Potential antioxidant, anticholinergic, antidiabetic and antiglaucoma activities and molecular docking of spiraeoside as a secondary metabolite of onion (Allium cepa)

Onion contains many dietary and bioactive components including phenolics and flavonoids. Spiraeoside (quercetin-4-O-β-D-glucoside) is one of the most putative flavonoids in onion. Several antioxidant techniques were used in this investigation to assess the antioxidant capabilities of spiraeoside, including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) scavenging, N,N-dimethyl-p-phenylenediamine radical (DMPD•+) scavenging, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS•+) scavenging activities, cupric ions (Cu2+) reducing and potassium ferric cyanide reduction abilities. In contrast, the water-soluble α-tocopherol analogue trolox and the conventional antioxidants butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and α-tocopherol were utilized as the standards for evaluation. Spiraeoside scavenged the DPPH radicals an IC50 of 28.51 μg/mL (r2: 0.9705) meanwhile BHA, BHT, trolox, and α-tocopherol displayed IC50 of 10.10 μg/mL (r2: 0.9015), 25.95 μg/mL (r2: 0.9221), 7.059 μg/mL (r2: 0.9614) and 11.31 μg/mL (r2: 0.9642), accordingly. The results exhibited that spiraeoside had effects similar to BHT, but less potent than α-tocopherol, trolox and BHA. Also, inhibitory effects of spiraeoside were evaluated toward some metabolic enzymes including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II) and α-glycosidase, which are related to a number of illnesses, such as Alzheimer's disease (AD), diabetes mellitus and glaucoma disorder. Spiraeoside exhibited IC50 values of 4.44 nM (r2: 0.9610), 7.88 nM (r2: 0.9784), 19.42 nM (r2: 0.9673) and 29.17 mM (r2: 0.9209), respectively against these enzymes. Enzyme inhibition abilities were compared to clinical used inhibitors including acetazolamide (for CA II), tacrine (for AChE and BChE) and acarbose (for α-glycosidase). Spiraeoside demonstrated effective antioxidant, anticholinergic, antidiabetic and antiglaucoma activities. With these properties, it has shown that Spiraeoside has the potential to be a medicine for some metabolic diseases.

Cytoprotective, antimutagenic/antirecombinogenic and antibacterial properties of Lallemantia iberica extracts

BACKGROUND

Plants have important chemical compounds to protect organisms from many mutagens but they may also have dangerous toxic substances that must be tested before use. Lallemantia iberica has been used by local people for treatment of some diseases but it was never tested for its cell protective and antimutagenic/antirecombinogenic properties. In this study, it was aimed to determine the cytoprotective, antimutagenic/antirecombinogenic, antibacterial, antioxidant and phenolic profile of L. iberica by MTS assay, micronucleus test/somatic mutation recombination test (SMART), disc diffusion method, ABTS/DPPH tests and liquid chromatography (LC), respectively.

RESULTS

MTS assay results showed that both of the extracts supported the normal growth of healthy human lymphocytes and there was no significant difference between extracts. Although there was no significant increase in micronucleus concentration (‰) of the cultures treated with ethanol or methanol extracts, methanol extract caused slightly lower micronucleus concentration (12.64 ± 3.65‰) than the ethanol extract (24.46 ± 4.50‰). SMART results showed that ethanol and methanol extracts prevented harmful mitotic recombination. Lallemantia iberica also showed antibacterial activity against all of the strains tested, and the largest inhibition zones were observed with Pseudomonas aeruginosa (17.9 mm) and Enterobacter aerogenes (13.8 mm). Methanol extracts showed better antioxidant activities (ABTS IC₅₀ : 104.07 μg mL^-1 , DPPH IC₅₀ : 58.8 μg mL^-1 ) than ethanol extracts (ABTS IC₅₀ : 344.03 μg mL^-1 , DPPH IC₅₀ : 233.7 μg mL^-1 ). According to the LC results, the most abundant phenolic compounds were rutin hydrate (1796.4 ± 62.9 mg kg^-1 ) and p-coumaric acid (228.1 ± 7.60 mg kg^-1 ).

CONCLUSION

Lallemantia iberica extracts had cell-protective, antimutagenic/antirecombinogenic, antibacterial and strong antioxidant characteristics in relation to their rich phenolic content. © 2022 Society of Chemical Industry.

Antibiotics: Conventional Therapy and Natural Compounds with Antibacterial Activity-A Pharmaco-Toxicological Screening

Antibiotics are considered as a cornerstone of modern medicine and their discovery offers the resolution to the infectious diseases problem. However, the excessive use of antibiotics worldwide has generated a critical public health issue and the bacterial resistance correlated with antibiotics inefficiency is still unsolved. Finding novel therapeutic approaches to overcome bacterial resistance is imperative, and natural compounds with antibacterial effects could be considered a promising option. The role played by antibiotics in tumorigenesis and their interrelation with the microbiota are still debatable and are far from being elucidated. Thus, the present manuscript offers a global perspective on antibiotics in terms of evolution from a historical perspective with an emphasis on the main classes of antibiotics and their adverse effects. It also highlights the connection between antibiotics and microbiota, focusing on the dual role played by antibiotics in tumorigenesis. In addition, using the natural compounds with antibacterial properties as potential alternatives for the classical antibiotic therapy is discussed.

The Protective Effect of Crataegus aronia Against High-Fat Diet-Induced Vascular Inflammation in Rats Entails Inhibition of the NLRP-3 Inflammasome Pathway

This study investigated whether the whole-plant aqueous extract of Crataegus aronia (C. aronia) could protect against or alleviate high-fat diet (HFD)-induced aortic vascular inflammation in rats by inhibiting the NLRP-3 inflammasome pathway and examined some mechanisms of action with respect to its antioxidant and hypolipidemic effects. Adult male Wistar rats were divided into five groups (n = 6/each): standard diet (10% fat) fed to control rats, control + C. aronia (200 mg/kg), HFD (40% fat), HFD + C. aronia, and HFD post-treated with C. aronia. The HFD was fed for 8 weeks and C. aronia was administered orally for 4 weeks. In addition, isolated macrophages from control rats were pre-incubated with two doses of C. aronia (25 and 50 μg/mL) with or without lipopolysaccharide (LPS) stimulation. Only in HFD-fed rats, co- and post-C. aronia therapy lowered circulatory levels of LDL-C and ox-LDL-c and aortic protein levels of LOX-1 and CD36. C. aronia also inhibited the nuclear accumulation of NF-κB and lowered protein levels of NLRP-3, caspase-1, and mature IL-1β. In vitro, in the absence of ox-LDL-c, C. aronia led to reduced nuclear levels of NF-κB, ROS generation, and protein NLRP-3 levels, in both LPS-stimulated and unstimulated macrophages, in a dose-dependent manner. However, protein levels of LOX-1 were not affected by C. aronia in unstimulated cells. In conclusion, C. aronia inhibits the NLRP-3 inflammasome pathway, induced by HFD feeding in the aorta of rats, mainly by its hypolipidemic effect and in vitro, in LPS-stimulated macrophages, by its antioxidant effect.

Characterization of Polysaccharides Extracted from Pulps and Seeds of Crataegus azarolus L. var. aronia: Preliminary Structure, Antioxidant, Antibacterial, α-Amylase, and Acetylcholinesterase Inhibition Properties

Polysaccharides from the pulps (CAP) and seeds (CAS) of Crataegus azarolus L. var. aronia were extracted by hot water method. Both polysaccharides were characterized by scanning electron microscopy (SEM), Congo red test, FT-IR spectroscopy, and their antioxidant, α-amylase, antiacetylcholinesterase, and antibacterial activities were evaluated. CAP showed the highest total carbohydrate (82.35%) and uronic acid (29.39%) contents. The Congo red test revealed the lack of triple-helical conformation for both polysaccharides. The comparison of both infrared spectra indicated similar patterns with the presence of typical bands of polysaccharides. However, the microstructure of both samples indicated differences when analyzed by SEM. CAP displayed higher antioxidant, α-amylase, and acetylcholinesterase inhibitory activities. Besides, CAP showed the strongest antimicrobial effects against seven microorganisms and, notably, the Gram-positive bacteria. Overall, the results suggest that polysaccharides from C. azarolus L. var. aronia may be considered as novel sources of antioxidants and recommended as enzyme inhibitory agents in food and pharmaceutical industries.

Differential Production of Phenylpropanoid Metabolites in Callus Cultures of Ocimum basilicum L. with Distinct In Vitro Antioxidant Activities and In Vivo Protective Effects against UV stress

Ocimum basilicum L. (Purple basil) is a source of biologically active antioxidant compounds, particularly phenolic acids and anthocyanins. In this study, we have developed a valuable protocol for the establishment of in vitro callus cultures of O. basilicum and culture conditions for the enhanced production of distinct classes of phenylpropanoid metabolites such as hydroxycinnamic acid derivatives (caffeic acid, chicoric acid, rosmarinic acid) and anthocyanins (cyanidin and peonidin). Callus cultures were established by culturing leaf explants on Murashige and Skoog medium augmented with different concentrations of plant growth regulators (PGRs) [thidiazuron (TDZ), α-naphthalene acetic acid (NAA), and 6-benzyl amino purine (BAP)] either alone or in combination with 1.0 mg/L NAA. Among all the above-mentioned PGRs, NAA at 2.5 mg/L led to the highest biomass accumulation (23.2 g/L DW), along with total phenolic (TPP; 210.7 mg/L) and flavonoid (TFP; 196.4 mg/L) production, respectively. HPLC analysis confirmed the differential accumulation of phenolic acid [caffeic acid (44.67 mg/g DW), rosmarinic acid (52.22 mg/g DW), and chicoric acid (43.89 mg/g DW)] and anthocyanins [cyanidin (16.39 mg/g DW) and peonidin (10.77 mg/g DW)] as a function of the PGRs treatment. The highest in vitro antioxidant activity was determined with the ORAC assay as compared to the FRAP assay, suggesting the prominence of the HAT over the ET-based mechanism for the antioxidant action of callus extracts. Furthermore, in vivo results illustrated the protective action of the callus extract to limit the deleterious effects of UV-induced oxidative stress, ROS/RNS production, and membrane integrity in yeast cell culture. Altogether, these results clearly demonstrated the great potential of in vitro callus of O. basilicum as a source of human health-promoting antioxidant phytochemicals.

Therapeutic potentials of Crataegus azarolus var. eu- azarolus Maire leaves and its isolated compounds

Background

Hyperglycemia is a complicated condition accompanied with high incidence of infection and dyslipidemia. This study aimed to explore the phyto-constituents of Crataegus azarolus var. eu- azarolus Maire leaves, and to evaluate the therapeutic potentials particularly antimicrobial, antihyperglycemic and antihyperlipidemic of the extract and the isolated compound (3β-O-acetyl ursolic acid).

Methods

Total phenolics and flavonoidal contents were measured by RP-HPLC analysis. Free radicals scavenging activity of different extraction solvents was tested in-vitro on DPPH free radicals. The antimicrobial activity of the ethanolic extract and its fractions as well as the isolated compounds were evaluated in-vitro on variable microorganisms. Animal models were used to evaluate the antihyperglycemic and antihyperlipidemic activities of the ethanolic extract along with the isolated compound (3β-O acetyl ursolic acid).

Results

RP- HPLC analysis of the phenolics revealed high content of rutin, salicylic and ellagic acids. Six compounds belonging to triterpenes and phenolics were isolated from chloroform and n-butanol fractions namely: ursolic acid, 3β-O-acetyl ursolic acid, ellagic acid, quercetin 3-O-β methyl ether, rutin and apigenin7-O-rutinoside. Ethanolic extract showed the highest DPPH radical scavenger activity compared to other solvents. Ethanolic extract, hexane fraction, ursolic acid, 3β-O acetyl ursolic acid and quercetin 3-O-methyl ether showed variable antimicrobial activity against E. coli, P. aeruginosa, S. aureus, and C. albicans. Administration of the ethanolic extract or 3β-O acetyl ursolic acid orally to the mice reduced blood glucose significantly in a time- and dose-dependent manner. Ethanolic extract significantly reduced LDL-C, VLDL-C, TC and TG and increased HDL-C in rats. Ethanolic extract and 3β-O acetyl ursolic acid reduced in-vitro activity of pancreatic lipase.

Conclusion

This study reveals that Crataegus azarolus var. eu- azarolus Maire has the efficiency to control hyperglycemia with its associated complications. This study is the first to evaluate antihyperglycemic and antihyperlipidemic potentials of 3β-O acetyl ursolic acid.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1729-9) contains supplementary material, which is available to authorized users.

Differential Effects of Thidiazuron on Production of Anticancer Phenolic Compounds in Callus Cultures of Fagonia indica

Fagonia indica, a very important anticancer plant, has been less explored for its in vitro potential. This is the first report on thidiazuron (TDZ)-mediated callogenesis and elicitation of commercially important phenolic compounds. Among the five different plant growth regulators tested, TDZ induced comparatively higher fresh biomass, 51.0 g/100 mL and 40.50 g/100 mL for stem and leaf explants, respectively, after 6 weeks of culture time. Maximum total phenolic content (202.8 μg gallic acid equivalent [GAE]/mL for stem-derived callus and 161.3 μg GAE/mL for leaf-derived callus) and total flavonoid content (191.03 μg quercetin equivalent [QE]/mL for stem-derived callus and 164.83 μg QE/mL for leaf-derived callus) were observed in the optimized callus cultures. The high-performance liquid chromatography (HPLC) data indicated higher amounts of commercially important anticancer secondary metabolites such as gallic acid (125.10 ± 5.01 μg/mL), myricetin (32.5 ± 2.05 μg/mL), caffeic acid (12.5 ± 0.52 μg/mL), catechin (9.4 ± 1.2 μg/mL), and apigenin (3.8 ± 0.45 μg/mL). Owing to the greater phenolic content, a better 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity (69.45 % for stem explant and 63.68 % for leaf explant) was observed in optimized calluses. The unusually higher biomass and the enhanced amount of phenolic compounds as a result of lower amounts of TDZ highlight the importance of this multipotent hormone as elicitor in callus cultures of F. indica.