*3.2.2. Abietatriene 20-7 lactones*

The abietatriene lactones are a group of compounds which possess an oxygen-containing ring which predominantly is in the form of lactones (i.e., abietatrien-20,7-olides). This group of abietanes are exemplified by carnosol (11,12-dihydroxy-8,11,13-20,7-olide). Carnosol possesses an aromatic C ring, carbon C-20 is a keto group, and carbons C-11 and C-12 are hydroxy groups. This abietane has displayed several biological activities. It displayed antioxidant, antimicrobial, anti-inflammatory, antitumor, and anti-HIV (IC50 = 8.0 μM) properties [57, 58].
