title: Enhancement of anti-inflammatory activity of Aloe vera adventitious root extracts through the alteration of primary and secondary metabolites via salicylic acid elicitation.
abstract: Aloe vera (Asphodeloideae) is a medicinal plant in which useful secondary metabolites are plentiful. Among the representative secondary metabolites of Aloe vera are the anthraquinones including aloe emodin and chrysophanol, which are tricyclic aromatic quinones synthesized via a plant-specific type III polyketide biosynthesis pathway. However, it is not yet clear which cellular responses can induce the pathway, leading to production of tricyclic aromatic quinones. In this study, we examined the effect of endogenous elicitors on the type III polyketide biosynthesis pathway and identified the metabolic changes induced in elicitor-treated Aloe vera adventitious roots. Salicylic acid, methyl jasmonate, and ethephon were used to treat Aloe vera adventitious roots cultured on MS liquid media with 0.3 mg/L IBA for 35 days. Aloe emodin and chrysophanol were remarkably increased by the SA treatment, more than 10-11 and 5-13 fold as compared with untreated control, respectively. Ultra-performance liquid chromatography-electrospray ionization mass spectrometry analysis identified a total of 37 SA-induced compounds, including aloe emodin and chrysophanol, and 3 of the compounds were tentatively identified as tricyclic aromatic quinones. Transcript accumulation analysis of polyketide synthase genes and gas chromatography mass spectrometry showed that these secondary metabolic changes resulted from increased expression of octaketide synthase genes and decreases in malonyl-CoA, which is the precursor for the tricyclic aromatic quinone biosynthesis pathway. In addition, anti-inflammatory activity was enhanced in extracts of SA-treated adventitious roots. Our results suggest that SA has an important role in activation of the plant specific-type III polyketide biosynthetic pathway, and therefore that the efficacy of Aloe vera as medicinal agent can be improved through SA treatment.
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Yun Sun
authors.initials: YS
authors.lastname: Lee
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hyun Kyoung
authors.initials: HK
authors.lastname: Ju
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Yeon Jeong
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, Republic of Korea.
authors.forename: Tae-Gyu
authors.initials: TG
authors.lastname: Lim
authors.affiliation: Department of Crop Science, Chungnam National University, Yuseong-Gu, Daejeon, Republic of Korea.
authors.forename: Md Romij
authors.initials: MR
authors.lastname: Uddin
authors.affiliation: Department of Crop Science, Chungnam National University, Yuseong-Gu, Daejeon, Republic of Korea.
authors.forename: Yeon Bok
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Kim Jeong Moon Aloe Co. LTD, SeoCho-Gu, Seoul, Republic of Korea.
authors.forename: Jin Hong
authors.initials: JH
authors.lastname: Baek
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Kwon
authors.affiliation: Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Seoul National University, Seoul, Republic of Korea.
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Lee
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea ; Bio-MAX Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Seo
authors.affiliation: Department of Crop Science, Chungnam National University, Yuseong-Gu, Daejeon, Republic of Korea.
authors.forename: Sang Un
authors.initials: SU
authors.lastname: Park
authors.affiliation: Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Tae-Jin
authors.initials: TJ
authors.lastname: Yang
mesh_terms: D000504:Aloe / Q000187:drug effects / Q000378:metabolism*; D000893:Anti-Inflammatory Agents / Q000378:metabolism*; D010936:Plant Extracts / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D061065:Polyketides / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology*
chemical_list: D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; D061065:Polyketides; D020156:Salicylic Acid