Schistosomicidal and Antioxidant Flavonoids from Astragalus englerianus

Abstract

Astragalus englerianus is a close relative of the traditional Chinese medicine plant Radix Astragali (Huang-qi) and is mainly distributed in Yunnan. It has been traditionally used as a substitute of “Huang-qi” for reducing fatigue and enhancing immunity by local folks. A phytochemical study of the methanol extract of the roots led to the isolation of three new flavonoids including one aurone (1) and two chalcones (2 and 3), as well as two known flavonoids (4 and 5). Their structures were elucidated based on the analyses of extensive spectroscopic data and comparison of their physicochemical properties. This is the first report on the occurrence of β-hydroxydihydrochalcone, 2′,5′-dioxygenchalcones, and 2′,5′-dioxygenaurone in the genus Astragalus. All the isolated compounds were tested in vitro for their schistosomicidal and antioxidant activities. Compounds 2 and 4 showed schistosomicidal activities with worm mortality rates of 100 % within 12 h in a drug-containing (0.70 and 0.77 mM, respectively) RPMI 1640 medium. Compounds 1 and 2 exhibited antioxidant activities in 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl free radical scavenging assays, with IC₅₀ values of 35.9 ± 1.1 and 12.2 ± 1.1 µM, respectively.

Key words

Astragalus englerianus - Fabaceae - flavonoids - schistosomicidal - antioxidant activity

• References

• 1 Editorial Board of China Herbal, State Administration of Traditional Chinese Medicine. China herbal. Shanghai: Scientific and Technical Publishers; 1999: 341-355
• 2 Chinese Pharmacopeia Committee. Pharmacopoeia of China. Beijing: China Medical Science Press; 2010: 283-285
• 3 Kunming Institute of Botany, Chinese Academy of Sciences. Flora Yunnanica. Beijing: Science Press; 2006: 701-739
• 4 Delectis Florae Reipublicae Popularis Sinicae Agendae Academiae Sinicae Edita. Flora Reipublicae Popularis Sinicae. Beijing: Science Press; 1997: 78-349
• 5 He ZQ, Findlay JA. Constituents of Astragalus membranaceus . J Nat Prod 1991; 54: 810-815
• 6 Hasan N, Osman H, Mohamad S, Chong WK, Awang K, Zahariluddin ASM. The chemical components of Sesbania grandiflora root and their antituberculosis activity. Pharmaceuticals 2012; 5: 882-889
• 7 Yoon JS, Sung SH, Park JH, Kim YC. Flavonoids from Spatholobus suberectus . Arch Pharm Res 2004; 27: 589-592
• 8 Zhao X, Mei W, Gong M, Zuo W, Bai H, Dai H. Antibacterial activity of the flavonoids from Dalbergia odorifera on Ralstonia solanacearum . Molecules 2011; 16: 9775-9782
• 9 Huang HQ, Li HL, Tang J, Lv YF, Zhang WD. A new aurone and other phenolic constituents from Veratrum schindleri Loes. f. Biochem Syst Ecol 2008; 36: 590-592
• 10 Alaniya MD, Kavtaradze NS, Lavoi S, Pichette A, Mshvildadze VD. Aurone from Astragalus microcephalus stems. Chem Nat Compd 2009; 45: 455-456
• 11 Albogami AS, Karama U, Mousa AA, Khan M, Al-Mazroa SA, Alkhathlan HZ. Simple and efficient one step synthesis of functionalized flavanones and chalcones. Orient J Chem 2012; 28: 619-626
• 12 Muiva LM, Yenesew A, Derese S, Heydenreich M, Peter MG, Akala HM, Eyase F, Waters NC, Mutai C, Keriko JM. Antiplasmodial β-hydroxydihydrochalcone from seedpods of Tephrosia elata . Phytochem Lett 2009; 2: 99-102
• 13 Verma AK, Pratap R. The biological potential of flavones. Nat Prod Rep 2010; 27: 1571-1593
• 14 Harborne JB, Williams CA. Anthocyanins and other flavonoids. Nat Prod Rep 2001; 18: 310-333
• 15 Harborne JB, Williams CA. Anthocyanins and other flavonoids. Nat Prod Rep 1995; 12: 639-657
• 16 Xiao SH, Keiser J, Chollet J, Utzinger J, Dong Y, Endriss Y, Vennerstrom JL, Tanner M. In vitro and in vivo activities of synthetic trioxolanes against major human schistosome species. Antimicrob Agents Chemother 2007; 51: 1440-1445
• 17 Moraes JD, Nascimento C, Lopes POMV, Nakano E, Yamaguchi LF, Kato MJ, Kawano T. Schistosoma mansoni: In vitro schistosomicidal activity of piplartine. Exp Parasitol 2011; 127: 357-364
• 18 Zhang LB, Lv JL, Chen HL. Japonicasins A and B, two new isoprenylated flavanones from Sophora japonica . Fitoterapia 2013; 87: 89-92