Pesticidal plants in Africa: a global vision of new biological control products from local uses

Botanical insecticides provide a multitude of chemistries for the development of new pest management products. Despite relatively low rates of expansion in botanically based pesticides, regulatory changes in many parts of the world are driving a renaissance for the development of new natural pest control products that are safer for human health and the environment. Africa is arguably the continent with the most to gain from developing natural plant-based pesticides. Hundreds of indigenous and exotic species with pesticidal properties have been reported from Africa through various farmer surveys and subsequent research, many of which have been confirmed to be active against a range of arthropod pests. Onfarm use of pesticidal plants, particularly among resource-poor smallholder farmers, is widespread and familiar to many African farmers. Until recently, the pyrethrum industry was dominated by East African production through small holder farmers, showing that non-food cash crop production of pesticidal plants is a realistic prospect in Africa when appropriate entrepreneurial investment and regulatory frameworks are established. This paper reviews the current status of research and commercialisation of pesticidal plant materials or botanically active substances that are used to control pests in Africa and establishes where major gaps lie and formulates a strategy for taking research forward in this area

第774回 千葉医学会例会・第二内科例会 64.

The apolipoprotein E (APOE) gene is the most highly associated susceptibility locus for late onset Alzheimer's Disease (AD), and augmenting the beneficial physiological functions of apoE is a proposed therapeutic strategy. In a high throughput phenotypic screen for small molecules that enhance apoE secretion from human CCF-STTG1 astrocytoma cells, we show the chrysanthemic ester 82879 robustly increases expressed apoE up to 9.4-fold and secreted apoE up to 6-fold and is associated with increased total cholesterol in conditioned media. Compound 82879 is unique as structural analogues, including pyrethroid esters, show no effect on apoE expression or secretion. 82879 also stimulates liver x receptor (LXR) target genes including ATP binding cassette A1 (ABCA1), LXRα and inducible degrader of low density lipoprotein receptor (IDOL) at both mRNA and protein levels. In particular, the lipid transporter ABCA1 was increased by up to 10.6-fold upon 82879 treatment. The findings from CCF-STTG1 cells were confirmed in primary human astrocytes from three donors, where increased apoE and ABCA1 was observed along with elevated secretion of high-density lipoprotein (HDL)-like apoE particles. Nuclear receptor transactivation assays revealed modest direct LXR agonism by compound 82879, yet 10 μM of 82879 significantly upregulated apoE mRNA in mouse embryonic fibroblasts (MEFs) depleted of both LXRα and LXRβ, demonstrating that 82879 can also induce apoE expression independent of LXR transactivation. By contrast, deletion of LXRs in MEFs completely blocked mRNA changes in ABCA1 even at 10 μM of 82879, indicating the ability of 82879 to stimulate ABCA1 expression is entirely dependent on LXR transactivation. Taken together, compound 82879 is a novel chrysanthemic ester capable of modulating apoE secretion as well as apoE-associated lipid metabolic pathways in astrocytes, which is structurally and mechanistically distinct from known LXR agonists

Efficacy of Major Plant Extracts/Molecules on Field Insect Pests

Insect pests are considered the major hurdle in enhancing the production and productivity of any farming system. The use of conventional synthetic pesticides has led to the emergence of pesticide-resistant insects, environmental pollution, and negative effects on natural enemies, which have caused an ecological imbalance of the predator-prey ratio and human health hazards; therefore, eco-friendly alternative strategies are required. The plant kingdom, a rich repertoire of secondary metabolites, can be tapped as an alternative for insect pest management strategies. A number of plants have been documented to have insecticidal properties against various orders of insects in vitro by acting as antifeedants, repellents, sterilant and oviposition deterrents, etc. However, only a few plant compounds are applicable at the field level or presently commercialised. Here, we have provided an overview of the broad-spectrum insecticidal activity of plant compounds from neem, Annona, Pongamia, and Jatropha. Additionally, the impact of medicinal plants, herbs, spices, and essential oils has been reviewed briefl

Commercial opportunities for botanical insecticides in a challenging regulatory landscape

Interest in plant-derived insecticides has grown markedly in the past 35 years, as the voluminous scientific literature dedicated to this subject attests. According to a recent bibliometric study, over 20% of scientific papers published on insecticides in 2011 dealt with botanical extracts or plant natural products. Until very recently this tremendous research effort had not been reflected in the commercial introduction of new botanical insecticides. While pyrethrum (Tanacetum cineraraeifolium) continues to be the most widely used botanical insecticide worldwide, insecticides based on neem (Azadirachta indica) and various plant essential oils (Rosmarinus, Syzygium, Mentha spp.) are gaining acceptance among growers, professional pest control operators, and consumers. Stringent regulatory regimes in the EU, USA and other industrially advanced countries have been a barrier to the introduction of new botanical insecticides, although a handful of new products have been registered. In contrast, acceptance of new botanical insecticides is moving at a faster pace in China, India and Brazil. Some examples of newer botanicals in these countries will be presented. Chemical variability of active principles in source plant material, owing to both biotic and abiotic factors, must be managed by producers to create products with consistent efficacy and stability in storage. This consistency is also demanded by regulatory agencies. In less developed countries, where arguably the worst cases of human poisoning and environmental contamination from synthetic insecticides have occurred, the use of simple plant preparations based on locally available plants is being promoted

Comparative Larval Growth of the Variegated Cutworm, Peridroma saucia, from a Laboratory Colony and a Wild Population

Larval growth of variegated cutwormS from a laboratory colony (maintained for over 12 generations) was compared with that of the F1 generation of field-collected larvae on an artificial medium. After eleven days of feeding , larvae from the wild population weighed, on average, over three times as much as those from the laboratory colony. However, when larvae from each population were reared on media spiked with an inhibitory plant extract, the degree of growth inhibition relative to their respective controls was equivalent

Insecticidal Activity of 28 Essential Oils and a Commercial Product Containing Cinnamomum cassia Bark Essential Oil against Sitophilus zeamais Motschulsky

Maize weevils, Sitophilus zeamais, are stored product pests mostly found in warm and humid regions around the globe. In the present study, acute toxicity via contact and residual bioassay and fumigant bioassay of 28 essential oils as well as their attraction–inhibitory activity against the adults of S. zeamais were evaluated. Chemical composition of the essential oils was analyzed by gas chromatography-mass spectrometry, and a compound elimination assay was conducted on the four most active oils (cinnamon, tea tree, ylang ylang, and marjoram oils) to identify major active constituents. Amongst the oils examined, cinnamon oil was the most active in both contact/residual and fumigant bioassays, and exhibited strong behavioral inhibitory activity. Based on the compound elimination assay and chemical analyses, trans-cinnamaldehyde in cinnamon oil, and terpinen-4-ol in tea tree and marjoram oils were identified as the major active components. Although cinnamon oil seemed promising in the lab-scale bioassay without rice grains, it failed to exhibit strong insecticidal activity when the container was filled with rice. When a cinnamon oil-based product was applied both in an empty glass jar and a rice-filled container, all weevils in the empty jar were killed, whereas fewer than 15% died in the rice-filled container.Land and Food Systems, Faculty ofNon UBCReviewedFacult