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Two novel diterpenoids, thecacorins A (1) and B (2), were isolated from Thecacoris batesii and their structures were established as ent-3β,20-epoxy-16-kaurene-3αα,12β-diol and ent-15-beyerene-2β,3β-diol, respectively, on the basis of extensive spectroscopic analysis, especially, 1D NMR spectra, in conjunction with 2D experiments, COSY, NOESY, HMQC and HMBC.

Phthalates are associated with preterm delivery. However, the mechanism is unclear. Progesterone formed by 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) and estradiol by aromatase (CYP19A1) in placenta are critical for maintaining pregnancy. In this study, we compared structure-activity relationships (SAR) of 14 phthalates varied in carbon atoms in alcohol moiety to inhibit human HSD3B1 in COS1 and CYP19A1 in JEG-3 cells. There were responses in that only diphthalates with 4–7 carbon atoms were competitive HSD3B1 inhibitors and diphthalates with 6 carbon atoms were CYP19A1 inhibitors. IC 50 s of dipentyl (DPP), bis(2-butoxyethyl) (BBOP), dicyclohexyl (DCHP), dibutyl (DBP), and diheptyl phthalate (DHP) were 50.12, 32.41, 31.42, 9.69, and 4.87 μM for HSD3B1, respectively. DCHP and BBOP inhibited CYP19A1, with IC 50 s of 64.70 and 56.47 μM. DPP, BBOP, DCHP, DBP, and DHP inhibited progesterone production in JEG-3 cells. In conclusion, our results indicate that there is clear SAR for phthalates in inhibition of HSD3B1 and CYP19A1. [ABSTRACT FROM AUTHOR]