Well, the first part is fine, but the problem is the word 'its'. Grammatically, you would need to say 'their' (because there are two metabolites).
However, I would suggest removing this word, and changing the following prepostion to 'to' (because sthg is toxic 'to' sthg). Therefore:
'The effects of RA8 and RA11 metabolites on Acanthamoeba sp. and cytotoxicity to TERT-NHUC and KB human cells.'
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