ENG
Chemical composition and biological activities of Helianthemum sessiliflorum Benabdelaziz, I.1; Haba, H. 1*; Lavaud, C.2; Marcourt, L.3; Benkhaled, M.1; Wolfender, J. L.3 ¹Prof, Batna-1 University, Chemistry Department, Laboratory of Chemistry and Envirnmental Chemistry LCCE, Batna, Algeria 2 Prof, Reims University, Institut de Chimie Moléculaire de Reims, CNRS UMR 6229, BP 1039, 51097 Reims Cedex 2, France 3 Prof, University of Geneva, Phytochemistry and Bioactive Natural Products, School of Pharmaceutical Science, Geneva, Switzerland *
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Introduction Helianthemum is a genus of plants including around 110 species, belongs to the Cistaceae family also known as rock rose. This genus is growing in America, Europe and Northern Africa. However, the Mediterranean region is considered its center of diversity (Mabberly, 1997). Helianthemum sessiliflorum Pers. is one of species of this genus that showed previously anti-inflammatory and analgesic activities. In addition, the aerial parts of this plant are recommended in folk medicine in case of cutaneous lesion. The phytochemical investigation of the AcOEt and n-BuOH extracts of the aerial parts of H. sessiliflorum resulted in the characterization of one new lignan named 1O-acetyl prinsepiol 1, together with twenty seven known bioactive compounds 2-28 (Benabdelaziz et al., 2015). Furthermore, the antioxidant and antibacterial activities of different extracts of H. sessiliflorum were determined. Method The structures of all the isolated compounds 1-28 were determined by spectral methods including 1D (1H and 13C NMR) and 2D NMR (COSY, HSQC, TOCSY, HMBC and NOESY), HR-ESI-MS, UV, IR, values of optical rotation and chemical correlations with known compounds that have been described in the literature. Dried aerial parts (1Kg) of the plant material were macerated with 70% EtOH (3 × 10 L) at room temperature. The EtOH extract was concentrated then diluted with H2O and partitioned successively with cyclohexane (3 × 150 mL), AcOEt (3 × 150 mL) and n-buthanol (3 × 150 mL). The AcOEt extract (3.2 g) was fractionated on VLC (SiO2) with the solvent system cyclohexane/AcOEt (100:0 to 0:100) then AcOEt/MeOH (100:0 to 0:100) to give four fractions (F1-F4). The purification of these fractions afforded twenty secondary metabolites 1-20. The n-butanol extract (8 g) was chromatographed on a polyamide column eluted with H2O/MeOH (100:0 to 0:100) to give five main fractions (F1F5). The purification of the obtained fractions gave eight polyphenolics 21-28. Results / Discussion / Conclusion Repeated column chromatography over silica gel (SiO2), reversed-phase (RP-18), polyamide SC-6 and sephadex LH-20, and HPLC (RP-18) of the AcOEt extract afforded twenty compounds, the new furofuran lignan; 1-O-acetyl prinsepiol 1, along with nineteen known ones named 1α-hydroxypinoresinol 2, (+)-cycloolivil 3, ( ̶ )˗pinellic acid 4, benzoic acid 5, p-hydroxybenzoic acid 6, protocatechuic acid 7, vanillic acid 8, gallic acid 9, ( ̶ )˗epicatechin 10, ( ̶ )˗catechin 11, ( ̶ )˗epigallocatechin 12, ( ̶ )˗gallocatechin 13, astragalin 14, tiliroside 15, quercetrin 16, isoquercetrin 17, myricitrin 18, β-sitosterol 19 and daucosterol 20. The chemical investigation of n-butanol extract using also several chromatographic methods, afforded eight known polyphenolic compounds called isolaricireinol 9'-O-β-D-glucopyranoside 21, nicotiflorin 22, kaempferol 3-O-vicianoside 23, rutin 24, neoisorutin 25, vicenin-2 26 and two auronols as enantiomeric pairs; hovetrichoside C 27 and 28. The antioxidant activity was performed by DPPH radical scavenging method which indicated that ethyl acetate extract had the best antioxidant potential (IC50 = 32.75 ± 2.07 µg/ml). The significant linear correlation was done between the values of the total phenolic/flavonoid contents and antioxidant activity of plant extracts. The antibacterial activity of different extracts was assessed against some bacterial strains. The ethyl acetate and n-butanol extracts showed moderate activity. This could be explaining the traditional use of this plant against skin infections. Bibliographic References
Mabberly DJ, 1997. The plant book. Cambridge university press, Cambridge. Benabdelaziz I, Haba H, Lavaud C, Harakat D, Benkhaled M, 2015. Lignans and other constituents from Helianthemum sessiliflorum. Records of Natural Products 9, pp 342-348.
rev.: 03.48.16 25.03.2017
