Insecticidal Activity of Myristicin from Piper mullesua

Abstract

Piper mullesua D. Don (syn. P. brachystachyum Wall. ex Hook. t.), commonly known as Pahari peepal, is indigenous to India and widely distributed in the Himalayas at an altitude of about 600 to 1500 m. In this paper, the isolation and insecticidal activity of myristicin, a 1,3-benzodioxole, from the hexane fraction of alcoholic extract of fruit bearing inflorescence of P. mullesua, is reported. Studies have been carried out on both the contact toxicity and antimetabolic activity against lepidopterous insect pest Spilarctia obliqua. Topical application of myristicin caused significant toxicity towards 4th instar larvae as compared to post-ingestive effect of the compound. Myristicin (4-methoxy-6[2-propenyl]-1,3-benzodioxole), belonging to the apiole group of compounds, was isolated and identified from the hexane fraction of alcoholic extract of Piper mullesua inflorescence. This compound efficiently killed fourth instar larvae of Spilarctia obliqua after 24 h by the topical application method. The LD 50 was found to be 104 µg/larva. Larvae, fed with single dose (200 µg/g diet) of myristicin in diet mix bioassay, resulted in low mortality after 24 h. However, with increased duration of time, the same single dose gave complete mortality after 72 h of feeding on fresh diet.