Cytotoxicity and effect of extraction methods on the chemical composition of essential oils of Moringa oleifera seeds
J Zhejiang Univ-Sci B (Biomed & Biotechnol)
1673-1581
Cytotoxicity and effect of extraction methods on the chemical composition of essential oils of Moringa oleifera seeds
Rowland Monday Ojo KAYODE 0
Anthony Jide AFOLAYAN 0
0 (Medicinal Plant and Economic Development Research Centre, Department of Botany, University of Fort Hare , Private Bag X1314, Alice 5700 , South Africa)
Renewed interest in natural materials as food flavors and preservatives has led to the search for suitable essential oils. Moringa oleifera seed essential oil was extracted by solvent-free microwave and hydrodistillation. This study assessed its chemical constituents. Cytotoxicity of the oils was investigated using hatchability and lethality tests on brine shrimps. A total of 16 and 26 compounds were isolated from the hydrodistillation extraction (HDE) and solvent-free microwave extraction (SME) oils, respectively, which accounted for 97.515% and 97.816% of total identifiable constituents, respectively. At 24 h when the most eggs had hatched, values of the SME (56.7%) and HDE (60.0%) oils were significantly different (P<0.05) from those of sea water (63.3%) and chloramphenicol (15.0%). Larva lethality was different significantly (P<0.05) between HDE and SME oils at different concentrations and incubation periods. The median lethal concentration (LC50) of the oils was >1000 mg/ml recommended as an index for non-toxicity, which gives the oil advantage over some antioxidant, antimicrobial, therapeutic, and preservative chemicals.
Moringa oleifera seed; Extraction methods; Essential oil; Cytotoxicity doi; 10; 1631/jzus; B1400303 Document code; A CLC number; Q946
1 Introduction
Moringa oleifera Lamarch is one of the most
widely distributed and naturalized species of the
monogeneric family Moringaceae
(Ramachandran
et al., 1980)
. The plant is known for its nutritional and
medicinal value. It contains some phytochemicals,
which make it a good source of antioxidant and
antimicrobial substances. The leaves, pod, and seed are
now being used as a food commodity in some tropical
countries where protein malnutrition exists. Moringa
leaves are reported to be a rich source of β-carotene,
protein, vitamin C, calcium, and potassium, which
makes it a good source of natural antioxidants and
thus may enhance the shelf-life of fat-containing
foods due to the presence of various types of
antioxidant compounds such as ascorbic acids, flavonoids,
phenolics, and carotenoids
(Dillard and German, 2000;
Siddhuraju and Becker, 2003)
. The ethanolic extract
of the seed has shown the presence of some bioactive
compounds such as benzyl carbamate, benzyl
isothiocyanate, niazimicin, sitosterol, and niazirin (Guevara
et al., 1999). In recent times, there has been growing
interest in Moringa plant propagation for industrial
application in developing countries like Nigeria.
Essential oils are aromatic and volatile
compounds found in most parts of plant materials such as
the leaves, seed, flower, bark, fruit, and peel
(Sánchez
et al., 2010)
. The chemical compositions of essential
oils are secondary metabolites, which play important
roles in a plant’s defense against microbial attacks
and have been added to foods as spices for decades
(Hyldgaard et al., 2012)
. The active compounds in
essential oils have been broadly divided into four
groups according to their chemical structures. The first
group is terpenes such as limonene, p-cymene,
sabinene, terpinene, and pinene. Terpenes are
hydrocarbons produced from a combination of several
isoprene units (C5H8), and are synthesized in the
cytoplasm of plant cells; they have a hydrocarbon
backbone, which can be rearranged into cyclic structures
by cyclases, thus forming monocyclic or bicyclic
structures
(Caballero et al., 2003)
. The main terpenes
are monoterpenes (C10H16) and sesquiterpenes (C15H24),
although other chains such as diterpenes (C20H32),
triterpenes (C30H40), and even longer chains exist
(Hyldgaard et al., 2012)
. The second group is
terpenoids such as thymol, citronellal, piperitone,
carvacrol, linalyl acetate, and menthol. Terpenoids are
terpenes that undergo biochemical modification via
enzymes that incorporate oxygen molecules and shift
or remove methyl groups
(Caballero et al., 2003)
.
According to
Caballero et al. (2003)
and
Hyldgaard
et al. (2012)
, terpenoids are subdivided into alcohols,
aldehydes, ketones, esters, ethers, epoxides, and
phenols. The third group is phenylpropenes, which
constitute a subfamily among the various groups of
organic compounds called phenylpropanoids that are
synthesized from the amino acid precursor
phenylalanines in plants. Phenylpropanoids have their names
from the six-carbon aromatic phenol group and the
three-carbon propene tail of cinnamic acid, produced
in the first step of phenylpropanoid biosynthesis
(Hyldgaard et al., 2012)
. In addition, there are
essential oils, which contain a number of different
degradation products originating from unsatur (...truncated)