IRIDOID GLUCOSIDES FROM PICCONIA-EXCELSA

An investigation of the iridoids of Picconia excelsa from Tenerife pro vided 17 iridoid glucosides together with verbascoside. Major constitu ents (> 0.5%) were loganin, ketologanin, oleoacteoside and the new pic conioside I-a bisiridoid consisting of loganin esterified with deoxylo ganin. Minor constituents were secoxyloganin, 8-epi-kingiside, 8-epi-k ingisidic, oleoside 11-methyl ester, excelsioside, ligstroside and log anic acid together with the new compounds ketologanic acid, 6 beta-hyd roxy-7-epi-loganin and picconiosides II-V, the latter four being ester s of loganin and menthiafolic, foliamenthic, 6-(Z)-foliamenthic or 6,7 -dihydrofoliamenthic acid. The structures were mainly elucidated by NM R spectroscopy. (C) 1997 Elsevier Science Ltd.