uma sugestão usando css:<div><br></div><div>coloque o texto que vc quer destacar dentro de um <span></div><div><br></div><div>Meu texto com <span>esta parte destacada</span></div><div><br></div><div>defina um estilo</div>
<div><br></div><div>.destacado {</div><div><span class="Apple-style-span" style="font-family: Consolas, 'Lucida Console', monospace; font-size: 12px; white-space: nowrap; -webkit-text-size-adjust: none; "><ol class="properties properties-tree monospace" tabindex="0" style="box-sizing: border-box; font-size: 12px !important; font-family: Consolas, 'Lucida Console', monospace; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 2px; padding-right: 4px; padding-bottom: 0px; padding-left: 8px; list-style-type: none; list-style-position: initial; list-style-image: initial; min-height: 18px; display: block; ">
<li title="box-shadow: 1px 1px 10px black;" style="box-sizing: border-box; margin-left: 12px; white-space: nowrap; text-overflow: ellipsis; overflow-x: hidden; overflow-y: hidden; -webkit-user-select: text; cursor: auto; ">
<input class="enabled-button" type="checkbox" style="box-sizing: border-box; display: block; float: right; font-size: 10px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 4px; vertical-align: top; position: relative; z-index: 1; "><span class="webkit-css-property" style="box-sizing: border-box; color: rgb(200, 0, 0); ">box-shadow</span>: <span class="value" style="box-sizing: border-box; ">1px 1px 10px <span title="Click to change color format" class="swatch" style="box-sizing: border-box; display: inline-block; vertical-align: baseline; margin-left: 1px; margin-right: 2px; margin-bottom: -1px; width: 1em; height: 1em; border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid; border-top-color: rgba(128, 128, 128, 0.597656); border-right-color: rgba(128, 128, 128, 0.597656); border-bottom-color: rgba(128, 128, 128, 0.597656); border-left-color: rgba(128, 128, 128, 0.597656); background-color: black; "></span><span style="box-sizing: border-box; ">black</span></span>;</li>
<li title="background-color: rgba(220, 220, 32, 0.8);" style="box-sizing: border-box; margin-left: 12px; white-space: nowrap; text-overflow: ellipsis; overflow-x: hidden; overflow-y: hidden; -webkit-user-select: text; cursor: auto; ">
<input class="enabled-button" type="checkbox" style="box-sizing: border-box; display: block; float: right; font-size: 10px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 4px; vertical-align: top; position: relative; z-index: 1; "><span class="webkit-css-property" style="box-sizing: border-box; color: rgb(200, 0, 0); ">background-color</span>: <span class="value" style="box-sizing: border-box; "><span title="Click to change color format" class="swatch" style="box-sizing: border-box; display: inline-block; vertical-align: baseline; margin-left: 1px; margin-right: 2px; margin-bottom: -1px; width: 1em; height: 1em; border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid; border-top-color: rgba(128, 128, 128, 0.597656); border-right-color: rgba(128, 128, 128, 0.597656); border-bottom-color: rgba(128, 128, 128, 0.597656); border-left-color: rgba(128, 128, 128, 0.597656); background-color: rgba(220, 220, 32, 0.796875); "></span><span style="box-sizing: border-box; ">rgba(220, 220, 32, 0.8)</span></span>;</li>
<li title="background-color: rgba(220, 220, 32, 0.8);" style="box-sizing: border-box; margin-left: 12px; white-space: nowrap; text-overflow: ellipsis; overflow-x: hidden; overflow-y: hidden; -webkit-user-select: text; cursor: auto; ">
<span class="webkit-css-property" style="box-sizing: border-box; color: rgb(200, 0, 0); ">padding</span>: <span class="value" style="box-sizing: border-box; ">1px 1px 1px 1px</span>;</li></ol></span></div><div>}<br><br></div>
<div>e adicione a classe destacado no span pra destacar ele</div><div><br></div><div>Meu texto com <span class="destacado">esta parte destacada</span></div><div><br><div class="gmail_quote">Em 5 de maio de 2011 09:18, Aguinaldo Silveira e Silva <span dir="ltr"><<a href="mailto:aguinald@labspot.ufsc.br">aguinald@labspot.ufsc.br</a>></span> escreveu:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div id=":p">uma disposição mais agradável para a leitura.<br></div></blockquote></div><br></div>