1
|
Deng X, Ye Z, Duan J, Chen F, Zhi Y, Huang M, Huang M, Cheng W, Dou Y, Kuang Z, Huang Y, Bian G, Deng Z, Liu T, Lu L. Complete pathway elucidation and heterologous reconstitution of (+)-nootkatone biosynthesis from Alpinia oxyphylla. THE NEW PHYTOLOGIST 2024; 241:779-792. [PMID: 37933426 DOI: 10.1111/nph.19375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 10/14/2023] [Indexed: 11/08/2023]
Abstract
(+)-Nootkatone is a natural sesquiterpene ketone widely used in food, cosmetics, pharmaceuticals, and agriculture. It is also regarded as one of the most valuable terpenes used commercially. However, plants contain trace amounts of (+)-nootkatone, and extraction from plants is insufficient to meet market demand. Alpinia oxyphylla is a well-known medicinal plant in China, and (+)-nootkatone is one of the main components within the fruits. By transcriptome mining and functional screening using a precursor-providing yeast chassis, the complete (+)-nootkatone biosynthetic pathway in Alpinia oxyphylla was identified. A (+)-valencene synthase (AoVS) was identified as a novel monocot-derived valencene synthase; three (+)-valencene oxidases AoCYP6 (CYP71BB2), AoCYP9 (CYP71CX8), and AoCYP18 (CYP701A170) were identified by constructing a valencene-providing yeast strain. With further characterisation of a cytochrome P450 reductase (AoCPR1) and three dehydrogenases (AoSDR1/2/3), we successfully reconstructed the (+)-nootkatone biosynthetic pathway in Saccharomyces cerevisiae, representing a basis for its biotechnological production. Identifying the biosynthetic pathway of (+)-nootkatone in A. oxyphylla unravelled the molecular mechanism underlying its formation in planta and also supported the bioengineering production of (+)-nootkatone. The highly efficient yeast chassis screening method could be used to elucidate the complete biosynthetic pathway of other valuable plant natural products in future.
Collapse
Affiliation(s)
- Xiaomin Deng
- National Key Laboratory for Tropical Crop Breeding/Ministry of Agriculture Key Laboratory of Biology and Genetic Resources of Rubber Tree/State Key Laboratory Breeding Base of Cultivation and Physiology for Tropical Crops, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, Hainan, China
- Department of Urology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Ziling Ye
- Wuhan Hesheng Technology Co., Ltd, Wuhan, 430074, Hubei, China
| | - Jingyu Duan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Fangfang Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Yao Zhi
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Man Huang
- Wuhan Hesheng Technology Co., Ltd, Wuhan, 430074, Hubei, China
| | - Minjian Huang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Weijia Cheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Yujie Dou
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Zhaolin Kuang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Yanglei Huang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Guangkai Bian
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Tiangang Liu
- Department of Urology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
- Wuhan Hesheng Technology Co., Ltd, Wuhan, 430074, Hubei, China
- Wuhan University of Taikang Medical School, Wuhan University, Wuhan, 430071, Hubei, China
| | - Li Lu
- Department of Urology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, 430071, Hubei, China
| |
Collapse
|
2
|
Siegel EL, Xu G, Li AY, Pearson P, D’hers S, Elman N, Mather TN, Rich SM. Ixodes scapularis Is the Most Susceptible of the Three Canonical Human-Biting Tick Species of North America to Repellent and Acaricidal Effects of the Natural Sesquiterpene, (+)-Nootkatone. INSECTS 2023; 15:8. [PMID: 38249014 PMCID: PMC10816182 DOI: 10.3390/insects15010008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/23/2024]
Abstract
Ticks are vectors of many human and animal zoonotic disease-causing agents causing significant global health and economic strain. Repellents and acaricides are integral to the human capacity for personal protection from tick bites. Nootkatone, a naturally occurring sesquiterpene found in the Alaskan cedar tree, grapefruit, and other sources, has been documented to be a potent acaricide. Research has also noted repellent effects against some tick species. In this study, our aim was to investigate the effect of synthetic, high-purity (+)-nootkatone on adult Ixodes scapularis, Dermacentor variabilis, and Amblyomma americanum ticks in an in vitro, vertical filter paper bioassay. (+)-nootkatone showed compelling tick repellency, but median effective concentrations (EC50) significantly differed among species. Ixodes scapularis were repelled at very low concentrations (EC50 = 0.87 ± 0.05 µg/cm2). Higher concentrations were required to repel D. variabilis (EC50 = 252 ± 12 µg/cm2) and A. americanum (EC50 = 2313 ± 179 µg/cm2). Significant post-exposure mortality, assessed 24 h after repellency trials, was also observed in I. scapularis but was absent entirely in D. variabilis and A. americanum. These tests demonstrate that nootkatone has a promising dual-action personal protection capacity against adult I. scapularis ticks, warranting further investigation in more natural environments and in the presence of host cues.
Collapse
Affiliation(s)
- Eric L. Siegel
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA; (E.L.S.); (P.P.)
| | - Guang Xu
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA; (E.L.S.); (P.P.)
| | - Andrew Y. Li
- United States Department of Agriculture, Agricultural Research Service, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, MD 20704, USA;
| | - Patrick Pearson
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA; (E.L.S.); (P.P.)
| | - Sebastián D’hers
- Computational Mechanics Center, Instituto Tecnológico de Buenos Aires (ITBA), Ciudad Autónoma de Buenos Aires C1106ACD, Argentina;
| | - Noel Elman
- GearJump Technologies, Limited Liability Company, Brookline, MA 02446, USA;
| | - Thomas N. Mather
- Center for Vector-Borne Disease, University of Rhode Island, Kingston, RI 02881, USA;
| | - Stephen M. Rich
- Laboratory of Medical Zoology, Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA; (E.L.S.); (P.P.)
| |
Collapse
|
3
|
Bauer IL. The oral repellent - science fiction or common sense? Insects, vector-borne diseases, failing strategies, and a bold proposition. Trop Dis Travel Med Vaccines 2023; 9:7. [PMID: 37381000 DOI: 10.1186/s40794-023-00195-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/09/2023] [Indexed: 06/30/2023] Open
Abstract
Over the last decades, unimaginable amounts of money have gone into research and development of vector control measures, repellents, treatment, and vaccines for vector borne diseases. Technological progress and scientific breakthroughs allowed for ever more sophisticated and futuristic strategies. Yet, each year, millions of people still die or suffer from potentially serious consequences of malaria or dengue to more recent infections, such as zika or chikungunya, or of debilitating consequences of neglected tropical diseases. This does not seem value for money. In addition, all current vector control strategies and personal protection methods have shortcomings, some serious, that are either destructive to non-target species or unsatisfactory in their effectiveness. On the other hand, the rapid decline in insect populations and their predators reflects decades-long aggressive and indiscriminate vector control. This major disruption of biodiversity has an impact on human life not anticipated by the well-meaning killing of invertebrates. The objective of this paper is to re-examine current control methods, their effectiveness, their impact on biodiversity, human and animal health, and to call for scientific courage in the pursuit of fresh ideas. This paper brings together topics that are usually presented in isolation, thereby missing important links that offer potential solutions to long-standing problems in global health. First, it serves as a reminder of the importance of insects to human life and discusses the few that play a role in transmitting disease. Next, it examines critically the many currently employed vector control strategies and personal protection methods. Finally, based on new insights into insect chemo-sensation and attractants, this perspective makes a case for revisiting a previously abandoned idea, the oral repellent, and its use via currently successful methods of mass-application. The call is out for focused research to provide a powerful tool for public health, tropical medicine, and travel medicine.
Collapse
Affiliation(s)
- Irmgard L Bauer
- College of Healthcare Sciences, Academy - Tropical Health and Medicine, James Cook University, Townsville, QLD, 4811, Australia.
| |
Collapse
|
4
|
Chilmeran M, Hodges M, Ni X. A kinetic study of biotransformation from valencene to nootkatone in an oscillatory baffled reactor. JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY (OXFORD, OXFORDSHIRE : 1986) 2023; 98:1356-1364. [PMID: 38516537 PMCID: PMC10953380 DOI: 10.1002/jctb.7350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2024]
Abstract
In this paper we report our kinetic study of an oxidation reaction from valencene to nootkatone using enzyme in an oscillatory baffled reactor. The aims of this work are to elucidate the reaction mechanism and evaluate reaction kinetics. Towards these objectives, a full kinetic model using the Langmuir-Hinshelwood method was established and applied to the experimental data, allowing reactor schemes and orders to be confirmed and reaction rate constants to be extracted. Our full kinetic analysis suggests that most of the reversible reaction steps can be treated as irreversible, simplifying the overall reaction schemes. The effect of mass transfer on the kinetics was also investigated. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).
Collapse
Affiliation(s)
- Mohamed Chilmeran
- Centre of Oscillatory Baffled Reactor Advancement (COBRA), School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghUK
| | | | - Xiong‐Wei Ni
- Centre of Oscillatory Baffled Reactor Advancement (COBRA), School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghUK
| |
Collapse
|
5
|
Zhang LL, Chen Y, Li ZJ, Fan G, Li X. Production, Function, and Applications of the Sesquiterpenes Valencene and Nootkatone: a Comprehensive Review. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:121-142. [PMID: 36541855 DOI: 10.1021/acs.jafc.2c07543] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Valencene and nootkatone, two sesquiterpenes, extracted from natural sources, have great market potential with diverse applications. This paper aims to comprehensively review the recent advances in valencene and nootkatone, including source, production, physicochemical and biological properties, safety and pharmacokinetics evaluation, potential uses, and their industrial applications as well as future research directions. Microbial biosynthesis offers a promising alternative approach for sustainable production of valencene and nootkatone. Both compounds exert various beneficial activities, including antimicrobial, insecticidal, antioxidant, anti-inflammatory, anticancer, cardioprotective, neuroprotective, hepatoprotective, and nephroprotective and other activities. However, most of the studies are performed in animals and in vitro, making it difficult to give a conclusive description about their health benefits and extend their application. Hence, more attention should be paid to in vivo and long-term clinical studies in the future. Moreover, valencene and nootkatone are considered safe for consumption and show great promise in the applications of food, cosmetic, pharmaceutical, chemical, and agricultural industries.
Collapse
Affiliation(s)
- Lu-Lu Zhang
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, People's Republic of China
| | - Yan Chen
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, People's Republic of China
| | - Zhi-Jian Li
- College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, People's Republic of China
| | - Gang Fan
- Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Xiao Li
- Key Laboratory of Environment Correlative Dietology, Ministry of Education, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| |
Collapse
|
6
|
Shiau AL, Liao CS, Tu CW, Wu SN, Cho HY, Yu MC. Characterization in Effective Stimulation on the Magnitude, Gating, Frequency Dependence, and Hysteresis of INa Exerted by Picaridin (or Icaridin), a Known Insect Repellent. Int J Mol Sci 2022; 23:ijms23179696. [PMID: 36077093 PMCID: PMC9456182 DOI: 10.3390/ijms23179696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Picaridin (icaridin), a member of the piperidine chemical family, is a broad-spectrum arthropod repellent. Its actions have been largely thought to be due to its interaction with odorant receptor proteins. However, to our knowledge, to what extent the presence of picaridin can modify the magnitude, gating, and/or the strength of voltage-dependent hysteresis (Hys(V)) of plasmalemmal ionic currents, such as, voltage-gated Na+ current [INa], has not been entirely explored. In GH3 pituitary tumor cells, we demonstrated that with exposure to picaridin the transient (INa(T)) and late (INa(L)) components of voltage-gated Na+ current (INa) were differentially stimulated with effective EC50’s of 32.7 and 2.8 μM, respectively. Upon cell exposure to it, the steady-state current versus voltage relationship INa(T) was shifted to more hyperpolarized potentials. Moreover, its presence caused a rightward shift in the midpoint for the steady-state inactivate curve of the current. The cumulative inhibition of INa(T) induced during repetitive stimuli became retarded during its exposure. The recovery time course from the INa block elicited, following the conditioning pulse stimulation, was satisfactorily fitted by two exponential processes. Moreover, the fast and slow time constants of recovery from the INa block by the same conditioning protocol were noticeably increased in the presence of picaridin. However, the fraction in fast or slow component of recovery time course was, respectively, increased or decreased with an increase in picaridin concentrations. The Hys(V)’s strength of persistent INa (INa(P)), responding to triangular ramp voltage, was also enhanced during cell exposure to picaridin. The magnitude of resurgent INa (INa(R)) was raised in its presence. Picaritin-induced increases of INa(P) or INa(R) intrinsically in GH3 cells could be attenuated by further addition of ranolazine. The predictions of molecular docking also disclosed that there are possible interactions of the picaridin molecule with the hNaV1.7 channel. Taken literally, the stimulation of INa exerted by the exposure to picaridin is expected to exert impacts on the functional activities residing in electrically excitable cells.
Collapse
Affiliation(s)
- Ai-Li Shiau
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Chih-Szu Liao
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Chi-Wen Tu
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Correspondence: ; Tel.: +886-6-2353535-5334; Fax: +886-6-2362780
| | - Hsin-Yen Cho
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
| | - Meng-Cheng Yu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
| |
Collapse
|
7
|
Norris EJ, Chen R, Li Z, Geldenhuys W, Bloomquist JR, Swale DR. Mode of action and toxicological effects of the sesquiterpenoid, nootkatone, in insects. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 183:105085. [PMID: 35430075 DOI: 10.1016/j.pestbp.2022.105085] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Nootkatone, a sesquiterpenoid isolated from Alaskan yellow cedar (Cupressus nootkatensis), is known to possess insect repellent and acaricidal properties and has recently been registered for commercial use by the Environmental Protection Agency. Previous studies failed to elucidate the mechanism of action of nootkatone, but we found a molecular overlay of picrotoxinin and nootkatone indicated a high degree of structural and electrostatic similarity. We therefore tested the hypothesis that nootkatone was a GABA-gated chloride channel antagonist, similar to picrotoxinin. The KD50 and LD50 of nootkatone on the insecticide-susceptible strain of Drosophila melanogaster (CSOR) showed resistance ratios of 8 and 11, respectively, compared to the cyclodiene-resistant strain of RDL1675, indicating significant cross-resistance. Nootkatone reversed GABA-mediated block of the larval CSOR central nervous system; nerve firing of 78 ± 17% of baseline in the CSOR strain was significantly different from 24 ± 11% of baseline firing in the RDL1675 strain (p = 0.035). This finding indicated that the resistance was expressed within the nervous system. Patch clamp recordings on D. melanogaster central neurons mirrored extracellular recordings where nootkatone inhibited GABA-stimulated currents by 44 ± 9% at 100 μM, whereas chloride current was inhibited 4.5-fold less at 100 μM in RDL1675. Taken together, these data suggest nootkatone toxicity in D. melanogaster is mediated through GABA receptor antagonism.
Collapse
Affiliation(s)
- Edmund J Norris
- Emerging Pathogens Institute, Entomology and Nematology Department, 2055 Mowry Road, University of Florida, Gainesville, FL 32610-0009, USA; USDA/ARS Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32610-0009, USA
| | - Rui Chen
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA
| | - Zhilin Li
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA
| | - Werner Geldenhuys
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
| | - Jeffrey R Bloomquist
- Emerging Pathogens Institute, Entomology and Nematology Department, 2055 Mowry Road, University of Florida, Gainesville, FL 32610-0009, USA
| | - Daniel R Swale
- Louisiana State University Agricultural Center, Department of Entomology, Baton Rouge, LA 70803, USA.
| |
Collapse
|
8
|
Yang R, Han M, Fan J, Cheng W, Ma N, Yan X, Guo Y. Development of Novel (+)-Nootkatone Thioethers Containing 1,3,4-Oxadiazole/Thiadiazole Moieties as Insecticide Candidates against Three Species of Insect Pests. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:15544-15553. [PMID: 34919380 DOI: 10.1021/acs.jafc.1c05853] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
To improve the insecticidal activity of (+)-nootkatone, a series of 42 (+)-nootkatone thioethers containing 1,3,4-oxadiazole/thiadiazole moieties were prepared to evaluate their insecticidal activities against Mythimna separata Walker, Myzus persicae Sulzer, and Plutella xylostella Linnaeus. Insecticidal evaluation revealed that most of the title derivatives exhibited more potent insecticidal activities than the precursor (+)-nootkatone after the introduction of 1,3,4-oxadiazole/thiadiazole on (+)-nootkatone. Among all of the (+)-nootkatone derivatives, compound 8c (1 mg/mL) exhibited the best growth inhibitory (GI) activity against M. separata with a final corrected mortality rate (CMR) of 71.4%, which was 1.54- and 1.43-fold that of (+)-nootkatone and toosendanin, respectively; 8c also displayed the most potent aphicidal activity against M. persicae with an LD50 value of 0.030 μg/larvae, which was closer to that of the commercial insecticidal etoxazole (0.026 μg/larvae); and 8s showed the best larvicidal activity against P. xylostella with an LC50 value of 0.27 mg/mL, which was 3.37-fold that of toosendanin and slightly higher than that of etoxazole (0.28 mg/mL). Furthermore, the control efficacy of 8s against P. xylostella in the pot experiments under greenhouse conditions was better than that of etoxazole. Structure-activity relationships (SARs) revealed that in most cases, the introduction of 1,3,4-oxadiazole/thiadiazole containing halophenyl groups at the C-13 position of (+)-nootkatone could obtain more active derivatives against M. separata, M. persicae, and P. xylostella than those containing other groups. In addition, toxicity assays indicated that these (+)-nootkatone derivatives had good selectivity to insects over nontarget organisms (normal mammalian NRK-52E cells and C. idella and N. denticulata fries) with relatively low toxicity. Therefore, the above results indicate that these (+)-nootkatone derivatives could be further explored as new lead compounds for the development of potential eco-friendly pesticides.
Collapse
Affiliation(s)
- Ruige Yang
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Meiyue Han
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Jiangping Fan
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Wanqing Cheng
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Nannan Ma
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Xiaoting Yan
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| | - Yong Guo
- School of Pharmaceutical Sciences, Zhengzhou University, No. 100, Science Avenue, Zhengzhou, 450001 Henan Province, P. R. China
| |
Collapse
|