In vitro and in silico ß-lactamase inhibitory properties and phytochemical profile of Ocimum basilicum cultivated in central delta of Egypt.

CONTEXT: Some studies reported the chemical content and antimicrobial properties of Ocimum basilicum L. (Lamiaceae), relevant to the ecological variations in some areas of Egypt and other countries, yet no research was conducted on the plant cultivated in the central delta region of Egypt. Also, no previous data reported on inhibition of ß-lactamases by O. basilicum. OBJECTIVE: To assess ß-lactamases inhibition by O. basilicum extracts and the individual constituents. MATERIALS AND METHODS: Dried aerial parts of O. basilicum were extracted by hydrodistillation for preparation of essential oil and by methanol for non-volatile constituents. Essential oil content and the methanol extract were analysed by GC-MS and UPLC-PDA-MS/MS, respectively. Methyl cinnamate was isolated and analysed by NMR. Broth microdilution method was used to investigate the antimicrobial against resistant clinical isolates of Escherichia coli identified by double disc synergy, combination disc tests and PCR. The most active oil content was further tested with a nitrocefin kit for ß-lactamase inhibition and investigated by docking. RESULTS: O. basilicum was found to contain methyl cinnamate as the major content of the essential oil. More interestingly, methyl cinnamate inhibited ESBL ß-lactamases of the type CTX-M. The in vitro IC50 using nitrocefin kit was 11.6 µg/mL vs. 8.1 µg/mL for clavulanic acid as a standard ß-lactamase inhibitor. DISCUSSION AND CONCLUSIONS: This is the first study to report the inhibitory activity of O. basilicum oil and methyl cinnamate against ß-lactamase-producing bacteria. The results indicate that methyl cinnamate could be a potential alternative for ß-lactamase inhibition.

Synthesis and characterization of polyvinyl alcohol/corn starch/linseed polyol-based hydrogel loaded with biosynthesized silver nanoparticles.

Nanocomposite hydrogel film was prepared from Polyvinyl alcohol [PVA], Corn Starch [CS], Linseed oil polyol [LP], and silver nanoparticles [NP]. LP was prepared by epoxidation and hydration of Linseed oil [LO]. IR and NMR supported the insertion of hydroxyl groups in LP by epoxide ring opening reaction at epoxidized LO. Silver NP were biosynthesized using aqueous leaves' extract from locally grown Ocimum forsskaolii Benth [LEO] plant. FTIR, XRD, UV and TEM confirmed the synthesis of NP (size 30 to 39 nm). Transparent and foldable hydrogel film resulted by blending the constituents (PVA, CS, LP and NP), crosslinking by glutaraldehyde, at room temperature, and showed expansion in water, different pH solutions, biodegradation and good antibacterial and antifungal activity against tested microbes. Linseed polyol influenced the structure, morphology, hydrophilicity, improved swelling ability and thermal stability and accelerated biodegradation of hydrogel films. NP were well adhered to LP globules that were embedded in PVA/CS matrix as strung set of beads (LP globules) decorated with black pearls (spherical NP). Silver NP conferred antimicrobial behavior to hydrogel film as observed by antimicrobial screening on different microbes. The results were encouraging and showed that such hydrogel films may find prospective applications in antimicrobial packaging.