Synthesis of 6-epi-Tuberiferin and the Biological Activities of Tuberiferin, Dehydrobrabrachylaenolide, 6-epi-Tuberiferin, and Their Synthetic Intermediates

Abstract Tuberiferin, 6-epi-tuberifelin, dehydrobrachylaenolide and two series of eudesmanolides, eudesmane-12,6 α-lactones and eudesmane-12,6β-lactones, were synthesized for the studies of the structure-activity relationships to explore novel anti-inflammatory, anti-cancer and crop disease prevention agents. The anti-inflammatory activities were tested by the inhibitory on the induction of inter-cellular adhesion molecule (ICAM-1), the permeation of leucocyte into inflammatory air pouch of murine, the killing function of cytotoxic T-lymphocytes (CTL), production of IL-1; The anti-cancer activities were established on the cytotoxic activities to six kinds of cell lines (P388, CCRF-CEM, VA-13, HepG2, QG-56, and WI-38). Results showed that Dehydrobrachylaenolide (an exo-endo cross conjugated dienone and α-methylene γ-lactone) was the most effective compound inhibiting ICAM-1 (IC50 3.0 μM) and the cell line VA-13 (IC50 0.45 μM); Compound 20 with an α-bromo-ketone moiety embraced the most potent inhibitory activity towards the permeation of leucocyte into inflammatory air pouches of murine in vivo (inhibitory ratio 54% at 10 mg); Compound 25 with an α-bromo-ketone and α-methylene trans-γ-lactone) showed the most significant inhibitory activity on the killing function of CTL (IC50 18 μM), as well as the cell lines of CCRF-CEM (IC50 1.1 μM) and P388 (IC50 1.21 μM) ; Tuberiferin (an α,β-unsaturated ketone and α- methylene γ-lactone) was on the top effective inhibitory on the production of IL-1; Compounds 19 with an α-bromo-ketone and α-methylene cis-γ-lactone exhibited the most potent inhibitory of QG-56 (IC50 12.5 μM); Compound 29 with an α-bromo-α,β-unsaturated ketone and α-methylene γ-lactone) showed significant inhibitory for HepG2 (IC50 1.23 μM) , though potently inhibited WI 38 (IC50 0.31 μM) as well. A conclusion may be reached that the α-Methylene γ-lactone moiety, exo-endo cross conjugated dienone moiety, and α-bromo-ketone withα-methylene moiety might be essential for eudesmanolides in the expression of their anti-inflammatory, anti-tumour biological activities. Similarly, the above mentioned key moieties are also responsible for the preventive activity of crop disease controlling.