Brazilian Journal of Chemical ISSN 0104-6632 Engineering Printed in Brazil www.abeq.org.br/bjche Vol. 36, No. 04, pp. 1679 - 1688, October - December, 2019 dx.doi.org/10.1590/0104-6632.20190364s20190099 MAXIMIZATION OF ESSENTIAL OIL ANTIOXIDANT CAPACITY VIA STAR ANISE HYDRODISTILLATION Bárbara Gomes Iarema Destro1, Regina Maria Matos Jorge1 and Alvaro Luiz Mathias1* 1 Universidade Federal do Paraná, Programa de Pós-Graduação em Engenharia de Alimentos, Departamento de Engenharia Química, Curitiba, PR, Brasil. ORCID: 0000-0002-3540-0413; ORCID: 0000-0003-3561-3555; E-mail: [email protected] - ORCID: 0000-0003-2536-4516 (Submitted: February 21, 2019 ; Revised: August 19, 2019 ; Accepted: August 20, 2019) Abstract - Chinese star anise essential oil (EO) is prized for its pleasant aroma and mainly due to its antioxidant capacity (AC), which can combat cancer and treat neurodegenerative diseases. This study shows the innovative approach of optimizing not only EO yield, but also to therapeutic activity. The product obtained follows the principle of the Pure Food and Drug Act and of eco-friendly technology. Also, the best analytical control methodology of the active principle during industrial production was also defined. The AC was found to be dependent on the extraction conditions, and the best antioxidant performance was reported after 3h of hydrodistillation time, using 500 mL distilled water and 8% dry fruits whose granulometry was inferior to 425 μm. Although all four analytical methodologies used for assessing AC are precise, they cannot be correlated. The antioxidant potential was 59.6±1.1 mg GAE/g EO for TP; 14.3±0.5 mmol TEAC/g EO for FRAP; 25.7±0.8 mmol TEAC/g EO for ABTS and 23.5±0.3 mmol TEAC/g EO for DPPH. The EO exhibited better AC than the trans-anethole and D-limonene standards, suggesting a positive synergistic effect. The DPPH method exhibited a good coefficient of determination (R²=0.9311) and has the advantage of using a solvent compatible with the EO. Keywords: Antioxidant capacity; DPPH; Essential oil; Hydrodistillation; Illicium verum Hook. INTRODUCTION on the best analytical methodology for estimating this property, much less whether the conditions Antioxidant substances have been described as a for obtaining this noble oil influenced this health preventive agent for degenerative processes that evolve protective activity. to chronic diseases such as cardiovascular diseases The extraction of antioxidants of plant origin with the (Vieira et al., 2011) (Shahidi and Ambigaipalan, 2015). use of solvents has been discouraged because recovery Star anise is an aromatic vegetable grown in Asian of the solvent causes oxidative transformations countries (Asif et al., 2016). It contains large amounts (López-Sebastián et al., 1998). So hydro-distillation, of an essential oil (EO) whose predominant component steam distillation and CO2-supercritical extraction is trans-anethole (Asif et al., 2016; Bhadra et al., 2011). have been described as the best alternatives (Conde- Recently, this EO has been receiving more attention Hernández et al., 2017). Hydrodistillation uses from researchers due to its many beneficial properties only water and has low energy demand, low-cost and usefulness in combating cancer (Asif et al., 2016) equipment, and moderate operating conditions. It is and treating neurodegenerative diseases (Bhadra et known that the yield and trans-anethole content in the al., 2011). Although its antioxidant properties have hydrodistilled aromatic oil (HD) is dependent on the also been documented (Wong et al., 2014), there is parameters of granulometry (G), dried fruit mass (m), very little data in the literature regarding star anise extraction time (t), and water volume (V): the highest EO production and its AC. Thus, no report was found oil yield was obtained by the use of smaller particles * Corresponding author: Alvaro Luiz Mathias - E-mail: [email protected] 1680 B. G. I. Destro et al. (<425 μm), high particle ratio to water (16%), and (Re et al., 1999). The results of the test are expressed longer hydrodistillation times (3h), but highest trans- with reference to trolox (Prior et al., 2005). anethole content (96.6% TA) was verified by using Finally, the DPPH assay method consists of using shorter time (1h) and lower particle ratio to water a stable organic nitrogen radical having a violet color (8%) than previously (80.4% TA) (Destro et al., 2019). and whose absorption ranges from 515 to 520 nm However, the individual or interaction effects of grain (Noipa et al., 2011). When antioxidant compounds size, fruit mass, extraction time and water volume on bind to the nitrogen of DPPH•, the solution turns from the AC of the essential oil obtained were not known. purple (Prior et al., 2005; Shahidi and Zhong, 2015) The condition with the highest volume of essential oil to yellow (Wong et al., 2014). These results may also is not necessarily the condition of highest AC per unit be expressed with reference to trolox (Shahidi and volume. Furthermore, oxidative capacity evaluation Zhong, 2015). can be performed by various techniques and it is not Thus, the objective of this study was to evaluate conclusive which method is best for star anise EO. the effect of hydrodistillation parameters on the in One of the methods used to evaluate AC vitro AC of star anise essential oil (EO), as determined is the Folin-Ciocalteau method (Huang et al., comparatively using four different methodologies, in 2005; Shahidi and Zhong, 2015), also called total order to verify if the AC is due exclusively to TA, also phenolic compounds (TP) method. It is based on the determine which one is best for use with this essential observation that phenolic compounds may present oil, in view of the scarce amount of data available antioxidant characteristics. The Folin-Ciocalteau in the literature for the fruit, its EO, or for their test correlations. reagent is composed of phosphotungstic (H3PW12O40) and phosphomolybdic (H3PMo12O40) acids, which are reduced by oxidation of the phenolic compounds under MATERIALS AND METHODS alkaline conditions, producing a blue chromophore, 4- Hydrodistillations of star anise (Illicium verum probably (PMoW11O40) , with an absorbance at 720 to 765 nm (Huang et al., 2005; Shahidi and Zhong, Hook) essential oils (EO) were conducted under nine 2015). Other methods that may be used to evaluate different sets of conditions (Table 1) , according to 4-1 in vitro AC include the Ferric Reducing Antioxidant a fractional factorial experimental design 2 with Power (FRAP) method (Huang et al., 2005), the ABTS three center points added, as reported by Destro et radical method [2,2′-azinobis (3-ethylbenzothiazoline- al. (2019) for dried fruits (moisture on a dry basis of 6-sulphonic acid)] (Huang et al., 2005) and the free 12.98 ± 0.14%, w/w). The effects of the granulometry radical sequestration method with 2,2-diphenyl-1- (G), fruit mass (m), extraction time (t), and water picrylhydrazyl (DPPH) (Huang et al., 2005; Shahidi volume (V) were evaluated initially to determine which and Zhong, 2015; Singleton et al., 1999). hydrodistillation parameters produce the highest yield and highest purity of EO (in terms of trans-anethole) In the FRAP method, the ferric salt Fe (III) (TPTZ)2Cl3 is used as an oxidant (TPTZ = 2,4,6-tripyridyl-s- (Destro et al., 2019). For the present study, the EOs triazina) and the reaction occurs in acidic conditions obtained under the same conditions were also analyzed (pH 3.6). The oxidant, called the “FRAP reagent”, is for AC. The extraction was conducted for 180 min in a prepared by mixing TPTZ, acetate buffer and ferric ® chloride (Huang et al., 2005). The AC is based on the Clevenger apparatus using a QUIMIS heating mantle ability of the antioxidant to reduce the Fe3+ ion of the (Q-321A25, 315 W). After being cooled and separated Fe(III)(TPTZ) complex to Fe2+, resulting in a strong by decantation in the apparatus itself, the oil was 2 added to microtubes (1.5 mL) and centrifuged in a blue color whose spectrophotometric wavelength is ® 593 nm (Shahidi and Zhong, 2015). The results may THERMO SCIENTIFIC Centrifuge (Heraeus Fresco be expressed as micromoles of Fe 2+ or with reference 21) at 10,000 rpm/5 min (14,257 xg at 5 min). The to a standard antioxidant such as trolox (Pulido et al., Table 1. Hydrodistillation conditions for star anise 2000). essential oil extraction. The ABTS radical method uses a blue-green ABTS radical cation chromophore (ABTS•+) produced from its precursor, 2,2-azino-bis (3-ethylbenzothiazoline)-6- sulfonic acid. The aqueous ammonium ABTS solution is dissolved in water, potassium persulfate is added, and the solution is left to rest at room temperature for 12-16 h, resulting in a dark blue solution (Huang et al., 2005). In the reaction medium, the antioxidant again reduces the monocation radical of ABTS to ABTS, resulting in a loss of coloration in the reaction medium ¹Center points in triplicate, i = 1-3. Source: Destro et al. (2019). Brazilian Journal of Chemical Engineering Maximization of Essential Oil Antioxidant Capacity via Star Anise Hydrodistillation 1681 lipid phase was transferred to another set of microtubes the samples containing trans-anethole, including containing approximately 7% (m/v) anhydrous the standard TA and all the EOs obtained from the sodium sulfate (CAS 7757-82-6, ANALYTICALS®), extraction optimization were used. The data were then commonly used as an oil drying agent (Zhai et al., plotted using Excel 2013® (Microsoft Corporation). 2009). The dehydrated oils were subsequently stored For each comparison between two individual methods, under refrigeration (4 ± 1°C) (Bhadra et al., 2011; a linear regression analysis was applied, with an Chempakam & Balaji, 2008; Wang et al., 2007), equation for the line and determination coefficient and after stabilization (overnight), they were again (R²pairs).