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Food Chemistry 132 (2012) 921–924

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Food Chemistry
journal homepage: www.elsevier.com/locate/foodchem

Heptadecanols from the leaves of Persea americana var. americana
Tzong-Huei Lee a, Yow-Fu Tsai b, Tzu-Tien Huang a, Pi-Yu Chen c, Wen-Li Liang c,⇑, Ching-Kuo Lee c,⇑
a

Graduate Institute of Pharmacognosy, Taipei Medical University,Taipei 110, Taiwan Department of Chemistry, Chung Yuan Christian University, Chung-Li 320, Taiwan c School of Pharmacy, Taipei Medical University, Taipei 110, Taiwan
b

a r t i c l e

i n f o

a b s t r a c t
From the leaves of Persea americana var. americana, eleven heptadecanol derivatives were identified. Their structures were elucidated on the basis of spectroscopic analyses. Theabsolute configurations were determined by chemical reaction, NOESY experiment and further comparison of the optical rotation value with the literature value. Additionally, the ratios of the contents of six heptadecanol derivatives in leaves, immature fruits, mature fruits and seeds of P. americana were estimated by LC–MS in multiple reaction monitoring (MRM) mode. Crown Copyright Ó 2011 Published byElsevier Ltd. All rights reserved.

Article history: Received 26 March 2011 Received in revised form 18 October 2011 Accepted 14 November 2011 Available online 20 November 2011 Keywords: Persea americana Heptadecanols Interconversion Leaves

1. Introduction The avocado (Persea americana var. americana), a fruit tree, is native to tropical America, and is widely cultivated in central and southernTaiwan. Its fruits have long been used as a healthy food for cholesterol-lowering, blood vessel-strengthening, hormone-regulating, anti-aging and constipation-preventing (Chiu & Chang, 1998), while its leaves were reported to exhibit anti-fungal (Prusky, Keen, Sims, & Midland, 1982; Prusky et al., 1991), antiinflammatory (Adeyemi, Okpo, & Ogunti, 2002) and anti-oxidant activities (Kim et al., 2000).Although several chemical entities have been identified from the fruits of the genus Persea (Adikaram, Ewing, Karunaratne, & Wijeratne, 1992; Chenga et al., 2002; Domergue, Helms, Prusky, & Browse, 2000; Gross, Gabai, Lifshitz, & Sklarz, 1974; Hashimura, Ueda, Kawabata, & Kasai, 2001; Jacques & Haslsm, 1974; Karikome, Mimaki, & Sashida, 1991; Kawagishi et al., 2001; Komae & Hayashi, 1972;Oberlies, Rogers, Martin, & Mclaughlin, 1998; Tomita, Lu, & Lan, 1965), the constituents of the other parts of these plants have been rarely studied, so far. In our preliminary pharmacological evaluation, the acetone extracts of the leaves of P. americana exhibited significant vasodilating activities at concentrations higher than 150 lg/ml (Huang, 2004). Based on this finding, we set out to investigate thechemical constituents of the leaves of P. americana; this has led to the isolation and identification of four novel chemical entities 1–4 together with seven known analogues 5–11 (Fig. 1). This paper deals with

the isolation and structural elucidation of the previously unreported compounds. 2. Materials and methods 2.1. General procedures Optical rotations were measured in a JASCO P-1020polarimeter. H and 13C NMR were acquired with a Bruker DRX-500 SB spectrometer. Low resolution and high resolution mass spectra were obtained, using a Finnigan TSQ-46C EI/MS and JEOL SX-102A HRFAB/MS, respectively. IR spectra were recorded on a Thermo Mattson IR-300 spectrometer.
1

2.2. Chemicals and reagents HPLC-grade solvents, n-hexane, ethyl acetate, acetone, and two reagents,2,2-dimethoxypropane and p-toluenesulfonic acid monohydrate, were purchased from Merck. Open column chromatography was performed on silica gel (70–230 mesh, Merck). TLC was carried out on silica gel 60 F254 plates (Merck), using mixtures of n-hexane–ethyl acetate for development and spots were detected by spraying with vanillin-sulfuric acid, followed by heating. 2.3. Plant materials Fresh leaves of P. americana...