Potential of Ageratum conyzoides in Inhibiting Nitric Oxide Synthase.

<b>Background and Objective:</b> Inflammation occurs <i>via</i> several mechanisms, one of which includes the production of Nitric Oxide (NO) catalyzed by inducible nitric oxide synthase (iNOS), which is inhibited selectively by isothioureas. <i>Ageratum conyzoides</i> L. has shown activity in reducing pain and inflammation, although the molecular mechanism had not been undertaken. The objectives of this work were (1) to study the mechanism of anti-inflammatory activity of <i>A. conyzoides</i> through inhibition of iNOS, (2) to correlate the iNOS inhibitory activity of the plant with the total flavonoid content of the plants and (3) to identify the flavonol synthase (FLS), an enzyme that catalyzes the production of quercetin. <b>Materials and Methods:</b> The inhibitory activity against iNOS was assayed by <i>in vitro</i> method. The total flavonoids (calculated as quercetin) of <i>A. conyzoides</i> were determined by fluorometry. The protein extraction of the leaves was carried out by employing Laing and Christeller's (2004) method, followed with SDS-PAGE. <b>Results:</b> The inhibitory activity (IC₅₀) of ethanol extract and ethyl acetate fraction of <i>A. conyzoides</i> against iNOS was 92.05 and 4.78 µg mL¹, respectively. Pearson correlation analysis resulted in 0.548 (ethanol extract) and 0.696 (ethyl acetate fraction). The total flavonoids (calculated as quercetin) contained in the ethanol extract and ethyl acetate fraction of <i>A. conyzoides</i> were 0.71 and 7.65%, respectively. The FLS in <i>A. conyzoides</i> leaves was identified at 31 kDa. <b>Conclusion:</b> <i>A. </i>c<i>onyzoides</i> L. is potential in inhibiting iNOS due to quercetin contained in the leaves. This report will add a scientific insight of <i>A. conyzoides</i> for biological sciences.

Seed germination ecology of Ageratum houstonianum: A major invasive weed in Nepal.

In recent years, spread of invasive alien plant species (IAPS) has been a major concern in Nepal. One such IAPS is Ageratum houstonianum, an Asteraceae, that is a prolific seed producer and difficult-to-control in farmland and various ecological regions causing crop yield and biodiversity losses. However, very little information is available on the germination biology and ecology of this species. Therefore, experiments were conducted to assess the effect of water stress, pH level, and light requirement on seed germination, and the effect of seed burial depth on seedling emergence. Water stress was simulated by polyethylene glycol solutions ranging from 0-5.56 MPa and pH solutions ranging from 4 to 9 were prepared using hydrochloric acid and sodium hydroxide. Germination tests were conducted in petri dishes lined with filter paper and placed in a controlled environment chamber set at 20° C. Light requirement comparisons were made by having petri dishes wrapped with aluminum foil or left unwrapped. Seedling emergence was evaluated by placing seeds at depths ranging from 0 to 20 mm in the soil. Results indicated that this species was moderately drought-tolerant because germination ceased beyond 0.51 MPa. Greater germination occurred at neutral to acidic than at alkaline pH levels. The seeds were positively photoblastic because no germination occurred under dark condition. No seedlings emerged from seeds placed more than 2 mm deep in the soil, indicating that this is a primarily surface germinating species. These findings will help predict future invasions and in development of management strategies for this IAPS.

Ethno medicinal survey of plants used by the indigenes of Rivers State of Nigeria.

CONTEXT: The medicinal plants used in the traditional medicine of Rivers State of Nigeria were surveyed. OBJECTIVE: The survey aims to identify and document the plants used amongst the indigenes of Rivers State. MATERIALS AND METHODS: Semi-structured interviews were conducted during a field trip to gather information from traditional medical practitioners (TMPs) and community elders. RESULTS: Medicinal plant species (188) representing 169 genera and 82 families used in the ethno medicine of the people of Rivers State were recorded from 460 households. The most represented genera were Ipomoea and Citrus providing four species each. The most important species showed the highest Fidelity level (FL) value and these included Ageratum conyzoides L. (Asteraceae) (100%) and Tridax procumbens L. (Asteraceae) (100%). The most important categories of diseases were those that showed the highest Informant consensus factor (ICF) value of 0.99, such as dermal or digestive problems and fever/malaria. The most used plant part was leaves (42%), while decoction was the main method of drug preparation (36%). DISCUSSION AND CONCLUSION: The survey shows that more than half of the medicinal plants gathered in Rivers State are also used in other countries of the world for various ailments. The high values of ICF recorded indicate high degree of agreement among the informants, while the high FL values suggest the popular use of the plants. The survey provides a useful source of information for TMPs and medicinal plant researchers. These medicinal plants gathered may bring about drug discovery and may also be incorporated into the healthcare delivery system of the country.

Temporal dynamics of the arthropod community in pear orchards intercropped with aromatic plants.

BACKGROUND: Increasing attention has been paid to enhancing biological control through habitat management in agricultural systems for enhanced pest management. Pest management benefits can be realised by intercropping, which can increase natural enemy abundance and, in turn, reduce pest abundance. In this study, the composition and temporal dynamics of arthropod communities in pear orchards when intercropped with aromatic plants were investigated, and the effectiveness and applicability of aromatic plants as intercrops for enhancing insect control were assessed. RESULTS: When compared with natural grasses or clean tillage, intercropping significantly reduced pest abundance and increased the ratio of natural enemies to pests. Intercropping also shortened the occurrence duration and depressed the incidence peak in annual dynamics curves of the pest subcommunity and the arthropod community, mainly because of the repellent effects of aromatic plants. Equally important, intercropping significantly reduced the numbers of major pests, such as Psylla chinensis, Aphis citricola and Pseudococcus comstocki, while their incidence period was delayed to varying degrees, and the numbers of their dominant natural enemies (Coccinella septempunctata, Phytoseiulus persimilis and Chrysoperla sinica) increased. CONCLUSION: Intercropping with aromatic plants led to a considerable improvement in arthropod pest management by enhancing the activity of the beneficial arthropod community within the pear orchard ecosystem.

Eco-physiological performance of two invasive weed congeners (Ageratum conyzoides L. and Ageratum houstonianum Mill.) in the Indo-Gangetic plains of India.

Morphological (easily measureable) and physiological (hard to measure) traits of two closely related invasive alien congeners-Ageratum conyzoides L. and Ageratum houstonianum Mill. were studied with a perspective that which species will be potentially be more successful as an invader in the Indo-Gangetic plains of India. Leaf construction cost (LCC) is considered as a quantifiable measure of energy demand for biomass production and is related to energy use efficiency as it include component of both morphological and physiological traits. We hypothesised that a low LCC would give the invaders growth advantage by utilizing energy efficiently. Low LCC of A. houstonianum on mass basis (0.54 g glucose g( -1)) and area basis (20.48 g m( -2)) gives insight into the success of this invasive weed over A. conyzoides. The present study gives evidence that how the morphological traits are linked to physiological traits that could directly affect invasive attributes of the invader, which in turn would be crucial to prioritize species for ecosystem management.

Estudo da divergência genética por características morfológicas entre acessos de mentrasto (Ageratum conyzoides L. ) coletados no estado do Tocantins em diferentes épocas / Genetic divergence study by morphologic traits among mentrasto (Ageratum conyzoides L. ) accessions collected in the state of Tocantins in different period

Este trabalho objetivou avaliar a divergência genética entre nove acessos de mentrasto (Ageratum conyzoides) por métodos multivariados utilizando caracteres morfológicos, em quatro épocas de colheita. Os nove acessos de mentrasto foram obtidos de plantas que ocorrem naturalmente nas cinco regiões climáticas do Estado do Tocantins. Em cada época de colheita foram avaliadas as características como biomassa fresca da parte aérea, biomassa seca, área foliar, número de folhas, floração e altura. Pela análise de agrupamento (método de Tocher) foram formados dois grupos na primeira e quarta épocas de colheita, três grupos na segunda época e quatro grupos na terceira época de colheita. Observou-se variação na constituição dos grupos pelos acessos nas épocas de colheita. A divergência genética entre acessos de mentrasto, avaliada por caracteres morfológicos, foi influenciada pelo estádio de desenvolvimento da espécie. A existência de variabilidade entre os acessos coletados em diferentes localidades fornece subsídio para a coleta sistematizada de germoplasma em A. conyzoides no Estado do Tocantins.

This study aimed to analyze the genetic divergence among nine mentrasto (Ageratum conyzoides) accessions by multivariate methods using morphologic traits for four harvesting periods. The nine accessions of mentrasto were obtained from plants that occur naturally in five climatic regions of the state of Tocantins. At each harvesting period, the following traits were evaluated: fresh biomass of the aerial part, dry biomass, leaf area, number of leaves, flowering and height. The grouping analysis (Tocher's method) identified two groups, in the first and fourth harvest periods, three groups in the second harvest period and four groups in the third harvest period. Variation was observed for the group constitutions among the different harvesting periods. The genetic divergence among mentrasto accessions, evaluated by morphologic traits, was influenced by developmental stage of specie. The existence of genetic variability among accessions from different regions supports the systematic collection of A. conyzoides germplasm in the state of Tocantins.

Análise de crescimento e anatomia foliar da planta medicinal Ageratum conyzoides L. (Asteraceae) cultivada em diferentes substratos / Growth analysis and leaf anatomy of the medicinal plant Ageratum conyzoides L. (Asteraceae) grown on different substrates

Ageratum conyzoides L. (Asteraceae) é uma espécie herbácea que ocorre em áreas de cerrado e, por se tratar de planta medicinal, é cultivada em escala familiar. O objetivo deste trabalho foi estudar possíveis alterações no desenvolvimento das plantas quando cultivadas em solos com texturas diferentes (solo de cerrado, franco arenoso ou solo de terra roxa, muito argiloso). Foram analisados aos 40, 70 e 90 dias, o comprimento do caule e da raiz, massa seca da parte aérea (caule e folhas) e das raízes, número de folhas e área foliar; além de parâmetros anatômicos foliares, como a densidade de tricomas. Os resultados mostraram que os comprimentos do caule e da raiz aumentaram no decorrer do experimento, independentemente do substrato (com exceção do comprimento da raiz de plantas cultivadas em solo de terra roxa). Porém, o comprimento do caule foi sempre maior nas plantas cultivadas em solo de cerrado, enquanto o comprimento da raiz foi significativamente maior somente aos 90 dias de cultivo neste solo. As biomassas secas da raiz e do caule também foram maiores nas plantas cultivadas em solo de cerrado por 70 e 90 dias, respectivamente. A massa seca foliar foi maior nas plantas cultivadas em solo de cerrado a partir dos 70 dias de experimento. Esse aumento foi devido ao maior número de folhas produzidas e a maior área foliar dessas plantas. No geral, a anatomia foliar não diferiu, porém o número de tricomas glandulares foi maior nas plantas cultivadas em solo de cerrado. Os resultados indicaram que esta espécie tem melhor desenvolvimento quando cultivada em solo mais arenoso.

Ageratum conyzoides L. (Asteraceae) is a herbaceous species found in cerrado areas and grown in family scale since it is a medicinal plant. The aim of this work was to study possible alterations in the plant development when grown in soils presenting different textures (a sandy-loam cerrado soil, or a very clayish red earth soil). At 40, 70 and 90 days, stem and root length, shoot (stem and leaves) and root dry matter, number of leaves and leaf area were evaluated, in addition to leaf anatomical parameters, such as trichome density. Stem and root length increased over the experiment under any substrate (except root length of plants grown on red earth soil). However, stem length was always higher in plants grown on cerrado soil, whereas root length was significantly higher only at 90 days of cultivation on this same soil. Root and stem dry biomass were also higher in plants grown on cerrado soil at 70 and 90 days, respectively. Leaf dry matter was higher in plants grown on cerrado soil from 70 days of experiment. This increase was due to the larger number of produced leaves and the higher leaf area of those plants. In general, leaf anatomy does not differ; however, the number of glandular trichomes was larger in plants grown on cerrado soil. Such results indicated that this species had a better development when grown on sandier soils.

Effect of parthenin--a sesquiterpene lactone from Parthenium hysterophorus--on early growth and physiology of Ageratum conyzoides.

A study was undertaken to assess the effect of parthenin--a sesquiterpene lactone from Parthenium hysterophorus--on the germination, growth, and some associated physiological changes in Ageratum conyzoides. The study reveals that germination and growth of A. conyzoides was severely reduced by parthenin in the concentration range of 50, 100, and 200 microM, while at 400 microM a complete inhibition of germination was observed. The radicle length of A. conyzoides was reduced more than the plumule length. Further, the content of the photosynthetic pigment chlorophyll was appreciably reduced in the leaves of test plants spray treated with parthenin at 200 microM concentration. However, this inhibitory effect declined with the passage of time and at 10 days after treatment only a 25% reduction in chlorophyll content was observed compared to 76% on the first day after spray. Likewise, the cellular respiration measured through 2,3,5-triphenyl tetrazolium chloride was found to be less in the treated leaves, and the inhibitory response also declined with time. The content of proteins and carbohydrates decreased with the passage of time after parthenin treatment. The specific activities of the enzymes protease and alpha- and beta-amylase were also adversely affected in the parthenin treated leaves. In the case of protease. the activity decreased with passage of time while those of the amylases increased. Thus, we conclude that parthenin affects the germination and growth of A. conyzoides by altering the contents of some macromolecules and the specific activities of some enzymes. Such observations may be helpful in further exploring parthenin's mode of action.