import re
matches = []
text = "Hi, How ARE You? SQLiteBrowser and I"
for line in text.splitlines():
    matches.extend([x for x in re.findall(r'\w+', line) if x[0].isupper() and all(i.islower() for i in x[1:])])
print(matches)
# => ['Hi', 'How', 'You', 'I']