Abstract: |
Taxol is one of the potential anticancer drugs; however, the yield of Taxol and its cytotoxicity
are common challenges. Thus, manipulating the Taxol biosynthetic pathway from endophytic fungi, in
addition to chemical modification with biocompatible polymers, is the challenge. Four fungal isolates,
namely, Aspergillus flavipes, A. terreus, A. flavus, and A. parasiticus, were selected from our previous
study as potential Taxol producers, and their potency for Taxol production was evaluated in response
to fluconazole and silver nitrate. A higher Taxol yield was reported in the cultures of A. flavipes
(185 µg/L) and A. terreus (66 µg/L). With addition of fluconazole, the yield of Taxol was increased 1.8
and 1.2-fold for A. flavipes and A. terreus, respectively, confirming the inhibition of sterol biosynthesis
and redirecting the geranyl phosphate pool to terpenoids synthesis. A significant inhibition of
ergosterol biosynthesis by A. flavipes with addition of fluconazole was observed, correlating with
the increase on Taxol yield. To increase the Taxol solubility and to reduce its cytotoxicity, Taxol was
modified via chemical conjugation with porphyrin, and the degree of conjugation was checked from
the Thin layer chromatography and UV spectral analysis. The antiproliferative activity of native and
modified Taxol conjugates was evaluated; upon porphyrin conjugation, the activity of Taxol towards
HepG2 was increased 1.5-fold, while its cytotoxicity to VERO cells was reduced 3-fold.
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