title: Plant-growth regulators alter phytochemical constituents and pharmaceutical quality in Sweet potato (Ipomoea batatas L.).
abstract: BACKGROUND
  Sweet potato (Ipomoea batatas L.) is one of the most important consumed crops in many parts of the world because of its economic importance and content of health-promoting phytochemicals.
  
  
  METHODS
  With the sweet potato (Ipomoea batatas L.) as our model, we investigated the exogenous effects of three plant-growth regulators methyl jasmonate (MeJA), salicylic acid (SA), and abscisic acid (ABA) on major phytochemicals in relation to phenylalanine ammonia lyase (PAL) activity. Specifically, we investigated the total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), and total β-carotene content (TCC). Individual phenolic and flavonoid compounds were identified using ultra-high performance liquid chromatography (UHPLC). Antioxidant activities of treated plants were evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and a β-carotene bleaching assay. Anticancer activity of extracts was evaluated against breast cancer cell lines (MCF-7 and MDA-MB-231) using MTT assay.
  
  
  RESULTS
  TPC, TFC, TAC, and TCC and antioxidant activities were substantially increased in MeJA-, SA-, and ABA-treated plants. Among the secondary metabolites identified in this study, MeJA application significantly induced production of quercetin, kaempferol, myricetin, gallic acid, chlorogenic acid, 3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid. Luteolin synthesis was significantly induced by SA application. Compared with control plants, MeJA-treated sweet potato exhibited the highest PAL activity, followed by SA and ABA treatment. The high DPPH activity was observed in MeJA followed by SA and ABA, with half-maximal inhibitory concentration (IC50) values of 2.40, 3.0, and 3.40 mg/mL compared with α-tocopherol (1.1 mg/mL). Additionally, MeJA-treated sweet potato showed the highest β-carotene bleaching activity, with an IC50 value of 2.90 mg/mL, followed by SA (3.30 mg/mL), ABA (3.70 mg/mL), and control plants (4.5 mg/mL). Extracts of sweet potato root treated with MeJA exhibited potent anticancer activity with IC50 of 0.66 and 0.62 mg/mL against MDA-MB-231 and MCF-7 cell lines respectively, compared to that of extracts of sweet potato treated with SA (MDA-MB-231 = 0.78 mg/mL; MCF-7 = 0.90 mg/mL) and ABA (MDA-MB-231 = 0.94 mg/mL; MCF-7 = 1.40 mg/mL). The results of correlation analysis showed that anthocyanins and flavooids are corresponding compounds in sweet potato root extracts for anticancer activity against breast cancer cell lines.
  
  
  CONCLUSIONS
  MeJA has great potential to enhance the production of important health-promoting phytochemicals in sweet potato.
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia. alighasemzadeh@upm.edu.my.
authors.forename: Ali
authors.initials: A
authors.lastname: Ghasemzadeh
authors.affiliation: Medicinal Plants Research Center, Shahed University, Tehran, Iran.
authors.forename: Daryush
authors.initials: D
authors.lastname: Talei
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Hawa Z E
authors.initials: HZ
authors.lastname: Jaafar
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Abdul Shukor
authors.initials: AS
authors.lastname: Juraimi
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Mahmud Tengku Muda
authors.initials: MT
authors.lastname: Mohamed
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Adam
authors.initials: A
authors.lastname: Puteh
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
authors.forename: Mohd Ridzwan A
authors.initials: MR
authors.lastname: Halim
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000085:Acetates / Q000494:pharmacology; D000872:Anthocyanins / Q000378:metabolism; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D044948:Flavonols / Q000378:metabolism; D027723:Ipomoea batatas / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D054883:Oxylipins / Q000494:pharmacology; D010636:Phenols / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology*; D020156:Salicylic Acid / Q000494:pharmacology; D019207:beta Carotene / Q000378:metabolism
chemical_list: D000085:Acetates; D000872:Anthocyanins; D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D003517:Cyclopentanes; D044948:Flavonols; D054883:Oxylipins; D010636:Phenols; D010937:Plant Growth Regulators; D019207:beta Carotene; D000040:Abscisic Acid; C072239:methyl jasmonate; D020156:Salicylic Acid
keywords: DPPH assay; Phenylalanine ammonia lyase; Plant-growth regulators; Sweet potato; UHPLC; β-carotene blenching assay