Croton is a genus included in Euphorbiaceae family which is widespread in northeastern Brazil. Its use in popular medicine is related to cancer treatment, constipation, diabetes, digestive

problems, dysentery, external wounds, fever, hypercholesterolemia, hypertension, inflammation, intestinal worms, malaria, pain, ulcers, and weight-loss.8 Previous phytochemical studies have shown that plants of this genus can produce a large number of diterpenoids,9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19 a class of natural products that exhibit a wide spectrum of important biological activities,8 which we can highlight the antimicrobial activity.20, 21 and 22 Casbane Diterpenes are a class of diterpenoids isolated from a few species of plants from Euphorbiaceae family with mainly anticancer and antibacterial activities.23, 24, 25, 26, 27, 28, 29, 30 and 31 The present study reports, for the first time, the antimicrobial

find more and antibiofilm activities of the Casbane Diterpene named 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane LY294002 (CD) isolated from Croton nepetaefolius against oral bacteria. Stalks from C. nepetaefolius were collected in May, 2004, in Caucaia, Ceará, Brazil. The sample material was identified by Dr. Edson Paula Nunes at Prisco Bezerra Herbarium, Biology Department, Federal University of Ceará, Fortaleza, CE, Brazil, where the vouchers specimens (No. 33.582) were deposited. The bark from stalks (5.0 kg) of C. nepetaefolius was powdered

and solubilized with ethanol (10 L × 3, at room temperature). The solvent was removed under reduced pressure to form an EtOH extract. The EtOH extract (58.2 g) was fractionated coarsely in a silica gel column, eluted with hexane (fractions 1–15), hexane/EtOAc 1:1 (fractions 16–25), EtOAc (fractions 26–40), and EtOH (fractions 41–48), affording a total of 48 fractions of 100 mL each. GPX6 The hexane fractions (22.5 g) were pooled and fractionated in a silica gel column using hexane (fractions 1′–10′), hexane/EtOAc 1:1 (fractions 11′–16′), EtOAc (fractions 17′–21′) and EtOH (fractions 22′–25′), providing 25 fractions of 100 mL each. Fractions 11′–16′ (14.0 g), obtained with hexane/EtOAc (1:1), were fractionated coarsely in a silica gel column eluted with hexane (fraction 1″), hexane/EtOAc 9:1 (fractions 2″–5″), 8:2 (fractions 6″–15″), 7:3 (fractions 16″–32″), EtOAc (fraction 33″), providing 33 fractions of 100 mL each. Fractions 10″–13″, obtained with hexane/EtOAc (8:2), yielded a diterpene named 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane (CD) (3.0 g, 0.06%) ( Fig. 1). The CD was solubilized in MiLi-Rios water and dimethylsulfoxide (DMSO) which were diluted in culture medium reaching a maximum concentration of 1% (v/v). This percentage of DMSO does not show interference on microbial growth (data not shown). 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane (CD). Green oil I.R. (KBr, cm−1): 3400, 2920, 1660, 1618, 1020, 756. 1H NMR: 0.99 (s, 3H-16), 1.