natural-products-in-plant-pest-management

Global Scenario and Natural Products 151.7 Higher Plant Products as Inhibitors of Aflatoxin SecretionsThe post-harvest colonization of various moulds on food commoditiesreduces their shelf life and market value, as well as rendering them unfit forhuman consumption because of the secretion of different types of mycotoxins,including aflatoxin, that cause undesirable effects on human health.Hence, both qualitative as well as quantitative losses of food commoditieshave been reported due to fungal infestations. For the complete protectionof stored food commodities from fungal biodeterioration, a fungitoxicantshould be inhibitory to fungal growth as well as aflatoxin secretion. Reducingaflatoxin residue levels in food or feed can confer international tradeadvantages in developing countries and there may also be long-term benefitsfor the local population through health improvement (Dichter, 1987). Somenatural products from plants such as allicin from garlic and onion extracts,clove oil, and black and white pepper have been reported to control fungaltoxins (Ankri and Mirelman, 1999). Leaves of Garcinia indica (Selvi et al.,2003), Morinda lucida and Azadirachta indica (Bankole, 1997) have been foundeffective in controlling aflatoxin production in food commodities. Some ofthe natural products, such as cinnamon and clove oil (Sinha et al., 1993), phenols(Singh, 1983), some spices (Hasan and Mahmoud, 1993) and many essentialoils (Razzaghi-Abyaneh et al., 2008) have been reported as effective inhibitorsof fungal growth and aflatoxin production. The extracts of several wild andmedicinal plants have also been tested against aflatoxin-producing fungi(Bilgrami et al., 1980). Essential oils from Cymbopogon citratus, Monodora myristica,Ocimum gratissimum, Thymus vulgaris and Zingiber officinale have beenreported for their inhibitory effect on food spoilage and mycotoxin-producingfungi. Recently, the essential oils of Cinnamomum camphora (Singh et al., 2008a),Thymus vulgaris (Kumar et al., 2008) and Pelargonium graveolens (Singh et al.,2008b) have been reported to suppress aflatoxin B 1secretion by different toxigenicstrains of A. flavus. However, there is little in the literature on the abilityto monitor aflatoxin secretions by toxigenic fungal strains on food commodities.1.8 ConclusionSustainable agriculture aims to reduce the incidence of pests and diseases tosuch a degree that they do not seriously damage the farmer’s crop withoutupsetting the balance of nature. One of the aims of sustainable agriculture isto rediscover and develop strategies of which the cost and ecological sideeffectsare minimal. The secondary compounds of plants are a vast repositoryof compounds with a wide range of biological activities. Unlike compoundssynthesized in the laboratory, secondary compounds from plants are virtuallyguaranteed to have biological activity and that activity is likely to functionin protecting the producing plant from a pathogen, herbivore, orcompetitor. Among the variety of nature’s ecosystem services, natural pestcontrol is an important aspect. Hence, it is pertinent to explore the pesticidalactivity of plant products.