metabolic studies involving the incorporation of [1-13c]-d-glucose into intact leaves of piper aduncum (piperaceae) have indicated that both the mevalonate (mva) and the pyruvate-triose (mep) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2h-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8-(3'-methyl-2'-butenyl)-2h-1-chromene-6-carboxylate (2). the pattern of incorporation of label from [1-13c]-d-glucose into these chromenes was determined by quantitative 13c nmr spectroscopy. the results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space.
