CHAPTER ONE
INTRODUCTION
Castor oil plant (Ricinus communis L.) is a non food, drought resistant, energy plant gaining
attention for producing biofuel as biodiesel in developing countries (Kamrun, 2013). As an oil
bearing biomass feedstock, it can ensure an alternative source of energy and reduce the over
dependency on fossil fuel (Kamrun, 2013). Ethiopia is considered to be the most probable site of
origin of castor oil plant because of the presence of high diversity (Anjani, 2012). However,
according to Sujatha et al. (2008) the plant originated from Abyssinia. It is distributed throughout
the tropics and the subtropics, and is well adapted to the temperate region (Sujatha et al., 2008).
Oil extracted from castor seeds is of economic importance especially in the chemical industries
(Abayeh et al., 1998). The economic importance of this plant has made it necessary that the plant
be properly investigated to develop the most reliable method of propagation. Conventional method
of cultivation using the seed is limited by problems of seed viability. Propagation through tissue
culture techniques employing embryo is necessary to eliminate the limitations of seed
germination.
1.1 Economic importance
Ogiri is a food condiment obtained by traditional fermentation of castor seeds in the eastern part of
Nigeria. This food condiment provides dietary fiber, energy, mineral and vitamins (Kolapo et al.,
2007). At present, the potentials of castor oil have not been fully explored in Nigeria (Oluwole et
al., 2012).
2
Castor seed is an important source of vegetable and medicinal oil and has numerous benefits to
humanity. The oil from castor seeds has many industrial applications. Dehydrated oil from castor
seeds is used in the paint and varnish industry. The oil is also used in the manufacture of a wide
range of sophisticated products like nylon fibers, jet engine lubricants, hydraulic fluids, plastics,
artificial leather, and fiber optics (Ogunniyi, 2006).
The seeds contain 40 to 60% oil that is rich in triglycerides mainly ricinolein, a toxic alkaloid
ricinine and very toxic albumen called ricin (Zohary, 1987). Oil from castor seed is prescribed for
infestation of intestinal worms. In vitro antiviral activity and hypoglycemic activity were also
reported from leaf extracts (Khafagi, 2007).
Oil from castor seeds also has great promise in the field of biodiesel production as it is
inexpensive and environment friendly (Ogunniyi, 2006). Consequently, there has been a steady
increase in the demand of castor oil and its products in the world market due to their renewable
nature, biodegradability and eco-friendliness (Ogunniyi, 2006).
Many phytochemicals found in the plant tissue and seeds of castor have potential medicinal uses
(Morris, 2004). Castor oil has been used as purgative since ancient times and it is still considered
to be a safe and effective laxative (Kalaiselvi et al., 2003). The ricin A-chain has also been linked
to antibodies able to target cancer cells while not harming normal cells (Olsnes and Pihl, 1981;
Lam et al., 2004). These immunotoxins have been reported to have many potential uses in modern
medicine (Scadden et al., 1998; Longo et al., 2000; Sandler et al., 2006). Experimental medicines
containing castor oil were also shown to be effective treatments of evaporative dry eye (Khanal et
al., 2007).
Historically, castor plant has been used as an ornamental plant (Coopman et al., 2009; Krenzelok,
2009). This species may also provide an option for phytoremediation of soils contaminated with
heavy metals since castor plant is tolerant to several heavy metals and a non food plant. Castor
plant is a hyperaccumulator of Lead (Pb) (Romeiro et al., 2006; Liu et al., 2008), an effective
accumulator of Nickel (Ni) (Sherene, 2009), and moderately tolerant to Cadmium (Niu et al.,
2007; Shi and Cai, 2009). Castor plants also grow well in a soil with high content of Zinc (Shi and
Cai, 2010).
1.2 Problem statement
During the past decades, worldwide petroleum consumption has permanently increased due to the
growth of human population and industrialization which has caused depleting fossil fuel reserves
(Bankovic-ilic et al., 2012). On the other hand, combustion of fossil fuel contributes to emission
of green house gases which lead to atmospheric pollution and global warming
INTRODUCTION
Castor oil plant (Ricinus communis L.) is a non food, drought resistant, energy plant gaining
attention for producing biofuel as biodiesel in developing countries (Kamrun, 2013). As an oil
bearing biomass feedstock, it can ensure an alternative source of energy and reduce the over
dependency on fossil fuel (Kamrun, 2013). Ethiopia is considered to be the most probable site of
origin of castor oil plant because of the presence of high diversity (Anjani, 2012). However,
according to Sujatha et al. (2008) the plant originated from Abyssinia. It is distributed throughout
the tropics and the subtropics, and is well adapted to the temperate region (Sujatha et al., 2008).
Oil extracted from castor seeds is of economic importance especially in the chemical industries
(Abayeh et al., 1998). The economic importance of this plant has made it necessary that the plant
be properly investigated to develop the most reliable method of propagation. Conventional method
of cultivation using the seed is limited by problems of seed viability. Propagation through tissue
culture techniques employing embryo is necessary to eliminate the limitations of seed
germination.
1.1 Economic importance
Ogiri is a food condiment obtained by traditional fermentation of castor seeds in the eastern part of
Nigeria. This food condiment provides dietary fiber, energy, mineral and vitamins (Kolapo et al.,
2007). At present, the potentials of castor oil have not been fully explored in Nigeria (Oluwole et
al., 2012).
2
Castor seed is an important source of vegetable and medicinal oil and has numerous benefits to
humanity. The oil from castor seeds has many industrial applications. Dehydrated oil from castor
seeds is used in the paint and varnish industry. The oil is also used in the manufacture of a wide
range of sophisticated products like nylon fibers, jet engine lubricants, hydraulic fluids, plastics,
artificial leather, and fiber optics (Ogunniyi, 2006).
The seeds contain 40 to 60% oil that is rich in triglycerides mainly ricinolein, a toxic alkaloid
ricinine and very toxic albumen called ricin (Zohary, 1987). Oil from castor seed is prescribed for
infestation of intestinal worms. In vitro antiviral activity and hypoglycemic activity were also
reported from leaf extracts (Khafagi, 2007).
Oil from castor seeds also has great promise in the field of biodiesel production as it is
inexpensive and environment friendly (Ogunniyi, 2006). Consequently, there has been a steady
increase in the demand of castor oil and its products in the world market due to their renewable
nature, biodegradability and eco-friendliness (Ogunniyi, 2006).
Many phytochemicals found in the plant tissue and seeds of castor have potential medicinal uses
(Morris, 2004). Castor oil has been used as purgative since ancient times and it is still considered
to be a safe and effective laxative (Kalaiselvi et al., 2003). The ricin A-chain has also been linked
to antibodies able to target cancer cells while not harming normal cells (Olsnes and Pihl, 1981;
Lam et al., 2004). These immunotoxins have been reported to have many potential uses in modern
medicine (Scadden et al., 1998; Longo et al., 2000; Sandler et al., 2006). Experimental medicines
containing castor oil were also shown to be effective treatments of evaporative dry eye (Khanal et
al., 2007).
Historically, castor plant has been used as an ornamental plant (Coopman et al., 2009; Krenzelok,
2009). This species may also provide an option for phytoremediation of soils contaminated with
heavy metals since castor plant is tolerant to several heavy metals and a non food plant. Castor
plant is a hyperaccumulator of Lead (Pb) (Romeiro et al., 2006; Liu et al., 2008), an effective
accumulator of Nickel (Ni) (Sherene, 2009), and moderately tolerant to Cadmium (Niu et al.,
2007; Shi and Cai, 2009). Castor plants also grow well in a soil with high content of Zinc (Shi and
Cai, 2010).
1.2 Problem statement
During the past decades, worldwide petroleum consumption has permanently increased due to the
growth of human population and industrialization which has caused depleting fossil fuel reserves
(Bankovic-ilic et al., 2012). On the other hand, combustion of fossil fuel contributes to emission
of green house gases which lead to atmospheric pollution and global warming
