&lt;strong&gt; Antiproliferative Activity and Effect on GABA&lt;sub&gt;A&lt;/sub&gt; Receptors of the Abietane &lt;/strong&gt;&lt;strong&gt;Diterpenoid Jiadifenoic Acid C and Other Callitrisic Acid &lt;/strong&gt;&lt;strong&gt;(4-Epidehydroabietic Acid) Derivatives&lt;/strong&gt;