JSFiddle - React, Tailwind, and code Playground

HTML

<select>
    <optgroup label="fruta">
        <option value="banana">banana</option>
        <option value="uva">uva</option>
    </optgroup>
    <optgroup label="legume">
        <option value="batata">batata</option>
        <option value="cenoura">cenoura</option>
    </optgroup>
</select>
<div id="label_value"></div>

JavaScript

$('select').change(function () {
    var label = $(this).find(':selected').closest('optgroup').attr('label');
    $('#label_value').html(label);
});