5 NEW PRENYLATED P-HYDROXYBENZOIC ACID-DERIVATIVES WITH ANTIMICROBIALAND MOLLUSCICIDAL ACTIVITY FROM PIPER-ADUNCUM LEAVES

Five new prenylated benzoic acid derivatives, methyl 3-(3,7-dimethyl-2 ,6-octadienyl)-4-methoxybenzoate (1), 1-(1-methylethyl)-4-methyl-3-cyc lohexenyl 3,5-bis(3-methyl-2-butenyl)-4-hydroxybenzoate (2), 1-(1-meth ylethyl)-4-methyl-3-cyclohexenyl 3,5-bis(3-methyl-2-butenyl)-4-methoxy benzoate (3), methyl 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoate (4) , and -methyl-2-butenoyl)-5-(3-methyl-2-butenyl)-benzoic acid (5) were isolated from the dried leaves of Piper aduncum L. (Piperaceae). Toge ther with the new metabolites, four known prenylated benzoic acid deri vatives, 3,5-bis(3-methyl-2-butenyl)-4-methoxybenzoic acid (6), 4-hydr oxy-3,5-bis(3-methyl-2-butenyl)-benzoic acid (nervogenic acid, 7), met hyl 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 (1 0), myristicin, and the three sesquiterpenes humulene, caryophyllene e poxide, 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 ID-and 2D-N MR spectroscopy. Isolates 4- 7, 9, and 10 were molluscicidal while 2, 5-7, and 9 displayed significant antibacterial activities.