In vitro cholinesterases, tyrosinase, α-glucosidase inhibitory and anticancer effects of novel silicon phthalocyanines containing geraniol/phytol

[Display omitted] •Synthesis of axially geraniol/phytol disubstituted silicon (IV) phthalocyanines.•Cytotoxic effects on L-929 cells of silicon (IV) phthalocyanines were investigated.•AChE/BuChE inhibitory effects of silicon (IV) phthalocyanines were investigated. The axially silicon phthalocyanines, consisting of different acyclic hydrocarbons, were generated by SiPcCl2 reacting with either geraniol or phytol in toluene in the presence of NaH. FT-IR, UV–Vis, MALDI TOF, and NMR spectroscopy all provided information about the structures of silicon phthalocyanines. The cholinesterase, tyrosinase, and α-glucosidase inhibitory effects of G-SiPc and P-SiPc were tested using spectrophotometric assays. The IC50 values of G-SiPc and P-SiPc were 7.22 ± 0.53 and 11.28 ± 2.73 µM for AChE; 70.05 ± 3.00 and 60.55 ± 3.80 µM for BuChE. In addition, G-SiPc and P-SiPc inhibited the tyrosinase enzyme with IC50 values of 280.36 ± 7.92 µM and 40.51 ± 3.88 µM, respectively. P-SiPc had about seven times stronger inhibitory properties than G-SiPc. The substances exhibited less inhibition than acarbose in the α-glucosidase inhibitory assay. Finally, the cytotoxic effects of G-SiPc and P-SiPc were investigated using the MTT assay on L-929 mouse fibroblast cells as normal cells. G-SiPc and P-SiPc did not reach IC50 values up to 100 μM.