In Vitro Evaluation Of Anti-HIV And Other STD Activities For Four Microbicide Candidates

Microbicides is an agent that inactivates or inhibits sexually transmitted pathogens, especially HIV-1. It is a topically applied agent before intercourse. Now 23 microbicide candidates have entered clinical trials. Experts estimated that at least one microbicide will be on the market as early as 2007.In order to find microbicide candidates, we studied on anti-HIV and anti-other STD pathogen activities of natural product derivatives and other compounds by 3 assays in vitro including inhibition of syncytial formation, MTT colorimetric assay and quantitative enzyme-linked immunosorbent assay (ELISA).The antimicrobial activity of 4 compounds including PS20, M36, LN43 and LN43-2 was evaluated. PS20 of a natural product derivatives has high anti-HIV IIIB activity and its effective concentration (EC60) and its therapeutic index (TI) was 5.19 g/ml and 663, respectively. The anti-HIV activity of PS20 was detected by p24 ELISA assay for R5 strain (HIVAda-M and HIVBal) and its EC50 was 9. 03 g/mland 18.09 g/ml, and its TI was 78 and 39, respectively. EC50 and TI of M36 for HIVIIIB was 4. 65 M and 88, and its EC50 for R5 strain (HIVAda-M and HIVBal) was 4.14 M and 9. 47 M, and its TI was 48 and 41, respectively. EC50 of LN43 and LN43-2 of rare earth compound in anti-HIVIIIB activity was 82. 38 M and 37. 39 M, its TI was 106 and 109, respectively. EC50 and TI of LN43 for HIVAda-M were 122.15 M and 26, and EC50 and TI of LN43-2 for HIVBal was 23. 02 M and 227. In order to study interaction of PS20 and LN43, we combined usage of PS20 with LN43 at molecular ratios of 1:1, 1:4 and 1:11 and at ECs50, 70 and 90. Theirmeans of anti-HIV-1 combination indeces (CIs) measured using mixed dose effect analyses and the CalcuSyn for windows software package were less than 0.5, and the strong synergism was shown. The time-of-addition experiment and the inhibition of cell fusion showed that PS20 and LN43 might target to early stage (binding/fusion) of HIV-1 replicate cycle. EC50 of PS20 in anti-HSV activity detected by plaque reduction assay was 68 g/ml. The minimum inhibition concentration (MIC) of LN43 defined as 90% inhibition compared to growth control was 2. 7 M for Candida albicans using an improved MTT test. All compounds had no inhibition activity for Neisseria gonorrhoeae.In summary, 4 compounds including PS20, M36, LN43 and LN43-2 showed strong anti-HIV and - other STD pathogen activities. Combined usage of PS20 with bW43 demonstrated the svnergistic action, and PS20 and LN43 showed anti-HSV and anti-Candida activities, respectively. These results suggest that our compounds may be potential candidates for microbicides development.