The aqueous extract of Portulaca oleracea was used as a biocatalyst for the reduction of Na₂SeO₃ to form Se-NPs that appeared red in color and showed maximum surface plasmon resonance at a wavelength of 266 nm, indicating the successful Phyto-fabrication of Se-NPs. A FT-IR chart clarified the role of plant metabolites such as proteins, carbohydrates, and amino acids in capping and stabilizing Se-NPs. TEM, SAED, and XRD analyses indicated the formation of spherical, well-arranged, and crystalline Se-NPs with sizes in the range of 2–22 nm. SEM-EDX mapping showed the maximum peaks of Se at 1.4, 11.3, and 12.4 KeV, with weight and atomic percentages of 36.49 and 30.39%, respectively. A zeta potential of −43.8 mV also indicated the high stability of the synthesized Se-NPs. The Phyto-synthesized Se-NPs showed varied biological activities in a dose-dependent manner, including promising activity against pathogenic bacteria and Candida species with varied MIC values in the range of 12.5−50 µg·mL⁻¹. Moreover, the Se-NPs showed antiviral activity toward HAV and Cox-B4, with percentages of 70.26 and 62.58%, respectively. Interestingly, Se-NPs showed a target orientation to cancer cell lines (HepG2) with low IC₅₀ concentration at 70.79 ± 2.2 µg·mL⁻¹ compared to normal cell lines (WI−38) with IC₅₀ at165.5 ± 5.4 µg·mL⁻¹. Moreover, the as-formed Se-NPs showed high activity against various instar larvae I, II, III, and IV of Culex pipiens, with the highest mortality percentages of 89 ± 3.1, 73 ± 1.2, 68 ± 1.4, and 59 ± 1.0%, respectively, at 50 mg L⁻¹. Thus, P. oleracea-based Se-NPs would be strong potential antimicrobial, anti-viral, anti-cancer, and anti-insect agents in the pharmaceutical and biomedical industries.

Oxaliplatin (Oxa)-associated adverse side effects have considerably limited the clinical use of the drug in colon cancer therapy. Mutant p53 has diverse mutational profiles in colon cancer, and it influences the potencies of various chemotherapeutic drugs, including Oxa. Thus, it would be highly beneficial to identify an alternative therapeutic strategy that not only reduces the toxicity of Oxa, but also exerts a synergistic effect against colon cancers, regardless of their p53 profiles. The present study was aimed at preparing and optimizing Teucrium polium L. essential oil nanoemulsion (TPO-NANO) and investigating its effect on the sensitivity of colon cancer cells with differences in p53 status (HCT116 wild-type and HT-29 mutant-type) to Oxa. The viability of treated cells was determined and the combination index (CI) was calculated. Morphological changes were determined under inverted microscopy, while percentage apoptosis was assayed using flow cytometry. Intracellular ROS and the protein levels of p53 and Bax were measured. The colony-forming potential of treated cells was determined using colony assay. The size of TPO-NANO was markedly increased from 12.90 ± 0.04 nm to 14.47 ± 0.53 nm after loading Oxa (p ≤ 0.05). The combination (Oxa + TPO-NANO) produced a synergetic effect in HCT116 and HT-29, with CI of 0.94 and 0.88, respectively. Microscopic examination and flow cytometric analysis revealed that cells treated with Oxa + TPO-NANO had a higher percentage of apoptosis than cells exposed to monotherapy. Cumulatively, Oxa exerted an apoptotic effect on wild or mutant p53 colon cancer cells when combined with TPO-NANO, through a mechanism involving ROS-mediated mitochondrial apoptosis.

This study was aimed at optimizing the conditions for producing oil-in-water nanoemulsion based on Teucrium polium L. essential oil (TP-EO) with high-pressure homogenization method using mixture of surfactants Tween 80 (Tw80) and Span 20 (Sp20). The experiment was designed based on the Box-Behnken method and the effect of % Sp20, Tw80:Sp20, and %TP-EO on size, polydispersity index (PDI) and zeta potential (ZP) of the prepared nano-emulsions were determined. Micro-broth dilution assay was utilized to determine the in vitro antibacterial effect of the optimized formulation of TP-NE. The results revealed that more desirable TP-NE with minimum particle size (153.75 ± 1.34 nm) and PDI (0.04 ± 0.003) and maximum ZP (−6.44 ± 0.13 mV) were obtained using 0.16%Sp20, 12 Tw80:Sp20 and 0.5%TP-EO. Furthermore, TP-NE had high growth inhibitory effect on S. aureus and MRSA, with IC₅₀ of 8.73 ± 0.07 and 9.38 ± 0.07% (v/v), respectively. In addition, TP-EO inhibited the growth of P. aeruginosa, S. sonnei, E. coli, and K. pneumonia, with IC₅₀ of 10.83 ± 0.09, 16.62 ± 0.1, 20.50 ± 0.2, and 28.64 ± 0.12% (v/v), respectively. The viabilities of S. aureus and MRSA treated with 16.67% (v/v) TP-NE were significantly reduced by 6.88 and 2.3-folds, respectively, relative to when they were treated with equivalent concentration of TP-EO. The growths of P. aeruginosa, E. coli, K. pneumonia, and S. sonnei, were inhibited 3.95, 2, 1.16, and 1.10-fold, respectively, after treatment with 16.67% (v/v) TP-NE, when compared with TP-EO-treated groups. In conclusion, the optimized TP-NE has antibacterial activity above that of pure oil. Graphical Abstract

Phormidesmis communis strain AB_11_10 was isolated and identified using microscopy and 16s rRNA sequencing, and its phytochemical constituents were determined using liquid chromatography-quadrupole time-of-flight mass spectrometry. The isolate had a segmented filamentous shape with a blue-green color. Many biomolecules, including organic compounds, amino acids, and fatty acids, were detected. P. communis strain AB_11_10 was used to synthesize gold nanoparticles (Ph-AuNPs) by adjusting the optimum reaction conditions. The concentration, algal/precursor ratio, temperature, reaction time, and pH significantly influenced the synthesis of the Ph-AuNPs. Mixing 1 mL of 0.5 mM of HAuCl₄ with 1 mL of algal extract and exposing the mixture to 100 °C for 30 min at pH 5.6 were the optimum conditions for the biosynthesis of Ph-AuNPs at a wavelength of 524.5 nm. The Ph-AuNPs were characterized using TEM, SEM, EDX, and mapping Zeta sizer and FTIR. The Ph-AuNPs had quasi-spherical to triangular shapes with an average diameter of 9.6 ± 4.3 nm. Ph-AuNPs composed of 76.10 ± 3.14% of Au and trace amounts of carbon and oxygen were detected, indicating that the P. communis strain AB_11_10 successfully synthesized Ph-AuNPs. The hydrodynamic diameter of the Ph-AuNPs was 28.5 nm, and their potential charge was −17.7 mV. O-H, N-H, C=C, N-O, C-H, and C-O were coated onto the surfaces of the Ph-AuNPs. These groups correspond to algal phytochemicals, which may have been the main reducing and stabilizing substances during the Ph-AuNP synthesis. The therapeutic activity of the Ph-AuNPs against osteosarcoma cancers was examined in MG-63 and SAOS-2 cell lines, while their biocompatibility was tested against Vero cell lines using a sulforhodamine B assay. The Ph-AuNPs had potent antitumor activity against the MG-63 and SAOS-2 cells, with a low toxicity toward Vero cells. Flow cytometry and cell cycle arrest analyses revealed that the Ph-AuNPs enhanced the apoptotic pathway and arrested the cell cycle in the MG-63 and SAOS-2 cells. P. communis strain AB_11_10 provides a new source to synthesize small, stable, and biocompatible AuNPs that act as apoptotic enhancers in osteosarcoma.