Chemical constituents from the seeds of Trifolium alexandrinum

Xanthosine, a purine glycoside mediates hepatic glucose homeostasis through inhibition of gluconeogenesis and activation of glycogenesis via regulating the AMPK/ FoxO1/AKT/GSK3β signaling cascade

Type 2 Diabetes Mellitus (T2DM) is characterized by hepatic insulin resistance, which results in increased glucose production and reduced glycogen storage in the liver. There is no previous study in the literature that has explored the role of Xanthosine in hepatic insulin resistance. Moreover, mechanistic explanation for the beneficial effects of Xanthosine in lowering glucose production in diabetes is yet to be determined. This study for the first time investigated the beneficial effects of Tribulus terrestris (TT) and its active constituent, Xanthosine on gluconeogenesis and glycogenesis in Free Fatty Acid (FFA)-induced CC1 hepatocytes and streptozotocin (STZ)-induced Wistar rats. Xanthosine enhanced glucose uptake and decreased glucose production through phosphorylation of AMP-activated protein kinase (AMPK) and forkhead box transcription factor O1 (FoxO1), and downregulation of two rate limiting enzymes of gluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression in FFA-induced CC1 cells. Xanthosine also prevented FFA-induced decreases in the phosphorylation of AKT/Protein kinase B, glycogen synthase kinase-3β (GSK3β), and increased glycogen synthase (GS) phosphorylation to increase the glycogen content in the hepatocytes. Moreover, in STZ-induced diabetic rats, oral administration of TT n-butanol fraction (TTBF) enriched with compound Xanthosine (10, 50 & 100 mg/kg body weight) improved insulin sensitivity, reduced fasting blood glucose levels, improved glucose homeostasis by reducing gluconeogenesis via AMPK/FoxO1-mediated PEPCK and G6Pase down-regulation and increasing glycogenesis via AKT/GSK3β-mediated GS activation. Overall, Xanthosine may be developed further for treating insulin resistance and hyperglycemia in T2DM.

Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications

Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.

Antimicrobial and Antioxidant Secondary Metabolites from Trifolium baccarinii Chiov. (Fabaceae) and Their Mechanisms of Antibacterial Action

The treatment of infectious diseases with antimicrobial agents continues to present problems in modern-day medicine with many studies showing significant increase in the incidence of bacterial resistance to several antibiotics. The screening of antimicrobial activity of plant extracts and natural products has shown that medicinal plants are made up of a potential source of new anti-infective agents. The aim of this study was to evaluate the antimicrobial and antioxidant activities of extracts and compounds from the whole plant Trifolium baccarinii Chiov. and to determine their modes of antibacterial action. The plant extracts were prepared by maceration in organic solvents. The antimicrobial activities were evaluated using the broth microdilution method. The antioxidant activity was evaluated using the 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assays. The mechanisms of antibacterial action were determined by lysis, salt tolerance assays, and antioxidant enzyme activities. The cytotoxic effect on the erythrocytes was determined by a spectrophotometric method. Biochanin A, formononetin, luteolin, luteolin-4'-O-β-D-glucopyranoside, 4,7,2'-trihydroxy-4'-methoxyisoflavanol, sissotrin, 1-methyl-β-D-glucopyranoside, ononin, D-mannitol, and 3-O-β-D-glucuronopyranosylsoyasapogenol B were isolated from Trifolium baccarinii. The MeOH, EtOAc, and n-BuOH extracts as well as biochanin A, formononetin, luteolin, luteolin-4'-O-β-D-glucopyranoside, 4,7,2'-trihydroxy-4'-methoxyisoflavanol, and sissotrin from Trifolium baccarinii displayed the highest antimicrobial and antioxidant activities. The MeOH extract and 4,7,2'-trihydroxy-4'-methoxyisoflavanol exhibited antibacterial activity through the bacteriolytic effect and reduction of the antioxidant defenses in the bacterial cells. The present study portrays Trifolium baccarinii as a potential natural source of antibacterial, antifungal, and antioxidant agents.

A New Brominated Norsesquiterpene Glycoside From the Rhizomes of Acorus tatarinowii Schott

A new brominated norsesquiterpene glycoside, acoruside (1), has been isolated from the rhizomes of Acorus tatarinowii Schott, together with 8 known compounds (2-9). Their structures were elucidated mainly based on 1-dimensional (1D) and 2D nuclear magnetic resonance spectra. The absolute configuration of compound 1 was determined by comparing its experimental and calculated electronic circular dichroism spectra. The in vitro tests indicated that at 10 µM, compounds 2, 3, and 4 aggravated serum deprivation injuries of PC12 cells, compound 2 aggravated rotenone-induced injuries of PC12 cells, and compounds 3 and 4 aggravated the oxygen-glucose deprivation-induced injuries of PC12 cells.

Complementary gene interaction and xenia effect controls the seed coat colour in interspecific cross between Trifolium alexandrinum and T. apertum

Trifolium alexandrinum (Egyptian clover) is a widely cultivated winter annual fodder. Present work deals with inheritance of the seed coat colour in segregating progenies of the interspecific cross between T. alexandrinum and T. apertum. Although, both the parent species possessed yellow seed coat, the F₁ seeds were black coloured in the reciprocal cross (T. apertum × T. alexandrinum). Seeds borne on individual F₂ plants and the advancing generations segregated in yellow and black seed coat colour, which confirmed xenia effect. F₂ seeds collected from individual F₁ plants exhibited nine black and seven yellow segregation ratio. The segregation of the seed coat colour recorded from F₃ to F₅ generations revealed that yellow seed coat was true breeding (i.e. non-segregating) in this interspecific cross (including the reciprocal crosses). However, the black seeded progenies were either true breeding or segregated in nine black: seven yellow ratio or three black: one yellow ratio suggesting a complementary gene interaction or duplicate recessive epistasis. It indicated that the seed coat colour is controlled by complementary gene interaction along with xenia effect in interspecific crosses between T. alexandrinum and T. apertum. Occurrence of the complementary genes across the species could suggest T. apertum to be the progenitor of T. alexandrinum. Inheritance of seed coat colour in reference to its importance in Egyptian clover breeding is also discussed.

Phenolic Content and Antioxidant Activity in Trifolium Germplasm from Different Environments

Phenolics are important mediators in plant-environment interactions. The presence and concentration of phenolic compounds and their antioxidant activity were evaluated in leaves and flowers of a set of Trifolium species originating from contrasting environments encompassing lowland and mountain sites. The current germplasm proved a great reservoir of phenolic compounds, with different chemical structure and, possibly, diversified biological activity. Germplasm groups with specific phenolic composition were observed. In some cases, different patterns bore a taxonomic meaning. Lowland germplasm showed higher concentration of total phenolics in leaves than mountain accessions (50.30 vs. 34.19 mg/g dry matter (DM)), while the latter had higher concentration in flowers (114.16 vs. 57.44 mg/g DM). Outstanding concentration of isoflavones was observed in leaves of lowland germplasm (24.19 mg/g DM), and of both proanthocyanidins and flavonoids in flowers of mountain germplasm (53.81 and 56.62 mg/g DM, respectively). The pattern of phenolic composition in lowland and mountain germplasm was suggestive of different adaptive strategies. Three assays of antioxidant activity were tested, which were characterised by rather different reactivity towards phenolic composition. The scavenging activity was higher for leaf extracts of lowland germplasm, and for flower extracts of mountain germplasm. Besides identifying germplasm of interest, this study also suggested possible links between environmental factors and concentration and composition of phenolic compounds.

Antibacterial activity of leaves extracts of Trifolium alexandrinum Linn. against pathogenic bacteria causing tropical diseases

OBJECTIVE

To investigate antibacterial potential of Trifolium alexandrinum (T. alexandrinum) Linn. against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.

METHODS

Non-polar and polar extracts of the leaves of T. alexandrinum i.e., hexane, dichloromethane (DCM), ethyl acetate (EtOAc), methanol (MeOH) and aqueous (AQ) extracts at five different concentrations (1, 2, 5, 10 and 15 mg/mL) were prepared to evaluate their antibacterial value. NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.

RESULTS

Polar extracts demonstrated significant antibacterial activity against tested pathogens. EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens. While AQ plant extract inhibited the growth of sixteen of the test strains. EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.

CONCLUSIONS

The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases. Since Egyptian clover is used as a fodder plant, it could be helpful in controlling various infectious diseases associated with cattle as well.

Phytochemical screening and protective effects of Trifolium alexandrinum (L.) against free radical-induced stress in rats

Trifolium alexandrinum is traditionally used in various human ailments, including renal dysfunctions. The present experiment was designed to investigate antioxidant and nephroprotective effect of T. alexandrinum methanolic extract (TAME) against CCl4-induced oxidative stress in albino rats. Results of in vitro study revealed significant (P < 0.05) antioxidant effects. The ameliorative role of TAME was also examined by investigating the level of antioxidant enzymes catalase (CAT), peroxidase (POD), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), nonenzymatic antioxidant viz; reduced glutathione contents (GSH) and lipid peroxidation products (TBARS) in the renal tissue homogenate in CCl4-treated rats. The intraperitoneal injection of 1 mL/kg b.w. CCl4 caused a significant depletion in the activity antioxidant enzymes and increased the TBARS contents. Supplementation of TAME at 200 mg/kg b.w. for 2 weeks significantly improved activities of antioxidant enzymes and reduced TBARS formation. Co-treatment of TAME also presented significant protection in maintaining renal urine and serum markers. Antioxidant and nephroprotective effects of TAME are associated with its polyphenolic constituents.

Abrogation by Trifolium alexandrinum root extract on hepatotoxicity induced by acetaminophen in rats

OBJECTIVE

Acetaminophen (APAP) is a substance that harms human health by stimulating free radical production. This study investigated the ability of Trifolium alexandrinum root (TAR) extract to reduce the hepatotoxicity induced by APAP in rats.

METHODS

Animals were classified into four groups and treated for 6 weeks. Group 1: normal control-treated (saline); Group 2: TAR extract-treated (100 mg/kg); Group 3: APAP-treated; Group 4: APAP plus TAR extract.

RESULTS

APAP significantly elevated AST (aspartate amino transferase), ALT (amino alanine transferase), ALP (alkaline phosphatase), GGTP (gamma glutamyl transpeptidase), bilirubin, and malondialdehyde with a significant decrease in glutathione, superoxide dismutase, glutathione peroxidase, catalase, and glutathione S-transferase compared with the control group. Administration of TAR extract combined with APAP improved the liver damage induced by APAP. Histopathological evidence, together with observed DNA fragmentation, supported the detrimental effect of APAP and the ameliorating effect of TAR extract on liver toxicity.

CONCLUSION

TAR extract has beneficial properties and can reduce the liver damage and toxicity induced by APAP.

DISCUSSION

Free radical mediated processes have been implicated in the pathogenesis of many diseases. The protective effect of TAR root extract on APAP-induced hepatotoxicity in rats appears to be related to inhibition of lipid peroxidation and enhancement of antioxidant enzyme levels, in addition to a free radical scavenging action.

Online extraction and isolation of highly polar chemical constituents from Brassica napus L. pollen by high shear technique coupled with high-performance counter-current chromatography

High shear technique coupled with high-performance counter-current chromatography was successfully used for the extraction and online isolation of seven highly polar chemical constituents from the Brassica napus L. The lower phase of ethyl acetate-n-butanol-water (1:4:5, v:v:v) was used as both the high shear technique solvent and high-performance counter-current chromatography mobile phase. Seven compounds of 14.2 mg of uridine, 4.6 mg of xanthosine, 7.8 mg of guanosine, 5.3 mg of adenosine, 19.5 mg of kaempferol-3,4'-di-O-β-D-glucopyranoside, 17.7 mg of kaempferol-3-O-(2-O-β-D-glucopyranosy1)-β-D-glucopyranoside, and 25.7 mg of an unknown compound, with a high-performance liquid chromatography (HPLC) purity over 95.0%, were obtained in a one-step extraction-separation process within 130 min from 20.0 g of raw material of pollen of Brassica napus L. Moreover, the mode of elution-extrusion was employed for the separation of the last one compound. The isolated compounds were analyzed by HPLC, and the chemical structures of the compounds mentioned above were identified by UV and NMR. It is the first time to combine the high shear technique and high-performance counter-current chromatography for the online isolation of the nature products.