Antibacterial Activity And Phytochemical Investigation Of Solanum Sp. (Solanaceae)

Solanum (Solanaceae) is a genus present in tropical and subtropical areas with approximately 1500 species mostly distributed in South America [1]. Solanum sp. is a plant species found in Brazilian Cerrado. The EtOH extract of leaves (SEE) of this species showed inhibition against Staphyloccocus aureus and Escherichia coli of 69.15 ± 6.16 and 48.79 ± 5.87%, respectively, and was selected for phytochemical study. The aim of this work was to fractionate the SEE and identify the obtained compounds. Portions of 50 mg of SEE were solubilized in MeOH: H2O (1:1), the suspensions obtained were centrifuged (10.000 rpm, 10 min) and 900µL of the supernatant was injected on to a preparative HPLC system. The elution was carried out using gradient elution of 0.1% formic acid (A) and MeCN with 0.1% formic acid (B), from 5 to 50% of B in 30 min, detection at λ= 210 and 280nm, flow rate of 20 mL/min, generating twelve fractions. TLC analysis of fractions 4, 5 and 6 showed one major spot with fluorescence characteristic of phenolic acids (fraction 4) and flavonoids (fractions 5 and 6). The conjunct analysis of the obtained chromatograms and MS spectra registered in the negative mode allowed the identification of fractions 4 – 6 as chlorogenic acid, rutin and a quercetin glucoside, respectively, by standards co-injection and/or comparison with literature data. Mono and bi-dimensional NMR will be performed to confirm the identification of the isolated compounds. Moreover, the antibacterial and antioxidant activities of the purified compounds will also be evaluated.

Acknowledgements: Authors are grateful to FAPEMIG for the financial support.

Reference: [1] da Silva TMS, Carvalho MG, et al. (2003) Quim. Nova, 26: 517 – 522