メールアドレスを抜き出す簡易的な正規表現です。

C#

    private string TEXT_EMAIL = "support@oborodukiyo.info";

Regex r02 = new Regex("([-0-9a-zA-Z!#$%&'*+/=?^_`{|}~(]+([.]?[-0-9a-zA-Z!#$%&'*+/=?^_`{|}~(])*@[0-9a-zA-Z]+([.]?[-0-9a-zA-Z])*)");
MatchCollection m02 = r02.Matches(TEXT_EMAIL);

foreach (Match m in m02)
{
    //結果は、m02:support@oborodukiyo.info
    this.textBox1.Text += "m02:" + m.Groups[1].Value + "\r\n";
}

//結果
//m02:support@oborodukiyo.info

VB.NET

        Private TEXT_EMAIL As String = "support@oborodukiyo.info"

        Dim r02 As Regex = New Regex("([-0-9a-zA-Z!#$%&'*+/=?^_`{|}~(]+([.]?[-0-9a-zA-Z!#$%&'*+/=?^_`{|}~(])*@[0-9a-zA-Z]+([.]?[-0-9a-zA-Z])*)")
        Dim m02 As MatchCollection = r02.Matches(TEXT_EMAIL)

        For Each m As Match In m02
            Me.TextBox1.Text += "m02:" & m.Groups(1).Value & vbCrLf
        Next

'結果
'm02:support@oborodukiyo.info