The fermentation of Camellia chrysantha leaves with Eurotium cristatum to yield biologically active compound

Microfungi have appeared as one of the most effective and eco-friendly catalysers for derivatizing bio-active molecules in green chemistry. The use of Eurotium cristatum has been established as a method of post-harvest handling and value addition for tea products, especially in enhancing their health-protective properties. From our study, a consortium of E. cristatum was selected and introduced as inoculum on Camellia chrysantha leaves substrate, yielding transformed products with chemo-preventive and antidiabetic potential. Biological activity-guided fractionation incorporated with chromatographic separation of the fermented products gave out compound THV-LM03 as the most active isolate exhibiting inhibitory effect against lipase, α-glucosidase, and cancerous cell growth. By means of 1 H-NMR, 13 C-NMR, HSQC and HMBC spectral analysis, THV-LM03 was elucidated as 22-O-tigloyloxycamelliagenin A – a triterpene which has not been isolated previously from Camellia materials. In vitro assays revealed THV-LM03 as a potent inhibitor against α-glucosidase (IC 50 value at 16.33 µg/mL) and against cancer cell lines LU-1 and MCF-7 (IC 50 values at 4.87 and 9.32 µg/mL, respectively). These findings brought out a new pharmacological aspect of microbial fermentation in C. chrysantha leaves, as well as contributed to highlight the potential of effective bio-transformation in a safer synthesis of target molecules.