Screening of phenolic compounds from crude extracts of Casearia sylvestris Swartz (Salicaceae) by capillary electrophoresis

Casearia sylvestris, commonly known as guaçatonga has been widespread used in Brazilian folk medicine with antiseptic, anti-inflammatory and anti-ulcer properties [1]. Phytochemical investigations revealed that the major compounds isolated from C. sylvestris were the casearins (clerodane diterpenes), that exhibited anti-fungal activities [2]. Beyond the casearins, C. sylvestris has other secondary metabolites such as flavonoids, sesquiterpenes and polyphenolic substances, which may also contribute to the pharmacological activity [3]. Protocols in capillary electrophoresis (CE) have been employed in the analysis of herbal extracts, showing high specificity, repeatability, and reproducibility [4]. CE protocols are methods, which were developed using different modes of capillary electrophoresis, electrolytes with different pH values and specific absorption wavelengths. The procedure is simple and consists in to inject crude extracts without previous purification under conditions that allow the ionization and separation of specific phytochemical classes. Screening of organic and aqueous extracts from casearia leaves were conducted by CE using specific protocols to determine flavonoids and phenolic acids. Flavonoid CE protocol was achieved using 40 mmol.L^-1 sodium tetraborate (pH 9.0) + 10% MeOH as background electrolyte, applied voltage 20 kV and UV detection at 350nm. It was possible to get a fingerprint of the phenolic compounds from crude extracts. Rutin and scopoletin were identified/quantified in the presence of other phytochemical substances and analyzed them quickly (up to 10 min). Phenolic acids CE protocols were conducted using sodium phosphate buffer 20 mmol.L^-1 (pH 6.5), applied voltage 20KV and UV detection at 214nm, but were not identified on the casearia extracts, because they were not relevant quantity for presents.

Keywords: Casearia sylvestris, capillary electrophoresis, flavonoids

References:

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