Pharmacologically significant penta, hexa, and heptacoordinate mono organosilicon (IV) Schiff base complexes derived from phenyl alanine: Synthesis, spectral characterization, antimicrobial, antioxidant, anti-inflammatory, and anti-diabetic studies

Mono organosiliocn (IV) Schiff base complexes 1a-2c derived from phenyl alanine were prepared and characterized. Six new complexes were evaluated in vitro against different bacteria; besides their antioxidant, antiinflammatory and antidiabetic properties were also tested. Combination of infrared and multinuclear NMR (1H NMR, 13C NMR and 29Si NMR) techniques evidenced the formation of penta, hexa, and heptacoordinated species. The in-vitro antileishmanial study for complexes 1a and 2b against the amastigote stage of the parasite, a mouse macrophage cell line infected with promastigotes expressing luciferase, the IC50 for all tested complexes was lower than that of the miltefosine (standard drug). In antibacterial activity, with the increase in the concentration the zone of inhibition increased. 2c showed the maximum percent inhibition for most number of bacteria which are E. coli (87.50 f 4.17 %), S. typhi (85.96 f 3.04 %), S. aureus (70.71 f 1.75 %), K. pneumonia (7.97 f 1.26%) and while 2a and 2b only showed maximum percent inhibition of 77.78 f 1.92% and 66.67 f 2.31 for the bacterium B. subtilis and S. abony respectively at a concentration of 10 mg/ml. Also the methyl silicon (IV) Schiff base complexes showed less antibacterial activity than the ethyl silicon (IV) Schiff base complexes. Pharmacological activities of mono organosilicon (IV) complexes increase with an increase in the number of organo group as well as ligands. 2c possessed the best antioxidant, anti-inflammatory, and anti-diabetic activities.