Well the i have google alot for extracting them separately and finally i got an idea .
If you are using sharp NLP Than Apply pos tagging and Apply if condition to retrieve specific tags like noun and verbs.And i am getting only NNP tags.
Here is a little effort.
richTextBox1.Show();
StringBuilder output = new StringBuilder();
string[] sentences = SplitSentences(rt2.Text);
foreach (string sentence in sentences)
{
string[] tokens = TokenizeSentence(sentence);
string[] tags = PosTagTokens(tokens);
for (int currentTag = 0; currentTag < tags.Length; currentTag++)
{
if (tags[currentTag] == "NNP")
{
output.Append(tokens[currentTag]).Append("/").Append(tags[currentTag]).Append(" ");
}
}
output.Append("\r\n\r\n");
}
richTextBox1.Text = output.ToString();
}