You shouldn't use LIs in email. They are unpredictable across email clients. Instead you have to code each bullet point like this:
<table width="100%" cellspacing="0" border="0" cellpadding="0">
<tr>
<td align="left" valign="top" width="10" style="font-family:Arial, Helvetica, Sans-Serif; font-size:12px;">•</td>
<td align="left" valign="top" style="font-family:Arial, Helvetica, Sans-Serif; font-size:12px;">This is the first bullet point</td>
</tr>
<tr>
<td align="left" valign="top" width="10" style="font-family:Arial, Helvetica, Sans-Serif; font-size:12px;">•</td>
<td align="left" valign="top" style="font-family:Arial, Helvetica, Sans-Serif; font-size:12px;">This is the second bullet point</td>
</tr>
</table>
This will ensure that your bullets work in every email client.