Insect feeding deterrent and growth inhibitory activities of scopoletin isolated from Artemisia annua against Spilarctia obliqua (Lepidoptera: Noctuidae)

Abstract

Artemisia annua (Asteraceae) is well known for its antimalarial activities due to presence of the compound artemisinin. We isolated a methoxy coumarin from the stem part of A. annua and confirmed its identity as scopoletin through mass spectral data. The structure was established from 1H‐nuclear magnetic resonance (NMR), 13C‐NMR. The compound scopoletin was evaluated for its feeding deterrence and growth inhibitory potential against a noxious lepidopteran insect, Spilartctia obliqua Walker. Scopoletin gave FD50 (feeding deterrence of 50%) value of 96.7 μg/g diet when mixed into artificial diet. S. obliqua larvae (12‐day‐old) exposed to the highest concentration (250 μg/g diet) of scopoletin showed 77.1% feeding‐deterrence. In a growth inhibitory assay, scopoletin provided 116.9% growth inhibition at the highest dose of 250 μg/g diet with a GI50 (growth inhibition of 50%) value of 20.9 μg/g diet. Statistical analysis showed a concentration‐dependent dose response relationship toward both feeding deterrent and growth inhibitory activities. Artemisinin is found mainly in the leaves of A. annua and not in the stems, which are typically discarded as waste. Therefore identification of scopoletin in stems of A. annua may be important as a source of this material for pest control.

Bioefficacy of cow urine based eco-friendly formulations against Spilarctia obliqua (Walker)

“…Cow urine alone was ineffective but the NSKE in urine resulted in no egg laying, minimum egg hatching (14-17% versus 88-89% in control) and maximum mortality of first instar larvae (93-97% versus 3-7% in control). Tripathi et al (2011) reported the deterrent and growth inhibitory activities of scopoletin isolated from Artemisia annua against Spilarctia obliqua (Lepidoptera: Noctuidae). Scopoletin gave FD 50 (feeding deterrence of 50%) value of 96.7 µg/g diet when mixed into artificial diet.…”

Current knowledge and future research perspectives on cassava (Manihot esculenta Crantz) chemical defenses: An agroecological view

“…This induction can confer resistance against the beetle by decreasing feeding preference (Olson and Roseland, 1991). Scopoletin (5) has also proved to be a feeding deterrent and has growth inhibition potential against Spilarctia obliqua (Lepidoptera: Noctuidae) (Tripathi et al, 2011). Recently esculin (7) has been involved in the inhibition of trehalases in insects, which may impair insect development (Silva et al, 2006).…”

“…These defenses can be expressed constitutively, without requiring any abiotic or biotic stress for synthesis. In addition to constitutive expression, chemical defenses can be induced upon herbivore damage or other types of environmental stress (Chen, 2008;Karban and Baldwin, 1997;Turlings and W€ ackers, 2004).…”

Activities and Novel Applications of Secondary Metabolite Coumarins

“…Scopoletin gave feeding deterrence of 50% (FD 50 ) value of 96.7 μg g -1 diet when mixed into an artificial diet. Spodoptera obliqua larvae (12-day-old) exposed to the highest concentration (250 μg g -1 diet) of scopoletin showed 77.1% feedingdeterrence (Tripathi et al, 2011). Surangin B isolated from M. siamensis showed high antifeedant toxicity to the 3rd instar larvae of P. xylostella L. (diamondback moth) with a very low percentage of damaged leaf area of 0.83 and 0.14% at the concentrations of 0.5 and 1.0 mg mL -1 , and it proved to be better than methomyl (used as a conventional insecticide) (Issakul et al, 2011).…”

“…Phytotoxic (Urbain et al, 2005) Scopoletin: 7-hydroxy-6-methoxy, 2H-1-Benzopyran-2-one Antifeedant (Barrero et al, 2013;Tripathi et al, 2011), Insecticidal (Sharma et al, 2006) 4 …”