Chemistry of Natural Compounds, Vol. 46, No. 3, 2010
SECONDARY METABOLITES OF AN ALGERIAN Phlomis bovei
AND THEIR ANTIOXIDANT ACTIVITIES
N. Zaabat,1,3 S. Akkal, N. Darboure, H. Laouer,
1
3
2
UDC 547.972
3
4
M. G. Dijoux Franca, and Helmut Duddeck
The plants of the genus Phlomis are native to Turkey, North Africa, Europe, and Asia. Phlomis bovei De Noe, syn.
Phlomis samia Desfontaines (Lamiaceae), is a rare Algerian endemic plant, commonly known as Kayat El Adjarah [1] in the
Algerian dialect or variously named Farseouan, Tarseouan, Iniji, Rꢀilef, and Azaref throughout the North of Africa [2]. It is one
among the nine endemic plants recorded in the Rapport National sur la Diversite Biologique [1]. P. bovei is a herbaceous
perennial plant, which grows up to 0.8 m and often develops a stout woody base.
Phlomis bovei was collected from the east of Algeria in june 2006 and was taxonomically identified by Dr. Hocine
Laouer from the Department of Biology, University of Setif.
About 465 g of the air powdered leaves were extracted with n-hexane, CH Cl , and MeOH in succession at room
2
2
temperature. The MeOH extract was fractionated over silica gel–VLC eluting with CH Cl followed by increasing concentrations
2
2
of MeOH. Fractions 3 and 4 (41 g), eluted with CH Cl –MeOH 50:50–25:75), were combined and further applied to column
2
2
chromatography over silica gel using CH Cl –EtOAc and EtOAc–MeOH. Fraction L (1.73 g), eluted with 95:5
2
2
EtOAc–MeOH, was subjected to RP18 MPLC with H O–MeOH. Purification of fraction L6 (18 mg) by Sephadex LH20
2
(
MeOH) allowed the isolation of compound 1. Purification of fraction L17 (112 mg) by SPE RP18 MeOH–H O and TLC on
2
silica gel (9–1) CH Cl –MeOH afforded compound 2. Fraction L22 (62 mg) was subjected to SiO TLC using (EtOAc–
2
2
2
MeOH–H O 100:10:5), yielding 3 (9 mg).
2
The structures of these compounds were elucidated by UV, H NMR, and 13C NMR, and all these data were in good
1
agreement with the respective literature data [3–8].
Compound 1, C H O , mp 347ꢁC, UV (MeOH, ꢂ , nm): 266, 330; +NaOH: 275, 324, 390; +AlCl : 277, 301,
1
5
10
5
max
3
1
3
41, 387; +AlCl /HCl: 277, 301, 341, 387; +NaOAc: 278, 300, 380; +NaOAc/H BO : 273, 279, 350. H NMR (400 MHz,
3
3
3
CD OD, ꢃ, ppm, J/Hz): 7.78 (2H, d, J = 8.9, H-2ꢀ, H-6ꢀ), 6.90 (2H, d, J = 8.9, H-3ꢀ, H-5ꢀ), 6.51 (1H, s, H-3), 6.42 (1H, d,
3
J = 2.1, H-8), 6.22 (1H, d, J = 2.1, H-6). This compound was characterized as 5,7,4ꢀ-trihydroxyflavone (apigenin) [6].
Compound 2, C H O , mp 226–228ꢁC, MS–ES positive 433, UV (MeOH, ꢂmax, nm): 269, 334; + NaOH: 267,
2
1 20 10
1
3
81; + AlCl : 277, 349 sh, 383; + AlCl /HCl: 279, 346 sh, 382. H NMR (400 MHz, CD OD, ꢃ, ppm, J/Hz): 7.91 (2H, d,
3 3 3
J = 8.8, H-2ꢀ, H-6ꢀ); 6.95 (2H, d, J = 8.8, H-3ꢀ, H-5ꢀ); 6.83 (1H, d, J = 2.5, H-8); 6.51 (1H, s, H-3), 6.54 (1H, d, J = 2.55, H-6);
5
.20 (1H, d, J = 7.5, H-1ꢀꢀ Glu); 3.05–3.90 (sugar protons). Identified as apigenin 7-O-glucoside or apigetrin [7].
Acid hydrolysis of 2 produced apigenin and D-glucose.
1
Compound 3, C H O , mp 110ꢁC, H NMR (400 MHz, CD OD, ꢃ, ppm, J/Hz): 7.66 (2H, d, J = 8.85, H-2ꢀ, H-6ꢀ);
1
0
10
2
3
1
3
6
.73 (2H, d, J = 7.56, H-3ꢀ, H-5ꢀ); 6.85 (1H, d, J = 12.6, H-4); 5.72 (1H, d, J = 12.6, H-3), C NMR (CD OD, 75 MHz): 112.6
3
(
C-3), 116.7 (C-3ꢀ,5ꢀ), 126.6 (C-1ꢀ), 133.9 (C-2ꢀ,6ꢀ), 145.6 (C-4), 170 (C-2). Identified as 4-(4ꢀ-hydroxyphenyl)-trans-but-3-
en-2-one [8].
1
) Laboratoire de Phytochimie et Analyses physicochimiques et Biologiques, Departement de Chimie, Faculte de
Sciences exactes, Universite Mentouri Constantine, Route dꢀAin el Bey, 25000 Constantine, Algerie, fax: 213 31 62 49 12,
e-mail: salah4dz@yahoo.fr; 2) Department of Biology, University Ferhat Abbas, 19000 Setif, Algeria; 3) Universite de Lyon,
UMR 5557 CNRS-UCBL, CESN, Dept de Botanique et Pharmacognosie, Faculte de Pharmacie, 8 avenue Rockefeller, 69373
Lyon Cedex 08, France; 4) Universitat Hannover, Institut fur Organische Chemie, Schneiderberg 1B, D-30167, Hannover,
Germany. Published in Khimiya Prirodnykh Soedinenii, No. 3, p. 384, May–June, 2010. Original article submitted November
1
4, 2008.
0
454
0009-3130/10/4603-0454 2010 Springer Science+Business Media, Inc.