Microbial transformation of steroids and evaluation of their biotransformed products as antiproliferative agents and acetylcholinesterase inhibitors (in-vitro and insilico studies) / Sharifah Nurfazilah Wan Yusop

• Main Author: Wan Yusop, Sharifah Nurfazilah
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: Pharmaceutical chemistry
• Online Access: https://ir.uitm.edu.my/id/eprint/60817/1/60817.pdf; https://ir.uitm.edu.my/id/eprint/60817/

Natural products account for 60% of the total market, making them a major source of drug discovery. Some of these are sourced from the cultivation of microorganisms. Microbial transformation is an example of the application of cultivation of microorganisms. It is a method of modifying the chemical structure of compounds such as steroids by microorganisms. The diversity of the possible reactions types in microbial transformation includes the process of oxidation, hydroxylation, esterification, isomerization, reduction, acetylation, hydrogenation and glycosylation. Therefore, the present study aims to screen new microbial strains which can carry out steroid bioconversions, and isolate prospective biologically active biotransformed products. No report on biotransformation of medroxyprogesterone has been published to date although biotransformations of medroxyprogesterone acetate have been studied by several groups. To date, only one study has published information on the microbial transformation of ethynodiol diacetate (ED), which is achieved by Cunninghamella elegans. In this study, the biotransformations of steroids medroxyprogesterone, and ethynodiol diacetate by a series of fungi (ATCC, endophytes and Antarctic) have been investigated. The literature on manipulations of the psychrotolerant fungi, specifically the Antarctic fungi for biotransformations is almost non-existent. Screening experiments were performed in 100 ml conical flasks containing 40 ml media and were autoclaved at 121°C for 15 minutes. After 3 days of inoculation, substrates were introduced aseptically into fermented liquid media and further fermentations were allowed for 4-12 days. Metabolic changes were observed by comparing the HPLC chromatograms of starting compounds, control cultures and fermented extracts. For medroxyprogesterone, Trichothecium roseum ATCC 13411, R3-2 SP17, Mucor plumbeus ATCC 47400, and Cunninghamella elegans ATCC 36112 were found to be suitable for large scale productions. Botrytis cinerea ATCC 36112, Trichothecium roseum ATCC 13411, and R3-2 SP17 were selected to proceed with large scale fermentation of ethynodiol diacetate. After separation and purification of the mixtures, the complete spectrometric analysis was performed to verify the structures of transformed products. The products with satisfactory quantity along with their precursors were subjected to anti-proliferative assay and acetylcholinesterase inhibition assay. From the analysis of the above data, one of the IC50 of the biotransformed products (the new biotransformed product, MP 2) is close to the limits of the active cytotoxic limit of a pure compound defined by the American National Cancer Institute, which is 4 μg/mL or less. Modification of steroid has also revealed to improve its antiacetylcholinesterase activity to some extent than its precursor specifically in the MP series. This is observed in MP 7, the new isolated biotransformed metabolite. The activities reported here deserve attention, and they are good examples in supporting the application of microbial transformation as a viable method of future development of anti-proliferative drug candidates, and acetylcholinesterase inhibitors.