Scientific Name
Vernonia amygdalina Delile
Synonyms
Bracheilema paniculatum R.Br., Cacalia amygdalina Kuntze, Cheliusia abyssinica Sch.Bip. ex A.Rich., Decaneurum amygdalinum DC., Vernonia adenosticta Fenzl ex Walp., Vernonia eritreana Klatt, Vernonia giorgii De Wild., Vernonia randii S.Moore, Vernonia vogeliana Benth., Vernonia weisseana Muschl. [1]
Vernacular Name
| English | Bitterleaf, common bitterleaf [2] |
| Kenya | Olusia [3] |
| Nigeria | Burzu, ewuro, ewuro gidi, ewuro jije, ewuro-oko, ewuroaja, olubo, olugbu, orikhue, orin, pako, sabulum-mata, shiwak, shiwaka, uha [3] |
| Southern Africa | Monqo (Yei), sikakadzi, sikavakadzi (Shona) [3] |
| Tanzania | Ekiluluza, mtugutu, omubilizi [3] |
| Uganda | Omubilizi, umubilizi, umuyobora [3] |
| West Africa | Bata liffi, bittas, e-bita lif [3] |
| France | Vernonie, Vernonie commune, ndole [2] |
| Portugal | Sucumdiera, pau fede [2]. |
Geographical Distributions
No documentation.
Botanical Description
Vernonia amygdalina is a member of the Asteraceae family. It is a shrub or small tree that can reach up to 10 m high with trunk diameter reaching up to 40 cm. The bark is grey to brown, smooth, becoming fissured and when young is densely pubescent. [2]
The leaves are alternate, simple, with petiole measuring 0.2-4 cm long. The leaf blade is ovate-elliptical to lanceolate and measures 4-15 cm x 1-4 cm, cuneate or rounded at base, shortly acuminated at the apex, margin minutely toothed to coarsely serrate, finely pubescent but often glabrescent. The inflorescence is in the form of a head, arranged in terminal, compound, umbel-like cymes. Head stalk is measure about 1 cm long, pubescent. [2]
The flowers are bisexyal, regular, 5-merous, strongly exserted from the involucres which are cylindrical to broadly ellipsoid.[2]
The fruit is a 10-ribbed achene measuring 1.5-3.5 mm long, pubescent and glandular, brawn to black, crowned by a much longer pappus bristles. [2]
Cultivation
No documentation.
Chemical Constituent
V. amygdalina has been reported to contain vernodaline, vernomygdin, vernodalol, vernolide, hydroxyvernolide, tannins, vitamin C, luteolin, luteolin 7-O-β-glucoronide, leteolin 7-O-β-glucoside, vernonioside D and E, vernolepin, vernonioside A1-A4, vernonioside B1-B3, vernodalinol, α-muurolol, 1,5-dicaffeoyl-quinic acid, dicaffeoyl-quinic acid, chlorogenic acid and luteolin-7-O-glucoside. [4][5][6][7][8][9][10]
Plant Part Used
Leaves, barks and seeds. [4]
Traditional Use
V. amygdalina had been introduced into the Malaysian herbal armamet and there has been quite a good followings on the use of the plant to treat diabetes, hypertension and hypercholesterolaemia. The plant is a vegetable in its native land and is put through a detoxification process before being cooked as food. The process involved boiling the leaves several times with change of water after each cycle until the bitterness disappears. [2][4]
The leaves are used on wounds as a substitute for iodine in Nigeria. The leaves are also used to treat fevers especially malaria, hepatitis, and skin parasitic infestations like scabies. The decoction of the V. amygdalina leaves is prescribed for cough, as a laxative and as a fertility inducer. It is also used to treat headache. [2]
In West Africa the decoction of the V. amygdalina leaves or bark is used in the treatment of diarrhea, dysentery and other gastrointestinal disorders. It is commonly used as a vermifuge not only by humans bit also chimpanzee. The young branches are chewed on to clean and strengthen teeth and clears gum infection. It also acts as an appetite stimulant and a tonic. [2][4]
The V. amygdalina root infusion are used to treat sexually transmitted diseases while that of the bark clears fever. The cold water extract of the roots together with leaves of Vigna sinensis is a traditional remedy for schistosomiasis [2][4]. The infusion of the roots is used as a douche for uterine pain [11].
Preclinical Data
Pharmacology
Antiplatelet activity
Vernolepin is a sesquiterpene lactone isolated from the dried fruit of V. amygdalina. It was found to have antiaggregating and diaggregating activity against rabbit platelet aggregation induced by arachindonic acid or ADP without inhibition of cyclo-oxygenase or lipoxygenase. Electronmicroscopy showed that the drug protects platelets against adhesion and desegregation effects. [7][8]
Antisickling activity
Methanol extract of V. amygdalina leaf exhibited significant antisickling activity but not as good as those of Solenostemon monostachyus, Carica papaya seed oil and Ipomoea involucratan in males with sickle-cell anaemia. The effects observed include a lowering of levels of sickle blood cells, reduction in Fe2+/Fe3+ ratio, increased in haemoglobin concentration, and inhibition of sickle cell polymerization. [12]
Antihaemolytic activity
Methanol extract of V. amygdalina was seen to be able to reduce tert-butyl hydropreoxide (t-BHP)-induced eryhtocyte lysis significantly. The effective dose range is between 25-150 μg/L. This protective effects seem to be related to the antioxidant activity of the extract. On the contrary, it has been found that infusion of the leaves induces haemolysis of mammalian erythrocyte in vitro, with Human genotype-SS (1024) having the highest susceptibility. Human genotype-AS were moderately affected while Human genotype-AA (256) were highly resistant. [13][14]
Antiallergic activity
Aqueous and methanol extracts of the leaves of V. amygdalina showed anti-allergic activity as a prophylactic and as curative. In the prophylactic protocol both extracts exerted significant inhibitory effects on the development of Atopic Dermatitis symptoms, the production of IgE, TNF-alpha, IL-5 and IFN-gamma and on the increase thickness of ear. In the curative protocol, it was found that topical application of both extracts markedly improved the skin lesions i.e. erythema/haemorrhage, scaling/dryness, erosion/excoriation and decrease ear thickness in mice. There were also decreases in serum total IgE, MCP-1 and eotaxin. The methanol extract was found to improved chronic eczema dermatitis skin symptoms in a patient. [15]
Myometrial contractility
Nine plants were screened for the myometrial contractile activity and included in this study was the leaves of V. amygdalina. It was found that the aqueous extract of V. amygdalina induced significant sustained increases in human myometrial smooth muscle contractility. [16]
Anticancer activity
Many studies had been conducted to determine the effects of V. amygdalina on the activity of cancer cells in particular the human breast cancer and prostatic cancer. It was found that V. amygdalina was able to inhibit the growth of MCF-7 cells in a dose dependent manner upon exposure for 48 hours. There was a slight increase in DNA damage seen in the form of slight increase in comet tail-length, tail arm and tail moment and percentage in DNA cleavage at all tested doses. This indicate that the plant induced minimal genotoxic damage in MCF-7 cells. Similar effects were seen in BT-549 i.e. cell growth inhibition and DNA synthesis inhibition. The plant also exhibited chemopreventive activity attributed to its ability to scavenge free radicals, induce detoxification, inhibit stress response proteins and interfere with DNA binding activity of some transcription factors. Vernodalinol, a sesquiterpene lactone, isolated from the leaves of V. amygdalina effectively inhibited breast cancerous cell growth at a dose of 25-50 μg/mL. The LC50 being 70-75 μg/mL in MCR-7 cells. [9][17][18][19][20][21]
Androgen-independent PC-3 cells are sensitive to V. amygdalina treatment in vitro. This qualifies the plants as a candidate agent for the treatment of Paclitaxel-resistant prostatic cancer. The sensitivity of TAX-resistant to V. amygdalina is probably due to the differential regulatory patterns of MAPK, c-Myc, AKT, and p-gp activities/expressions. [22]
Irradiation protection activity
Methanol extract of V. amygdalina leaves exhibited antioxidant activity. Antioxidant is known to mitigate radiation damage in tissues. Rat pretreated with methanol extract of V. amygdalina were subjected to irradiation to their heads. At autopsy it was found that the tested group of rats did not show the effects of gamma irradiation i.e. reduction of relative weight of whole brain, relative weight of the cerebellum, the maximum width, rosrocaudal dimension and dorsoventral extent of the cerebellum. [23]
Induction of hyperacidity and increase intestinal motility
Aqueous extract of V. amygdalina when infused intragastrically caused a significant increase in acid production in rats. This was reduced by ranitidine or atropine. The extract also evoked contraction of isolated guinea pig ileum which was inhibited by atropine. [24]
Hypolipidaemic activity
Aqueous extract of V. amygdalina leaves showed hypolipidaemic and antioxidant activity in streptozotosin induced diabetic rats. This is evidenced by the fact that the extract was able to reduce malondialdehyde levels, significantly reduce triglyceride levels and normalized cholesterol concentration. Methanol extract of V. amygdalina leaves also exhibited lipid-lowering effects in hypercholesterolaemic and also diabetic rats. The plasma and post mitochondrial fraction cholesterol and LDL-cholestrol levels were observed to have reduced following administration of 100 mg/kg and 200 mg/kg dose of the extract. There was a corresponding increase in HDL-cholesterol and an augmentation of cholesterol-induced decrease in PMF glutathiones levels. The extracts also decrease significantly lipid peroxidation. These were observed in hypercholestrolaemic rats but not in normal rats. [25][26]
Antihypertensive activity
In a survey on the use of complementary and alternative medicine amongst 225 hypertensive patients in Nigeria, it was found that 9.1% used V. amygdalina together with their antihypertensive therapy. The polyphenolic fraction (cholorophyllic fraction) of the leaf extract of V. amygdalina displayed high potency against angiotensin converting enzyme (ACE) and rennin. This provide some rationale in the use of the plant in the treatment of hypertension. [27][28]
Antidiabetic activity
V. amygdalina leaves had been used in the treatment of diabetes in African countries with reasonable success. Most used the leaves in combination with conventional antidiabetic therapy. In a study to evaluate the antidiabetic activity of the leaves of V. amygdalilna it was found that the ethanol extract could improve the glucose tolerance test in STZ-induced diabetic rats. The following were also observed: a) decrease in fasting blood glucose level; b) protection of pancreatic beta-cells against STZ-induced damage and c) decrease triglyceride and total cholesterol level. There is evidence that it may stimulate skeletal muscle’s glucose uptake since there were increase in expression of GLUT 4 in diabetic rat skeletal muscles and also increase in GLUT 4 tanslocation to plasma membrane thus its ability to restore skeletal muscle glycogenesis. At the same time the extract inhibited hepatic gluconeogenesis by inhibiting glucose-6-phosphatase. A study of the antidiabetic effects of combining V. amygdalina with Azadirachta indica was done and it was found that in combination the hypoglycaemic effects were rapid and a reversal of hepatic and pancreatic histology was observed. This synergy was believed to be exerted by oxidative stress attenuation, insulin mimetic action and beta-cell regeneration. [29][30][31][32]
Hepatoprotective activity
V. amygdalina leaves possess hepatoprotective activity against a number of liver toxins i.e. carbon tetrachloride, acetaminophen and even irradiation. The presence of sesquiterpene lactones in the leaves had been suggested as being responsible for the activity. Administration of various extracts (aqueous/ethanol) prior to induction of liver injury by the mentioned poisons had succeeded in prevention of the occurrence of the damage. This was evidenced by a significant reduction in activities of ALT, AST and OCT and also histologically in animals pretreated with the extracts. There was evidence to suggest this protective activity is mediated through the antioxidant activity in the leaf extracts. [33][34][35][36][37]
Antimicrobial activities
Antiparasitic
The chloroform and methanol extracts of V. amygdalina showed anti-leishmanial activity. The amstigotes appears to be more sensitive to the extracts than the promastigotes. Between the two extracts, the chloroform extracts had stronger parasitical activity against Leishmania aethiopica with ED50 of 74.4 μg/mL. In the case of Leishmania major the methanol extract was found to be the most potent compared to aqueous and hexane extracts of the leaves. There were high suppression of infectivity and viability of intracellular amastigotes at levels lower than that which elicited cytotoxicity in macrophages. Infected mice treated with the methanol extract showed delayed onset of the disease with a significant reduction in lesion size and attenuation of the histopathological outcome characterized by intact epidermis and less tissue destruction in skin, spleen and liver. [38][39]
In a survey on the use of plants in the treatment of malaria in Uganda, V. amygdalina seem to be frequently mentioned. In a screening of seven medicinal plant ethanol extracts and twenty fractions from the partition of initial ethanol extracts, the ethanol extract of V. amygdalina leaves showed antimalarial activity (5<IC50 < 10 μg/mL) while the petroleum ether fraction showed more pronounced antiplasmodial activity (IC50< 3 μg/mL). The extracts of the leaves and root bark showed significant antiplasmodial activity. Prophylactic use of V. amygdalina extract in combination with chloroquin proved to be more effective against P. berghei in infected mice as compared to chloroquin alone. In this case it was observed that there were a) shortened parasite clearance time; b) prolonged recrudescent time; and c) improved day 14 cure rate. In a clinical trial to assess the efficacy and safety of the infusion of fresh V. amygdalina leaves for the treatment of uncomplicated malaria in patients 12 years and above, the investigators found no evidence of significant side-effects or toxicity from the use of the medication. The adequate clinical response (ACR) at day 14 was 67% and complete parasite clearance was 32% of the ACR and of these recrudescence occurred in 71%. [40][41][42][43][44][45][46][47]
Antifungal
Two sesquiterpene lactones (vernolide and vernodalol) isolated from the leaves of V. amygdalina exhibited differing antifungal activities. In the case of vernolide the activity was high against Penicillium notatu (LD50 = 0.2 mg/mL), Aspergillus flavus and Aspergillus niger (LD50 = 0.3 mg/mL) and Mucor hiemalis (LD50 = 0.4 mg/mL), while vernodalol showed moderate inhibition against Aspergillus flavus (LD50 = 0.3 mg/mL), Penicillium notatum (LD50 = 0.4 mg/mL) and Aspergillus niger (LD50 = 0.5 mg/mL). [48]
Antibacterial
Methanol extract of V. amygdalina leaf did not show significant antibacterial activity being only effective against S. aureus but not against P. aeruginosa. The two sesquiterpene lactone (vernolide and vernodalol) isolated from the leaves were found to be effective against gram positive bacteria but not the gram negative ones. [48][49][50]
Toxicity
No documentation.
Clinical Data
Clinical findings
No documentation.
Precautions
No documentation.
Side effects
No documentation.
Pregnancy/Breast Feeding
Aqueous extract of the V. amgydalina leaves can induced significant myometrial contraction. While this may be useful during the conduct of labours to assist delivery, its use for whatever reason during pregnancy should be contraindicated for fear of leading to abortion. [16]
Age limitation
No documentation.
Adverse reaction
Some of the constituents must be regarded as being toxic, and little in known of their effects in humans, In West Africa, V. amygdalina is widely used as a vegetable. It is preprocessed before being consumed to remove the bitterness (toxic elements). The preprocess varies form country to country from repeated boiling and decanting the water to remove the bitter principle to soaking in water to be left to stand before being cooked, a process that removes the bitter taste and presumably reduces the toxic effects of the sesquiterpenes. [2][4]
Interaction & Depletion
No documentation.
Interaction with drug
It has been found that co-administration of V. amygdalina and digoxin increases the absorption of the latter. This is due to the fact that V. amygdalina inhibit p-gp (permeability glycoprotein) and modulating the pharmacokinetic disposition of other p-gp substrate drug. Patients on digoxin should exercise extra caution when taking V. amygdalina leaves either as vegetable or as an alternative/complimentary medication. [51][52]
There is a risk of potentiation of anticoagulant activity in patients on anticoagulant therapy. There is a possible additive effect on lipid-lowering drug and antihypertensive drugs when used together in therapy. Patients on medications should consult or inform their physicians of their use of the plant as adjuvant to therapy [6][7][25][26]. It would be wise for diabetics on antidiabetic therapy to inform their physician when they are taking the leaves of V. amygdalina. There would eventually arise the need to modify the antidiabetic therapy to suite the probable changes in glycaemic control [29][30][31][32].
Interaction with other Herbs
No documentation.
Contraindications
No documentation.
Poisonous Management
No documentation.
Line Drawing
No documentation.
References
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