inula helenium. The structures of the new compounds (1-5) were determined by extensive spectroscopic data interpretation, single-crystal X-ray diffraction analysis and ECD calculations. Six compounds can synergistically enhance cisplatin effect against ovarian cancer cells, the structure - activity relationship for the synergistic effect of these compounds with cisplatin was revealed for the first time, which provides useful clues to develop novel sensitizers to overcome drug resistance in cancer. In addition, fifteen sesquiterpenes exhibited significant anti-inflammatory activity, which provided promising candidates for development of anti-inflammatory agent.

Chemical Constituents from Roots of Sophora davidii (Franch.) Skeels and Their Glucose Transporter 4 Translocation Activities

Sophora davidii (Franch.) Skeels is a multi-purpose traditional medicine that has long been used for the treatment of various diseases. To discover the potential bioactive composition of S. davidii, a chemical investigation was thus performed. In this research, two new stilbene oligomers, Davidiol E–F (1–2), one new 4-aryl-substituted isoflavan Davidinin A (3), and one new 2-arylbenzofuran dimer, Shandougenine C (4), as well as six known compounds (5–10) were obtained from the ethyl acetate fraction of Sophora davidii (Franch.) Skeels. The structures of new compounds were established by extensive 1D and 2D nuclear magnetic resonance (NMR) spectra with mass spectroscopy data. The absolute configuration of 1–3 was assigned by comparing its experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1–10 promoted glucose transporter 4 (GLUT-4) translocations by the range of 1.28–2.60 folds, respectively. Compound 9 showed the most potent glucose transporter 4 translocations with 1.60 fold enhancement. The result attained in this study indicated that the separation and characterization of these compounds plays an important role in the research and development of new anti-diabetic drugs and pharmaceutical industry.