Diesel Trees - Bioenergy Crop Plants - page 620

3 years in Amazônia (Alencar 1982; Pedroni et al. 2002). Furthermore, most up-to-date references
on Copaifera taxonomy are in Portuguese, which hampers the interchange of information among
the mainstream of scientists.
Copaifera species found in Africa are biochemically distinct from those discussed above because
they produce resins that harden into a solid copal, which fossilizes into amber, whereas New
World species produce a liquid oleoresin because of the higher concentrations of sesquiterpenes
(Langenheim 1973). Oleoresin, which results from tapping Copaifera trees, was listed as a drug
in the London Pharmacopoeia in 1677 and to the United States Pharmacopoeia in 1820. In Brazil,
the oleoresin produced by Copaifera trees has been used by native people as a local medicine
for healing wounds; an antiseptic; to relieve pain; and for a host of skin, respiratory, and urinary
ailments (Plowden 2004). They have also been used for more esoteric purposes such as a snake bite
remedy, aphrodisiac, removal of intestinal parasites, and as a contraceptive.
More recently, several scientific studies have verified the medicinal properties of various
Copaifera oleoresin fractions for anti-inflammatory activity (Veiga Junior et al. 2007), stomach
ulcers and intestinal damage mitigation (Paiva et al. 1998, 2004), anticancer activity (Ohsaki
et al. 1994; Lima et al. 2003; Gomes et al. 2008), reduced pain sensitivity (Gomes et al. 2007), and
increased rate of wound healing (Paiva et al. 2002). The oleoresin and oils of Copaifera species
have also been used in varnishes and lacquers, as lumber, cosmetic products, and tracing paper
(Plowden 2004; Lima and Pio 2007).
Additionally, in 1980 the Nobel Prize-winning chemist Melvin Calvin noted that the oleoresin
from Copaifera trees was being used as diesel fuel directly from the tree with no-to-minimal
processing (Calvin 1980). Calvin began his search for plants that could produce liquid fuels to be
used directly in engines after the 1973 oil embargo. He later wrote two more papers in 1983 and
1986 on the potential for production of hydrocarbon fuels from living plants, the issue of global
warming, and the pressing need to address U.S. foreign oil dependency which now, some 20 years
later, seems almost prophetic. Plantations of Copaifera trees were established in Manaus, Brazil to
test the viability of biofuel production in the 1980s, but they were later shifted to focus on production
of timber and the oleoresin for pharmaceutical and industrial purposes (Plowden 2004). The direct
reasons for this shift were undoubtedly economic when diesel fuel returned to being relatively
cheap.
24.2 chemIcals Present In copAiferA oleoresIns
Copaifera oleoresins, in general, are unique because they contain a greater fraction of sesquiterpenes
compared with mono- and diterpenes. In Copaifera multijuga , approximately 80% of the oleoresin
is composed of sesquiterpenes, whereas in Copaifera guianensis only approximately 44% of the
oleoresin was composed of sesquiterpenes (Cascon and Gilbert 2000). These authors also noted that
the majority ratio of diterpene acids and sesquiterpenes oscillated back and forth throughout the
growing season in Copaifera duckei .
A wealth of original articles and review papers has focused on describing terpene biosynthesis. As
such, only a brief description of the major terpene constituent characteristics and their biosynthesis
in relation to conifer and Copaifera structures will be attempted here.
In short, isoprene units, the building blocks of terpenoids, are derived from either the mevalonic
acid (MVA) pathway present in the cytosol of cells, or the 2-C-methylerythritol-4-phosphate (MEP)
pathway, also known as the nonmevalonate pathway, which occurs in plastids (Lichtenthaler 1999).
Condensation of isopentenyl diphosphate and its isomer dimethylallyl diphosphate, the products
of the MVA and MEP pathways, leads to the formation of geranyl pyrophosphate (GPP), farensyl
pyrophosphate (FPP), or geranyl geranyl pyrophosphate (GGPP) which are the common precursors
for mono-, sesqui-, and diterpenes, respectively. These three intermediates are catalyzed to form
mono-, di-, and sesquiterpenes by the action of terpene synthases (TPSs). Individual TPSs can
generate either one product or multiple products that, in turn, can be linear or cyclic. Mono- and