Isolation of long-chain esters from the rhizome of Polygonatum verticillatum by potent tyrosinase inhibition
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Med Chem Res (2013) 22:2088–2092 DOI 10.1007/s00044-012-0194-8
ORIGINAL RESEARCH
Isolation of long-chain esters from the rhizome of Polygonatum verticillatum by potent tyrosinase inhibition Haroon Khan • Muhammad Saeed • Murad Ali Khan • Izhar-ul-Haq • Naveed Muhammad • Rukhsana Ghaffar
Received: 23 May 2012 / Accepted: 6 August 2012 / Published online: 2 September 2012 Ó Springer Science+Business Media, LLC 2012
Keywords Polygonatum verticillatum Long-chain ester Propyl pentadecanoate 20 ,30 -Dihydroxypropyl pentadecanoate Tyrosinase inhibition
The rhizome of P. verticillatum has been recommended in various disorders worldwide (Singh, 2006; Ballabh et al., 2008). Of the different ethnobotanical uses of the plant, more recently we have validated some of them like analgesic (Khan et al., 2010, 2011a), phytotoxicity without cytotoxicity (Saeed et al., 2010a), accumulation of various nutrients (Saeed et al., 2010b; Khan et al., 2012e) and antimalarial activity in the light of isolated compounds (Khan et al., 2012c), antimicrobial activity (Khan et al., 2012a), and antipyretic activities (Khan et al., 2012b). Based on the literature survey, it is worthwhile that no such evidence of isolation is documented from this plant species. In the present study, we made an attempt to isolate secondary metabolites from the rhizomes of the plant.
Introduction
Materials and methods
Polygonatum verticillatum [L.] All. (Nooreallam), a perennial rhizomatous herb belongs to family Convallariaceae (Szczecinska et al., 2006). In Pakistan, four species of polygonatum have been confirmed by flora of Pakistan (Khan et al., 2012d).
General experimental conditions
Abstract Of plant origin, a new long-chain ester 1 along with a known 2 has been isolated from the rhizome of Polygonatum verticillatum. The structures of these compounds were elucidated as propyl pentadecanoate and 20 , 30 -dihydroxypropyl pentadecanoate on the basis of various modern techniques including HREI-MS, 1D, and 2D NMR. Compound 1 and 2 showed potent inhibition of tyrosinase, 22.34 and 9.45 lM, respectively.
H. Khan (&) M. Saeed (&) N. Muhammad R. Ghaffar Department of Pharmacy, University of Peshawar, Peshawar 25120, Pakistan e-mail: [email protected] M. Saeed e-mail: [email protected] M. A. Khan Izhar-ul-Haq Department of Chemistry, Kohat University of Science and Technology, Kohat, Pakistan H. Khan Gandhara College of Pharmacy, Gandhara University, Peshawar, Pakistan
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The 1H-NMR spectra were measured in MeOD at 500 mHz on Bruker AC-300, AM-300, AM-400 or AMX-500 nuclear magnetic resonance spectrometer using Aspect-3000 data systems at a digital resolution of 32 K. TMS was used as an internal standard. The 13C-NMR spectra were recorded in MeOD at 400 mHz on the same instruments. The other related techniques like COSY, HMQC, NOESY, and HMBC spectra were measured on Bruker spectrophotometers at 400 or 500 mHz. Mass spectrometric analysis was based on electron impact mass spectrometry (EIMS) and high resolution fast atom bombardment mas
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