80 research outputs found
Métodos de secagem e rendimento dos extratos de folhas de Plectranthus barbatus (boldo-da-terra) e P. ornatus (boldo-miúdo)
Novel agmatine derivatives in Maerua edulis with bioactivity against Callosobruchus maculatus, a cosmopolitan storage insect pest
Food security in developing countries is threatened by crop pests and ectoparasites in livestock. Strategies for their management still rely on synthetic pesticides which are not always effective and the active ingredients persist in the environment with negative consequences for beneficial arthropods, farmers and consumers, hence necessitating research on sustainable alternatives. Botanical insecticides are increasingly relevant, typically having lower impacts on users, consumers and the environment. One example is the southern African shrub the Blue bush-berry, Maerua edulis. Recent work reported effective pest control using this plant species against cattle ticks, storage beetles and vegetable pests. However, little is known about the chemistry underlying activity and this is essential to optimize its use. Here, we identified two novel plant chemical tructures, the E and Z isomers of cinnamoyl-4-aminobutylguanidine along with the E and Z isomers of 4-hydroxycinnamoyl-4-aminobutylguanidine in the leaves of M. edulis. We isolated these compounds from the leaves and elucidated their chemical structures
using various spectroscopic techniques including High Resolution Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy. We also identified a further 11 closely related structures of which 6 are tentatively reported here for the first time. Stachydrine and 3-hydroxystachydrine were also identified in the leaf extract, and occurred at very high concentrations; up to 2% w/w of dry leaves. We tested these two compounds, along with the 4 main cinnamoylamides and the crude M. edulis leaf extract against the cowpea bruchid Callosobruchus maculatus at concentrations equivalent to those present in extracts used by smallholder farmers. Mortality of insects exposed to crude plant extracts after 72 h was significantly higher than the untreated control although still lower than for insects exposed to rotenone, the positive control. The two new compounds and stachydrine showed similar activity to the crude extracts suggesting that these compounds explained the activity of the extract. After 6 days, the mortality of insects exposed to crude extracts and isolated compounds was similar to that recorded with the positive control. The stachydrine fraction and the E and Z isomers of cinnamoyl-4-aminobutylguanidine also inhibited oviposition activity in fecund female beetles. Our data show that methanol extracts of M. edulis were toxic to C. maculatus and inhibited oviposition even at 0.1% w/v so these foliar chemicals may explain the activity of the plant material. We also synthesized the amides which facilitated structural elucidation, produced adequate quantities for testing and demonstrated the potential for commercial
synthesis
Antimicrobial, Antioxidant and Cytotoxic Activities and Phytochemical Screening of Some Yemeni Medicinal Plants
The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities
Screening of Tanzanian medicinal plants for anti-Candida activity
BACKGROUND: Candida albicans has become resistant to the already limited, toxic and expensive anti-Candida agents available in the market. These factors necessitate the search for new anti-fungal agents. METHODS: Sixty-three plant extracts, from 56 Tanzanian plant species obtained through the literature and interviews with traditional healers, were evaluated for anti-Candida activity. Aqueous methanolic extracts were screened for anti-Candida activity by bioautography agar overlay method, using a standard strain of Candida albicans (ATCC 90028). RESULTS: Twenty- seven (48%) out of the 56 plants were found to be active. Extracts of the root barks of Albizia anthelmintica and Balanites aegyptiaca, and roots of Plectranthus barbatus showed strong activity. CONCLUSION: The extracts that showed strong anti-Candida activity are worth of further investigation in order to isolate and identify the active compounds
ChemInform Abstract: New Clerodane Diterpenoid and Flavonol-3-methyl Ethers from Dodonaea viscosa
ChemInform Abstract: Two New Naphthalene and Anthraquinone Derivatives from Asphodelus tenuifolius.
Chromosomal abnormalities as a cause of recurrent abortions in Egypt
Background: In 4%-8% of couples with recurrent abortion, at least one
of the partners has chromosomal abnormality. Most spontaneous
miscarriages which happen in the first and second trimesters are caused
by chromosomal abnormalities. These chromosomal abnormalities may be
either numerical or structural. Material and Methods : Cytogenetic
study was done for 73 Egyptian couples who presented with recurrent
abortion at Genetic Unit of Children Hospital, Mansoura University.
Results : We found that the frequency of chromosomal abnormalities was
not significantly different from that reported worldwide. Chromosomal
abnormalities were detected in 9 (6.1%) of 73 couples. Seven of
chromosomal abnormalities were structural and two of them were
numerical. Conclusion : Our results showed that 6.1% of the couples
with recurrent abortion had chromosomal abnormalities, with no other
abnormalities. We suggest that it is necessary to perform cytogenetic
in vestigation for couples who have recurrent abortion
Chromosomal abnormalities as a cause of recurrent abortions in Egypt
Background: In 4%-8% of couples with recurrent abortion, at least one
of the partners has chromosomal abnormality. Most spontaneous
miscarriages which happen in the first and second trimesters are caused
by chromosomal abnormalities. These chromosomal abnormalities may be
either numerical or structural. Material and Methods : Cytogenetic
study was done for 73 Egyptian couples who presented with recurrent
abortion at Genetic Unit of Children Hospital, Mansoura University.
Results : We found that the frequency of chromosomal abnormalities was
not significantly different from that reported worldwide. Chromosomal
abnormalities were detected in 9 (6.1%) of 73 couples. Seven of
chromosomal abnormalities were structural and two of them were
numerical. Conclusion : Our results showed that 6.1% of the couples
with recurrent abortion had chromosomal abnormalities, with no other
abnormalities. We suggest that it is necessary to perform cytogenetic
in vestigation for couples who have recurrent abortion
Cytoprotective effect of honey against chromosomal breakage in fanconi anemia patients in vitro
Background : Natural honey is widely used all over the world as a
complementary and alternative medicine in various disorders including
Fanconi anemia (FA). FA is a rare genetic chromosomal instability
syndrome caused by impairment of DNA repair and reactive oxygen species
(ROS) imbalance. This disease is also related to bone marrow failure
and cancer. The aim of this study was to evaluate the cytoprotective
effect of honey on mitomycin C (MMC-) induced chromosomal damage in
peripheral lymphocytes from FA patients. Materials and Methods
:Treatment of these complications with alkylation agents MMC may
enhance chromosomal breakage. We have evaluated the effect of honey on
MMC- induced chromosomal breakage in FA blood cells using chromosomal
breakage assay. The basal chromosomal breakage count was higher among
FA patients than healthy subjects. Results : The addition of MMC alone
gave a significantly higher of chromosomal breakage in FA patients than
control group (P < 0.0001). Pre- treatment with honey significantly
inhibited breakage induced by MMC in FA patients by its antioxidant
effect. Conclusion : Honey can prevent MMC- induced chromosomal
breakage by its antioxidant effect
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