1. Sulfur-Containing Polybromoindoles from the Formosan Red Alga Laurencia brongniartii Ali A. EI-Gamal, Wei-Lung Wang, and Chang-Yih Duh Department of Marine Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan & Department of Biology, National Changhua University of Education, Changhua, Taiwan, Republic of China

2. Abstract Five new sulfur-containing polybromoindoles, 2- methylsulfinyl-3-methylthio-4,5,6-tribromoindole (1), 3- methylsulfinyl-2,4,6-tribromoindole (2), 4,6-dibromo-2,3- di(methylsulfinyl)indole (3), 3,3’-bis(2’-methylsulfinyl-2- methylthio-4,6,4’,6’-tetrabromo)indole (4), and 3,3-bis(4,6- dibromo methylsulfinyl)indole (5), as well as seven known sulfur- containing polybromoindoles, 3-methylthio-2,4,6-tribromoindole (6), 3-methylthio-2,4,5,6-tetrabromoindole (7), 4,6-dibromo-2,3- di(methylthio)indole (8), 2,3-di(methylthio)- 4,5,6-tribromoindole (9), 4,6-dibromo-2-methylsulfinyl 3(methylthio)indole (10), 4,6- dibromo-2-(methylthio)indole (11), and 3,3-bis(4,6-dibromo-2- methylthio)indole (12), have been isolated from the Formosan red alga Laurencia brongniartii. The structures were elucidated by extensive spectral analysis, and their cytotoxicity against selected cancer cells was measured in vitro.

3. Aim of Study The red alga Laurencia brongniartii was reported to be source of polybrominated and sulfur-containing indoles. As part of our search for bioactive substances from marine organisms, Formosan red alga L. brongniartii was studied because EtOAc extracts showed significant cytotoxicity to A549 (human lung adenocarcinoma), HT- 29 (human colon adenocarcinoma), NUGC-3 (human gastric adenocarcinoma), HONE-1 (human nasopharyngeal carcinoma), and P-388 (mouse lymphocytic leukemia) cell cultures as determined by standard procedures. Bioassay-guided fractionation resulted in the isolation of five new sulfur-containing polybromoindoles, (1-5) as well as seven known sulfur- containing polybromo-indoles (6-12). Compounds 4 and 5 exhibited cytotoxicity against selected cancer cell lines.

4. A Photo of Red algae Laurencia brongniartii

5. Extraction, Seperation and Purification Schem for red alga Laurencia brongiartii Compound 4 exhibited cytotoxicity against HT-29 and P-388, while compound 5 exhibited cytototxicity against P-388 cell line. The other isolates were not cytotoxic against P-388 and HT-29 cell lines.

6. Sulfur-Containing Polybromoindoles from the Formosan Red Alga Laurencia brongniartii

7. 1 HNMR of Compound 1 1 HNMR of Compound 1 7

8. 13 C NMR and DEPT 90 0 Expermint of Compound 1 13 C NMR and DEPT 90 0 Expermint of Compound 1

9. 1 HNMR of Compound 2

10. EIMS with clusters of Isotopic Peaks of Compound 2 m/z 417 C 9 H 6 79 Br 81 Br 2 NOS

11. 13 C NMR of Compound 2 13 C NMR of Compound 2

12. HRMS of Compound 2 HRMS of Compound 2 m/z 416.7662 C9H679Br81Br2NOS

13. EIMS of compound 3 showed clusters of isotopic peaks EIMS of compound 3 showed clusters of isotopic peaks m/z 398.8421 C10H979Br81BrNO2S2

14. HRMS of Compound 3 HRMS of Compound 3 m/z 398.8421 C 10 H 9 79 Br 81 BrNO 2 S 2

15. 1 H NMR of Compound 3 1 H NMR of Compound 3 NH 5 7 SOMeSOMe

16. 1 H NMR of Compound 4 1 H NMR of Compound 4 NH-1 NH-1’ SMe SOMe 55’ 77’

17. HRMS of Compound 4 HRMS of Compound 4 m/z 655.7028 C18H1279Br281Br2N2OS2

18. 1 H NMR of Compound 5 1 H NMR of Compound 5 NH 5 7 SOMe SOMe

19. HRMS of Compound 5 HRMS of Compound 5 m/z 671.6988 C18H1279Br281Br2N2O2S2

20. HRMS of Compound 5 showed Clusters of Isotopic peaks HRMS of Compound 5 showed Clusters of Isotopic peaks m/z 671.6988 C18H1279Br281Br2N2O2S2

21. 1 HNMR of Compound 6 1 HNMR of Compound 6

22. 13 C NMR and DEPT Experiments of Compound 6 13 C NMR and DEPT Experiments of Compound 6

23. 1 HNMR of Compound 7 1 HNMR of Compound 7

24. 13 CNMR and DEPT 90 0 of Compound 7 13 CNMR and DEPT 90 0 of Compound 7

25. MS of Compound 8 showed Clusters of Isotopic Peaks m/z 367 C 10 H 9 79 Br 81 BrNS 2

26. 1 HNMR of Compound 8

27. 1 HNMR of Compound 9

28. EIMS of Compound 9 Showed Clusters of Isotopic Peaks EIMS of Compound 9 Showed Clusters of Isotopic Peaks m/z 447 C 10 H8 79 Br 2 81 8BrNS 2

29. MS of Compound 8 showed Clusters of Isotopic Peaks m/z 367 C10H979Br81BrNS2

30. 1 H NMR of Compound 10 5 7 SOMe SCH 3

31. 13 C NMR of Compound 10 13 C NMR of Compound 10

32. 1 H NMR of Compound 11 1 H NMR of Compound 11

34. m/z 640 C 18 H 12 79 Br 2 81Br 2 N 2 S 2 EIMS of Compound 12 EIMS of Compound 12

35. 1 H NMR of Compound 12 1 H NMR of Compound 12

36. EIMS of Compound 12 showed Clusters of Isotopic Peaks