Synthesizes, characterization, molecular modelling studies and bioactivity of a novel bicyclic compound of δ-lactam with oxazepine ring containing-sulphur substitute using an economic method

Penicillin resistance is a commonly present and controversial matter due to the misuses by people for various reasons. However, little studies have been examined the bioactivity of the 5 and 6 membered rings. In this study, we aimed to synthesize a new compound contain 5- membered ring following a short and low cost method and combined it with oxazepine ring via Schiff bases to produce a bicyclic molecule (Lactozepine). In vitro examinations were implemented to assess the bioactivity of the prepared compound such as anti-bacterial, anti-fungal and anti-oxidant which has shown a wide zone of inhibition of lactozepine against Streptococcus pneumoniae but no inhibition was shown against Kelbesilla pneumoniae and Staphylococcus aureus except at a high concentration similar to the result of the anti-fungal assessment. Furthermore, lactozepine showed worthy anti-oxidant activity against free radical formation. The molecular modelling and docking assessment showed availability of lactozepine to bind to bacterial proteins and inhibit their growth with lowest free energy for the greatest and strong binding affinity with the PDB crystal structures 1VQQ, 2WAE, 1PYY and 1IYS were between − 6.5 and − 7.9 kcal/mol. Moreover, the molecular MD dynamic simulation showed that RMSF (root mean square fluctuation) for the assessed protein's amino acids remained consistent and tightly bound to lactozepine in the dynamic state. The novel compound of lactozepine having δ-lactam rings attached to oxazepine showed a bioactivity that are hopeful for in vivo studies in the future.