View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Tsukuba Repository Antioxidant Activity and Selected Chemical Components of 10 Zingiber spp. in Thailand 著者 Kantayos Vipada , Paisooksantivatana Yingyong journal or Journal of Developments in Sustainable publication title Agriculture volume 7 number 1 page range 89-96 year 2012 URL http://hdl.handle.net/2241/00125481 Journal of Developments in Sustainable Agriculture 7: 89-96 ( 2012) Antioxidant Activity and Selected Chemical Components of 10 Zingiber spp. in Thailand Vipada Kantayos and Yingyong Paisooksantivatana* Department of Horticultural, Faculty of Agricultural, Kasetsart University Zingiber officinale (ginger) is the one of most commonly used spices and is a traditional herbal medicine in Thailand. Thailand is home to various Zingiber wild species. However, the biological activity evidence of these other species is less well studied than that of Z. officinale. In this study, we investigated the rhizomes of 10 Zingiber species to determine the correlations between total phenolic content, total curcuminoid content, and antioxidant activity, as determined by means of DPPH (2,2-Diphenyl-l-picrylhydrazyl) and ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6- sulfonic acid) diammonium salt) assays. We also used high-performance liquid chromatography and gas chromato- graphy to determine the quantities of 6-gingerol and terpinen-4-ol, respectively which are the two most important active compounds associated with antioxidant and anti-inflammatory action. Antioxidant activity was highly corre- lated with total phenolic content. To the best of our knowledge, this is the first report of the antioxidant activities of three of the species (Z. rubens, Z. bisectum,andZ. barbatum). The rhizome extracts of Z. montanum showed the highest total curcuminoid content and yielded the highest amount of essential oil and terpinen-4-ol content. 6-Gingerol was detected in only two species: Z. officinale and Z. cornubracteatum. Our results suggest that Z. montanum may be an excellent natural remedy owing to its considerable antioxidant activity and the large amounts of known bioactive chemical constituents it contains. It may be a source of additional bioactive compounds. Key words: Zingiber, antioxidant activity, 6-gingerol, terpinen-4-ol ─────────────────────── notably inhibitory effects on oxidation and inflam- Introduction matory activity (Schwertner and Deborah, 2007) and In South and Southeast Asian countries, products terpinen-4-ol is an anti-inflammatory agent (Sukatta et obtained from plants of the genus Zingiber are used as al., 2009). food, flavorings, and medicines. Common ginger Antioxidants are chemical compounds that inhibit (Zingiber officinale (L.) Rosc.), pinecone ginger (Z. the oxidation of lipids and other molecules in living zerumbet (L.) Roscoe ex Smith), and cassumunar gin- cells (Zheng and Shiow, 2001). Antioxidant activity ger (Z. cassumunar (Koenig) Link ex. Dietr.) are part plays a crucial role in many chronic diseases, including of the daily diet in this region and are well-known for cardiovascular disease, diabetes, Alzheimer’s disease, their anti-inflammatory properties, as well as their and various inflammatory diseases (Gan et al., 2010), ornamental uses. Several scientific reports were in- and interest in obtaining antioxidants from natural dicated that various parts of the plants consist of sources is rapidly increasing. leaves, shoots, flowers, and rhizomes, exhibit various Thailand is a rich source of Zingiber diversity; at biological effects, including antioxidant activity (Habsah least 50 species have been reported in Thailand (Tri- et al., 2000). The biological activities of Zingiber boun, 2005). However, the information about the con- powder rhizome have been attributed to various tent of antioxidants and other compounds in these chemical constituents. For instance, 6-gingerol most species is lacking. Therefore, the objectives of the Received: July 22, 2011, Accepted: December 7, 2011 * Corresponding author: Department of Horticultural, Faculty of Agricultural, Kasetsart University, 50 Phaholyothin Rd., Ladyao, Jatujak, Bangkok, Thailand 10900. Tel: ＋66-2-579-0308, Fax: ＋66-2-579-1915 (112), E-mail: [email protected] 90 J. Dev. Sus. Agr. 7 (1) present study were to determine the content of Briefly, an ABTS･＋ (Fluka, ≥99%) stock solution antioxidants and related compounds in some Zingiber was prepared by mixing 7 mM ABTS and 2.45 mM K2 species to identify the potential uses of such S2O8 at a ratio of 8:12 v/v; the mixture was kept in the compounds in the food and drug industries. dark at 4℃ for 12 h for complete reaction. A working solution of ABTS･＋ was prepared by diluting the Materials and Methods stock solution with distilled 95% ethanol at a ratio of 5: Plant materials 100 v/v. The ABTS solution (3 mL) were allowed to We used the rhizomes of the following 10 Zingiber react with Zingiber rhizome extracts (0.5 mL) and kept species: Z. montanum, Z. ottensii, Z. rubens, Z. cor- in the dark for 20 min., the optical densities of the nubracteatum, Zingiber ‘Phlai-chompoo’, Z. zerumbet, solutions were taken at 734 nm. An ascorbic acid was Z. officinale, Z. bisectum, Z. spectabile,andZ. bar- use as a positive control an a synthetic antioxidant. batum. To identify Zingiber species in the field, we All sample were analyzed in triplicate. The antioxi- relied on the taxonomic descriptions of Triboun dant activity was expressed as IC50 values (the con- (2005). Rhizomes were collected from various loca- centration of an antioxidant at which 50% inhibition of tions in Thailand and were planted at the Department free radical activity is observed). The percentage in- of Horticulture of Kasetsart University, Thailand. hibition was calculated using the following equation: Rhizomes were harvested from 10-month-old plants % Inhibition ＝[(A1−A0)/A0)]100 for ethanol extraction and essential oil distillation. where A0 and A1 are the absorbance measured for the Preparation of crude extracts control reaction and for the sample extracts, respec- Zingiber rhizomes (ages 10-12 months) were air tively. The lower the IC50 number, the greater the dried until dry weight stable and milled into crude overall effectiveness of the antioxidant. powder using blender. The crude powder rhizomes Total phenolic content were macerated in distilled 95% ethanol (powder/ The total phenolic content was determined with alcohol ratio, 0.025-0.133 w/v) for 24 h at room tem- Folin-Ciocalteu reagent according to the method of perature, and the solids were filtered off with filter Chan et al. (2007). Briefly, the rhizome extracts (300 paper. The supernatant was kept at −4℃ until it was μL) were mixed with Folin-Ciocalteu reagent (10 times screened for antioxidant activity. dilution) and aqueous sodium carbonate (7.5% w/v). Determination of antioxidant activity The mixture was allowed to stand for 30 min, and then Radical scavenging activity was determined by a the absorbance at 765 nm was measured. Total phe- spectrophotometric method based on the reduction of a nolic content is expressed in terms of gallic acid equiv- methanol solution of DPPH and ABTS. alents per dry weight (mg GAE/g DW). All samples DPPH radical scavenging assay were run in triplicate. Radical scavenging activity of Zingiber rhizome ex- Total curcuminoid content tracts was determined spectrophotometrically accord- Curcumin standard solutions were prepared accord- ing to the method of Bua-in and Paisooksantivatana ing to the method of Pothitirat and Gritsanapan (2006) (2009). At first, the rhizome powder and ascorbic acid with the following modifications. For preparation of were weight accurately and dissolve in ethanol and standard solution, standard curcumin (2. 00 mg) was distilled water, respectively, to make the different di- accurately weighed and transferred to a 5-ml volumet- lutions of ethanol extract (0.05-0.005 g/ml). Here ric flask. ascorbic acid was taken as positive control. Next, Ethanol was added and adjusted to a final concent- DPPH (Sigma-Aldrich, Lot. D9132) was weight and ration of 400 mg/ml. From this solution, concentra- dissolve in ethanol to make 0.1 mM solution. 3 mL of tions of 0.005, 0.01, 0.0125, 0.015 and 0.02 mg/mL DPPH solution was applied on test tube with 0.5 mL of were prepared and used for preparation of the calibra- the rhizome extracts. The mixtures were kept in the tion curve. For preparation of sample solution from dark for 20 min. at room temperature, and the optical Zingiber powder rhizome, the powder (100 mg) of densities were measured at 517 nm. each species was added 20 mL ethanol and the absor- ABTS radical scavenging assay bance at 420 nm were measured spectrophotometri- The effect of the extracts on ABTS radical was de- cally. termined by the method of Chaichana et al. (2009). Kantayos and Paisooksantivatana: Antioxidant Activity and Chemical Compound of Zingiber spp. 91 6-Gingerol analysis hold for 10 min. Terpinen-4-ol standard solutions were Zingiber powder (0.50 g) was extracted with 5 mL prepared at concentrations of 0.025‒0.1%v/vinn- ethanol, and the mixture was filtered through Whatman hexane. No. 4 filter paper. The filtrate was subsequently pas- Data analysis sed through a 0.20-µm nylon membrane filter. 6-Gin- Data were analyzed statistically using analysis of gerol content was determined by means of reverse- variance (ANOVA), and the differences between sam- phase high-performance liquid chromatography ples were determined by Duncan’s multiple range test (HPLC) on a C18 column (250 mm×4.6 mm, Phenomenex, (p＜0.05). The Pearson’s correlations (p＜0.01 and p USA) The mobile phase was methanol:water (65:35 ＜0.05) between antioxidant activities determined by v/v) at a flow rate of 1.0 mL/min, the injection volume means of the two methods, total phenolic content, and was 20 μL, and the chromatographic run time was 30 total curcuminoid content were evaluated.