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Insect pest management is facing the economic and ecological challenge worldwide due to the human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanicals containing active insecticidal phytochemicals appear to be promising to address some of these problems. Therefore, there is a continuous need to explore new active molecules with different mechanisms of action. Secondary metabolites present in plants apparently function as defense (toxic), which inhibits reproduction and other processes. The phytochemical biomolecules could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability. In this article, the current state of knowledge on phytochemical sources and insecticidal activity, their mechanism of action in insects, resistance, and promising advances made in phytochemical research are reviewed. 相似文献
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May Fern TohJoanna E. Burdette 《Fitoterapia》2011,82(1):67-70
The biological mechanism of action for any botanical extract is a necessary part of discovery to determine pharmacological use and safety. Interestingly, many activities that are governed by endogenous compounds are not fully understood making the characterization of mechanisms elusive. For example, phytoestrogens are being consumed for menopausal symptoms while the biological action of estradiol are still being investigated. Therefore, long term efficacy and safety issues are a challenge in the field. As new activities are associated with new biological pathways, an important component of therapeutic discovery will need to be the re-evaluation of negative or less active natural products to determine their relative use as medicines. 相似文献
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M. Bengtsson E. Wulff H. J. Lyngs Jørgensen A. Pham M. Lübeck J. Hockenhull 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(2):187-198
The effect of an extract of Yucca schidigera on the control and infection process of the apple scab pathogen, Venturia inaequalis, was examined and compared with the chemical resistance inducer, acibenzolar-S-methyl (ASM). In seedling assays, both materials significantly reduced apple scab symptoms and pathogen sporulation on leaves
and both showed similar control efficacies as the reference treatment, sulphur. Whereas yucca extract and sulphur gave significant
inhibition of conidial germination in vitro, ASM did not inhibit germination. Histopathological studies of the infection process of V. inaequalis in apple leaves showed that the yucca extract primarily acted by inhibiting pre-penetration events and penetration itself.
In contrast, the ASM treatment significantly inhibited more stages of the infection process (pre-penetration, penetration
and post-penetration events). These observations suggest that the yucca extract acted mainly by a direct fungitoxic effect
whereas ASM, as expected, acted as a resistance inducer. However, expression studies of two genes encoding the PR proteins,
PR1 and PR8, in apple seedlings indicated that yucca extract may also affect plant defence as expression of both genes was
up-regulated following yucca treatment, to a level similar to that observed after treatment with ASM. The fungitoxic effect
of sulphur on V. inaequalis was also confirmed in this study. 相似文献
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Toxicity and repellent activities of aqueous extracts of nine medicinal plants were evaluated on different life stages of
the sweet potato whitefly, Bemisia tabaci. Tomato plants infested with whiteflies were dipped in 10% (wt/wt) of each plant extract for toxicity evaluation. Repellency
was evaluated in a choice experiment with detached tomato leaves. All extracts evaluated were relatively ineffective against
the adult stage. Extracts of Ruta
chalepensis, Peganum harmala and Alkanna strigosa were effective in reducing the numbers of B. tabaci immatures similar to the reduction observed in the imidacloprid treatment. These three extracts were not detrimental B. tabaci parasitoid, Eretmocerus mundus. In addition, the plant extracts Urtica pilulifera and T. capita were repellent to B. tabaci adults. These results indicate that the extracts from the plants R. chalepensis, P. harmala and A. strigosa could act as a potential source for natural product developed for B. tabaci management. 相似文献
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Tim C. Thoden Johannes Hallmann Michael Boppré 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):27-36
1,2-Dehydropyrrolizidine alkaloids (PAs), known to be nematotoxic in vitro, represent a class of secondary plant metabolites from hundreds of plant species worldwide. Pot experiments with the commercially
available PA-containing plants Ageratum houstonianum, Borago officinalis, Senecio bicolor, and Symphytum officinalis demonstrate that Meloidogyne hapla is not per se repelled by these plants as all species were infested with nematodes. However, the development of M. hapla juveniles was completely suppressed on A. houstonianum and S. bicolor. Soil in which A. houstonianum and S. bicolor were cultivated and incorporated contained 200–400 times less nematodes than soil treated with Lycopersicon esculentum. Depending on their qualitative composition of PAs at least some of these plants thus appear to be valuable tools for integrated
root-knot nematode management. 相似文献
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The Office of Dietary Supplements (ODS) and the National Center for Complementary and Alternative Medicine (NCCAM) were both established by Congress in the 1990s. ODS aims to strengthen knowledge and understanding of dietary supplements (DS). NCCAM promotes exploration of complementary and alternative medicine in the context of rigorous science. Together, they developed the Botanical Research Centers Program to promote interdisciplinary study of botanicals, particularly those found in DS, by supporting research activities ranging from plant and characterization to preclinical and early-phase clinical studies. These Centers are part of the coordinated efforts of ODS and NCCAM to enhance botanical research. 相似文献
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