Lipophilic extractive metabolites from needles and defoliated twigs of Pinus armandii and P. kwangtungensis were studied by GC/MS. Needles of P. armandii contained predominantly 15-O-functionalized labdane type acids (anticopalic acid), fatty acids, nonacosan-10-ol, sterols, nonacosan-10-ol and sterol saponifiable esters, and acylglycerols, while P. kwangtungensis needles contained no anticopalic acid, but more trinorlabdane (14,15,16-trinor-8(17)-labdene-13,19-dioic acid) and other labdane type acids, nonacosan-10-ol and its saponifiable esters. The major compounds in the P. armandii defoliated twig extract were abietane and isopimarane type acids, fatty acids, sterols, labdanoids (cis-abienol), cembranoids (isocembrol and 4-epi-isocembrol), saponifiable sterol esters, and acylglycerols. The same extract of P. kwangtungensis contained larger quantities of fatty acids, caryophyllene oxide, serratanoids, sterols, saponifiable sterol esters, and acylglycerols, but lesser amounts of abietane and isopimarane type acids, cis-abienol, and lacked cembranoids. Both twig and needle extracts of P. armandii and P. kwangtungensis, as well as the extracts' fractions, significantly inhibited the growth of Gram-negative bacteria Serratia marcescens with MIC of 0.1 mg ml-1 , while in most cases they slightly stimulated the growth of Gram-positive bacteria Bacillus subtilis at the same concentrations. Thus, lipophilic extractive compounds from the needles and defoliated twigs of both pines are prospective for the development of antiseptics against Gram-negative bacteria.
Keywords: Bacillus subtilis; GC/MS; Pinus armandii; Pinus kwangtungensis; Serratia marcescens; antibacterial activity.
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