CZ-7, a new derivative of Claulansine F, ameliorates 2VO-induced vascular dementia in rats through a Nrf2-mediated antioxidant responses


Vascular dementia (VD) results from accumulated damage in the vascular system, which is characterized by progressive impairments in memory and cognition and is second only to Alzheimer’s disease (AD) in prevalence among all types of dementia. In contrast to AD, there is no FDA-approved treatment for VD owing to its multiple etiologies. In this study, we investigated whether CZ-7, a new derivative of Claulansine F (Clau F) with verified neuroprotective activity in vitro, could ameliorate the cognitive impairment of rats with permanent occlusion of bilateral common carotid arteries (2VO) and its potential mechanisms of action. The 2VO rats were orally administered CZ-7 (10, 20, 40 mg/kg) from day 27 to day 53 post-surgery. Morris water maze tests conducted at day 48–51 revealed that CZ-7 administration significantly reduced the escape latency in 2VO rats. After the rats were sacrificed on day 53, morphological studies using Nissl and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining showed that administration of CZ-7 markedly attenuated the pathological changes in CA1–CA3 area of the hippocampus, including neuronal cell loss, nuclear shrinkage, and dark staining of neurons, and significantly decreased the chronic cerebral hypoperfusion-induced cell loss. Klüver–Barrera staining study revealed that CZ-7 administration significantly improved the white matter lesions. 8-OHdG and reactive oxygen species (ROS) immunofluorescent analyses showed that CZ-7 administration significantly decreased oxidative stress in CA1–CA3 area of the hippocampus. Finally, we found that the CZ-7-improved oxidative stress might be mediated via the Nrf2 pathway, evidenced by the double immunofluorescent staining of Nrf2 and the elevation of expression levels of oxidative stress proteins HO-1 and NQO1. In conclusion, CZ-7 has therapeutic potential for VD by alleviating oxidative stress injury through Nrf2-mediated antioxidant responses.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10


  1. 1.

    Kua EH, Ho E, Tan HH, Tsoi C, Thng C, Mahendran R. The natural history of dementia. Psychogeriatrics. 2014;14:196–201.

  2. 2.

    O’Brien JT, Thomas A. Vascular dementia. Lancet. 2015;386:1698–706.

  3. 3.

    Sahathevan R, Brodtmann A, Donnan GA. Dementia, stroke, and vascular risk factors; a review. Int J Stroke. 2012;7:61–73.

  4. 4.

    Korczyn AD, Vakhapova V, Grinberg LT. Vascular dementia. J Neurol Sci. 2012;322:2–10.

  5. 5.

    Venkat P, Chopp M, Chen J. Models and mechanisms of vascular dementia. Exp Neurol. 2015;272:97–108.

  6. 6.

    Wang J, Zhang HY, Tang XC. Cholinergic deficiency involved in vascular dementia: possible mechanism and strategy of treatment. Acta Pharmacol Sin. 2009;30:879–88.

  7. 7.

    Versijpt J. Effectiveness and cost-effectiveness of the pharmacological treatment of Alzheimer’s disease and vascular dementia. J Alzheimer Dis. 2014;42(Suppl 3):S19–25.

  8. 8.

    Dichgans M, Leys D. Vascular cognitive impairment. Circ Res. 2017;120:573–91.

  9. 9.

    Chu SF, Zhang JT. Recent advances in the study of (-)clausenamide: chemistry, biological activities and mechanism of action. Acta Pharm Sin B. 2014;4:417–23.

  10. 10.

    Chu S, Liu S, Duan W, Cheng Y, Jiang X, Zhu C, et al. The anti-dementia drug candidate, (-)-clausenamide, improves memory impairment through its multi-target effect. Pharmacol Ther. 2016;162:179–87.

  11. 11.

    Liu H, Li CJ, Yang JZ, Ning N, Si YK, Li L, et al. Carbazole alkaloids from the stems of Clausena lansium. J Nat Prod. 2012;75:677–82.

  12. 12.

    Li JW, Ning N, Ma YZ, Zhang R, Tan F, Chen NH. Claulansine F suppresses apoptosis induced by sodium nitroprusside in PC12 cells. Free Radic Res. 2013;47:488–97.

  13. 13.

    Ma YZ, Ning N, He WB, Li JW, Hu JF, Chu SF, et al. Claulansine F promotes neuritogenesis in PC12 cells via the ERK signaling pathway. Acta Pharmacol Sin. 2013;34:1499–507.

  14. 14.

    Huang JY, Ma YZ, Yuan YH, Zuo W, Chu SF, Liu H, et al. Claulansine F promoted the neuronal differentiation of neural stem and progenitor cells through Akt/GSK-3beta/beta-catenin pathway. Eur J Pharmacol. 2016;786:72–84.

  15. 15.

    Zang Y, Song X, Li C, Ma J, Chu S, Liu D, et al. Pyrano[3,2-a]carbazole alkaloids as effective agents against ischemic stroke in vitro and in vivo. Eur J Med Chem. 2017;143:438–48.

  16. 16.

    Ji HJ, Hu JF, Wang YH, Chen XY, Zhou R, Chen NH. Osthole improves chronic cerebral hypoperfusion induced cognitive deficits and neuronal damage in hippocampus. Eur J Pharmacol. 2010;636:96–101.

  17. 17.

    Zhao XL, Fang XB, Li DP. Establishing vascular dementia model in rats. J Chin Med Univ. 2002;31:166–7.

  18. 18.

    He XL, Wang YH, Bi MG, Du GH. Chrysin improves cognitive deficits and brain damage induced by chronic cerebral hypoperfusion in rats. Eur J Pharmacol. 2012;680:41–8.

  19. 19.

    Zhang T, Gu J, Wu L, Li N, Sun Y, Yu P, et al. Neuroprotective and axonal outgrowth-promoting effects of tetramethylpyrazine nitrone in chronic cerebral hypoperfusion rats and primary hippocampal neurons exposed to hypoxia. Neuropharmacology. 2017;118:137–47.

  20. 20.

    Sugawara T, Lewen A, Noshita N, Gasche Y, Chan PH. Effects of global ischemia duration on neuronal, astroglial, oligodendroglial, and microglial reactions in the vulnerable hippocampal CA1 subregion in rats. J Neurotrauma. 2002;19:85–98.

  21. 21.

    Choi BR, Kim DH, Back DB, Kang CH, Moon WJ, Han JS, et al. Characterization of white matter injury in a rat model of chronic cerebral hypoperfusion. Stroke. 2016;47:542–7.

  22. 22.

    Di Minno A, Turnu L, Porro B, Squellerio I, Cavalca V, Tremoli E, et al. 8-Hydroxy-2-deoxyguanosine levels and cardiovascular disease: a systematic review and meta-analysis of the literature. Antioxid Redox Signal. 2016;24:548–55.

  23. 23.

    Wu LL, Chiou CC, Chang PY, Wu JT. Urinary 8-OHdG: a marker of oxidative stress to DNA and a risk factor for cancer, atherosclerosis and diabetics. Clin Chim Acta. 2004;339:1–9.

  24. 24.

    Bae YS, Oh H, Rhee SG, Yoo YD. Regulation of reactive oxygen species generation in cell signaling. Mol Cells. 2011;32:491–509.

  25. 25.

    Barzilai A, Yamamoto K. DNA damage responses to oxidative stress. DNA Repair (Amst). 2004;3:1109–15.

  26. 26.

    Etherton-Beer CD. Vascular cognitive impairment in dementia. Maturitas. 2014;79:220–6.

  27. 27.

    Farkas E, Luiten PG, Bari F. Permanent, bilateral common carotid artery occlusion in the rat: a model for chronic cerebral hypoperfusion-related neurodegenerative diseases. Brain Res Rev. 2007;54:162–80.

  28. 28.

    Otori T, Katsumata T, Muramatsu H, Kashiwagi F, Katayama Y, Terashi A. Long-term measurement of cerebral blood flow and metabolism in a rat chronic hypoperfusion model. Clin Exp Pharmacol Physiol. 2003;30:266–72.

  29. 29.

    Vorhees CV, Williams MT. Value of water mazes for assessing spatial and egocentric learning and memory in rodent basic research and regulatory studies. Neurotoxicol Teratol. 2014;45:75–90.

  30. 30.

    Liu C, Yin H, Gao J, Xu X, Zhang T, Yang Z. Leonurine ameliorates cognitive dysfunction via antagonizing excitotoxic glutamate insults and inhibiting autophagy. Phytomedicine. 2016;23:1638–46.

  31. 31.

    Kadar A, Wittmann G, Liposits Z, Fekete C. Improved method for combination of immunocytochemistry and Nissl staining. J Neurosci Methods. 2009;184:115–8.

  32. 32.

    Liu H, Zhang J. Cerebral hypoperfusion and cognitive impairment: the pathogenic role of vascular oxidative stress. Int J Neurosci. 2012;122:494–9.

  33. 33.

    Bennett S, Grant MM, Aldred S. Oxidative stress in vascular dementia and Alzheimer’s disease: a common pathology. J Alzheimers Dis. 2009;17:245–57.

  34. 34.

    Dubinina EE, Kovrugina SV, Konovalov PV. The factors of oxidative stress in neurodegenerative diseases (vascular dementia, Alzheimer disease). Adv Gerontol. 2007;20:109–13.

  35. 35.

    Kim HA, Miller AA, Drummond GR, Thrift AG, Arumugam TV, Phan TG, et al. Vascular cognitive impairment and Alzheimer’s disease: role of cerebral hypoperfusion and oxidative stress. Naunyn-Schmiedeberg’s Arch Pharmacol. 2012;385:953–9.

  36. 36.

    Lim J, Luderer U. Oxidative damage increases and antioxidant gene expression decreases with aging in the mouse ovary. Biol Reprod. 2011;84:775–82.

  37. 37.

    Mazlumoglu MR, Ozkan O, Alp HH, Ozyildirim E, Bingol F, Yoruk O, et al. Measuring oxidative DNA damage with 8-hydroxy-2’-deoxyguanosine levels in patients with laryngeal cancer. Ann Otol Rhinol Laryngol. 2017;126:103–9.

  38. 38.

    Chien JW, Wang LY, Cheng YS, Tsai YG, Liu CS. Urinary 8-hydroxy-2′-deoxyguanosine (8-oxodG) level can predict acute renal damage in young children with urinary tract infection. Biomarkers. 2014;19:326–31.

  39. 39.

    Mehrdad R, Aghdaei S, Pouryaghoub G. Urinary 8-hydroxy-deoxyguanosine as a biomarker of oxidative DNA damage in employees of subway system. Acta Med Iran. 2015;53:287–92.

  40. 40.

    Ock CY, Kim EH, Choi DJ, Lee HJ, Hahm KB, Chung MH. 8-Hydroxydeoxyguanosine: not mere biomarker for oxidative stress, but remedy for oxidative stress-implicated gastrointestinal diseases. World J Gastroenterol. 2012;18:302–8.

  41. 41.

    Gao X, Lai CQ, Scott T, Shen J, Cai T, Ordovas JM, et al. Urinary 8-hydroxy-2-deoxyguanosine and cognitive function in Puerto Rican adults. Am J Epidemiol. 2010;172:271–8.

  42. 42.

    Shi GX, Liu CZ, Wang LP, Guan LP, Li SQ. Biomarkers of oxidative stress in vascular dementia patients. Can J Neurol Sci. 2012;39:65–8.

  43. 43.

    Kroese LJ, Scheffer PG. 8-Hydroxy-2'-deoxyguanosine and cardiovascular disease: a systematic review. Curr Atheroscler Rep. 2014;16:452

  44. 44.

    Luca M, Luca A, Calandra C. The role of oxidative damage in the pathogenesis and progression of Alzheimer’s disease and vascular dementia. Oxid Med Cell Longev. 2015;2015:504678.

  45. 45.

    Gackowski D, Rozalski R, Siomek A, Dziaman T, Nicpon K, Klimarczyk M, et al. Oxidative stress and oxidative DNA damage is characteristic for mixed Alzheimer disease/vascular dementia. J Neurol Sci. 2008;266:57–62.

  46. 46.

    Hirayama A, Yoh K, Nagase S, Ueda A, Itoh K, Morito N, et al. EPR imaging of reducing activity in Nrf2 transcriptional factor-deficient mice. Free Radic Biol Med. 2003;34:1236–42.

  47. 47.

    Suzuki T, Yamamoto M. Molecular basis of the Keap1-Nrf2 system. Free Radic Biol Med. 2015;88:93–100.

  48. 48.

    Niture SK, Khatri R, Jaiswal AK. Regulation of Nrf2—an update. Free Radic Biol Med. 2014;66:36–44.

  49. 49.

    Huang Y, Li W, Su ZY, Kong AN. The complexity of the Nrf2 pathway: beyond the antioxidant response. J Nutr Biochem. 2015;26:1401–13.

  50. 50.

    Chapple SJ, Siow RC, Mann GE. Crosstalk between Nrf2 and the proteasome: therapeutic potential of Nrf2 inducers in vascular disease and aging. Int J Biochem Cell Biol. 2012;44:1315–20.

Download references


This work was supported by the National Natural Science Foundation of China (Nos. 81730096, 81730093, U1402221, 81603316, 81560685), the CAMS Innovation Fund for Medical Sciences (No. CIFMS) (No. 2016-I2M-1-004), the State Key Laboratory Fund Open Project (No. GTZK201610), the China Postdoctoral Science Foundation (No. 2013M540066), the PUMC Graduate Education and Teaching Reform Project (No. 10023201600801), the Scientific Research Foundation of the Higher Education Institutions of Hunan Province (No. 15K091), the Project of NDRC and State Administration of Traditional Chinese Medicine (No. 60011000), and the Hunan Provincial Key Laboratory for Standardization of Important Chinese Herbal Pieces (No. BG201701, 4981-0901020).

Author contribution

N-hC, S-fC, XH, Z-hH, H-sS, and Z-pF designed research; D-dL, XY, CC, QR, PL, M-yL, S-sW, T-bZ and Q-dA performed research; Y-dZ and D-mZh contributed new analytical tools and reagents; D-dL and XY analyzed data; D-dL and XY wrote the paper.

Author information

Correspondence to Nai-hong Chen.

Ethics declarations

Competing interests

The authors declare no competing interests.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark


  • claulansine F
  • CZ-7
  • vascular dementia
  • 2VO rats
  • chronic cerebral hypoperfusion
  • spatial memory
  • oxidative stress
  • Nrf2
  • HO-1
  • NQO1

Further reading