Report on Vincristine-Producing Endophytic Fungus Nigrospora zimmermanii from Leaves of Catharanthus roseus.

Vincristine is an anti-cancer compound and one of the most crucial vinca alkaloids produced by the medicinal plant Catharanthus roseus (L.) G. Don. (Apocynaceae). This plant is home to hundreds of endophytic microbes, which produce a variety of bioactive secondary metabolites that are known for their medicinal properties. In this study, we focused on isolating an endophytic fungus that could increase the yield of vincristine under laboratory conditions as an alternative to plant-mediated extraction of vincristine. The endophytic fungus Nigrospora zimmermanii (Apiosporaceae) was isolated from Catharanthus roseus and it was found to be producing the anticancer compound vincristine. It was identified using high-performance thin-layer chromatography by matching the Rf value and spectral data with the vincristine standard and mass spectrometry data and the reference molecule from the PubChem database. The generation study of this microbe showed that the production of vincristine in the parent fungus was at its maximum, i.e., 5.344 µg/mL, while it was slightly reduced in subsequent generations. A colonization study was also performed and it showed that the fungus N. zimmermanii was able to re-infect the plant Catharanthus roseus after 20 days of inoculation. The colonization study showed that N. zimmernanii could infect the plant after isolation. This method is an efficient and easy way to obtain a high yield of vincristine, as compared to plant-mediated production.

Enhancement of vincristine under in vitro culture of Catharanthus roseus supplemented with Alternaria sesami endophytic fungal extract as a biotic elicitor.

Vincristine, one of the major vinca alkaloid of Catharanthus roseus (L.) G. Don. (Apocynaceae), was enhanced under in vitro callus culture of C. roseus using fungal extract of an endophyte Alternaria sesami isolated from the surface-sterilized root cuttings of C. roseus. Vindoline, a precursor molecule for vincristine production, was detected for the first time in the fungal endophyte A. sesami which was used as a biotic elicitor in this study to enhance vincristine content in the C. roseus callus. It was identified using high-performance liquid chromatography and mass spectroscopy techniques by matching retention time and mass data with reference molecule. Supplementing the heat sterilized A. sesami endophytic fungal culture extract into the callus culture medium of C. roseus resulted in the enhancement of vincristine content in C. roseus callus by 21.717% after 105-day culture.