No abstract

Background: Moringa oleifera is rich in various active phyto-constituents (tannins, sterols, terpenoids, flavonoids, saponins, anthraquinones, alkaloids, and vitamins) in addition to different minerals in its leaves and seeds. Presence of these constituents is responsible for the antioxidant activity and the ability to protect against oxidative damage. Based on measurements of the cytotoxic activities, M. oleifera leaves were found to be more effective than the plant seeds. Therefore, the plant leaves were selected for preparation of silver plant nano-extract during the present study. Methods: The silver nanoparticles (Ag-NPs) were synthesized then characterized by transmission electron microscope (TEM), ultraviolet-visible (UV-VIS) spectroscopy and dynamic light scattering (DLS) measurements. Moreover, the in vitro antioxidants were assayed in M. oleifera leaves extract before and after incorporating Ag-NPs through measurement of total polyphenolic compounds and scavenging activities against free radicals in addition to the cytotoxic activity against growth of human colon carcinoma. Furthermore, the phenolic compounds were detected by gas chromatography coupled with a mass spectrometer (GC/MS) and fourier transform infrared (FT-IR) spectroscopy. Also, the median lethal dose (LD 50) of the extract and nano-extract was evaluated. Results: It was showed that incorporation of Ag-NPs into the M. oleifera leaves extract enhanced the total antioxidant capacity, concentration of total polyphenolic compounds, reducing power and scavenging activity against attack of free radicals in addition to increasing the cytotoxicity against growth of colon cancer cells. This might be related to increasing the phenolic compounds as a result of incorporation of Ag-NPs and detected by the GC/MS and FT-IR analysis. It was found that there was no wide gap in the LD 50 between M. oleifera leaves extract and silver nano-extract. The LD 50 values of the M. oleifera leaves extract and silver nano-extract were about 14,250 and 13,750 mg/Kg, respectively. Conclusion: The study revealed that incorporation of Ag-NPs into the M. oleifera extract enhanced the in vitro antioxidative efficiency and might be related to increasing the phenolic compounds.

Graphical abstract

The strategy of utilizing nitrogen compounds in various biological applications has recently emerged as a powerful approach to exploring novel classes of therapeutics to face the challenge of diseases. A series of pyrazolo[1,5‐a]pyrimidine‐based compounds 3a–l and 5a–f were prepared by the direct cyclo‐condensation reaction of 5‐amino‐1H‐pyrazoles 1a, b with 2‐(arylidene)malononitriles and 3‐(dimethylamino)‐1‐aryl‐prop‐2‐en‐1‐ones, respectively. The structures of the new pyrazolo[1,5‐a]pyrimidine compounds were confirmed via spectroscopic techniques. The in vitro biological activities of all pyrazolo[1,5‐a]pyrimidines 3a–l and 5a–f were evaluated by assaying total antioxidant capacity, iron‐reducing power, the scavenging activity against 1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) and 2, 2'‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radicals, anti‐diabetic, anti‐Alzheimer, and anti‐arthritic biological activities. All compounds displayed good to potent bioactivity, and three compounds 3g, 3h, and 3l displayed the most active derivatives. Among these derivatives, compound 3l exhibited the highest antioxidant (total antioxidant capacity [TAC] = 83.09 mg gallic acid/g; iron‐reducing power [IRP] = 47.93 µg/ml) and free radicals scavenging activities with (DPPH = 18.77 µg/ml; ABTS = 40.44%) compared with ascorbic acid (DPPH = 4.28 µg/ml; ABTS = 38.84%). Furthermore, compound 3l demonstrated the strongest inhibition of α‐amylase with a percent inhibition of 72.91 ± 0.14 compared to acarbose = 67.92 ± 0.09%. Similarly, it displayed acetylcholinesterase inhibition of 62.80 ± 0.06%. However, compound 3i showed a significantly higher inhibition percentage for protein denaturation and proteinase at 20.66 ± 0.00 and 26.42 ± 0.06%, respectively. Additionally, some in silico ADMET properties were predicted and studied. Finally, molecular docking simulation was performed inside the active site of α‐amylase and acetylcholinesterase to study their interactions.

A Schiff base ligand of o -vanillin and 4-aminoazobenzene and its transition metal complexes of Ni(II), Co(II), Zn(II), Cu(II), Mn(II), and Zr(IV) were prepared under microwave irradiation as a green approach compared to the conventional method. The structures of new compounds have been characterized and elucidated via elemental and spectroscopic analyses. In addition, magnetic susceptibility, electron spin resonance, and electronic spectra of the synthesized complexes explained their geometrical structures. The thermal stability of Cu(II), Zn(II), and Zr(IV) complexes was studied by thermo-gravimetric analyses (TGA). Coats–Redfern and Horowitz–Metzger equations were used to calculate the thermal and dehydration decomposition activities of proposed structures kinetically. Surface morphologies of the solid compounds were imaged by scanning electron microscopy (SEM). The particle size of prepared complexes was measured by using a particle size analyzer at a diffraction angle of 10.9°. The geometry structures of the synthesized compounds were verified utilizing electronic spectra, ESR spectrum, and magnetic moment value. The newly synthesized compounds were screened for antimicrobial activity. Also, the anticancer activity of the free Schiff base ligand and its metal complexes were studied against two cell lines: human colon (HCT-116) and human liver cancer cells (HepG-2). The obtained results showed that the Cu(II) complex displayed the highest cytotoxic activity (IC 50 = 18 and 22 μg/mL for HepG-2 and HCT, respectively) compared to the free Schiff base ligand.