Biological Activity of Ethanolic Extract Fractions of Dracaena arborea Against Infestation of Stored Grains by Two Storage Insect Pests

Abstract

As part of on-going efforts to use eco-friendly alternatives to chemical pesticides, ethanolic extract of dried leaves of Dracaena arborea (Willd.) Link (Dragon tree; Dracaenaceae) dissolved in distilled water and partitioned between equal volumes of n-hexane, chloroform, ethyl acetate and butanol was assessed in the laboratory against infestation by Sitophillus zeamais Motsch. and Callosobruchus maculatus Walp. in stored maize and cowpea, respectively. One hundred grams each of maize grains and cowpea seeds were treated with 400 mg kg(-1) of each extract fraction to evaluate contact toxicity, damage assessment, effect on eggs and immature stages and progeny production in both insect species. Contact toxicity by topical application, toxicity upon filter paper application and repellency using area preference method were carried out on the two insect species. Results showed that the extract fraction caused significant (p < or = 0.05) mortality of both insect pests with a high residual contact activity against S. zeamais. Grain damage was significantly (p < or = 0.01) reduced, while progeny production and development of eggs within grains were inhibited. The extract fractions evoked a strong repellent action against S. zeamais but moderate action against C. maculatus. The full potentials of using extract fractions of D. arborea as grain protectant against infestation by insect pests is discussed.

Evaluation of Local Spices as Biopesticides for the Control of Ootheca mutabilis, Shalbera and Clavigralla tomentosicollis (Stal.) on Cultivated Cowpea (Vigna unguiculata L.) in Nigeria

“…The spices could have acted as deterrents thus preventing the insect pests from settling, feeding and ovipositing on cowpea. Furthermore, the spices may have had toxic effect on adult and immature stages of the insect pests, thus leading to the decreased mean number of insects observed on treated plots (Obeng-Ofori, 1995;Epidi & Udo, 2009). …”

“…It has been reported (Emosairue & Uguru, 2001;Denloye & Makanjuola, 2001) that spices contain chemical principles capable of deterring insect pests from treated plants thus, preventing insects from staying longer on the crop and therefore minimizing the degree of damage. Therefore, the presence of repellent properties in spices has contributed to increased crop production and giving the fact that they are eco-friendly makes them a choice material for replacing synthetic pesticides (Epidi & Udo, 2009). Apart from the deterrent and repellent properties in the spices, there could be possible mortality arising from insect contact with the spices and this would further reduce the number of insects attacking cultivated cowpea (Udo, 2009 Generally, the significant reduction in pest population, damage level observed and the increased in pod yield in treated plots is a strong indication of the presence of insecticidal properties in the spices which prevented insect attack and damage to flower buds necessary for pod development and yield.…”

Dracaena arborea leaf extract: A phytotherapeutic option for ameliorating oxidative stress-mediated endocrine and testicular disorders in alloxan-induced diabetic rats

“…The mechanisms of action of DAE in ameliorating diabetic and testicular lesions in diabetic rats may be associated with pharmacological activities of its phytochemical constituents such as those in antioxidant activities [34]. Androgenic effects may also be mediated by phytochemical constituents of DAE, such as flavonoids [10,11,13], phenols, anthraquinones [13,31], saponins, tannins [31], alkaloids and phytosterols [13,31]. All of these phytochemicals were identified and confirmed to be present in D. arborea leaf extract in our preliminary phytochemical screening study [25].…”

“…Alloxan (ALX) monohydrate is a strong oxidizing agent that has diabetogenic properties due to its ability to destroy β-cells of the pancreatic islet, possibly by excess free radical generation leading to oxidative stress conditions [11]. ALX monohydrate and its reduction product; dialuric acid, generates a futile redox cycle that leads to the formation of superoxide radicals [12].…”

“…One of such promising plant with antioxidant properties is Dracaena arborea (D. arborea), which belongs to the family Asparagaceae [10]. The genus is composed of about 500 species of woody stemmed plants mostly native to countries in the tropics and subtropics [10,11]. D. arborea root and leaf extracts (DAE) have since been used locally in many countries as aphrodisiac to treat sexual inadequacy and to stimulate sexual vigor [11,12].…”