Why is my published article seemingly not indexed by Google or Google Scholar?
Although you asked a generic question, the answer is very particular to your own particular article. Most likely, @HoboSci, got the correct answer: you published in a journal of questionable ethical editorial policy that Google Scholar refuses to index. That is, "Journal of Chemical and Pharmaceutical Research" is probably such a journal (see https://bradleymonk.com/Beall%27s_List_of_Questionable_Journals).

I looked up the issue where your own article is published: JOCPR Volume 6 Issue 3: http://www.jocpr.com/archive/jocpr-volume-6-issue-3-year-2014.html. I searched Google Scholar for your article "Potential inhibitors against acetylcholinesterase and glutathione S-transferase associated with alzheimer's disease". I also searched for a couple other articles in that same special issue and none of them showed up in Google Scholar.

Unfortunately, I don't think there's anything you can do about it because once you've published in a journal like that, you can't republish the same article anywhere else. So,the lesson is to only publish your work in reputable journals, or else your published work might become almost invisible on the Web. :-(