Antimicrobial drugs face numerous challenges, including drug resistance, systemic toxic effects, and poor bioavailability. To date, treatment choices are limited, which warrants the search for novel potent antivirals, including those extracted from natural products. The seeds of Peganum harmala L. (Zygophyllaceae family) have been reported to have antimicrobial, antifungal, and anticancer activities. In the present study, a 2-hydroxy propyl-β-cyclodextrin (HPβCD)/harmala alkaloid-rich fraction (HARF) host–guest complex was prepared using a thin-film hydration method to improve the water solubility and bioavailability of HARF. The designed complex was then co-encapsulated with ascorbic acid into PLGA nanoparticles coated with polyethylene glycol (HARF–HPßCD/AA@PLGA-PEG NPs) using the W/O/W multiple emulsion-solvent evaporation method. The average particle size, PDI, and zeta potential were 207.90 ± 2.60 nm, 0.17 ± 0.01, and 31.6 ± 0.20 mV, respectively. The entrapment efficiency for HARF was 81.60 ± 1.20% and for ascorbic acid was 88 ± 2.20%. HARF–HPßCD/AA@PLGA-PEG NPs had the highest antibacterial activity against Staphylococcus aureus and Escherichia coli (MIC of 0.025 mg/mL). They also exhibited high selective antiviral activity against the H1N1 influenza virus (IC50 2.7 μg/mL) without affecting the host (MDCK cells). In conclusion, the co-encapsulation of HPCD–HARF complex and ascorbic acid into PLGA-PEG nanoparticles significantly increased the selective H1N1 killing activity with minimum host toxic effects.

This work aims to develop and optimize blended polylactide-co-glycolide (PLGA) and poly(ε-caprolactone, PCL) loaded with Boswellia sacra oil (BO) to improve BO’s physicochemical properties and anti-breast cancer effects via enhancing apoptosis. In this context, BO was extracted from B. sacra oleo gum resins (BO) via hydrodistillation and chemically characterized by evaluating its essential oil’s composition using gas chromatography–mass spectrometry. Then, BO/PLGA–PCL NPs were formulated using the emulsion (O/W) solvent evaporation technique using a PLGA–PCL mixture at five different ratios (1:1, 2:1, 3:1, 1:2, and 1:3, respectively). The optimized NPs had a spherical morphology with no agglomerations and the lowest hydrodynamic size (230.3 ± 3.7 nm) and polydispersity index (0.13 ± 0.03) and the highest ζ potential (−20.36 ± 4.89 mV), as compared to the rest of the formulas. PLGA–PCL NPs could entrap 80.59 ± 3.37% of the BO and exhibited a controlled, sustained release of BO (83.74 ± 3.34%) over 72 h. Encapsulating BO in the form of BO/PLGA–PCL NPs resulted in a lower IC50 value as assessed by the MTT assay. Furthermore and upon assessing the apoptotic effect of both BO and BO/PLGA–PCL NPs, there was an increase in the percentage of apoptotic and necrotic cell percentages compared to the control and free BO. Encapsulation of BO in PLGA–PCL NPs doubled the percentage of apoptotic and necrotic cells exerted by free BO. These findings support the potential use of BO/PLGA–PCL NPs in treating breast cancer.

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