EXTRACTION AND SCREENING OF PHENOLICS OF SOME SPODOPTERA LITTORALIS (BOISD.) HOST PLANTS

Abstract

Total phenols of some cotton leafworm, Spodoptera littoralis (Boisd.) host plant leaves were extracted by using homogenizing method and aqueous (80%, v/v) methanol and acetone. Quantification of phenolics was carried out by Folin- Ciocalteau method. The results revealed that the amount of phenols significantly differed among the tested host plants in the following order: Castor bean < garden rocket < cabbage < grapevine. The total phenols of cabbage and castor bean leaves extracted by methanol were significantly higher than those extracted by acetone. They were 5.83 and 4.63 mg GA/dw for cabbage and castor bean leaves extracted by methanol, respectively, while they equaled to 5.2 and 4.03 mg GA/dw for those extracted by acetone, respectively. On the other hand, the results revealed that the amount of phenolics was not proportional to the amount of crude extract produced. It could be concluded that aqueous methanol is more efficient than aqueous acetone in extracting phenolics from the tested host plants of the cotton leafworm, and by using homogenizing methods, the yield of phenols was satisfactory and rapidly extracted. The situation that fulfils the requirement of more screening of these compounds in different S. littoralis host plants, since current strategies to control insects using natural pesticides and transgenic plants might rely on phenolic compounds that confer resistance to field crops.