Moringa oleifera is widely cultivated species of the genus Moringa, the only genus in the
Moringaceae. This plant is rich in unique compounds such as glucosinolates and isothiocyanates. Natural products such as 4-(4'-O-acetyl--L-rhamnopyranosyloxy)benzyl isothiocyanate, 4-(-L-rhamnopyranosyloxy)benzyl isothiocyanate, niazimicin, benzyl isothiocyanate (1) pterygospermin (2), and 4-(-L-rhamnopyranosyloxy)benzyl glucosinolate isolated from Moringa species have been reported to have hypotensive and anticancer activity. Phytochemicals such as the carotenoids (-carotene or pro-vitamin A have also been isolated [17, 18]. The structure of two of these compounds are shown in Figure 1.
Figure 1. Benzyl isothiocyanate (1) and Pterygospermin (2) from Moringa oleifera.
The leaves are the most nutritious and contain significant amount of vitamin B6, vitamin
C, provitamin A, -carotene, magnesium and protein. Calcium in Moringa oleifera leaves are usually complexed as crystals of calcium oxalate.
Moringa oleifera provides a rich and rare combination of zeatin, quercetin, kaempferom
and many other phytochemicals such as hexadecanoic acid, ethyl palmitate, palmitic acid, ethyl ester, 2,6-Dimethyl-1, 7-octadiene-3-ol, 4-Hexadecen-6-yne, 2-hexanone, and 3- cyclohexyliden-4-ethyl - E2- Dodecenylacetate [17]. It is very important for its medicinal value. Various parts of the plant such as the leaves, roots, seed, bark, fruit, flowers and immature pods act as cardiac and circulatory stimulants, possess antitumour, antipyretic, antiepileptic, antinflammatory, antiulcer [17-18]
Moringa oleifera preparations have been used for its antitrypanosomal, hypotensive,
antispasmodic, antiulcer, anti-inflammatory, hypocholesterolemic, and hypoglycemic activities, as well as having considerable efficacy in water purification by flocculation, sedimentation, antibiosis and even reduction of Schistosome cercariae titer [19].
A new biflavonol glycoside, Solanoflavone was isolated from aerial part of Solanum
melongena. The chemical structure was elucidated as isorhamnetin-3-O-beta-D-
glucopyranoside-(4'->O->4''')-galangin-3''-O-beta-D-glucopyranoside on the basis of physicochemical and spectroscopic techniques, including 2D NMR spectral techniques [20].
O N N O S S O O N C S (2) (1) O N N O S S O O N C S (2) (1)
Flavanoids, isolated from Solanum melongena have been shown to possess potent antioxidant activity. Concentrations of malondialdehyde, hydroperoxides and conjugated dienes were lowered significantly [21].
Phenylethyl cinnamides, potential alpha-glucosidase inhibitors were isolated from the roots of Solanum melongena (Solanaceae). Bioassay-guided fractionation against alpha- glucosidase resulted in isolation and identification of six phenolic compounds from the 70% EtOH extract of the roots. Three of the phenylethyl cinnamides, N-trans-feruloyl tyramine, N-trans-p-coumaroyl tyramine and N-cis-p-coumaroyl tyramine possessed inhibitory activity against alpha-glucosidase with IC50 values of 500.6, 5.3 and 46.3 microM, respectively. Mechanisistic studies revealed these phenylethyl cinnamides as non-competitive inhibitors. The above is the first study of the alpha-glucosidase inhibitory activities of the roots of
Solanum. melongena, suggesting potential medicinal use of this herb [22]
Phytochemical screening of the methanolic and aqueous extracts of the fruit and crown of
Solanum Melongena revealed the presence of alkaloids, saponins, steroids, tannins/ phenolics,
flavonoids, proteins and carbohydrates. Ascorbic acid and phenolics both which are powerful antioxidants were also present in fruit. The presence of saponins and glycoalkaloids protect the plant from microbial pathogens [23].
Various parts of Solanum melongena (Solanaceae) are useful in the treatment of inflammatory conditions, cardiac debility, neuralgia, ulcers of nose, cholera, bronchitis and asthma. Roots are used as antiasthmatic and general stimulant, juice is employed for otitis, applied to ulcers of the nose. Leaves are used in the treatment of bronchitis, asthma and dysuria, also given in liver complaints and they stimulate the inter hepatic metabolism of cholesterol. The fruit of Solanum melongena has a high percentage of Vitamin B2. The fruit is
also used in the treatment of diabetes [23].
Brassica rapa chinensis, Artocarpus altilis and their related species have medicinal uses
and Natural Products/Phytochemicals with medicinal properties have been isolated from both plants or related species. Brassica rapa chinensis and related species have antirheumatic, antiarthritic, antiscorbutic and resolvent properties [25].
Brassica rapa vegetables have been shown to possess glucosinolates with antioxidant
properties [26]. The juice from the leaves of Brassica rapa species such as Turnip (Brassica
rapa L.) have been shown to have hepatoprotective action through its antioxidative potentials
[26-27].
Compounds isolated from related species of turnip (Brassica rapa ssp. campestris (Brassicaceae) have been shown to exhibit high inhibitory activity against the growth of human cancer lines, HCT-116, MCF-7, and HeLa, with IC50 values ranging from 15.0 to 35.0 μM and against LDL-oxidation with IC50 values ranging from 2.9 to 7.1 μM [28]
Phenolic natural products were isolated from Pak choi (Brassica rapa chinensis) and seven other vegetables. These compounds were found to be hydroxybenzoic acids, hydroxycinnamic acids and flavonoids. Salicylic acid was found to be the most common hydroxybenzoic acid, ranging from 4.40 to 117.36 μg/g fresh frozen weight (ffw). Vanilic, gallic, caffeic, chlorogenic, p-coumaric, ferulic and m-coumaric acids were also found in all of these vegetables. Isoquercetin and Rutin, the most common flavonoids, ranged from 3.70 to 19.26 and 1.60 to 7.89 μg/g ffw, respectively [28].
Phytochemical, and spectroscopic investigations of related species of turnip (Brassica
rapa ssp. campestris (Brassicaceae) revealed the presence of a novel phenanthrene
dione, brassicaphenanthrene, along with two known diarylheptanoid compounds, 6-paradol and trans-6-shogaol. These compounds have been reported to have anticancer activity [28].
The breadfruit (Artocarpus altilis) is edible. The leaves and the sap have been used for various medicinal purposes. The tea of breadfruit leaves are used to lower blood pressure and treat diabetes. The sap is applied to contagious skin ailments to prevent their spreading and promote healing [29].
Artocarpus altilis leaf extracts have been shown to have cytoprotective, anti-
inflammatory, cytotoxic, negative inotropic effect, anti-cancer, antitubercular and antiplasmodial activities. An ethanol extract of the leaves showed potent ACE (Angiotensin- converting enzyme) inhibitory activity, supporting its use in folk medicine for the treatment of hypertension. The isolated compounds exhibited antitubercular and antiplasmodial activities [30].
Artocarpus altilis leaf extracts were investigated against angiotensin-converting enzyme
(ACE) activity. Amongst the extracts tested, hot ethanol extract exhibited a potent ACE- inhibitory activity with an IC₅₀ value of 54.080.29µgmL⁻¹, followed by cold EtOAc extract (IC₅₀ of 85.44±0.85µgmL⁻¹). In contrast, the hot aqueous extracts showed minimum inhibition with the IC₅₀ value of 765.5211.97µgmL⁻¹ at the maximum concentration tested. The high content of glycosidic and phenolic compounds could be involved in exerting ACE- inhibitory activity, supporting the utilisation of A. altilis leaf in the folk medicine for the better treatment of hypertension [30-31].
Phytochemical and spectroscopic studies of the methanol extract of Artocarpus altilis resulted in the isolation and spectroscopic characterisation of a new prenylated aurone, artocarpaurone, together with eight known compounds, including two prenylated chalcones, three prenylated flavanones, and three triterpenes. The structure of the new compound was elucidated as 6-hydroxy-2-[8-hydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran- 5-ylmethylene)-3(2H)-benzofuranone. It showed moderate nitric oxide radical scavenging activity, whereas two compounds had moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging effect, compared with the positive control (+)-catechin [32].
Antitubercular and antimalarial activity-guided study of the roots of Artocarpus altilis led to the isolation of nine prenylated flavones. Cycloartocarpin (1), Artocarpin (2), and Chaplashin (3) were isolated from the CH2Cl2 extract of the root stems, whereas Morusin (4),
Cudraflavone (5), Cycloartobiloxanthone (6), Artonin (7), Cudraflavone (8) and Artobiloxanthone (9) were found in the root barks. The isolated compounds exhibited antitubercular and antiplasmodial activities, and also showed moderate cytotoxicity against KB (human oral epidermoid carcinoma) and BC (human breast cancer) cell lines [33-34].
The cytoprotective effects of various solvent extracts of Artocarpus altilis (Parkinson) Fosberg were evaluated. These effects were determined in human U937 cells incubated with oxidized LDL (OxLDL) using the 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate (WST-1) assay. Results demonstrated that the EtOAc extract showed cytoprotective activities. To identify the main cytoprotective components, a bioassay guided isolation of the ethyl acetate extract afforded -sitosterol and six flavonoids. Their chemical structures were established on the basis of spectroscopic evidence and comparison with literature data. One of these compounds was obtained from A. altilis for the first time. The cytoprotective effect offers good prospects for the medicinal applications of A. Altilis [34].
Figure 2. Isolates from Artocarpus altilis.
Flavonoids, 10-oxoartogomezianone, 8-geranyl-3-(hydroxyprenyl)isoetin, hydroxylarto- flavone, isocycloartobiloxanthone, and furanocyclocommunin, together with 12 known compounds, were isolated from heartwood and cortex of Artocarpus altilis, and were
OH H3CO O O O OH H3CO O O OH OH (1) (2) OH H3CO O O OH (3) O OH OH Cycloartocarpin Artocarpin Chaplashin OH O O OH O Morusin (4) OH O O OH (5) HO O Cudraflavone O O O OH OH O O HO Cycloartobiloxanthone (6) O O O OH OH O O HO (7) Artonin
spectroscopically characterised. The flavonoids isolated from A. altilis may be suspected candidate antioxidants and/or skin-whitening agents [35].
M
ATERIALS ANDM
ETHODSReagents and materials: Antibiotics, Ampicillin, Mueller Hinton Agar, agar plates were
purchased from Meditron Scientific Limited. Bacterial and fungal cultures were obtained from the Georgetown Public hospital, GPHC.