Five new prenylated benzoic acid derivatives, methyl 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxybenzoate (1), 1-(1-methylethyl)-4-methyl-3-cyclohexenyl 3,5-bis(3-methyl-2-butenyl)-4-hydroxybenzoate (2), 1-(1-methylethyl)-4-methyl-3-cyclohexenyl 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoate (3), methyl 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoate (4), and 4-hydroxy-3-(3-methyl-2-butenyl)-5-(3-methyl-2-butenyl)-benzoic acid (5) were isolated from the dried leaves of Piper aduncum L. (Piperaceae). Together with the new metabolites, four known prenylated benzoic acid derivatives, 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoic acid (6), 4-hydroxy-3,5-bis(3-methyl-2-butenyl)-benzoic acid (nervogenic acid, 7), methyl 4-hydroxy-3,5-bis(3-methyl-2-butenyl)-benzoate (8), and methyl 4-hydroxy-3-(3-methyl-2-butenyl)-benzoate (9) as well as, dillapiol (10), myristicin, and the three sesquiterpenes humulene, caryophyllene epoxide, and humulene epoxide were isolated. Compounds 7, 8, and 9 are reported as natural products for the first time. The structures of the isolates were elucidated by spectroscopic methods, mainly 1D-and 2D-NMR spectroscopy. Isolates 4-7, 9, and 10 were molluscicidal while 2, 5-7, and 9 displayed significant antibacterial activities.

A new HPLC-method for separation and quantitative determination of ginsenosides in Panax ginseng, Panax quinquefolium and in pharmaceutical drug preparations is elaborated. A reversedphase-system with pBondapak C18 column (3.9 mm I. D . x 30 cm) using acetonitrile-water (30:70) 2 ml/min and acetonitrile-water (18:82) 4 ml/min is suitable for the base-line separation of Rb,, Rbz, Rc, Rd, Rf, R k , respectively Re, Rg, in 30 minutes. The ginsenosides are directly detected at 203 nm (without derivatization) with the LC-55 or LC-75 spectrophotometer (Perkin-Elmer) at 100 % transmission. Detection limit is 300 ng at a signal-to-noise ratio of 10:l.The calibration curve of each ginsenoside has a correlation coefficient very near to 1. Relative standard deviation for quantitative determinations depends upon the amount of ginsenosides and is approximately I % for ginsenoside contents of 1 %. This method is adaptable for routine analysis in quality control laboratories.

A new method for separation and quantitative determination of ginsenosides Rg,, Rf, Rg, and Re in Panax ginseng, .Panax quinquefoliurn and in pharmaceutical drug preparations with HPLC was elaborated. A pPorasil column using n-heptane-n-butanol-acetonitril-water (1000:446:132:36) as mobile phase was employed. The ginsenosides were separated in 40 min.

A new method for separation and quantitative determination of arbutin, methylarbutin, hydroquinone and hy-droquinonem~nometh~lether in Arctostaphylos alpina, Arctostaphylos Uva-r~rsi, Bergenia crassifolia, Calluna vulgaris, and Vaccinium Vitis-idaea with HPLC was elaborated. A reversed-phase system with a p-Bondapak Cia column using methanol-Teil einer Dissertation: F. SOLDATI, ETH Zurich, in Bearbeitung.