RESUMO
We isolated 61 endophyte isolates from the bark of 4 plants, Ginkgo biloba L, Albizzia julibrissin Durazz, Ailanthus sltissima (Mill) Swingle and Melia azedarach L. At the test concentration of 200 ?g/mL, higher than 50% of antitumor activities were demonstrated with crude extracts from 45.9% of fungal culture in MTT assay. Six isolates, YX5, YX17, YX36, KL1, CC1 and CC5, still showed higher cytotoxicity at 50 ?g/mL. No isolates from A. julibrissin had inhibitory effect towards EC109 at the test concentration of 50 ?g/mL; while about 15.8% of isolates from G. biloba were active. IC50 of the extract from the most active isolate YX5 against EC109, HONE1 and HeLa were 18.3 ?g/mL, 3.6 ?g/mL and 6.5 ?g/mL, respectively. Our results indicate that endophytes from G. biloba could be regarded as a potent source of antitumor drugs.