Chemical constituents, cytotoxic, antifungal and antimicrobial properties of Centaurea diluta Ait. subsp. algeriensis (Coss. & Dur.) Maire

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• 作者：Hanè ; ne Zater¹ ; ² ; ³ ; Jo&euml ; lle Huet⁴ ; Vé ; ronique Fontaine⁵ ; Samir Benayache¹ ; Caroline Sté ; vigny³ ; Pierre Duez³ ; ⁶ ; ^{pierre.duez@umons.ac.be" class="auth_mail" title="E-mail the corresponding author} ; Fadila Benayache¹ ; ^{fbenayache@yahoo.fr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Flavonoids ; Lignans ; Centaurea diluta ; Asteraceae ; Cytotoxic activity
• 刊名：Asian Pacific Journal of Tropical Medicine
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：9
• 期：6
• 页码：554-561
• 全文大小：813 K

文摘

To investigate the chemical composition of a moderately polar extract (CHCl₃ soluble part of the MeOH–H₂O extract) obtained from the aerial parts (leaves and flowers) of Centaurea diluta Ait. subsp. algeriensis (Coss. & Dur.) Maire, a species endemic to Algeria and Morocco on which no reports are available to date. To evaluate in vitro the cytotoxic, antifungal and antimicrobial activities of this extract and the cytotoxic and antimicrobial activities of its isolated secondary metabolites.

Methods

The cytotoxic effects of the extract were investigated on 3 human cancer cell lines i.e. the A549 non-small-cell lung carcinoma (NSCLC), the MCF7 breast adenocarcinoma and the U373 glioblastoma using a MTT colorimetric assay. Biological data allowed to guide the fractionation of the extract by separation and purification on silica gel 60 (CC and TLC). The isolated compounds which were characterized by spectral analysis, mainly HR-ESIMS, HR-EIMS, UV and NMR experiments (¹H, ¹³C, COSY, ROESY, HSQC and HMBC) and comparison of their spectroscopic data with those reported in the literature, were evaluated for cytotoxic activities on six cancer cell lines (A549, MCF7, U373, Hs683 human glioma, PC3 human prostate and B16-F10 murine melanoma). The direct and indirect antibacterial and antifungal activities were determined using microdilution methods for the raw extract and TLC-bioautography and microdilution methods against standard and clinical strains for the isolated compounds.

Results

The raw extract reduced cell viability with IC₅₀s of 27, 25 and 21 μg/mL on A549, MCF7 and U373, respectively. Five secondary metabolites: two phenolic compounds (vanillin lass="boldFont">1, paridol lass="boldFont">3), a lignan [(−)-arctigenin lass="boldFont">2] and two flavonoid aglycones (eupatilin lass="boldFont">4 and jaceosidin lass="boldFont">5), were then isolated from this extract. Moderate cytotoxic effects were observed for (−)-arctigenin lass="boldFont">2 (IC₅₀s: 28 and 33 μM on Hs683 and B16-F10, respectively), eupatilin lass="boldFont">4 (IC₅₀s: 33 and 47 μM on B16-F10 and PC3, respectively) and jaceosidin lass="boldFont">5 (IC₅₀s: 32 and 40 μM on PC3 and B16-F10, respectively).

Conclusions

All the isolated compounds were described for the first time from this species. Although inactive against 7 tested microorganisms (fungi, bacteria and yeast, human or plant pathogens), the raw extract was able to potentiate the effect of beta-lactam antibiotics on methicillin-resistant Staphylococcus aureus (MRSA), reducing the minimal inhibitory concentrations (MICs) by a factor of 2-32-fold. No synergy was found between the extract and streptomycin. From the five isolated compounds only jaseosidin lass="boldFont">5 showed a moderate antimicrobial activity.