import re
text = '''
    (A) Match these:
    *** star* st**r

    (B) Not these:
    800*m *4,500 

    (C) And not these:
    800**m **4,000
    '''
print(re.findall(r'(?<!\S)(?!\*+\d)[a-zA-Z]*\*[a-zA-Z*]*', text))