V. amygdalina (Del. composite of the familythe plant is used for treatment of various ailments inAstaraceae) commonly called bitter leaf and/or alsohuman as well as animal health in different parts of thereferred to as iron weed is the most widely cultivatedcountry.
Species of the genus Vernoniawhich has about 1,000The objective of this paper is to review the medicinalspecies of shrubs.
It was named after an English values of V. amygdalina in human and veterinary botanist William Vernon.V. amygdalina is frequentlymedicines.foundin gardens, adapt to a variety of climates unlikeother plants that are native to certain areas and Compound Isolated from V. amygdalina: Several grown in many countries, in savannah zones and cultivated fields.
Although most popularly used for food, it has also, been traditionally used for its medicinal properties.
Medicinal Values of V. amygdalina
Anti-Bacterial Activity: The antimicrobial activity of hot and cold ethanolic extract of V. amygdalina showed that the extracts possess antibacterial activity against S. aureus, P. aeruginosa and E. coli.
P. aeruginosa found the most sensitive organisms to the hot ethanolic extract of V. amygdalina with the zone of inhibition of 13.00 mm and S. aureus show zone of inhibition of 6.00 mm at the same concentration (200 mg/ml) [41-43].
A similar plant species, V. tenoreana, contains saponins, flavonoids, tannins and anthraquinones was found to have very potent antibacterial as well as antifungal activities .
These phytochemical constituents are responsible for many antimicrobial activities of different plant species in human and animal health [45-46].
Aqueous extracts of V. amygdalina leaves was evaluated in-vitro for anti-microbial activity against S. aureus and E. coli .
The minimal inhibitory concentration of the aqueous extract was found to be 62.50 mg/ml, while the minimal bactericidal concentration of the aqueous extract was 250mg/ml.
Anti-Inflammatory and Anti-pyretic Activity: Inflammation is a common tissue phenomenon when tissue exposed to trauma or injury [48-50].
The preliminary phytochemical test on the leaves of V. amygdalina showed the presence of saponins, alkaloids, flavonoids, tannins, glycosides, carbohydrate and reducing sugar.
Many plants containing alkaloids and flavonoids have been shown to have diuretic, antispasmodic, antiinflammatory and analgesic action .
The anti-inflammatory activity of the extract of V. amygdalina which was comparable in magnitude to the activity of dexamethasone may be explained in part, to be a consequence of the presence of flavonoids, tannins, glycosides and trace elements such as zinc, copper and manganese .
The leaf and root extract of V. amygdalina possess antipyretic property. The antipyretic activity is strongly noticed with the leaf extract as compared to the root.
Brewer’s yeast has been shown to induce pyrexia in laboratory animals, in similar manner to lipopolysaccharides.
Such induction activates the arachidonic acid pathway and has been associated with elevated prostaglandin E2 (PGE2) level in the hypothalamus.
Antipyretic agents in the plant have been shown to antagonize the PGE2 elevation by inhibiting the activity of cyclo-oxygenase there by suppressing pyrexi.
Anti-Malarial Activity: Malaria is one of the most important tropical diseases and the greatest cause of hospitalization and death among children age 6 months to 5 years .
The alarming rate at which plasmodium falciparum has developed resistance to chloroquine and other synthetic anti-malarial drugs makes it necessary to search for the more effective anti malarial compounds.
Traditional medicinal plants are frequently used to treat or cure malaria.
Both aqueous and ethanolic extracts of the stem bark and leaves of V. amygdellinaare reported to have been used as purgative, antimalarial and in the treatment of eczema.
The leaves, root and twig of the plant are used for treating malaria infection.
The presence of some bitter sesquiterpenes lactones compounds such as, vernolide, vernodalin, hydroxy vernolides and the steroid related constituents, vernoniosid B and vernonoid B in the bitter leaf are 11 responsible for anti-plasmodia activity especially P. falciparum.
These compounds found to be present in the leaves and the pith of young shoots of the plants which may be responsible for its bitter taste and significant bioactivity.
Anti-Cancer Activity: There has been growing interest in combination therapy for cancer as it induces a greater effect in the improvement of patients’ survival.
Since cancer is the result of the accumulation of numerous mutations, it is rational to combine two or more drug with different mechanisms of action to increase cell killing.
V. amygdalina Del (Composite) is an African medicinal plant well known for providing the anticancer agents like vernodaline and vernolide.
Vernodaline and vernolide elicited anti tumor activities in leukemia cell.
Recentlyreported that some peptide (Edotides) from the aqueous extract of V. amygdalina showed cell growth inhibitory effects in prostate cancer cell line (PC-3).
V. amygdalina combines with a current chemotherapeutic alkylating agent, doxorubicin, to determine their synergistic effect in human breast cancer cells.
Doxorubicin exerts its effects by intercalating base pairs between DNA, there by inhibiting both DNA and RNA synthesis.
In addition, it mediates its main cytotoxic action through inhibiting the activity of topoisomerase II, which is an enzyme responsible for the uncoiling of DNA.
The anti-cancer effect of V. amygdalina was first show in human carcinoma of nasopharynx and later in leukemia cell p-388 and L-1210 using the chloroform extract of V. amygdalina and similar effects were also reported in valuable domestic animals.
Anti-Helminthic Activity: The anti-helminthic efficacy of the aqueous crude extract from V. amygdalina on Toxocaracanis (Ascarids) and Ancylostoma caninum (Hook worm) is well established.
The anti-helminthic activity of the crude extracts could be attributed to secondary plant metabolites that could be present .
The ethanolic extract of this plant inhibited 55.4% larval migration at 2mg/ml and the dichloromethane extract showed 67.1% inhibition of migration at 3mg/ml while ethanol extracts inhibited egg hatching by 72.6% by the lowest concentration tested (0.15mg/ml).
However, there was no activity on larval migration inhibition (LMI) with n-hexane extract at any concentration explored despite, both the ethanolic and dichloromethane extract inhibited egg hatching by >90% at higher concentration.
The anti-helminthic assay performed on adult earthworms (Lumbricus terrestris) due to its physiological resemblance with the intestinal roundworm parasite of human being also gave clue on the effect of the plant.
From phytochemical screening all the extracts have alkaloids, tannins and glycosides which have been associated with anthelmintic activity.
Alkaloids in the aerial parts of Cissampelos c apensis (Menispermaceae) and Macleaya microcarpa (Maxim) fade is known to be responsible for their anti-helminthic activity .
Tannins are known to produce antihelminthic activity by binding to glycoprotein on the cuticle of the parasite.
They hinder energy production in helminthic parasites by uncoupling oxidative phosphorylation .
This effect is also true in most nematodes in human and veterinary medicines.
Comparing anthelmintic activity of V. amygdalina and Alstoniaboonei to piperazine (A known GABA mimetic anthelmintic), the extracts may contain constituents that could probably have weak GABA-mimetic effect similar to piperazine citrate.