Microbial transformation of thymoquinone

In this present work, thymoquinone a monoterpene quinine, which is the major constituent of the essential oil of Black Cumin seed (Nigella sativa L.) was subjected to microbial biotransformation studies by using 35 different microorganisms. Among the screened strains Aspergillus niger ATCC 10549 was the most metabolite-yielding species with six metabolites identified by thin layer chromatography (TLC), gas chromatography/mass spectroscopy (GC-MS) and nuclear magnetic resonance spectroscopy (NMR), respectivelty. Thymohydroquinone was the only metabolite characterized for the first time transformed by 23 of the tested microorganisms among others. The preparative biotransformation of thymoquinone by the fungus A. parasiticus (NRRLY 2999) yielded the chromatographically purified thymohydroquinone for bioactivity tests.The in vitro antimicrobial (antibacterial and anticandidal), antioxidant (DPPH and ABTS radical scavenging), and enzyme inhibition [Acetylcholineesterase (AchE) butyrylcholineesterase (BuChE)] bioactivities of thymoquinone and thymohydroquinone were evaluated.As a result the biotransformation metabolite thymohydroquinone showed better biological activities when compared with the substrate in the tested bioassays.