Fitoterapia 72 Ž2001. 568᎐571
Short report
Insect antifeedant and growth regulating activities of quassinoids from Samadera indica T.R. GovindachariU , G.N. Krishna Kumari, G. Gopalakrishnan, G. Suresh, S.D. Wesley, T. Sreelatha Centre for Natural Products, SPIC Science Foundation, 111, Mount Road, Madras 600 032, India
Received 11 May 2000; accepted in revised form 12 December 2000
Abstract Four quassinoids, indaquassin C (1), samaderins C (2), B (3) and A (4), isolated from the seeds and bark of Samadera indica, were tested for insect antifeedant and growth regulatory activities against the tobacco cutworm, Spodoptera litura. Indaquassin C was the most effective antifeedant. Samaderin C increased pupal duration and induced pupal mortality. 䊚 2001 Elsevier Science B.V. All rights reserved. Keywords: Samadera indica; Quassinoids; Antifeedant activity
Plant. Samadera indica Gaertn. ŽSimaroubaceae., seeds and bark were collected in December 1998 from Kerala, India and the plant was identified by Dr R.N. Ravindran, Indian Institute of Spices Research, Calicut, India. Uses in traditional medicine. The bark is used as a febrifuge; bark juice for skin infections w1x. U
Corresponding author. Tel.: q91-44-2351903. E-mail address:
[email protected] ŽT.R. Govindachari.. 0367-326Xr01r$ - see front matter 䊚 2001 Elsevier Science B.V. All rights reserved. PII: S 0 3 6 7 - 3 2 6 X Ž 0 0 . 0 0 3 4 2 - 7
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Previously isolated constituents. Quassinoids w2,3x.
Tested materials. Indaquassin C (1) w3x Žyield: 0.006%; from seed kernels., samaderin C (2) w2x Ž0.05; bark., samaderin B (3) w2x Ž0.001; bark., and samaderin A (4) w2x Ž0.003; bark.. Studied activity. Insect antifeedant activity, insect growth regulating activity and mortality as previously described w4x. However, the exposure of the insects to the treated leaves in the experiments reported in the present paper was 24 h instead of the whole larval duration. Azadirachtin A, a potent insect antifeedant and growth regulatory compound was kept as active control w4x. Used insect. The test insect, Spodoptera litura L., was reared in the laboratory on Ricinus communis Žcastor. leaves at 25 " 2⬚C and 3rd instar larvae were used for testing. Results. Reported in Tables 1 and 2. Conclusions. Triterpenoids are known to possess insect antifeedantrgrowth regulating activity against a variety of agricultural pests. Quassinoids, as modified triterpenoids, can be expected to show similar activity. However, the quassinoids Table 1 Antifeedant activity of quassinoids from Samadera indica against Spodoptera lituraa Concentrationb
1
2
3
4
Azadirachtin A
0.5 1.0 5.0
47.6 Ž2.4. 48.9 Ž2.1. 62.5 Ž2.1.
15.0 Ž1.5. 16.1 Ž2.1. 55.3 Ž3.4.
16.3 Ž1.6. 25.9 Ž3.5. 63.1 Ž8.5.
18.9 Ž2.1. 16.2 Ž2.3. 21.1 Ž3.3.
91.6 Ž2.8. 94.8 Ž2.8. 95.4 Ž2.6.
a
Antifeedant activity Ž%. s 100 Ž1, area fed in treatedrarea fed in control.. Values are mean ŽS.D.., n s 5. 1, indaquassin C; 2, samaderin C; 3, samaderin B; 4, samaderin A. b grcm2 castor leaf area Ž180 cm2 . offered to S. litura larvae w4x.
570
a
Compound
3rd instar duration
4th instar duration
5th instar duration
6th instar duration
Total larval duration
Pupal duration
Pupal mortality Ž%.
Control 1 2 3 4 Azadirachtin A
2.8 Ž0.8. 2.3U Ž0.5. 2.7 Ž0.8. 3.1U Ž0.5. 2.9 Ž0.4. 3.2U Ž0.2.
3.7 Ž1.0. 3.8 Ž.0.7. 4.4U Ž0.6. 3.8 Ž0.9. 3.6 Ž0.7. 4.1U Ž0.2.
3.2 Ž0.6. 3.4 Ž0.7. 3.8U Ž0.9. 3.4 Ž0.3. 3.6U Ž0.3. 3.3 Ž0.7.
4.7 Ž0.7. 4.9 Ž0.7. 4.4 Ž0.5. 5.1U Ž0.4. 4.8 Ž0.6. 5.4U Ž1.2.
14.5 Ž1.5. 14.2 Ž1.6. 15.3 Ž0.4. 15.6 Ž1.2. 15.1 Ž1.3. 16.1 Ž1.3.
8.4 Ž0.06. 8.5 Ž0.04. 9.7 Ž0.04. 9.3 Ž0.08. 8.8 Ž0.03. 9.3 Ž0.07.
7.1 10.5 54.1 37.5 7.4 62.5
a
Experiments initiated with 25 individuals Žfive replicates with five individuals each.. Tested concentration s 0.5 grcm2 area of castor leaf fed for 24 h. Duration in days; values are mean ŽS.D..; U P - 0.05 vs. control. 1, indaquassin C; 2, samaderin C; 3, samaderin B; 4, samaderin A.
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Table 2 Larval and pupal durations and mortality of Spodoptera litura fed on quassinoids from S. indica
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isolated from Samadera indica had not so far been tested for their antifeedancy against Spodoptera litura and hence the study was taken up. Among them, indaquassin C was the most effective as an antifeedant even at concentration of 0.5 g rcm2 , being half as active as azadirachtin A. Samaderin C and B significantly increased larval and pupal durations and induced mortality and were comparable to azadirachtin A.
References w1x Ambasta SP. The useful plants of India. New Dehli: Publication and Information Directorate, CSIR, 1986:508. w2x Zylber J., Polonsky J. Bull Soc Chim Fr 1964; 2016. w3x Koike K, Ohmoto T. Phytochemistry 1994;35:459. w4x Govindachari T.R., Narasimhan N.S., Suresh G., Partho P.D., Geetha Gopalakrishnan, Krishna Kumari G.N. J Chem Ecol 1995;21:1585.