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INFORMATION ON DOCTORAL THESIS
1. Full name: Tran Thi Nhu Hang 2. Sex: Female
2. Date of birh: 05-09-1969 4. Place of birth: Ha Noi, Viet Nam
5. Admission decision number: 150/SĐH, dated: 06/07/2005, of Hanoi National University
6. Changes in academic process: Extension decision number 1133/SĐH.
7. Official thesis title: Study of biological activity and chemical nature of some bioactive compounds isolated from endophytes of kho sam (Croton tonkinensis Gagnep.) and bum bup (Mallotus apelta Lour.)”
8. Major: Microbiology 9. Code: 62.42.40.01
10. Supervisors:Prof. Dr. Lê Mai Hương
Prof. Dr. Ngo Tu Thanh
11. Summary of the new findings of the thesis:The study of this thesis is the first study on endophytes of the kho sam and the bum bup in Vietnam.
- From different tissues of kho sam and bum 55 fungal endophytes strains were isolated. Among them 10 strains was selected for high antimicrobial activity.
- 10 these strains were classified as 10 species (5 Penicillium strains, 3 Trichoderma strains, and 2 Fusarium strains).
In particular, this is the first time Trichoderma konilangbra was found in Vietnam.
- Some biological activities of 10 selected strains were determined, through their fermentation broths or ethylacetate extracts of the broths. This determination showed that: all 10 strains represented antimicrobial activity towards 1-8 tested microorganisms; 8 strains exhibited cytotoxic activity against 1-3 cell lines including; 7 strains exhibited antioxidant activity; 9 strains showed 1-3 extracellular enzyme activities
Among 10 selected strains, Trichoderma konilangbra KS14 was superior to the other in all 4 biological activities tested (antimicrobial, cytotoxic, antioxidant, and extracellular enzyme activity).
- From fermentation extract of Trichoderma konilangbra KS14, five compounds were isolated:
+ KS14-1:ergosta-5, 7, 22-trien- 3-ol (ergosterol)
+ KS14-2: 3-acetyl-4-hydroxy-6-metyl-2H-pyran-2-one (dehydracetic acid)
+ KS14-3: 1,3-dihydroxy-3,5-dimethylphenyl)-2,4-hexadien-1-one (sorbicillin)
+ KS14-4: 16-hydroxyoctadecanoic acid
+ KS14-5: 5,8-Epidioxy-5a, 8a-ergosta-6,22-E-dien-3b-ol (ergosterol peroxid).
Among them
· The compounds KS14-1, KS14-3, KS14-4 and KS14-5 were active against 1-7 miroorganisms tested. The KS14-4, for the first time, was known active against Staphylococcus aureus with MIC= 25 mg /ml.
· The compound KS14-3 exhibited cytotoxic activity vis- a-vis cell lines Hep- G2 and RD; the KS14-5, toxic towards Hep- G2, RD and Fl.
- It is the first time, the preparations were made from endophytes of kho sam and exhibited their influence on host plants: the liquid preparation increased the content of ent-kauran by 50,43%; both the liquid and powder preparations increased the average length of root system by 25%.
12. Practical applicability: Using the endophytic strains to produce microbial products that capable of growth stimulating, especially of enhancing bioactive compounds inside plants.
13. Futher research directions: Following researches on the relationship between endophytic community and host plants.
14. Thesis-related publications:
1. Tran Thi Nhu Hang,Le Mai Huong, Tran Thi Hong Ha, Do Huu Nghi and Mai Ngoc Toan (2005), “Investigating the biochemical and biophysical conditions which have effect on antibiotical producing of some endophytic fungal isolated from plants of Me Linh garden”, Vietnamese journal of Science and Technology 43(6A), pp. 143-148.
2. Tran Thi Hong Ha, Le Mai Huong, Tran Thi Nhu Hang (2005) “Evaluation on cytotoxicity activity of extracts from isolated endophytic fungi”, Vietnamese journal of Science and Technology 43(6A), pp. 137-142.
3. Le Mai Huong, Tran Thi Nhu Hang, Tran Huy Thai, Duong Đuc Huyen(2005),“Isolation, screening of antifungal, antibacterial properties of endo- parasitic vegetable species of mushroom isolated from some medicinal plant gardens in North Vietnam”, Pharmaceutical journal 352, pp. 20-23.
4. Tran Thi Nhu Hang,Le Mai Huong, Tran Thi Hong Ha (2007), “Investigation antimicrobial activity of endophytic fungal isolated from “kho sam” plant (Croton tonkinensis Gagnep.)”, Vietnamese journal of Science and Technology 45(1B), pp. 264-268.
5. Tran Thi Nhu Hang,Le Mai Huong, Tran Thi Hong Ha, Le Thi Hoang Yen (2008), “Study on effect of some cultural conditions on antimicrobial activity of endophytic fungal KS14 and their r- DNA sequence”, Journal of Chemistry 46(5A), pp. 245-249.
6. Hoang Kim Chi, Le Mai Huong, Tran Thi Nhu Hang, Tran Thi Hong Ha (2008), “Screening and investigating of endophytic fungi from medicinal plant Croton tonkinensis Gagnep.”, Journal of Chemistry46(5A), pp. 301-305.
7. Le Mai Huong, Tran Thi Nhu Hang, Tran Thi Hong Ha, Do Huu Nghi and Mai Ngoc Toan (2008), “The potential of endophytic fungi isolated from Vietnamese medicinal plant”, International scientific conference on “Chemmistry for development and integration”, Hanoi, pp.464-468.
8. Tran Thi Nhu Hang, Le Mai Huong, Tran Thi Hong Ha, Le Minh Ha (2009), “Structural confirmation and bioactivities of ergosterol peroxide isolated from the Trichoderma konilangbraendophytic on the plant Croton tonkinensis Gagnep.”, Pharmaceutical journal 400(49), pp. 47-50.
Hanoi, 15/5/2010
PhD. Tran Thi Nhu Hang
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