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ABSTRACT Eugenia uniflora L., Myrtaceae, popularly known as "pitanga", is used in traditional medicine due the properties attributed to its chemical content, these being mainly hydrolysable tannins and flavonoids. This study provides a qualitative and quantitative evaluation of chemical profile from leaves of E. uniflora. The HPLC analysis was carried out on a C18 column (4.6 mm × 250 mm, 5 µm) by gradient elution with methanol and water (acidified with trifluoracetic acid); and silica gel Plates 60-F 254 with 10-12 µm and 5-6 µm particles, respectively for TLC and High HPTLC analysis. The chromatographic data obtained from HPLC, TLC and HPTLC presented bands and peaks related to flavonoids (myricitrin and derivatives) and tannins (gallic and ellagic acids), which were observed from different samples. The chromatographic similarities enabled the building of a typical fingerprint for the herbal material. The similarity analysis of the sample data by Pearson correlation showed R values >0.9 among peaks (HPLC) and bands (HPTLC). In addition, the analytical methodology developed by HPLC enabled the satisfactory quantification of marker substances [ellagic acid = 0.22% and 0.20% (m/m); gallic acid = 0.20% and 0.43%; myricitrin = 0.42 and 1.74% (m/m) in herbal drug and crude extract, respectively]. The procedure was also validated in accordance with the assays required by Brazilian legislation. Thus, the HPTLC and HPLC methods developed in this study provide helpful and simple tools for the quality evaluation both qualitatively and quantitatively of raw materials and extractives from leaves of E. uniflora.
RESUMO
BACKGROUND: The traditional use of Eugenia uniflora L. ("Pitanga") is reported due to several properties, which have often been related to its flavonoid content. OBJECTIVE: The aim was to evaluate analytical procedures for quantification of total flavonoids content (TFCs) by ultraviolet-visible (UV-Vis) spectrophotometry in the herbal material (HM), crude extract (CE), and fractions from leaves of E. uniflora. MATERIALS AND METHODS: The method for quantification of flavonoids after complexation with aluminum chloride (AlCl3) was evaluated: amount of sample (0.25-1.5 g); solvent (40%-80% ethanol); reaction time and AlCl3 concentration (2.5%-7.5%). The procedures by direct dilution (DD) and after acid hydrolysis (AH) were used and validated for HM and CE and applied to the aqueous fraction (AqF), hexane fraction, and ethyl acetate fractions (EAF). RESULTS: The ideal conditions of analysis were ethanol 80% as solvent; 0.5 g of sample; λmax of 408 (DD) and 425 nm (AH); 25 min after addition of AlCl3 5%. The procedures validated for standards and samples showed linearity (R2 > 0.99) with limit of detection and limit of quantification between 0.01 and 0.17 mg/mL (rutin and quercetin); and 0.03 and 0.09 mg/mL (quercetin), for DD and AH, respectively. The procedures were accurate (detect, practice, and repair < 5% and recovery >90%), and stable under robustness conditions (luminosity, storage, reagents, and equipment). The TFCs in AqF and EAF were 0.65 g% and 17.72 g%, calculated as rutin. CONCLUSIONS: UV-Vis methods for quantification of TFC in HM, CE, and fractions from leaves of E. uniflora were suitably validated. Regarding the analysis of fractions, the EAF achieved enrichment of about nine times in the content of flavonoids. SUMMARY: The total flavonoids content (TFCs) of herbal material, crude extract, and fractions from Eugenia uniflora can be quantified by ultraviolet-visibleThe spectrophotometric methods (direct dilution and acid hydrolysis) were reproducible and able to quantify TFC in raw material and derivatives from leaves of E. unifloraHigher flavonoids content was observed in ethyl acetate fractions after enrichment. Abbreviations Used: HM: Herbal material, CE: Crude extract, AqF: Aqueous fraction, HF: Hexanic fraction, EAF: Ethyl acetate fraction, TFC: Total flavonoids content, HCl: Hydrochloric acid, DD: Direct dilution, AH: After hydrolysis, RSD: Relative standard, A.U.: Absorption units.
RESUMO
BACKGROUND: Libidibia ferrea (Mart. ex Tul.) L.P. Queiroz (Fabaceae) is a tree which is native to Brazil, widely known as "Jucá," where its herbal derivatives are used in folk medicine with several therapeutic properties. The constituents, which have already been described in the fruit, are mainly hydrolysable tannins (gallic acid [GA] and ellagic acid [EA]). OBJECTIVE: The aim of this study was to investigate the phenolic variability in the fruit of L. ferrea by ultraviolet/visible (UV/VIS) and chromatographic methods (high-performance liquid chromatography [HPLC]/high-performance thin layer chromatography [HPTLC]). MATERIALS AND METHODS: Several samples were collected from different regions of Brazil and the qualitative (fingerprints by HPTLC and HPLC) and quantitative analysis (UV/VIS and HPLC) of polyphenols were performed. RESULTS: The HPTLC and HPLC profiles allowed separation and identification of both major analytical markers: EA and GA. The chemical profiles were similar in a number of spots or peaks for the samples, but some differences could be observed in the intensity or area of the analytical markers for HPTLC or HPLC, respectively. Regarding the quantitative analysis, the polyphenolic content by UV/VIS ranged from 13.99 to 37.86 g% expressed as GA or from 10.75 to 29.09 g% expressed as EA. The contents of EA and GA by liquid chromatography-reversed phase (LC-RP) method ranged from 0.57 to 2.68 g% and from 0.54 to 3.23 g%, respectively. CONCLUSION: The chemical profiles obtained by HPTLC or HPLC, as well as the quantitative analysis by spectrophotometry or LC-RP method, were suitable for discrimination of each herbal sample and can be used as tools for the comparative analysis of the fruits from L. ferrea. SUMMARY: The polyphenols of fruits of Libidibia ferrea can be quantified by UV/VIS and HPLCThe HPLC method was able to detect the gallic and ellagic acids in several samples of fruits of Libidibia ferreaThe phenolic profiles of fruits from Libidibia ferrea by HPTLC and HPLC were reproductible. Abbreviations used: HPTLC: high performance thin layer chromatography, HPLC: high performance liquid chromatography, UV-Vis: spectrophotometry.
