A new acyclic diterpene acid and bioactive compounds from Knema glauca

Abstract

Investigation of the chemical constituents of the fruits of Knema glauca (Myristicaceae) yielded a new acyclic diterpene acid, named glaucaic acid 4, together with four acylphenols, including 1-(2,6-dihydroxyphenyl) tetradecan-1-one 1, malabaricone A 6, dodecanoylphloroglucinol 7 and 1-(2,4,6-trihydroxyphenyl)-9-phenylnonan-1-one 8, two lignans sesamin 2 and asarinin 3, and a flavan, myristinin D 5. In addition, myristinin A 9 and (+/-)-7,4'-dihydroxy-3'-methoxyflavan 10 were isolated from its leaves and stems, respectively. When tested against small-cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, compounds 1, 6-8 and 10 displayed weak to moderate cytotoxicity. The acylphenols 6-8 displayed antituberculosis activity against the microbe Mycobacterium tuberculosis with MIC values of 25, 50 and 100 microg/mL, respectively, and antiviral activity against herpes simplex virus type 1, with 7 as the most active compound (IC(50) = 3.05 microg/mL). Malabaricone A 6 was also active against the malarial parasite Plasmodium falciparum with an IC(50) value of 2.78 microg/mL.