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Omar M Sabry - One of the best experts on this subject based on the ideXlab platform.
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acovenoside a induces mitotic catastrophe followed by apoptosis in non small cell lung cancer cells
Journal of Natural Products, 2017Co-Authors: Menna El Gaafary, Omar M Sabry, Abeer El M Sayed, Shahira M Ezzat, Susanne Hafner, Sophia J Lang, Michael Schmiech, Tatiana Syrovets, Thomas SimmetAbstract:We investigated the cytotoxic potential of the cardenolide glycoside acovenoside A against non-small-cell lung cancer cells. Lung cancer is the leading cause of cancer-related mortality and the second most common cancer diagnosed. Epidemiological studies revealed a direct correlation between the regular administration of cardiac glycosides and a lower incidence of various cancers. Acovenoside A, isolated from the pericarps of Acokanthera oppositifolia, potently inhibited proliferation and induced cytotoxicity in A549 non-small-cell lung cancer cells with an IC50 of 68 ± 3 nM after 48 h of exposure. Compared to the antineoplastic agent doxorubicin, acovenoside A was more potent in inhibiting the viability of A549 cancer cells. Moreover, acovenoside A exhibited selectivity against cancer cells, being significantly less toxic to lung fibroblasts and nontoxic for peripheral blood mononuclear cells. Analysis of the cell cycle profile in acovenoside A-treated A549 cells revealed mitotic arrest, due to accumulat...
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a new antibacterial lupane ester from the seeds of Acokanthera oppositifolia lam
Natural Product Research, 2016Co-Authors: Abeer El M Sayed, Shahira M Ezzat, Omar M SabryAbstract:AbstractAs a part of ongoing investigation of Acokanthera oppositifolia (Lam.) Codd., four compounds were isolated from its seeds, a new compound; lup-20(29)-en-3β-O-(3′-β-hydroxy) palmitate (1), three known compounds; a triterpene; lupeol (2), a cardiac glycoside; acovenoside A (3) and a sterol; β-sitosterol (4). Their structures were investigated using 1D & 2D- 1H and 13CNMR spectroscopy. Antimicrobial potential of the compounds was evaluated against 10 microorganisms responsible for endocarditis. The minimum inhibitory concentration (MIC) of the compounds was determined using broth microdilution method. The new compound (1) evidenced significant antibacterial activity especially aganist Pseudomonas aeruginosa with (MIC 7.81 μg/ml). Lupeol (2) exhibited remarkable antimicrobial activity against Methicillin-resistant Staphylococcus aureus, Aspergillus fumigates and Candida albicans (MIC 3.9, 0.24 and 3.9 μg/ml, respectively). On the other hand, acovenoside A (3) inhibited the growth of Escherichia coli (...
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bioactive compounds from Acokanthera oblongifolia
Advances in Life Science and Technology, 2016Co-Authors: Omar M Sabry, Abeer El M Sayed, Shahira M Ezzat, Zeinab YousefAbstract:One cardiotonic glycoside, three triterpenes and one steroidal glycoside were isolated from Acokanthera oblongifolia fruits (pericarp) growing in Libya . Their structures were investigated by extensive application of IR, MS, 1DNMR and 2DNMR spectroscopy. The isolated compounds have evidenced in-vitro cytotoxicity on selected human cell lines (A-549, H-1299) when compared to doxorubicin . Keywords: Cardenolide; Acokanthera oblongifolia; antitumor activity; lung carcinoma cell line (A-549, H-1299) .
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A new antibacterial lupane ester from the seeds of Acokanthera oppositifolia Lam.
2016Co-Authors: Abeer El M Sayed, Shahira M Ezzat, Omar M SabryAbstract:As a part of ongoing investigation of Acokanthera oppositifolia (Lam.) Codd., four compounds were isolated from its seeds, a new compound; lup-20(29)-en-3β-O-(3′-β-hydroxy) palmitate (1), three known compounds; a triterpene; lupeol (2), a cardiac glycoside; acovenoside A (3) and a sterol; β-sitosterol (4). Their structures were investigated using 1D & 2D- 1H and 13CNMR spectroscopy. Antimicrobial potential of the compounds was evaluated against 10 microorganisms responsible for endocarditis. The minimum inhibitory concentration (MIC) of the compounds was determined using broth microdilution method. The new compound (1) evidenced significant antibacterial activity especially aganist Pseudomonas aeruginosa with (MIC 7.81 μg/ml). Lupeol (2) exhibited remarkable antimicrobial activity against Methicillin-resistant Staphylococcus aureus, Aspergillus fumigates and Candida albicans (MIC 3.9, 0.24 and 3.9 μg/ml, respectively). On the other hand, acovenoside A (3) inhibited the growth of Escherichia coli (MIC 0.98 μg/ml). We herein present the potential of A. oppositifolia as a cardioprotective agent against the microorganisms responsible for endocarditis.
Abeer El M Sayed - One of the best experts on this subject based on the ideXlab platform.
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acovenoside a induces mitotic catastrophe followed by apoptosis in non small cell lung cancer cells
Journal of Natural Products, 2017Co-Authors: Menna El Gaafary, Omar M Sabry, Abeer El M Sayed, Shahira M Ezzat, Susanne Hafner, Sophia J Lang, Michael Schmiech, Tatiana Syrovets, Thomas SimmetAbstract:We investigated the cytotoxic potential of the cardenolide glycoside acovenoside A against non-small-cell lung cancer cells. Lung cancer is the leading cause of cancer-related mortality and the second most common cancer diagnosed. Epidemiological studies revealed a direct correlation between the regular administration of cardiac glycosides and a lower incidence of various cancers. Acovenoside A, isolated from the pericarps of Acokanthera oppositifolia, potently inhibited proliferation and induced cytotoxicity in A549 non-small-cell lung cancer cells with an IC50 of 68 ± 3 nM after 48 h of exposure. Compared to the antineoplastic agent doxorubicin, acovenoside A was more potent in inhibiting the viability of A549 cancer cells. Moreover, acovenoside A exhibited selectivity against cancer cells, being significantly less toxic to lung fibroblasts and nontoxic for peripheral blood mononuclear cells. Analysis of the cell cycle profile in acovenoside A-treated A549 cells revealed mitotic arrest, due to accumulat...
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a new antibacterial lupane ester from the seeds of Acokanthera oppositifolia lam
Natural Product Research, 2016Co-Authors: Abeer El M Sayed, Shahira M Ezzat, Omar M SabryAbstract:AbstractAs a part of ongoing investigation of Acokanthera oppositifolia (Lam.) Codd., four compounds were isolated from its seeds, a new compound; lup-20(29)-en-3β-O-(3′-β-hydroxy) palmitate (1), three known compounds; a triterpene; lupeol (2), a cardiac glycoside; acovenoside A (3) and a sterol; β-sitosterol (4). Their structures were investigated using 1D & 2D- 1H and 13CNMR spectroscopy. Antimicrobial potential of the compounds was evaluated against 10 microorganisms responsible for endocarditis. The minimum inhibitory concentration (MIC) of the compounds was determined using broth microdilution method. The new compound (1) evidenced significant antibacterial activity especially aganist Pseudomonas aeruginosa with (MIC 7.81 μg/ml). Lupeol (2) exhibited remarkable antimicrobial activity against Methicillin-resistant Staphylococcus aureus, Aspergillus fumigates and Candida albicans (MIC 3.9, 0.24 and 3.9 μg/ml, respectively). On the other hand, acovenoside A (3) inhibited the growth of Escherichia coli (...
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bioactive compounds from Acokanthera oblongifolia
Advances in Life Science and Technology, 2016Co-Authors: Omar M Sabry, Abeer El M Sayed, Shahira M Ezzat, Zeinab YousefAbstract:One cardiotonic glycoside, three triterpenes and one steroidal glycoside were isolated from Acokanthera oblongifolia fruits (pericarp) growing in Libya . Their structures were investigated by extensive application of IR, MS, 1DNMR and 2DNMR spectroscopy. The isolated compounds have evidenced in-vitro cytotoxicity on selected human cell lines (A-549, H-1299) when compared to doxorubicin . Keywords: Cardenolide; Acokanthera oblongifolia; antitumor activity; lung carcinoma cell line (A-549, H-1299) .
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A new antibacterial lupane ester from the seeds of Acokanthera oppositifolia Lam.
2016Co-Authors: Abeer El M Sayed, Shahira M Ezzat, Omar M SabryAbstract:As a part of ongoing investigation of Acokanthera oppositifolia (Lam.) Codd., four compounds were isolated from its seeds, a new compound; lup-20(29)-en-3β-O-(3′-β-hydroxy) palmitate (1), three known compounds; a triterpene; lupeol (2), a cardiac glycoside; acovenoside A (3) and a sterol; β-sitosterol (4). Their structures were investigated using 1D & 2D- 1H and 13CNMR spectroscopy. Antimicrobial potential of the compounds was evaluated against 10 microorganisms responsible for endocarditis. The minimum inhibitory concentration (MIC) of the compounds was determined using broth microdilution method. The new compound (1) evidenced significant antibacterial activity especially aganist Pseudomonas aeruginosa with (MIC 7.81 μg/ml). Lupeol (2) exhibited remarkable antimicrobial activity against Methicillin-resistant Staphylococcus aureus, Aspergillus fumigates and Candida albicans (MIC 3.9, 0.24 and 3.9 μg/ml, respectively). On the other hand, acovenoside A (3) inhibited the growth of Escherichia coli (MIC 0.98 μg/ml). We herein present the potential of A. oppositifolia as a cardioprotective agent against the microorganisms responsible for endocarditis.
A Elshazli - One of the best experts on this subject based on the ideXlab platform.
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phagostimulants from Acokanthera spectabilis hook tested on spodoptera littoralis boisd lepid noctuidae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, F Elgayar, A ElshazliAbstract:Sterols were the only ingredients that displayed phagostimulant effect on S. littoralis larvae. These sterols were found in two forms: one of them has an Rf value of 0.42 (identical with B-sitosterol), the other has an Rf value of 0.55. The aforementioned sterols increased castor oil leaves consumption from 44.1 to 59.3% when the leaf disks were immersed in ethanolic solutions containing 2000 or 3000 ppm sterols in respect. When these sterols were applied to Vanderzant-diet (1962) as modified by Keaster and Harrendorf (1965) at concentrations of 100 or 50 ppm, mean larval weight increased to 776.8 and 210.3 mg in respect. Whereas those fed on castor oil leaves or meridic diet deprived of sterols reached 480.1 and 177.8 mg in respect. Also mortalities due to virus infections dropped from 60–70 % to 30 % when the larvae were kept on meridic diet containing 100 ppm sterols. Larvae kept on the latter diet entered the pupal stage faster than the others. Zusammenfassung Ein Phagostimulans aus Acokanthera spectabilis Hook., gepruft an Spodoptera littoralis Boisd. (Lepid., Noctuidae) Sterole waren die einzigen Stoffe, die eine phagostimulierende Wirkung gegenuber S. littoralis-Larven zeigten. Diese Sterole wurden in. 2 Formen gefunden: eines hatte einen Rf-Wert von 0,42 (identisch mit B-Sitosterol), das andere hatte einen Rf-Wert von 0,55. Wurden Rhizinus-Blattscheiben mit einer in Athanol gelosten Konzentration von 2000 oder 3000 ppm Sterol getrankt, so nahm der Verbrauch an diesen Blattern von 44,1 bis 59,3 % zu. Wurden diese Sterole in Konzentrationen von 100 oder 50 ppm einer nach Keaster und Harrendorf (1965) modifizierten Diat von Vanderzant (1962) zugefugt, so stieg das durchschnittliche Larvengewicht auf 776,8 und 210,3 mg. Demgegenuber ergab eine Futterung mit Rhizinusblattern oder “meridic diet” ohne Sterole nur ein Larvengewicht von 480,1 und 177,8 mg. Es sank auch die Mortalitat bei Virusinfektionen von 60–70 % auf 30 %, wenn die Larven auf einer Diat gehalten wurden, die 100 ppm Sterole enthielt. Larven, die bei einer solchen Diat erzogen wurden, erreichten das Puppenstadium schneller als Larven ohne Sterol-Diat.
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a new antifeedant to spodoptera littoralis boisd lepid noctuidae from Acokanthera spectabilis hook apocynaceae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, A Elshazli, F ElgayarAbstract:Of the compounds isolated from A. spectabilis, i.e. triterpenes, cardenolide glycosides and sterols, the triterpene, friedelin (m.p. 225° C-256° C; Rf value = 0.76), showed antifeedant effect against S. littoralis 3rd instar larvae but was nontoxic to the same larvae (LC50 > 6000 ppm) or to Culex pipiens pipiens 4th instar larvae (LC50 > 800 ppm). Friedelin was compared with the classical antifeedant “Du-Ter”. Castor oil leaf disks dipped in 0.25 % or 0.5 % friedelin solutions in acetone and offered to S. littoralis larvae caused the suppression of the feeding ratio to 7.1 and 3.3 % in respect. While, “Du-Ter” at the same concentrations caused the feeding ratio to reach 6.7 and 1.1 % in respect. Only 16 % mortality was obtained at 0.5 % friedelin 48 hrs after treatment. While, 0.25 and 0.5 % “Du-Ter” caused 42 and 60 % mortalities in respect, which are higher than the 22 % mortality obtained in control, untreated starved, larvae within 48 hrs. Both “Du-Ter” and “Friedelin” induced marked decrease in larval body weight within 24 hrs, but the differences between the two treatments were very slight. “Friedelin” persisted under field conditions for 48 hrs as strong antifeedant and another 24 hrs as weak antifeedant. It proved to be as active as some other antifeedants from plant origin. Zusammenfassung Ein neuer Frashemmstoff aus Acokantbera spectabilis Hook. (Apocynaceae) fur Spodoptera littoralis (Boisd.) (Lepid., Noctuidae) Von den aus A. spectabilis isolierten Komponenten, vor allem Triterpene, cardenolide Glykocide und Sterole, zeigte das Triterpen “Friedelin” (Schmelzpunkt 255–256° C und Rf-Wert 0,76) einen Antifeedant-Effekt gegenuber S.-littoralis-Larven des 3. Stadiums, war aber nicht toxisch fur diese Larven (LC50 6000 ppm) oder fur Culex-pipiens-pipiens-Larven des 4. Stadiums (LC50 800 ppm). “Friedelin” wurde mit dem gebrauchlichen Antifeedant “Du-Ter” verglichen. Scheiben von Rhizinus, eingetaucht in 0,25 % oder 0,5 %ige Friedelin-Losung in Azeton und S.-littoralis-Larven angeboten, senkten die Futterration auf 7,1 oder 3,3 %. Im Vergleich dazu verursachte die “Du-Ter”-Behandlung in den gleichen Konzentrationen eine verringerte Futteraufnahme von 6,7 oder 1,1 %. 48 Stunden nach der Behandlung wurde bei 0,5 % Friedelin nur 16 % Sterblichkeit festgestellt. Demgegenuber verursachte eine Behandlung mit 0,25 oder 0,5 % “Du-Ter” 60 % Sterblichkeit, was hoher war als die 22 % Mortalitat in der Kontrolle mit unbehandelten hungernden Larven. Nach 24 Stunden ergab sich bei beiden Mitteln “Du-Ter” und “Friedelin” eine bemerkenswerte Verringerung im Korpergewicht der Larven, jedoch waren die Unterschiede zwischen beiden Behandlungen nur sehr gering. “Friedelin” ist unter Feldbedingungen 48 Stunden als starkes Antifeedant persistent und weitere 24 Stunden noch als schwaches Antifeedant. Offensichtlich ist es somit ebenso wirkungsvoll wie andere Antifeedants pflanzlichen Ursprungs.
F Elgayar - One of the best experts on this subject based on the ideXlab platform.
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phagostimulants from Acokanthera spectabilis hook tested on spodoptera littoralis boisd lepid noctuidae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, F Elgayar, A ElshazliAbstract:Sterols were the only ingredients that displayed phagostimulant effect on S. littoralis larvae. These sterols were found in two forms: one of them has an Rf value of 0.42 (identical with B-sitosterol), the other has an Rf value of 0.55. The aforementioned sterols increased castor oil leaves consumption from 44.1 to 59.3% when the leaf disks were immersed in ethanolic solutions containing 2000 or 3000 ppm sterols in respect. When these sterols were applied to Vanderzant-diet (1962) as modified by Keaster and Harrendorf (1965) at concentrations of 100 or 50 ppm, mean larval weight increased to 776.8 and 210.3 mg in respect. Whereas those fed on castor oil leaves or meridic diet deprived of sterols reached 480.1 and 177.8 mg in respect. Also mortalities due to virus infections dropped from 60–70 % to 30 % when the larvae were kept on meridic diet containing 100 ppm sterols. Larvae kept on the latter diet entered the pupal stage faster than the others. Zusammenfassung Ein Phagostimulans aus Acokanthera spectabilis Hook., gepruft an Spodoptera littoralis Boisd. (Lepid., Noctuidae) Sterole waren die einzigen Stoffe, die eine phagostimulierende Wirkung gegenuber S. littoralis-Larven zeigten. Diese Sterole wurden in. 2 Formen gefunden: eines hatte einen Rf-Wert von 0,42 (identisch mit B-Sitosterol), das andere hatte einen Rf-Wert von 0,55. Wurden Rhizinus-Blattscheiben mit einer in Athanol gelosten Konzentration von 2000 oder 3000 ppm Sterol getrankt, so nahm der Verbrauch an diesen Blattern von 44,1 bis 59,3 % zu. Wurden diese Sterole in Konzentrationen von 100 oder 50 ppm einer nach Keaster und Harrendorf (1965) modifizierten Diat von Vanderzant (1962) zugefugt, so stieg das durchschnittliche Larvengewicht auf 776,8 und 210,3 mg. Demgegenuber ergab eine Futterung mit Rhizinusblattern oder “meridic diet” ohne Sterole nur ein Larvengewicht von 480,1 und 177,8 mg. Es sank auch die Mortalitat bei Virusinfektionen von 60–70 % auf 30 %, wenn die Larven auf einer Diat gehalten wurden, die 100 ppm Sterole enthielt. Larven, die bei einer solchen Diat erzogen wurden, erreichten das Puppenstadium schneller als Larven ohne Sterol-Diat.
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a new antifeedant to spodoptera littoralis boisd lepid noctuidae from Acokanthera spectabilis hook apocynaceae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, A Elshazli, F ElgayarAbstract:Of the compounds isolated from A. spectabilis, i.e. triterpenes, cardenolide glycosides and sterols, the triterpene, friedelin (m.p. 225° C-256° C; Rf value = 0.76), showed antifeedant effect against S. littoralis 3rd instar larvae but was nontoxic to the same larvae (LC50 > 6000 ppm) or to Culex pipiens pipiens 4th instar larvae (LC50 > 800 ppm). Friedelin was compared with the classical antifeedant “Du-Ter”. Castor oil leaf disks dipped in 0.25 % or 0.5 % friedelin solutions in acetone and offered to S. littoralis larvae caused the suppression of the feeding ratio to 7.1 and 3.3 % in respect. While, “Du-Ter” at the same concentrations caused the feeding ratio to reach 6.7 and 1.1 % in respect. Only 16 % mortality was obtained at 0.5 % friedelin 48 hrs after treatment. While, 0.25 and 0.5 % “Du-Ter” caused 42 and 60 % mortalities in respect, which are higher than the 22 % mortality obtained in control, untreated starved, larvae within 48 hrs. Both “Du-Ter” and “Friedelin” induced marked decrease in larval body weight within 24 hrs, but the differences between the two treatments were very slight. “Friedelin” persisted under field conditions for 48 hrs as strong antifeedant and another 24 hrs as weak antifeedant. It proved to be as active as some other antifeedants from plant origin. Zusammenfassung Ein neuer Frashemmstoff aus Acokantbera spectabilis Hook. (Apocynaceae) fur Spodoptera littoralis (Boisd.) (Lepid., Noctuidae) Von den aus A. spectabilis isolierten Komponenten, vor allem Triterpene, cardenolide Glykocide und Sterole, zeigte das Triterpen “Friedelin” (Schmelzpunkt 255–256° C und Rf-Wert 0,76) einen Antifeedant-Effekt gegenuber S.-littoralis-Larven des 3. Stadiums, war aber nicht toxisch fur diese Larven (LC50 6000 ppm) oder fur Culex-pipiens-pipiens-Larven des 4. Stadiums (LC50 800 ppm). “Friedelin” wurde mit dem gebrauchlichen Antifeedant “Du-Ter” verglichen. Scheiben von Rhizinus, eingetaucht in 0,25 % oder 0,5 %ige Friedelin-Losung in Azeton und S.-littoralis-Larven angeboten, senkten die Futterration auf 7,1 oder 3,3 %. Im Vergleich dazu verursachte die “Du-Ter”-Behandlung in den gleichen Konzentrationen eine verringerte Futteraufnahme von 6,7 oder 1,1 %. 48 Stunden nach der Behandlung wurde bei 0,5 % Friedelin nur 16 % Sterblichkeit festgestellt. Demgegenuber verursachte eine Behandlung mit 0,25 oder 0,5 % “Du-Ter” 60 % Sterblichkeit, was hoher war als die 22 % Mortalitat in der Kontrolle mit unbehandelten hungernden Larven. Nach 24 Stunden ergab sich bei beiden Mitteln “Du-Ter” und “Friedelin” eine bemerkenswerte Verringerung im Korpergewicht der Larven, jedoch waren die Unterschiede zwischen beiden Behandlungen nur sehr gering. “Friedelin” ist unter Feldbedingungen 48 Stunden als starkes Antifeedant persistent und weitere 24 Stunden noch als schwaches Antifeedant. Offensichtlich ist es somit ebenso wirkungsvoll wie andere Antifeedants pflanzlichen Ursprungs.
M A Abbassy - One of the best experts on this subject based on the ideXlab platform.
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phagostimulants from Acokanthera spectabilis hook tested on spodoptera littoralis boisd lepid noctuidae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, F Elgayar, A ElshazliAbstract:Sterols were the only ingredients that displayed phagostimulant effect on S. littoralis larvae. These sterols were found in two forms: one of them has an Rf value of 0.42 (identical with B-sitosterol), the other has an Rf value of 0.55. The aforementioned sterols increased castor oil leaves consumption from 44.1 to 59.3% when the leaf disks were immersed in ethanolic solutions containing 2000 or 3000 ppm sterols in respect. When these sterols were applied to Vanderzant-diet (1962) as modified by Keaster and Harrendorf (1965) at concentrations of 100 or 50 ppm, mean larval weight increased to 776.8 and 210.3 mg in respect. Whereas those fed on castor oil leaves or meridic diet deprived of sterols reached 480.1 and 177.8 mg in respect. Also mortalities due to virus infections dropped from 60–70 % to 30 % when the larvae were kept on meridic diet containing 100 ppm sterols. Larvae kept on the latter diet entered the pupal stage faster than the others. Zusammenfassung Ein Phagostimulans aus Acokanthera spectabilis Hook., gepruft an Spodoptera littoralis Boisd. (Lepid., Noctuidae) Sterole waren die einzigen Stoffe, die eine phagostimulierende Wirkung gegenuber S. littoralis-Larven zeigten. Diese Sterole wurden in. 2 Formen gefunden: eines hatte einen Rf-Wert von 0,42 (identisch mit B-Sitosterol), das andere hatte einen Rf-Wert von 0,55. Wurden Rhizinus-Blattscheiben mit einer in Athanol gelosten Konzentration von 2000 oder 3000 ppm Sterol getrankt, so nahm der Verbrauch an diesen Blattern von 44,1 bis 59,3 % zu. Wurden diese Sterole in Konzentrationen von 100 oder 50 ppm einer nach Keaster und Harrendorf (1965) modifizierten Diat von Vanderzant (1962) zugefugt, so stieg das durchschnittliche Larvengewicht auf 776,8 und 210,3 mg. Demgegenuber ergab eine Futterung mit Rhizinusblattern oder “meridic diet” ohne Sterole nur ein Larvengewicht von 480,1 und 177,8 mg. Es sank auch die Mortalitat bei Virusinfektionen von 60–70 % auf 30 %, wenn die Larven auf einer Diat gehalten wurden, die 100 ppm Sterole enthielt. Larven, die bei einer solchen Diat erzogen wurden, erreichten das Puppenstadium schneller als Larven ohne Sterol-Diat.
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a new antifeedant to spodoptera littoralis boisd lepid noctuidae from Acokanthera spectabilis hook apocynaceae 1
Journal of Applied Entomology, 2009Co-Authors: M A Abbassy, A Elshazli, F ElgayarAbstract:Of the compounds isolated from A. spectabilis, i.e. triterpenes, cardenolide glycosides and sterols, the triterpene, friedelin (m.p. 225° C-256° C; Rf value = 0.76), showed antifeedant effect against S. littoralis 3rd instar larvae but was nontoxic to the same larvae (LC50 > 6000 ppm) or to Culex pipiens pipiens 4th instar larvae (LC50 > 800 ppm). Friedelin was compared with the classical antifeedant “Du-Ter”. Castor oil leaf disks dipped in 0.25 % or 0.5 % friedelin solutions in acetone and offered to S. littoralis larvae caused the suppression of the feeding ratio to 7.1 and 3.3 % in respect. While, “Du-Ter” at the same concentrations caused the feeding ratio to reach 6.7 and 1.1 % in respect. Only 16 % mortality was obtained at 0.5 % friedelin 48 hrs after treatment. While, 0.25 and 0.5 % “Du-Ter” caused 42 and 60 % mortalities in respect, which are higher than the 22 % mortality obtained in control, untreated starved, larvae within 48 hrs. Both “Du-Ter” and “Friedelin” induced marked decrease in larval body weight within 24 hrs, but the differences between the two treatments were very slight. “Friedelin” persisted under field conditions for 48 hrs as strong antifeedant and another 24 hrs as weak antifeedant. It proved to be as active as some other antifeedants from plant origin. Zusammenfassung Ein neuer Frashemmstoff aus Acokantbera spectabilis Hook. (Apocynaceae) fur Spodoptera littoralis (Boisd.) (Lepid., Noctuidae) Von den aus A. spectabilis isolierten Komponenten, vor allem Triterpene, cardenolide Glykocide und Sterole, zeigte das Triterpen “Friedelin” (Schmelzpunkt 255–256° C und Rf-Wert 0,76) einen Antifeedant-Effekt gegenuber S.-littoralis-Larven des 3. Stadiums, war aber nicht toxisch fur diese Larven (LC50 6000 ppm) oder fur Culex-pipiens-pipiens-Larven des 4. Stadiums (LC50 800 ppm). “Friedelin” wurde mit dem gebrauchlichen Antifeedant “Du-Ter” verglichen. Scheiben von Rhizinus, eingetaucht in 0,25 % oder 0,5 %ige Friedelin-Losung in Azeton und S.-littoralis-Larven angeboten, senkten die Futterration auf 7,1 oder 3,3 %. Im Vergleich dazu verursachte die “Du-Ter”-Behandlung in den gleichen Konzentrationen eine verringerte Futteraufnahme von 6,7 oder 1,1 %. 48 Stunden nach der Behandlung wurde bei 0,5 % Friedelin nur 16 % Sterblichkeit festgestellt. Demgegenuber verursachte eine Behandlung mit 0,25 oder 0,5 % “Du-Ter” 60 % Sterblichkeit, was hoher war als die 22 % Mortalitat in der Kontrolle mit unbehandelten hungernden Larven. Nach 24 Stunden ergab sich bei beiden Mitteln “Du-Ter” und “Friedelin” eine bemerkenswerte Verringerung im Korpergewicht der Larven, jedoch waren die Unterschiede zwischen beiden Behandlungen nur sehr gering. “Friedelin” ist unter Feldbedingungen 48 Stunden als starkes Antifeedant persistent und weitere 24 Stunden noch als schwaches Antifeedant. Offensichtlich ist es somit ebenso wirkungsvoll wie andere Antifeedants pflanzlichen Ursprungs.
