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A series of new extensively conjugated E-stilbene azomethines (5a-5h) were synthesized and screened for their antioxidant and antimicrobial activity. The compounds were tested against bacterial (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis) and fungal strains (Aspergillus niger, A. flavus, and Trichoderma harzianum) using the agar well diffusion method. Among the tested compounds, N '-(4-nitrobenzylidene)-2-((E)-styryl)benzohydrazide (5g) was found to possess potent antimicrobial activity higher than some drugs with significant activity reported in the literature, e.g., cefradine and terbinafine hydrochloride. Additionally, compounds 5a-5h were also evaluated for antioxidant potential using DPPH free radical scavenging and ferric thiocyanate (FTC) assays. Among these, N '-(4-hydroxybenzylidene)-2-((E)-styryl)benzohydrazide (5e) exhibited significant antioxidant potential by both assays. Compound 5e demonstrated higher DPPH free radical scavenging activity (IC 50 = 22 ± 0.19 µ g/mL) than the standard, butylated hydroxytoluene (BHT; IC 50 = 28 ± 0.10 µ g/mL). A similar trend was observed for compound 5e in FTC assay, which exhibited 86 ± 0.19% inhibition, whereas the BHT control showed 81 ± 0.21% inhibition of linoleic acid peroxidase. The structure elucidation of the synthesized compounds was carried out by UV-Vis, FT-IR, 1 H NMR, 13 C NMR, and elemental analysis and mass spectrometry. These results suggest possible use of these compounds for the rational design of new antimicrobial and antioxidant agents.

a b s t r a c tA group of new nitro substituted benzoxazinones (3a-k) were synthesized from easily available 4nitroanthranilic acid. All the synthesized compounds were characterized by FT-IR, 1 H NMR, 13 C NMR, mass spectrometry and elemental analysis. Anti-proliferative and pro-apoptotic potential of all the synthesized compounds (3a-k) was evaluated by MTT and Hoechst 33258 staining assay respectively whereas their antioxidant properties were determined via DPPH free radical scavenging assay. The most active compounds (3a, 3c and 3k) showed significant cytotoxic potential against HeLa cells with an inhibition of cell viability that ranged between 28.54 and 44.67% (P < 0.001). Albeit statistically different, the anti-proliferative effect of 3c was in close match with that of the reference drug doxorubicin. Likewise, the test compounds showed profound pro-apoptotic potential with an apoptotic index that ranged between 52.86 and 75.61%. Besides, the docking studies revealed a higher efficiency for compounds (3a and 3h) owing to their better affinity and inhibition constant (K i ¼ 4.397 and 3.713 nmol) respectively. The antioxidant potential of synthesized benzoxazinones (3a-k) was in close agreement with the experimental anticancer results with a percent inhibition from 34.45 to 85.93% as compared to standard (90.56%).

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