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A new 5H-purin-6-amine from the leaves of Sedum sarmentosum

Abstract

Phytochemical constituents were isolated from Sedum sarmentosum leaves using open column chromatography and medium-pressure liquid chromatography. Their structures were identified as 2,4-pyrimidinedione (1), N-methylhydroxylamine (2), 5H-purin-6-amine (3), uridine (4), l-tyrosine (5), and l-prolyl-l-tyrosine (6) using mass spectrometry and 1H- and 13C-nuclear magnetic resonance spectroscopic analysis. Among them, compound 3 (5H-purin-6-amine) was isolated for the first time from a natural source.

Introduction

Sedum sarmentosum Bunge is a perennial herb distributed across Asia, Europe, and North America [1]. It is commonly known as Dolnamul in Korea. Fresh leaves of S. sarmentosum have been used in salads as an alternative to pepper because of their pungent taste. Moreover, traditionally, it has been used as a hepatoprotective medicinal plant in Asian countries [2]. Few studies have focused on the biological activities of S. sarmentosum [1]. S. sarmentosum shows unique angiotensin-converting enzyme inhibitory activity. Some flavonoids also show this activity [3]. Kim et al. [4] suggested that S. sarmentosum contains estrogens to promote a better life in menopausal women [4].

The objective of this study was to find new bioactive compounds from the leaves of S. sarmentosum. Therefore, our investigation was designed for the systematic isolation and identification of these valuable phytochemicals.

Materials and methods

Plant materials

Fresh S. sarmentosum leaves were cultivated at Juksan-myeon, Anseong, Republic of Korea.

Apparatus and chemicals

Nuclear magnetic resonance (NMR) spectra were recorded with a Bruker Avance 500 NMR (Rheinstetten, Germany) spectrometer. Mass spectrometry (MS) was performed using a JEOL JMS-600 W (Tokyo, Japan) mass spectrometer. Optical rotations were measured on a Jasco P-2000 digital polarimeter (Tokyo, Japan). Medium-pressure liquid chromatographic separation was carried out on the Biotage (Uppsala, Sweden) system.

Extraction, fractionation, and isolation

The fresh S. sarmentosum leaves were dried for 3 days, and the powdered S. sarmentosum leaves (1.3 kg) were subjected to extraction with EtOH (8 L × 10) under reflux at 65–75 °C. The filtrate was concentrated until dry in vacuo to afford a dark green EtOH extract (286.1 g). The EtOH extract (250.5 g) was suspended in H2O and then partitioned successively using n-hexane (57.8 g), CH2Cl2 (5.5 g), EtOAc (6.9 g), and n-BuOH (76.5 g). Among the fractions, a portion of the EtOAc fraction (5 g) was subjected to medium-pressure liquid chromatography (MPLC) with a gradient elution of CHCl3–MeOH (1:0 → 5:5) to yield 21 (EF1 to EF21) sub-fractions. EF9 sub-fraction was recrystallized under CHCl3–MeOH to yield compound 1. A portion of the n-BuOH fraction (60 g) was subjected to MPLC on silica gel using a gradient elution of CHCl3–MeOH (100:0 → 50:50) to obtain ten (BF1 to BF10) fractions. BF2 fraction was recrystallized under CHCl3–MeOH to yield compound 2. BF6 fraction was repeatedly chromatographed on a Sephadex LH-20 column (St. Louis, MO, USA) to obtain seven (BF6-1 to BF6-7) fractions, and BF6-3 fraction was recrystallized to yield compound 3. BF8 and BF9 fractions were repeatedly subjected to MPLC and eluted with CHCl3–MeOH (80:20 → 50:50) to yield five (BF8-1 to BF8-5) and six (BF9-1 to BF9-6) fractions, respectively. BF8-3 fraction was separated on a Sephadex LH-20 column to obtain seven fractions (BF8-3-1 to BF8-3-7) and isolated compound 4. BF9-4 fraction was repeatedly chromatographed on a Sephadex LH-20 column to obtain five (BF9-4-1 to BF9-4-5) fractions, and BF9-4-5 fraction was recrystallized to yield compound 5. BF9-5 fraction was separated on a Sephadex LH-20 column and isolated compound 6.

Compound 1

EI-MS: m/z (rel. int.) 112 [M]+ (100), 85 (0.9), 69 (45), 57 (3.8); 1H-NMR (DMSO-d 6 , 500 MHz): δ 5.44 (1H, d, J = 7.6 Hz, H-5), 7.38 (1H, d, J = 7.6 Hz, H-6), 10.81 (NH), 11.00 (NH); 13C-NMR (DMSO-d 6 , 125 MHz): δ 100.1 (C-5), 142.0 (C-6), 151.3 (C-2), 164.4 (C-4).

Compound 2

1H-NMR (DMSO-d 6 , 500 MHz): δ 3.16 (3H, d, J = 5.5 Hz, –CH3), 4.08 (1H, q, J = 5.0 Hz, –NH), 8.31 (1H, s, –OH); 13C-NMR (DMSO-d 6 , 125 MHz): δ 48.5 (–NCH3).

Compound 3

EI-MS: m/z (rel. int.) 135 [M]+ (100), 119 (1.4), 108 (25.3), 92 (1.1), 81 (9.7), 66 (4.4), 54 (6.1); 1H- and 13C-NMR (DMSO-d 6 , 500 MHz): see Table 1.

Table 1 1H- and 13C-NMR spectral data for compound 3 (DMSO, 500 MHz)

Compound 4

EI-MS: m/z (rel. int.) 154 (10.0), 151 (21.0), 112 (100), 95 (17.4), 83 (8.7), 69 (23.2); 1H-NMR (DMSO-d 6 , 500 MHz): δ 3.58 (1H, dd, J = 2.5, 12.0 Hz, H-5′), 3.70 (1H, dd, J = 2.5, 12.0 Hz, H-5′), 3.88 (1H, m, H-4′), 3.95 (1H, t, J = 5.5 Hz, H-3′), 4.02 (1H, t, J = 5.5 Hz, H-2′), 5.71 (1H, d, J = 3.5 Hz, H-4), 5.99 (1H, d, J = 8.0 Hz, H-1′), 8.21 (1H, d, J = 8.0 Hz, H-3); 13C-NMR (DMSO-d 6 , 125 MHz): δ 60.1 (C-5′), 69.0 (C-3′), 74.1 (C-2′), 84.5 (C-4′), 89.4 (C-1′), 93.8 (C-4), 143.1 (C-3), 159.1 (C-2), 168.1 (C-5).

Compound 5

[α] 27D -6.5 (c 0.4, DMSO); EI-MS: m/z (rel. int.) 181 [M]+ (6.5), 136 (3.2), 119 (1.5), 107 (100), 91 (8.2), 77 (7.7), 68 (2.5); 1H-NMR (DMSO-d 6 , 500 MHz): δ 3.01 (2H, br d, CH2), 4.09 (1H, br s, CH), 6.66 (2H, d, J = 8.0 Hz, H-2, H-6), 7.03 (2H, d, J = 8.0 Hz, H-3, H-5). 13C-NMR (DMSO-d 6 , 125 MHz): δ 48.6 (C-7), 55.9 (C-8), 127.2 (C-1), 115.1 (C-3, C-5), 130.2 (C-2, C-6), 155.5 (C-4), 177.2 (C=O).

Compound 6

[α] 27D -60 (c 0.075, MeOH); EI-MS: m/z (rel. int.) 181 (9.7), 151 (8.3), 140 (14.5), 112 (25.4), 107 (100), 91 (5.3), 77 (6.8); 1H-NMR (DMSO-d 6 , 500 MHz): δ 3.02 (2H, br d, CH2), 3.95 (1H, br s, CH), 7.04 (2H, d, J = 8.5 Hz, H-2, H-6), 8.04 (2H, d, J = 8.5 Hz, H-3, H-5); 13C-NMR (DMSO-d 6 , 125 MHz): δ 48.6 (C-7), 53.4 (C-8), 60.3 (C-13), 69.1 (C-12), 74.1 (C-14), 84.3 (C-11), 115.4 (C-3, C-5), 124.6 (C-1), 130.5 (C-2, C-6), 156.6 (C-4), 170.5 (C-10), 175.9 (C-9).

Results and discussion

A chromatographic separation of the MeOH extract obtained six compounds (Fig. 1). The known compounds, 2,4-pyrimidinedione (1) [5], N-methylhydroxylamine (2) [6], uridine (4) [5], l-tyrosine (5) [7], and l-prolyl-l-tyrosine (6) [8], were identified by comparison with spectroscopic data from the studies.

Fig. 1
figure 1

Structures of compounds 1–6

Compound 3 was obtained as a white amorphous powder. A molecular ion peak was measured at m/z 135 [M]+ in the EI-MS, which corresponds to a molecular formula of C5H5N5 by HREI-MS (m/z 135.0546 [M]+, calcd. for 135.0545). 1H-NMR spectra of 3 showed a methine proton at δ 3.16 and the presence of two aromatic protons at δ 8.45 and 8.46. The 13C-NMR spectrum indicated 5 carbon resonances. The 13C-NMR spectrum showed a methine carbon at δ 48.5 and two olefin quaternary and two olefin methane carbons at δ 142.7, 146.1, 149.3 and 151.4. The structure of 3 was similar to that of adenine [9]. Thus, the structure of 3 was assigned as 5H-purin-6-amine via spectroscopic analysis.

Six compounds were isolated for the first time from S. sarmentosum leaves. According to previous studies, compound 3 (5H-purin-6-amine) was isolated for the first time from a natural source.

References

  1. Kang TH, Pae HO, Yoo JC, Kim NY, Kim YC, Ko GI, Chung HT (2000) Antiproliferative effects of alkaloids from Sedum sarmentosum on murine and human hepatoma cell lines. J Ethnopharmacol 70:177–182

    Article  CAS  Google Scholar 

  2. Qin F, Sun HX (2008) Immunosuppressive activity of the ethanol extract of Sedum sarmentosum and its fractions on specific antibody and cellular response to ovalbumin in mice. Chem Biodiv 5:2699–2709

    Article  CAS  Google Scholar 

  3. Oh H, Kang D-G, Kwon J-W, Kwon T-O, Lee S-Y, Lee D-B, Lee H-S (2004) Isolation of angiotensin converting enzyme (ACE) inhibitory flavonoids from Sedum sarmentosum. Biol Pharm Bull 27:2035–2037

    Article  CAS  Google Scholar 

  4. Kim WH, Park YJ, Park MR, Ha TY, Lee SH, Bae SJ, Kim M (2004) Estrogenic effects of Sedum sarmentosum Bunge in ovariectomized rats. J Nutr Sci Vitaminol 50:100–105

    Article  CAS  Google Scholar 

  5. Lee HJ, Lee KT, Park Y, Lee MW (2002) Chemical constituents of the sclerotia of Grifola umbellata. J Korean For Eng 21:16–24

    Google Scholar 

  6. Bissot TC, Parry RW, Campbell DH (1957) The physical and chemical properties of the methylhydroxylamines. J Am Chem Soc 79:796–800

    Article  CAS  Google Scholar 

  7. Jeong IS (2009) Antimicrobial activity of garlic depending on PH, heating time and isolations of water-soluble compounds. Thesis of Sejong University

  8. Khedr AIM, Mohamed GA, Orabi MAA, Ibrahim SRM, Yamada K (2015) Staphylopeptide A, a new cyclic tetrapeptide from culture broth of Staphylococcus sp. Phytochem Lett 13:11–14

    Article  CAS  Google Scholar 

  9. Dorcier A, Hartinger CG, Scopelliti R, Fish RH, Keppler BK, Dyson PJ (2008) Studies on the reactivity of organometallic Ru-, Rh- and Os-pta complexes with DNA model compounds. J Inorg Biochem 102:1066–1076

    Article  CAS  Google Scholar 

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Acknowledgments

We thank the National Center for Inter-University Research Facilities (Seoul National University, Republic of Korea) for the measurement of spectroscopic data.

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Correspondence to Sanghyun Lee.

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Cho, S., Lee, J., Rodriguez, J.P. et al. A new 5H-purin-6-amine from the leaves of Sedum sarmentosum . Appl Biol Chem 60, 109–111 (2017). https://doi.org/10.1007/s13765-017-0257-0

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