An Acad Bras Cienc (2020) 92(3): e20181116 DOI 10.1590/0001-3765202020181116 Anais da Academia Brasileira de Ciências | Annals of the Brazilian Academy of Sciences Printed ISSN 0001-3765 I Online ISSN 1678-2690 www.scielo.br/aabc | www.fb.com/aabcjournal CHEMICAL SCIENCES Levels of phenylpropanoids and iridoids in Running title:LEVELS OF extracts and infusions of Verbena minutiflora PHENYLPROPANOIDS AND IRIDOIDS IN GERVÃO KELLY C.N. SOARES, KARLOS EDUARDO PIANOSKI, DAIANE FINGER, CHRISTIANE S. MACHADO, SUELI P. QUINÁIA & YOHANDRA R. TORRES Academy Section: Chemical Abstract: Herein we report for the first time the levels of phenylpropanoids and Sciences iridoids in extracts and infusions of V. minutiflora consumed in Brazil to treat urinary and infectious disorders. An in house validation study demonstrated good accuracy and precision to determine the bioactive compounds in V. minutiflora by HPLC-DAD. e20181116 Phenylpropanoids varied in the extracts (leaves 139.70 to 221.20 mg g-1, flowers 106.43 to 227.22 mg g-1, stems 42.18 to 56.48 mg g-1). Verbascoside occurred in higher concentration in extracts of leaves (87.66 – 136.16) mg g-1 and flowers (58.12 – 148.96) mg -1g than in 92 stems (19.24 – 24.62) mg g-1. Iridoids in extracts were as follows: leaves (46.60 − 54.79) mg (3) g-1, flowers (55.88 − 93.87) mg -1g and stems (40.05 to 61.74) mg g-1. High levels of iridoids 92(3) -1 -1 (314.70 − 415.10) μg mL , phenylpropanoids (1996.39 − 2674.13) μg mL and verbascoside (1029.38 − 1456.42 μg mL-1) in infusions support the popular consume of V. minutiflora. Key words: medicinal plants, Verbenaceae, Gervão, analytical validation, Verbascoside, Hastatoside. INTRODUCTION antifungal, analgesic, antinociceptive, neuroprotective effects and antioxidant (Souza Medicinal plants are used since ancient times et al. 2005, El-Hela et al. 2010, Schönbichler et and continue to attract worldwide attention al. 2013, Hernández et al. 2000, Casanova et al. because of their benefic effects on human health 2008, Calvo et al. 1998, Deepak & Handa 2000, (Pan et al. 2015). However, the efficacy and safety Speroni et al. 2007, Calvo 2006, Rehecho et al. of many species are not well established and 2011, Braga et al. 2012, Lai et al. 2006, Bilia et al. researches about the chemical, pharmacological 2008). Verbena officinalisL. is a typic species and toxicological properties of medicinal plants of Verbena and its main classes of metabolites are essential to ensure their quality (Souza- are phenylpropanoids (verbascoside, Moreira et al. 2008). isoverbascoside and β-OH-verbascoside), The Verbenaceae family includes about 100 iridoids (hastatoside and verbenalin) and genera and 250 species distributed around the flavonoids (luteolin and apigenin) (Figure 1) (El- globe, in temperate, tropical, and subtropical Hela et al. 2010, Schönbichler et al. 2013, Bilia et areas. Among them, representative species of al. 2008, Castro-Gamboa & Castro 2004). Verbena are popularly used for the treatment Verbena minutiflora occurs in southern of fever, diarrhea, gastrointestinal disorders and Brazil and is popularly known as “gervão”. some sexually transmitted diseases. Further The species is often used in folk medicine indications are: diuretic, expectorant, anti- as infusions for the treatment of infections rheumatic, anti-inflammatory, antibacterial, and urinary disorders. However, there is a An Acad Bras Cienc (2020) 92(3) KELLY C.N. SOARES et al. LEVELS OF PHENYLPROPANOIDS AND IRIDOIDS IN GERVÃO Figure 1. Main compounds found in Verbena species. lack of scientific studies about the chemical MATERIALS AND METHODS composition or pharmacological activity of V. Plant material, extracts and infusions minutiflora. In previous work, we reported the V. minutiflora (cadastro SisGen n° A9406D5) presence of verbascoside, isoverbascoside and was collected in Guarapuava, Paraná state, hastatoside in ethanol extracts and infusions southern Brazil (25 23’08.57 ‘’S, 51 ° 26’50 63. ‘’W; of aerial parts (leaves, flowers, and stems) ofV. altitude 1,115 m). The species was identified and minutiflora (Figure 1) (Soares et al. 2015). Since classified by Osmar Ribas Santos, curator of the pharmacological activity of Verbena is mostly the Museu Botânico Municipal in Curitiba/PR/ associated with the presence of verbascoside BR. A voucher specimen was deposited in the and its derivatives, in this research we aimed referred herbarium under No. 359683. Samples to determine the levels of phenylpropanoids were collected at the same location for four and iridoids in extracts and infusions of V. consecutive years from 2009 to 2012 and always minutiflora. The plant material was collected in November (spring) when the plant has many during four consecutive years to verify the flowers and leaves (Soares et al. 2015). quantitative variability of these metabolites. The extracts and infusions of V. minutiflora Additionally, an in house validation study was were prepared as described in Soares et al. (2015). performed according to international and The aerial parts of the plant (leaves, flowers and national guidelines for foods and beverages to stems), collected in 2009, 2010, 2011 and 2012 ensure the reliability of the quantitative results were dried at room temperature and separately (ANVISA 2003, AOAC 2012). This is the first study macerated in ethanol (plant material/ethanol about the quantitative composition of specific 1:20 w/v) under stirring at room temperature. bioactive compounds in V. minutiflora. Dried ethanolic extracts of leaves, flowers and stems were obtained after solvent evaporation. An Acad Bras Cienc (2020) 92(3) e20181116 2 | 13 KELLY C.N. SOARES et al. LEVELS OF PHENYLPROPANOIDS AND IRIDOIDS IN GERVÃO The infusions of V. minutiflora were prepared samples of V. minutiflora, leaves 2010, flowers with 10 g of leaves and 200 mL of boiling water. 2011 and stems 2012 were randomly selected The capped mixture was maintained for 20 to evaluate all validation parameters. Stock minutes, then cooled and filtered. solutions of verbascoside and geniposide were made in methanol at 500 μg mL-1. For all HPLC-DAD analyses validation steps and subsequent application Extracts and infusions were analyzed by of the chromatographic method to determine HPLC (Waters 600 Controller) with UV diode phenylpropanoids, methanolic solutions of array detection (Waters 2996) (HPLC-DAD). extracts of leaves, flowers and stems of V. Chromatography was performed on a Waters XT minutiflora were made at concentrations 2.300, Terra MS C18 column (250 mm × 4.6 mm, 5 μm) 2.200 and 6.200 μg mL-1, respectively. On the maintained at 26 ° C and with pre-column at other hand, to determine iridoids, methanolic the same stationary phase. The mobile phase solutions of extracts of leaves, flowers and stems flow rate was 0.8 mL min-1 and consisted of an of V. minutiflora were made at concentrations aqueous formic acid solution at pH 3.2 (solvent 8.200, 8.100 and 6.100 μg mL-1, respectively. A) and acetonitrile (solvent B). The linear gradient was performed according to Bilia et al. Selectivity (2008). The elution started with 87% of solvent A The selectivity of the HPLC-DAD method was and a linear gradient was carried out until 85% assessed by comparison of retention times of solvent A in 10 min. After this, a second linear and UV-DAD spectra of analytical standards gradient was stablished up to 25% of solvent A verbascoside and geniposide with the in 20 minutes. This mobile phase composition chromatographic peaks assigned to verbascoside was held for 6 minutes and then the percentage and its structurally related derivatives and of solvent A was gradually decreased to 5% in 2 to iridoids in all samples of aerial parts of V. minutes and remained unchanged for 2 minutes minutiflora. (total chromatographic running time of 30 minutes). Afterward, the initial elution condition Linearity was established in one minute and maintained To assess the linearity of the method, an by 10 minutes for column equilibration before analytical curve was built in the concentration subsequent injection. The UV-VIS spectra for range of 40 to 200 μg mL-1 for verbascoside chromatographic peaks were recorded between and of 50 to 500 μg mL-1 for geniposide. Each 220 and 500 nm and the chromatograms were analytical curve was made with seven levels of monitored at 240, 330 and 350 nm according concentration, each concentration in triplicate. to previous reports by Bilia et al. (2008). Each A linear regression at 95% confidence level sample was injected in triplicate. was adjusted to the experimental data (peak area and concentration). The linearity of the Validation study model was assessed by applying an analysis Verbascoside 86.87% HWI Analytik GMBH of variance and a lack-of-fit test F( lof) at 95% Solutions Pharma (Germany) was used as an confidence level. analytical standard representative of the class of phenylpropanoids while geniposide 98% (Sigma-Aldrich) was used for iridoids. Three An Acad Bras Cienc (2020) 92(3) e20181116 3 | 13 KELLY C.N. SOARES et al. LEVELS OF PHENYLPROPANOIDS AND IRIDOIDS IN GERVÃO Limit of Detection (LOD) and Limit of RESULTS AND DISCUSSION Quantification (LOQ) Validation of the HPLC-DAD method to The limits of detection and quantification determine Verbascoside and its derivatives were calculated from parameters of the linear and iridoids in extracts and infusions of equation: LOD = (3 × SD)/m and LOQ = (10 × Verbena minutiflora SD)/m, where SD is the standard deviation of Firstly, in the present study we carried out an intercept of the analytical curve and m is the in house validation to determine verbascoside slope of the analytical curve (Araujo 2009). and other phenylpropanoids and also iridoids in extracts and infusions of aerial parts of Precision V. minutiflora. Validation parameters such The precision was estimated for repeatability as selectivity, linearity, Limit Of Detection and the intermediate precision.