ABSOLUTE STEREOCHEMISTRIES OF SYLVATICIN AND 12,15-CIS-SYLVATICIN, BIOACTIVE C-20,23-CIS NON-ADJACENT BISTETRAHYDROFURAN ANNONACEOUS ACETOGENINS, FROM ROLLINIA-MUCOSA

A new acetogenin, 12, 15-cis-sylvaticin (2), and its stereoisomer, syl vaticin (1), a known acetogenin whose stereochemical structure has rem ained unsolved until now, were isolated, using activity-directed fract ionation, from the leaf extracts of Rollinia mucosa (Jacq.) Baill. (An nonaceae). 1 is cis at C-20, 23 and trans at C-12, 15; 2 is cis at C-2 0, 23 and at C-12, 15. A key step in solving their absolute stereochem istries was the determination of the relative configurations (cis or t rans) of their 1, 4-diols; this was achieved by a new procedure using the pattern recognition of the NOSEY spectra of their 1, 4-diol formal dehyde acetal derivatives (1b and 2b). Both 1 and 2 showed potent and selective cytotoxicities, against the A-549 lung cancer and the PACA-2 pancreatic cancer, in a panel of six human solid tumor cell lines.