Phytoecdysone of Pteridium aquilinum (L) Kuhn (Dennstaedtiaceae) and its pesticidal property on two major pests

Abstract

Preliminary phytochemical and HPLC analyses of Pteridium aquilinum (L) Kuhn (Pteridophyceae) was carried out in the Chloroform (CE) and ethanol extracts (EE) and also the hexane (HF) and aqueous fractions (AF) obtained during the process of phytoecdysteroid separation and crude phytoecdysteroids fraction (CEF). Except in aqueous fraction, all other fraction consists of steroids. Alkaloids are absent in all the extracts. Saponins and xanthoprotiens were present in CE, EE and AF but were absent in HF and CEF. Tannins and flavonoids are present in EE and AF and were absent in CE, EE and CEF. HPLC analysis of P. aquilinum has both ∝ and β ecdysones. CE recorded β-ecdysone having a Rt value 2.46 (81.3%) and 2.49 (18.6%). In addition to the β ecdysone the EE and CEF contains α ecdysone [RT = 1.52 (30.96%) and 0.85 (63.0%)]. Among the three extracts tested, EE was the most effective, followed by CEF. Of the two experimental animals, Helicoverpa armigera showed more susceptibility to the fern extracts than Spodoptera litura. The different extracts of the same plant showed differences in their toxic as well as growth disrupting responses. The order of concentration required for 50% mortality (LD₅₀) of H. armigera was 0.198, 0.112 and 0.198 percentages for CE, CEF and EE. As observed in H. armigera, S. litura also recorded the highest lethal activity in EE (0.141%) followed by 0.128% of CEF and 0.160% of CE.

Keywords:

• Pteridium aquilinum
• phytochemistry
• phytoecdysone
• Helicoverpa armigera
• Spodoptera litura

Acknowledgements

The senior author (K.SR) is thankful to DST, Govt. of India, New Delhi for financial support for this work and to Rev. Fr. A. Antonysamy, S.J. Principal and Prof. M. Thomas Punithan, Head Dept. of Zoology, St. Xavier’ college, Palayamkottai for institutional facilities.