Rangarajulu Senthil Kumaran

Taxol from Phyllosticta citricarpa, a Leaf Spot Fungus of the Angiosperm Citrus medica

Phyllosticta citricarpa, a leaf spot fungus isolated from the diseased leaves of Citrus medica, displayed the production of taxol, an anticancer drug on M1D and potato dextrose broth medium in culture for the first time. The presence of taxol was confirmed by spectroscopic and chromatographic methods of analysis. The maximum amount of taxol production was recorded in the fungus grown on M1D medium (265 microg/l) followed by PDB medium (137 microg/l). The production rate was increased to 5.3 x 10(3) fold than that observed in the culture broth of an earlier reported fungus, Taxomyces andreanae.

Screening of species of the endophytic fungus Phomopsis for the production of the anticancer drug taxol

Three different strains of the endophytic fungus Phomopsis were isolated from the healthy leaves of Taxus cuspidata (Japanese yew), Ginkgo biloba (ginkgo or maidenhair tree) and Larix leptolepis (Japanese larch) and screened for the production of taxol on a modified liquid medium for the first time. The presence of taxol was confirmed by spectroscopic and chromatographic analyses. The amount of taxol produced by this fungus was quantified by HPLC. The maximum amount of fungal taxol production was recorded as 418 μg/litre in the strain BKH 27. The yield was increased to 8360‐fold that found for the fungus Taxomyces andreanae reported previously [Stierle, Strobel and Stierle (1993) Science 260, 214–216]. The fungal taxol extracted also showed a strong cytotoxicity towards the human cancer cells in an apoptosis assay. All the three isolates showed positive sign towards PCR for the conserved sequence of the taxadiene synthase gene. The results suggest that Phomopsis could be an excellent alternative source for taxol and may serve as a potential genetic‐engineered species for the enhanced production of taxol.

Isolation and identification of an anticancer drug, taxol from Phyllosticta tabernaemontanae , a leaf spot fungus of an angiosperm, Wrightia tinctoria

Phyllosticta tabernaemontanae, a leaf spot fungus isolated from the diseased leaves of Wrightia tinctoria, showed the production of taxol, an anticancer drug, on modified liquid medium (MID) and potato dextrose broth (PDB) medium in culture for the first time. The presence of taxol was confirmed by spectroscopic and chromatographic methods of analysis. The amount of taxol produced by this fungus was quantified using high performance liquid chromatography (HPLC). The maximum amount of taxol production was recorded in the fungus grown on MID medium (461 μg/L) followed by PDB medium (150 μg/L). The production rate was increased to 9.2 × 103 fold than that found in the culture broth of earlier reported fungus, Taxomyces andreanae. The results designate that P. tabernaemontanae is an excellent candidate for taxol production. The fungal taxol extracted also showed a strong cytotoxic activity in the in vitro culture of tested human cancer cells by apoptotic assay.

Isolation of taxol, an anticancer drug produced by the endophytic fungus, Phoma betae

Phoma betae, an endophytic fungus, was isolated from the healthy leaves of Ginkgo biloba . The fungus was screened for the production of taxol on a modified liquid medium for the first time. The fungal species were identified by their characteristic culture morphology and molecular analysis. The presence of taxol was confirmed by spectroscopic: ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR), liquid chromatography–mass spectrometry (LC-MS); and chromatographic: thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) methods of analysis. The taxol production was quantified by HPLC analysis. The maximum amount of taxol production was recorded as 795 μg/L. The production rate was 15,900-fold more than that found in the culture broth of earlier reported fungus, Taxomyces andreanae . The extracted fungal taxol demonstrate a strong cytotoxic activity in the in vitro culture of tested human cancer cells by apoptotic assay. This indicates that the increase in taxol concentration induced an increased cell death. A polymerase chain reaction (PCR) based screening for taxadiene synthase (ts), a unique gene in the formation of the taxane skeleton was confirmed as a molecular blueprint for taxol biosynthesis. These results designate that the fungus, P. betae is an excellent candidate for taxol supply and can serve as a potential species for genetic engineering to enhance the production of taxol to a higher level. Key words : Taxol production, Phoma betae, analytical methods, cytotoxicity assay, taxadiene synthase.