Lipoxygenase Inhibitors from the Latex of Calotropis Procera

Wael M. Abdel-Mageed1,2, Nadia H. Mohamed3,4, Miaomiao Liu5,6, Ali A. El-Gamal1, Omer A. Basudan1, Mady Ahmed Ismail3, Ronald J Quinn7, Xueting Liu5†,Lixin Zhang5†, Ahmed A. M. Shoreit3†

Affiliation

1Pharmacognosy Department, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia

2Pharmacognosy Department, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt

3Department of Botany, Faculty of Science, Assiut University, Assiut, Egypt

4Department of Biology, Faculty of Science and Art, Samtah, Jazan University, Saudi Arabia

5Key Laboratory of Pathogenic Microbiology andImmunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China

6Graduate University of Chinese Academy of Sciences, Beijing 100049, China

7Eskitis Institute, Griffith University, Brisbane, QLD 4111, Australia

†Address for correspondence

Prof. Dr. Ahmed A. M. Shoreit, Department of Botany and Microbiology, Faculty of Science, Assiut University, Assiut, Egypt, Tel. 002-01003406161, Fax. 002-0882080209,E-mail:

Prof. Dr. Lixin Zhang and Dr. Xueting Liu, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, P. R. China. Tel/Fax: +86-10-64807665, E-mail: ,

Abstract

A radical-scavenging, guided phytochemical study of the latex of Calotropis Procera afforded five lignans (1-5), including a new one (4). The structural determination was accomplished using 1D- and 2D-NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and correlation with known compounds.Among the isolated compounds, acylated lignans (3-5) showed stronger antioxidant activity than non-acylated derivatives (1,2). Anti-inflammatory activity was evaluated by determining the inhibitory potential against 5- and 15-lipoxygenase enzymes. The highest anti-inflammatory activity was observed in compound 4, with IC50s values of 7.6 µM and 2.7 µM against 5-LOX and 15-LOX, respectively.

Keywords

Calotropis procera; lignans; antioxidants; anti-inflammatory; lipoxygenase inhibitors

Content

Content / Page
S1. NMR Data for 1, 2 and 5
Table 1H NMR spectroscopic data of compounds 1,2and 5 / 04
Table 2 13C NMR spectroscopic data of compounds 1,2 and 5 / 06
S2. NMR Data for 3 and 4
Figure 1.1H NMR spectrum of compound (3) (400 MHz, DMSO_d6) / 04
Figure 2.13C NMR spectrum of compound (3) (100 MHz, DMSO_d6) / 04
Figure 3.1H-13C HSQC spectrum of compound (3) (400 MHz, DMSO_d6) / 05
Figure 4.1H-1H COSY spectrum of compound (3) (400 MHz, DMSO_d6) / 05
Figure 5.1H-13C HMBC spectrum of compound (3) (400 MHz, DMSO_d6) / 06
Figure 6.1H NMR spectrum of compound (4) (400 MHz, DMSO_d6) / 07
Figure 7.13C NMR spectrum of compound (4) (100 MHz, DMSO_d6) / 07
Figure 8.1H-13C HSQC spectrum of compound (4) (400MHz, DMSO_d6) / 08
Figure 9.1H-13C HMBC spectrum of compound (4) (400 MHz, DMSO_d6) / 08
Figure 10.HRESIMS of compound (4) / 09

S1. NMR data of compounds 1, 2 and 5.

Table 1

1H NMR spectroscopic data of compounds 1, 2 and 5in DMSO_d6 (400 MHz).

No. / 1
δ1H/ppm, mult, J/Hz / 2
δ1H/ppm, mult, J/Hz / 5
δ1H/ppm, mult, J/Hz
Aglycone
1 / - / - / -
2 / 6.95 (1H,d,1.6) / 6.66 (1H, brs) / 6.93 (1H,d,1.6)
3 / - / - / -
4 / - / - / -
5 / 7.04 (1H, d, 8.6) / - / 7.03 (1H, d, 8.5)
6 / 6.85 (1H, dd, 1.6,8.6) / 6.66 (1H, brs) / 6.73 (1H, m)
7 / 4.67 (1H,d,5.2) / 4.66 (1H,d,5.2) / 4.57 (1H,m)
8 / 3.06 (1H,m) / 3.06 (1H,m) / 2.89 (1H,m)
9 / 4.13 (1H,m)
3.77 (1H,m) / 4.15 (1H,m)
3.79 (1H,m) / 4.02 (1H,m)
3.66 (1H,m)
3-OCH3 / 3.76 (3H, s) / 3.76 (3H, s) / 3.76 (3H, s)
5-OCH3 / - / 3.76 (3H, s) / -
1′ / - / - / -
2′ / 6.89 (1H, d, 1.5) / 6.89 (1H, d, 1.5) / 6.88 (1H, d, 1.5)
3′ / - / - / -
4′ / - / - / -
5′ / 6.73 (1H,d,8.1) / 6.73 (1H,d,8.1) / 6.73 (1H,m)
6′ / 6.75 (1H,dd,1.5,8.1) / 6.76 (1H,dd,1.5,8.1) / 6.73 (1H,m)
7′ / 4.61 (1H,d,5.2) / 4.61 (1H,d,5.2) / 4.55 (1H,m)
8′ / 3.04 (1H,m) / 3.04 (1H,m) / 2.90 (1H,m)
9′ / 4.14 (1H,m)
3.75 (1H,m) / 4.16 (1H,m)
3.76 (1H,m) / 4.03 (1H,m)
3.66 (1H,m)
3′-OCH3 / 3.76 (3H, s) / 3.76 (3H, s) / 3.77 (3H, s)
4′-OH / 8.90 (1H, s) / 8.89 (1H, s) / 8.87 (1H, s)
Sugar moiety / Glucose / Glucose / Glucose
1′′ / 4.87 (1H, d, 7.3) / 4.87 (1H, d, 7.3) / 4.90 (1H, d, 7.2)
2′′ / 3.24 (1H, m) / 3.19 (1H, m) / 3.32 (1H, m)
3′′ / 3.24 (1H, m) / 3.19 (1H, m) / 3.38 (1H, m)
4′′ / 3.15 (1H, m) / 3.12 (1H, m) / 3.25 (1H, m)
5′′ / 3.27 (1H, m) / 3.03 (1H, m) / 4.33 (1H, m)
6′′ / 3.66 (1H, m)
3.44 (1H, m) / 3.59 (1H, m)
3.41 (1H, m) / 4.37 (1H, m)
4.24 (1H, m)
Ester moiety / Feruloyl
1′′′ / - / - / -
2′′′ / - / - / 7.33 (1H, d, 1.5)
3′′′ / - / - / -
4′′′ / - / - / -
5′′′ / - / - / 6.81 (1H, d, 8.4)
6′′′ / - / - / 7.10 (1H, dd, 1.5, 8.4)
7′′′ / - / - / 7.55 (1H, d, 15.5)
8′′′ / - / - / 6.47 (1H,d, 15.5)
9′′′ / - / - / -
3′′′-OCH3 / - / - / 3.82 (3H, s)
4′′′-OH / - / 9.96 (1H, s)

Table 2

13C NMR spectroscopic data of compounds 1, 2 and 5in DMSO_d6 (100 MHz).

No. / 1
δ13C/ppm, mult. / 2
δ13C/ppm, mult. / 5
δ13C/ppm, mult.
Aglycone
1 / 135.2, s / 137.2, s / 135.2, s
2 / 110.5, d / 104.2, d / 110.6, d
3 / 148.9, s / 152.6, s / 148.8, s
4 / 145.8, s / 133.7, s / 145.6, s
5 / 115.2, d / 152.6,s / 115.3, d
6 / 118.1, d / 104.2, d / 117.9, d
7 / 84.9, d / 85.1, d / 84.7, d
8 / 53.7, d / 53.7, d / 53.7, d
9 / 70.9, t / 71.1, t / 70.8, t
3-OCH3 / 55.7, q / 56.5, q / 55.7, q
5-OCH3 / - / 56.5, q / -
1′ / 132.2, s / 132.2, s / 132.1, s
2′ / 110.4, d / 110.5, d / 110.4, d
3′ / 147.5, s / 147.6, s / 147.5, s
4′ / 145.9, s / 145.9, s / 145.9, s
5′ / 115.1, d / 115.2, d / 115.1, d
6′ / 118.7, d / 118.7, d / 118.6, d
7′ / 85.2, d / 85.2, d / 85.1, d
8′ / 53.5, d / 53.5, d / 53.5, d
9′ / 71.2, t / 71.2, t / 70.8, t
3′-OCH3 / 55.6, q / 55.6, q / 55.6, q
Sugar moiety / Glucose / Glucose / Glucose
1′′ / 101.1, d / 102.7, d / 100.1, d
2′′ / 74.2, d / 74.2, d / 73.2, d
3′′ / 76.5, d / 76.5, d / 76.7, d
4′′ / 69.9, d / 69.9, d / 70.0, d
5′′ / 77.2, d / 77.2, d / 75.3, d
6′′ / 60.9, t / 60.9, t / 63.2, t
Ester moiety / Feruloyl
1′′′ / - / - / 125.6,s
2′′′ / - / - / 111.1,d
3′′′ / - / - / 148.0,s
4′′′ / - / - / 149.4,s
5′′′ / - / - / 115.4,d
6′′′ / - / - / 123.2,d
7′′′ / - / - / 145.1,d
8′′′ / - / - / 114.3,d
9′′′ / - / - / 166.4,s
3′′′-OCH3 / - / - / 55.7,q

S2. NMR Data for 3 and 4

Figure 1S.1H NMR spectrum of compound (3) (400 MHz, DMSO_d6)

Figure 2S.13C NMR spectrum of compound (3) (100 MHz, DMSO_d6)

Figure 3S.1H-13C HSQC spectrum of compound (3) (400MHz, DMSO_d6)

Figure 4S.1H-1H COSY spectrum of compound (3) (400MHz, DMSO_d6)

Figure 5S.Key1H-13C HMBC spectrum of compound (3) (400MHz, DMSO_d6)

Figure 6S.1H NMR spectrum of compound (4) (400MHz, DMSO_d6)

Figure 7S.13C NMR spectrum of compound (4) (100MHz, DMSO_d6)

Figure 8S.1H-13C HSQC spectrum of compound (4) (400MHz, DMSO_d6)

Figure 9S.1H-13C HMBC spectrum of compound (4) (400 MHz, DMSO_d6)

Figure 10S.HRESIMS of compound (4)

1