Is the word interessantes the same in Brazilian and European Portuguese?

Yes

The meaning, spelling, and grammatical function of "interessantes" are identical in both Brazilian and European Portuguese. The only difference lies in pronunciation.

In Brazilian Portuguese, the vowels are generally more "open" and clearly articulated, even in unstressed syllables. In Continental (European) Portuguese, there is a much stronger tendency toward vowel reduction. This means the unstressed "e" in the suffix "-es" might be "swallowed" or pronounced as a very short, nearly silent sound, making the word sound more compressed and consonant-heavy compared to the more melodic Brazilian pronunciation.

Brazilian Portuguese Examples

1. Estes livros são muito interessantes. (These books are very interesting.)
2. Eu vi uns vídeos bem interessantes ontem. (I saw some very interesting videos yesterday.)
3. Ela tem ideias muito interessantes para o projeto. (She has very interesting ideas for the project.)
4. As aulas de música são bastante interessantes. (Music classes are quite interesting.)
5. Encontrei uns sites interessantes na internet. (I found some interesting websites on the internet.)

European Portuguese Examples

1. Estes livros são muito interessantes. (These books are very interesting.)
2. Vi uns vídeos muito interessantes ontem. (I saw some very interesting videos yesterday.)
3. Ela tem ideias muito interessantes para o projeto. (She has very interesting ideas for the project.)
4. As aulas de música são bastante interessantes. (Music classes are quite interesting.)
5. Encontrei uns sites interessantes na internet. (I found some interesting websites on the internet.)