Thermally induced Actinidine production in biological samples

Authors: SHI, QINGXING - Guangdong Academy Of Agricultural Sciences; HE, YURONG - South China Agricultural Univerisity; LEI, YANYUAN - Guangdong Academy Of Agricultural Sciences; QI, GUOJUN - Guangdong Academy Of Agricultural Sciences; Chen, Jian; LU, LIHUA - Guangdong Academy Of Agricultural Sciences

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2020
Publication Date: 10/22/2020
Citation: Shi, Q., He, Y., Lei, Y., Qi, G., Chen, J., Lu, L. 2020. Thermally induced Actinidine production in biological samples. Journal of Agricultural and Food Chemistry. 68:12252-12258. https://doi.org/10.1021/acs.jafc.0c02540.
DOI: https://doi.org/10.1021/acs.jafc.0c02540

Interpretive Summary: Actinidine, a methylcyclopentane monoterpenoid alkaloid, was first reported in a plant, Actinidia polygama Maxim (Ericales:Actinidiaceae), and has been found in many other plants. In addition to plants, actinidine has also been found in many insect species including ants, sawflies, rove beetles, stick insects, etc. Actinidine has been reported as a feline attractant and a defensive compound in insects. In this study, occurrence of actinidine was reinvestigated for four organisms under different sample preparation temperatures, including two ant species Tapinoma melanocephalum (Fabricius) and Iridmyrmex anceps Roger (Hymenoptera: Formicidae) and two plant species, A. polygama Maxim (Ericales: Actinidiaceae), and Nepeta cataria L. (Lamiales: Lamiaceae). All four tested species have been previously reported as actinidine producers. Within a temperature range of 50, 100, 150, 200 and 250', no actinidine was detected at 50'in all four species, but it appeared when the temperature was over 100'. A positive relationship was observed between temperature and actinidine production. The results indicate that actinidine may not naturally occur in all four tested organisms; however, it could be generated at the accelerated temperature. We demonstrated that presence of methylcyclopentane monoterpenoid iridoids (iridodials and nepetalactone) was needed for the thermally induced actinidine production in all tested samples. Therefore, in the chemical analysis of biological samples containing methylcyclopentane monoterpenoid iridoids, it must be very careful to interpret the presence of actinidine, particularly when samples are analyzed by solid injection technique in gas chromatography or heating is involved during sample preparation.

Technical Abstract: Actinidine, a methylcyclopentane monoterpenoid alkaloid, was first reported in a plant, Actinidia polygama Maxim (Ericales: Actinidiaceae), and has been found in many other plants. In addition to plants, actinidine has also been found in many insect species including ants, sawflies, rove beetles, stick insects, etc. Actinidine has been reported as a feline attractant in plants and a defensive compound in insects. In this study, occurrence of actinidine was reinvestigated under different sample preparation temperatures for four organisms, including two ant species Tapinoma melanocephalum (Fabricius) and Iridmyrmex anceps Roger (Hymenoptera: Formicidae) and two plant species, A. polygama Maxim (Ericales: Actinidiaceae), and Nepeta cataria L. (Lamiales: Lamiaceae). All these four species have been previously reported as actinidine producers. For all four species, no actinidine was detected at 50 ', but it appeared when the temperature was over 100 '. A positive relationship was observed between temperature and actinidine production. The results indicate that actinidine may not naturally occur in all four tested organisms; however, it could be produced at the accelerated temperature. We demonstrated that presence of methylcyclopentane monoterpenoid iridoids (iridodials and nepetalactone) was needed for the thermally induced actinidine production in all tested samples. Therefore, in the chemical analysis of biological samples containing methylcyclopentane monoterpenoid iridoids, it must be very careful to interpret the presence of actinidine, particularly when samples are analyzed by solid injection technique in gas chromatography or heating is involved during sample preparation.