Ageratum conyzoides (L.) L.

Last updated: 22 Feb 2017

Scientific Name

Ageratum conyzoides (L.) L.

Synonyms

Ageratum album Hort.Berol. ex Hornem., Ageratum album steudel [Invalid], Ageratum arsenei B.L.Rob., Ageratum brachystephanum Regel, Ageratum ciliare L., Ageratum ciliare Lour., Ageratum coeruleum Desf. [Illegitimate], Ageratum conyzoides f. album (Willd.) B.L.Rob., Ageratum conyzoides f. conyzoides, Ageratum conyzoides var. conyzoides, Ageratum conyzoides subsp. conyzoides, Ageratum conyzoides var. hirtum (Lam.) DC., Ageratum conyzoides var. inaequipaleaceum Hieron., Ageratum conyzoides f. obtusifolia (Lam.) Miq., Ageratum conyzoides var. pilosum Blume, Ageratum cordifolium Roxb., Ageratum hirsutum Lam., Ageratum hirsutum Poiret, Ageratum hirsutum Poir., Ageratum hirtum Lam. [Illegitimate], Ageratum humile Larran., Ageratum humile Salisb. [Illegitimate], Ageratum humile Larrañaga, Ageratum iltisii R.M.King & H.Rob., Ageratum latifolium Cav., Ageratum latifolium var. galapageium B.L.Rob., Ageratum latifolium var. latifolium, Ageratum microcarpum (Benth. Ex Benth.) Hemsl., Ageratum muticum Griseb., Ageratum nanum Hort. Ex Sch.Bip. [Illegitimate], Ageratum obtusifolium Lam., Ageratum odoratum Vilm., Ageratum odoratum Bailly, Ageratum suffruticosum Regel, Alomia microcarpa f. torresii Standl., Cacalia mentrasto Vell. Conc., Caelestina latifolia (Cav.) Benth. ex Oerst., Caelestina microcarpa Benth. ex Benth. [Illegitimate], Caelestina microcarpa Benth. xx Oerst., Caelestina suffruticosa Sweet [Illegitimate], Carelia brachystephana (Regel) Kuntze, Carelia conyzoides (L.) Kuntze, Carelia mutica (Griseb.) Kuntze, Eupatorium conyzoides (L.) E.H.L.Krause [Illegitimate], Eupatorium conyzoides (L.) E.H. Krause, Eupatorium paleaceum Sessé & Moc., Sparganophorus obtusifolius Lag. [1]

Vernacular Name

Malaysia Daun misai kuching, rumput jalang, rumput pereh jarang, rumput sekedok, sekedok, selaseh dandi, selasik dandi, senarong kambing, sianggit, tahi anjing, tahi ayam, tombok tombok jantan; oran, serak semalam, suokning (Sarawak) [2]
English Appa grass, bastard arimony, Billy-goat weed, blueweed, conyzoid floss-flower, goat weed, tropic ageratum, white dung herb, white weed [2]
China Huo xiang ji, sheng hong ji [2]
India Ajganda, ajgandha, anename, appa, appa sedi, appakkoti, bhakumbar, dholi sadedi, dochunti, dochuntry, dochunty, gandhri, gendelabon, gha buti, ghanera, osaasi, ghaneraosadi, gondhoabon, gondria, helukasa, imchenriza, injenriza, jangli, pudina, kang-khapau, kattappa, khongjai batblu myngai, makadmari, mekipu, muriyan pacca, myngai, naayi thulasi, narsa gida, nilam, oorala gida, ooralada gida, osaadi, osadi, padre ban, parosaola, pashpai, pasupau, pokabanthi, pokapanthi povu, pokasunga, pokasungaa, pum-pillu, pumpillu, pumppillu,m pumpul, semandulu, uchauty, uchunti, vai len hlo, vaihlenhlo, vailenhlo, vattai sedi, visadodi, visa-mustih, voilenhlo, vosadi [2]
Bangladesh Achunai [2]
Nepal Gande, ilame jhar, nimane jhar, raunja, than ninoba [2]
Indonesia Babadotan, babadotan jukut bau, babandotan, babandotan leutik, bandotan, berokah, dus bedusan, dus wedusan ki bau, udu pute bua, udu tai pute, wedusan [2]
Thailand Saapraeng saapkaa, thiam mae hang, ya saap raeng [2]
Philippines Asipukpuk, bahug-bahug, bulak-manok, bulak-manuk, damong-kambing, damong-pailaya, damong-palias, gamut-tulisan, kamubuag, karokanding, kolong-kogong, pagpagai, singilan [2]
Vietnam Bu xich, cay cut lon, c[aa]y b[oo]ng c[uws]t heo, c[aa]y hoa c[uws]t l[owj]n, c[aa]y b[oo]ng th[us]i, co hoi, nho hat bo, thang hong ke [2]
Japan Kakkô-azami [2]
Arabic Berqam, borgoman [2]
Central Africa Republic Dagere [2]
East Africa Adwolo, atiraja, bukabuka, butabuta, bwutabwuta, galagachui, gathenge, ifuna, ilusa, ipfuna, itawana, ivuna, karura, kimavi cha kuku, knughai, kundambara, matawana, mososoyiah, mujungujungu, munywaniwenkanda, murigana, mwigara, nakache, namatori, namirembe, osa, ntaenyeka, ol crowil el aijok, ao erowie el aijok, omonyaitira [2]
South Africa Bokkruid, indringer-ageratum (=invading ageratum) [2]
West Africa Belkeyan, wait head, yanigbei [2]
Congo Basolo ba, isolo a m’mboli, konko, mudiadianga [2]
Madagascar Bemaimbo, bembo, tsiafakanakandriana [2]
Nigeria Ebebekeze, eighojedoban [2]
Sierra Leone Ngu gbe [2]
S. Rhodesia muNyani [2]
Tanzania Beenge, kalula, kamiyambo, kundambara, matawana, mbelenge, ol crowil el aijok, olesongoyo [2]
Yoruba Ako yunyun, akwekwe-nwaosi n’aka, arun sansan, imi-eshu, imi esu [2]
Papua New Guinea Akikikanabebe, kalese, noingkepek, sambura, sikong [2]
Central America Celestina, flor noble, ierba de chucho, mastranto, mejorana, mejorana chaparral, retentina, Santa Lucía [2]
Hawaii Maile hohono, maile honohono, maile kula [2]
Tonga Te’ekosi [2].

Geographical Distributions

Ageratum conyzoides originated from Central and South America, but now is a pantropical weed that is very common throughout India, Burma (Myanmar), Indo-China, southern China, Thailand and Malesia.

Botanical Description

A. conyzoides is a member of Compositae family. [1] It is an annual erect herb that sometimes is decumbent and rooting at the base. It can reach up to 120(-150) cm tall. The stems have long hairs on the nodes and younger parts. [3]

The leaves are egg-shaped, triangular-ovate or rhomboid-ovate, size (0.5-)1-10 cm x 0.5-7 cm, with obtuse or rounded base. [3]

The flowering head is about 4-6 mm long. The number of flowers is 60-75. The outermost ring of the bract is beset with only simple non-gland hairs while the inner bracts are with abruptly contracted apex. The petal is between 1-2.5 mm long. [3]

The fruit is hairless or very sparingly hairy. [3]

Cultivation

A. conyzoides is very common in fields, roadsides and waste places up to 2500 m altitude. [3]

Chemical Constituent

A. conyzoides have been reported to contain flavonoids, alkaloids, coumarins, essential oils, tannins, chromenes, benzofurans and terpenoids. The main chemicals found in the plant are: 6,7-dimethoxy-2,2-dimethylchromene, 6-demetoxyageratochromene, 6-vinyl-demethoxy-ageratochromene, ageratochromene (precocene II), α-cubebene, α -pinene, α -terpinene, β-caryophyllene, β -cubebene, β-elemene, β-farnesene, β-myrcene, β-pinene, β-selinene, β-sitosterol, cadinene, caryophyllene-oxide, conyzorigin, coumarin, dotriacontene, endo-borneol, endo-bornyl-acetate, ethyl-eugenol, ethyl-vanillin, farnesol, friedelin, HCN, hexadecenoic-acid, kaempferol, kaempferol-3,7-diglucoside, kaempferol-3-o-rhamnosylglucoside, linoleic-acid, quercetin, quercetin-3,7-diglucoside, and quercetin-3-o-rhamnosylglucoside [4], and 5,6,7,8,3′,4′,5′-heptamethoxyflavone [5]

The essential oils of A. conyzoides has been reported to contain chromenes precocene I and precocene II. The chromenes precocene I (7-methoxy-2,2-dimethylchromene) of A. conyzoides was determined to be 687 ± 21 mg/mL whilst the precocene II (6,7-methoxy-2,2-dimethylchromene) was determined to be 20 ± 2 mg/mL. [6] The essential oil of A. conyzoides fresh leaves contained 86% of precocene I and 8% of β-caryophyllene. [7]

The essential oil of A. conyzoides has been reported to contain isodihydroeuparin derivatives identified as thoxybenzofuran [2-(2’-methylethyl)-5,6-dimethoxybenzofuran], chromene [2-(1’-oxo-2’-methylpropyl)-2-methyl-6,7-dimethoxy-chromene], chromone [3-(2’-methylpropyl)-2-methyl-6,8-dimethoxy-chrom-4-one] and a chromanone [2-(2’-methylprop-2’-enyl)-2-methyl-6,7-dimethoxy-chroman-4-one]. [8]

The main chemical components of the volatile oil of the aerial parts of A. conyzoides were found to be ageratochromene (32.9%), 6-methoxyquinoline-1-oxide (20.77%), β-caryophyllene (19.79%), β-sinensal (5.82%), β-sesquiphelandrene (1.99%) and τ-cadinene (1.44%). [9]

A concentrated n-hexane extract of the aerial parts of A. conyzoides contained 6-(1methoxyethyl)-7-methoxy-2,2-dimethylchromene,6-(I-hydroxyethyl)-7-methoxy-2,2-dimethylchromene,6-(1-ethoxyethyl)-7-melhoxy-2,2-dimethylchromene, encecaline, 6-vinyl-7-methoxy-2,2-dimethylchromene, encecanescin -9, -10, -11, lignan±sesamin, caryophyllene oxide. [10]

The fraction of A. conyzoides extract also contained non-phenolic compounds such as 5,6,7,5’-tetramethoxy-3’,4’-methylenedioxyflavone, 5,6,7,8-tetramethoxy-3’,4’-methylenedioxyflavone (linderoflavone B), 5,6,7,8,5’-pentamethoxy-3’,4’-methylenedioxyflavone (eupalestin), 5,6,7,8,3’,4’,5’-heptamethoxyflavone (5’-methoxynobiletin) [5][11], 5,6,7,8,3’,4’-hexamethoxyflavone (nobiletin), 5,6,7,3’,4’,5’-hexamethoxyflavone [11][12], and 5,6,7,3’,4’-pentamethoxyflavone (sinensetin) [11].

New flavones were isolated from A. conyzoides namely ageconyflavones A (5.6,7-trimethoxy-3’,4’-methylenedioxytlavone), B (5,6,7,3’-tetramethoxy-Y-hydroxyflavone) and C (5,6,7,3’,5’-pentamethoxy4’-hydroxyflavone). [11]

The phenolic compound identified in the extract of A. conyzoides was known as 8-hydroxy-5,6,7,3’,4’,5’-hexamethoxyflavone. [13]

The light petroleum extract of A. conyzoides has been reported to contain friedelin, sitosterol and stigmasterol. [14]

Elements detected in the dried roots of A. conyzoides were Al, Br, Ca, Co, Cr, Fe, K, Mg, Mn, Na, Sc, V, Zn, Sr (122 mg/g), Ba (118 mg/g) and Rb (62 mg/g). Calcium was the major essential element present at 2.6% in the plant sample. Iron, manganese, zinc, sodium and potassium, were present in the plant at 1650, 132, 106, 490 mg/g and 2% concentrations, respectively. Elements such as Br, Co, Cr, Sc and V are present at trace levels (less than 10 mg/g). [15]

Plant Part Used

Leaves, roots, and aerial parts. [7][9][10][11]

Traditional Use

In Brazil, an infusion is prepared with the leaves of the entire plant. The infusion is used to treat colic, colds and fevers, diarrheal, flatulence, urinary infections, rheumatism, spasms and is used as anti-inflammatory, analgesic and as a tonic. It is also highly recommended for burns and wounds. In Africa, A. conyzoides is used to treat fever, rheumatism, headache, colic, wounds caused by burns, dyspepsia, eye problem, uterine disorders and pneumonia. In other countries such as Latin and South America, the plant is widely used for its antibacterial properties and for numerous infectious conditions. [4]

A.conyzoides is widely utilised in traditional medicine systems wherever it grows. This plant is used in folk remedies as a purgative, febrifuge, for ophthalmia, treatment of ulcers and as a wound dressing. [16]

Among the Nigerians, A. conyzoides is popular for skin diseases and wound healing. A decoction of the plant is taken internally to treat diarrheal and to relieve pain associated with the navel in children. Based on a questionnaire-guided ethno-medical survey of the Igede people of Nigeria, A. conyzoides is the only plant used in treating HIV/AIDS. A decoction of the A. senegalensis stem, bark with the leaves and aerial parts of A. conyzoides is taken 3 times daily in the treatment of diarrheal. These people also macerated A. conyzoides, S. indica and S. guineensis for use in diabetic illnesses. The tribe also used A. conyzoides to treat ache ear using the exudates from the squeezed warmed leaves. Leaves of A. conyzoides are used to treat infertility. [17]

A. conyzoides is also used to treat prostate problems and is given to women after childbirth and for promoting menstruation. [18]

Preclinical Data

Pharmacology

Anti-inflammatory activity

Hydroalcoholic extract of A. conyzoides leaves has been reported to exhibit anti-inflammatory activity on subacute (cotton pellet-induced granuloma) and chronic (formaldehyde-induced arthritis) models of inflammation in rats. Granulomatous lesions were induced by surgically implanting two cotton pellets (50±1mg) subcutaneously in the dorsal region of the rats. Plant extract (250 mg/kg body wt.) or vehicle (5 mL/kg body wt.) were given orally once daily for 7 consecutive days. On day 8, the rats were anesthetised under light ether, and the pellets covered by granulomatous tissue were dissected and dried to a constant weight. The dry weights of granulomatous tissue surrounding the pellets were significantly lower for the group treated with the hydroalcoholic extract of A. conyzides leaves after 7 days treatment (116.5±4.5) as compared to the control group (189.7±13.4). However, no significant differences in adrenal weights were observed between the treated (20.672.6 mg/100 g body wt.) and the control groups (25.573.1 mg/100 g body wt.). In this model of inflammation, the plant extract (250mg/kg body wt.; p.o.) produced a consistent anti-inflammatory activity where the granulomatous tissue was significantly suppressed to the level of 38.8%. [19]

Chronic arthritis was induced in male rats using a subplantar injection of 0.1 mL of 2% (v/v) formaldehyde, administered to the right hind paw on the first and third days of the experiment. The hydroalcoholic extract of A. conyzides leaves, (250 mg/kg body wt.) or vehicle (5 mL/kg body wt.) were administered orally once daily for 10 days. The paw volumes were measured plethysmographically, before the formaldehyde injection and repeated every day, for 10 days. Based on the findings, continuous treatment with hydroalcoholic extract of A. conyzides leaves, (250 mg/kg body wt.) reduced the edema which was induced by formaldehyde. There was no significant difference in paw volume between the treated and the control groups during the first 2 days, however a significant effect appeared after the third day of the treatment. Macroscopic examination of the gastric mucosa did not reveal any treatment-related tissue damage, which is a collateral effect of many anti-inflammatory drugs, including aspirin and related compounds. [19]

The production of an anti-inflammatory activity without gastric lesions showed that the active principle of the hydroalcoholic extract of A. conyzides leaves did not interfere with prostanoid production. They might also act by selective inhibition of COX-2. This could be of therapeutic advantage because this isoenzyme is probably involved in prostaglandin production at the site of inflammation but not at any other site such as the gastrointestinal tract or kidney. The hydroalcoholic extract of A. conyzoides leaves demonstrated a significant anti-inflammatory effect in the two inflammation models, with no significant alteration in serum transaminase level or any treatment related tissue damage during the short period of treatment. [19]

In vivo and in vitro studies of anti-inflammatory activity were done using the water extract of A. conyzoides. Oral administration (p.o.) of the water extract (0.1 to 5 g/kg) to rats and mice induced quietness and reduced the spontaneous motility. The sleeping time induced by sodium pentobarbital (50 mg/kg, i.p.) in mice was not altered after treatment with the water extract of A. conyzoides (2 g/kg, p.o.). The same treatment did not influence the paw edema induced by carrageenan or dextran, nor did it reduce the chronic paw edema induced by complete Freund's adjuvant or formaldehyde in rats. The tail flick response in immersion test and writhing induced by 0.8% acetic acid in mice were not altered by the water extract of A. conyzoides, either. In the isolated guinea-pig ileum, the water extract of A. conyzoides (0.4 to 4 mg/mL) did not alter the EC50 values of histamine or acetylcholine, but reduced the maximal response to the agonists by 20 to 50%. The water extract of A. conyzoides (0.01 to 10 mg/mL) produced tonic contractions of the ileal smooth muscle in proportion to the doses, reaching a maximum of 75% relatively to the maximum value obtained with histamine. These contractions were blocked by diphenhydramine (10 nM) and reduced by 32% in the presence of atropine (10 nM). The results indicated that oral treatment of rodents with A. conyzoides did not reduce the inflammatory edema or decreased the reaction to pain stimuli. In vitro study of the A. conyzoides water extract presented an unexpected histamine-like activity characteristic of a partial agonist. The results obtained did not confirm the popular traditional medicinal indications of the plant. [20]

Wound healing activity

The wound healing properties of methanolic extracts of A. conyzoides leaves were compared to honey. Thirty Wistar rats were randomized into 3 groups of 10 animals each. They were fed with standard rat chow and tap water, weighed and acclimatized to laboratory conditions for one week. Under anesthesia, each animal had the skin of its dorsolateral flank shaved after which an area of the skin was excised. On achieving haemostasis, the wounds were packed with gauze soaked in the appropriate dressing for each group. Measurement of the wound size, and wound biopsies were taken on the 10th day post-wound creation. Together with healed wound samples, these were processed for histology. Fibroblast and blood vessel densities per unit area of wound were determined for the healed wound samples. Histologically, sections from the 10th day of A. conyzoides treatment showed fewer inflammatory cells compared with sections from the honey treatment and control. Besides that, healed scar sections of wounds dressed with the herb extract showed more fibrosis. Base on the findings, treatment with honey and A. conyzoides caused significantly greater wound contraction than controls. Healed wounds from the A. conyzoides group have significantly fewer fibroblasts than the honey treated group or controls. [21]

Wound healing property of the methanolic extract of A. conyzoides leaves was determined using the excision wound model. A circular incision of about 20 mm in diameter was made on the disinfected area of the skin surface and the skin carefully dissected out. The wound area was measured immediately by placing a transparent tracing paper over the wound and tracing it out before placing the tracing paper on 1 mm2 graph sheet and traced out. The squares were counted and the area recorded. Treatment, which started shortly after the wound was produced, consisted of applying 0.2 mL of 20 mg/mL of the methanolic extract of A. conyzoide leaves. A group which received application of Cicatrin® powder (an antibiotic preparation containing neomycin and bacitracin) on the wound acted as the positive control whilst the application of sterile distilled water served as the negative control. The extracts as well as the antibiotic powder and sterile distilled water were applied topically once daily for 10 days. Each application was done after cleaning the wound with a dilute solution of Dettol®. The percentage of wound healing on these days was determined based on the wound area of each animal measured under light diethyl ether anesthesia on the 1st, 4th, 7th, 10th, 14th, and 17th day post surgery. Based on the findings, more than 90% of wound healing was recorded using the methanolic extracts of A. conyzoide leaves and Cicatrin® powder-treated groups by 14 days post surgery, whereas only 72% healing was observed in the distilled water-treated group. The percentage healing in the water-treated group was significantly lower compared to the group treated with the methanolic extracts of A. conyzoide leaves and the antibiotic-treated group. The results of this study showed that the methanolic extract of A. conyzoide leaves have wound healing activity and can be developed into phytomedicines for the management of septic wounds. [22]

Antibacterial activity

The methanolic extract of A. conyzoide leaves has been reported to exhibit antibacterial properties. Antibacterial activities of the extract was studied against eleven wound isolates namely Staphylococcus aureus (four strains), E. coli (two strains), Pseudomonas aeruginosa (one strain), Proteus spp. (three strains), and Shigella spp. (one strain) using the well diffusion method. A volume of 0.1 mL of 20 mg/mL solutions of the extract was dissolved in dimethylsulfoxide (DMSO) and delivered into each of five wells. The 6th well contained only DMSO and served as a negative control. The extracts and the DMSO were allowed to diffuse into the media after which the plates were inverted and incubated at 37°C for 24 h. After incubation, inhibition zone diameters (IZD) were measured. Based on the results obtained, A. conyzoides methanolic extract did not inhibit growth of any of the test organisms. [22]

Water and ethanol extracts of A. conyzoides leaves were investigated for its anti-methicillin resistant Staphylococcus aureus (MRSA) activity. The MRSA strains used in this study were clinical isolates from urethral swab, seminal fluid, urine, high virginal swab, blood, skin swab and sputum of patients presenting with symptoms of S. aureus associated diseases. A standardized inoculum (1–2 × 107 cfu/mL 0.5 McFarland standards) was introduced onto the surface of sterile agar plates, and a sterile glass spreader was used for even distribution of the inoculum. A sterile paper disc previously soaked in a known concentration of extract (20 mg/mL per disc) was carefully placed at the centre of the labeled seeded plate. The same procedure was applied for all the MRSA strains used. The plates were incubated aerobically at 37°C and examined for zones of inhibition after 24 hr. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 43.0 and 63.2 mg/mL were recorded for the ethanol extract and 71.0 and 84.2 mg/mL for the water extract of A. conyzoides, respectively. Based on the results, the crude extracts (water and ethanol) of A. conyzoides leaves were weakly effective against the MRSA. These findings disagree with the practice of the traditional therapeutic practitioners who used these plant extracts solely without combining with other plant extracts for the treatment of MRSA-associated skin and respiratory diseases. [23]


Insecticidal activity

The ethanolic extract of A. conyzoides and other medicinal plants of Brazil have been reported to exhibit insecticidal activity. Results obtained show that a high LC50 value of 148 mg/L of A. conyzoides compared to other oils and extracts. Although the LC50 value was high, this oil is known to induce morphogenetic abnormalities in mosquito larvae. A previous study reported that precocenes I and II, which are present in the oil, possessed anti-juvenile hormone activity that contributed to precocious metamorphosis by eliminating the control of gene expression normally exerted by the juvenile hormones in some insects. In this study, it was observed that after treatment with different concentrations of A. conyzoides oil, the larvae of A. aegypti that were not killed showed problems in completing their development. The pupae were pigmented or incompletely emergent, adults showed intense rings of pigmentation on the tarsus and abdomen, and some developed very stunted wings and low production of eggs were observed. Thus, the oil of A. conyzoides may be use in the fight against A. aegypti and other Culicid vectors. Together with its larvicidal activity, the effects that the essential oils of A. conyzoides have on insect metamorphosis would decrease the reproductive efficiency of the adult insect, thus reduce the population of A. aegypti. [24]

Petroleum ether extract of Eichhornia crassipes and acetone extracts of A. conyzoidesCleome icosandraTagetes erectes and Tridax procumbens showed significant growth inhibitory activities and have juvenile hormone mimicking activity to the treated larvae of C. quinquefasciatus. A few changes were observed after administration of these extracts, such as larval pupal intermediates, demalanised pupae, defective egg rafts and adults with deformed flight muscles. Biting behaviour was observed to be affected significantly only with A. conyzoides, Cleome icosandra and Tridax procumbens extracts. Loss of fecundity was observed in the treated mosquitoes but no sterile effects could be seen. Adults, obtained from larvae exposed to the plant extracts produced significantly shorter egg-rafts compared to control. [25]

Analgesic activity

The raw extract of A. conyzoides was investigated for antinociceptive properties in the rat. The raw extract of A. conyzoides constituted of the lyophilised powder of the juices extract of the leaves which was prepared by using a crusher. A dilution of 1% in NaCl 0.9% was prepared using the lyophilisate. Wistar rats of both sexes (200-250 g) were used in this study. Several doses of the extract (25, 50, 100, 125, 150 mg/kg) were administered intraperitonealy to the animals. The animals’ behaviour was observed macroscopically and the spontaneous motor activity and the rectal temperature were measured in each rat. Evaluation of analgesic activity was done using the hot plate method and acetic acid-induced writhing test. Effects of the raw extract of A. conyzoides were compared to morphine, (7.5 mg/kg, s.c.) and control (0.9% NaCl, i.p.). Doses of 50 and 100 mg/kg of the raw extract were used because all doses equal or higher than 125 mg/kg caused mortality to the rats. Based on these findings, A. conyzoides caused a precocious ataxia, sedation and a slight ptosis. These effects disappeared six hours after injection and a reduction in the spontaneous motor activity of the rats were observed. [26]

Radioprotective activity

The alcoholic extract of A. conyzoides was studied for its protective effect against radiation-induced mortality in mice exposed to 10 Gy of gamma radiation. Various doses (0, 25, 50, 75, 100, 125, 150, 300, 600 and 900 mg/kg) were administered to the mice. Administration of the alcoholic extract resulted in a dose-dependent decline in radiation-induced mortality up to a dose of 75 mg/kg, the dose at which the highest number of survivors (70.83%) was observed. Thereafter, the number of survivors declined with increasing doses of the A. conyzoides alcoholic extract and a nadir was reached at 900 mg/kg. The acute toxicity studies showed that the A. conyzoides alcoholic extract was non-toxic up to a dose of 3000 mg/kg, the highest dose that could be tested for acute toxicity. Since the number of survivors was highest for 75 mg/kg, this was considered the optimum dose for radioprotection and was used in further studies in which mice were treated with 75 mg/kg of the extract before being exposed to 6, 7, 8, 9, 10 and 11 Gy of gamma radiation. Treatment of mice with 75 mg/kg dose of the extract reduced the severity of the symptoms of radiation sickness and mortality at all exposure doses. A significant increase in survival was observed in the treated group compared to the non-treated irradiated group. Treatment with A. conyzoides alcoholic extract effectively protected mice against the gastrointestinal as well as bone marrow related death, as revealed by the increased number of survivors at all irradiation doses. The dose reduction factor was found to be 1.3. [27]

Radical scavenging activity

Various doses of the A. conyzoides alcoholic extract were also evaluated for their in vitro scavenging action on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a chemically stable free radical, in other to understand the mechanism of action. The A. conyzoides alcoholic extract was found to scavenged DPPH radicals in a concentration-dependent manner, indicating that the radioprotection afforded by the A. conyzoides alcoholic extract may be due to the scavenging of reactive oxygen species induced by ionising radiation. [27]

Electrophysiological activity

An extract obtained from the leaves of A. conyzoides was investigated for its electrophysiological effects. Based on the findings of this study, the extract of the A. conyzoides leaves changed the electrocardiogram, the velocity of the atrial impulses, and the resistance of coronary vessels in the isolated guinea-pig heart. The alterations in the electrocardiography were the P-R interval which significantly increased from 80±1.4 ms to 105 ± 14 ms while the Q-T interval significantly decreased from 170 ± 2 ms to 154 ± 7 ms. The heart rate was also significantly decreased from 170 ± 17 bpm to 152 ± 21 bpm, and the velocity of the atrial impulses also significantly decreased from 51 ± 2 cm/s to 45 ± 3 cm/s. Meanwhile, the time spent for the impulse to be conducted from the atrium to the His bundle was significantly elevated from 73 ± 13 ms to 100 ± 24 ms. However all of these electrophysiological effects of the extract obtained from the leaves of A. conyzoides disappeared after a washout. [28]

Spasmolitic activity

Effects of the water soluble fraction of A. conyzoides were studied in isolated rat uterus and intestinal smooth muscles in order to evaluate its popular use as a spasmolytic. The water soluble fraction of A. conyzoides (0.2 and 0.4 mg/mL) increased EC50 values and decreased maximum responses to acetylcholine and calcium chloride. The water soluble fraction of A. conyzoides (0.5-3.3 mg/mL) also produced direct myorelaxant effect on smooth muscle preparations. Theophylline (10-3 M) potentiated the relaxant action of the water soluble fraction of A. conyzoides. Theophylline also prevented the decrease in maximum response promoted by this compound in acetylcholine concentration-effect curves. These results seem to be partially linked to calcium mobilisation. The data also suggest that this compound could act synergistically with theophylline in the inhibition of cyclic AMP phosphodiesterase. The findings from this study supported the traditional medicinal usage of A. conyzoides as a spasmolytic. [29]

Antithrombotic activity

Six medicinal plants indigenous to Africa were evaluated for their activity on experimental thrombosis in mice. This study established the antithrombotic effect of the extracts of Azadirachta indicaBridelia ferrugineaCommiphora molmolGarcinia kola, Curcuma longa, and A. conyzoides. Of the plants screened, only the extract of Commiphora molmol exhibited the strongest antithrombotic activity, while the extract of A. conyzoides showed no significant activity. [30]

Toxicity

Hepatotoxic activity

A previous study indicated the presence pyrrolizidine alkaloids in A. conyzoides which are known to be hepatotoxic and to cause lung cancer and variety of other ailments. [19]

Acute toxicity

A study on chronic toxicity was done using A. conyzoides plant extract (250 mg/kg body wt. or 500 mg/kg body wt) or vehicle (5 mL/kg body wt) administered orally on a daily basis for 90 days. No mortality or toxicity was observed except for a reduction of serum glutamic pyruvic transaminase (SGPT) level in rats treated with the hydroalcoholic extract of A. conyzides leaves at 500 mg/kg body weight. [19]

Clinical Data

No documentation.

Dosage

No documentation.

Poisonous Management

No documentation.

Line drawing

 

301

Figure 1: The line drawing of A. conyzoides [3].

References

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