Patwardhan Juilee, Bhatt Purvi
Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS (Deemed-to-be) University, Mumbai, Maharashtra, India.
Pharmacogn Mag. 2016 May;12(Suppl 2):S129-38. doi: 10.4103/0973-1296.182175. Epub 2016 May 11.
Ultraviolet-B (UV-B) radiation is a smaller fraction of the total radiation reaching the Earth but leads to extensive damage to the deoxyribonucleic acid (DNA) and other biomolecules through formation of free radicals altering redox homeostasis of the cell. Abelmoschus esculentus (okra) has been known in Ayurveda as antidiabetic, hypolipidemic, demulscent, antispasmodic, diuretic, purgative, etc.
The aim of this study is to evaluate the protective effect of flavonoids from A. esculentus against UV-B-induced cell damage in human dermal fibroblasts.
UV-B protective activity of ethyl acetate (EA) fraction of okra was studied against UV-B-induced cytotoxicity, antioxidant regulation, oxidative DNA damage, intracellular reactive oxygen species (ROS) generation, apoptotic morphological changes, and regulation of heme oxygenase-1 (HO-1) gene through nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway.
Flavonoid-rich EA fraction depicted a significant antioxidant potential also showing presence of rutin. Pretreatment of cells with EA fraction (10-30 μg/ml) prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, oxidative DNA damage, intracellular ROS production, apoptotic changes, and overexpression of Nrf2 and HO-1.
Our study demonstrated for the 1(st) time that EA fraction of okra may reduce oxidative stress through Nrf2-ARE pathway as well as through endogenous enzymatic antioxidant system. These results suggested that flavonoids from okra may be considered as potential UV-B protective agents and may also be formulated into herbal sunscreen for topical application.
Flavonoid-enriched ethyl acetate (EA) fraction from A. esculentus protected against ultraviolet-B (UV-B)-induced oxidative DNA damageEA fraction prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, and intracellular reactive oxygen species productionEA fraction could reduce oxidative stress through the Nrf2-ARE PathwayEA fraction was found to be nongenotoxic and prevented apoptotic changes.
Flavonoids from Abelmoschus esculentus protected from ultraviolet-B-induced damageThey were capable of reducing oxidative stress through Nrf2-ARE PathwayThey are nongenotoxic and do not possess mutagenic potentialFlavonoids from A. esculentus can be studied and explored further for its topical application as sunscreen. Abbreviations used: ABTS: 2,2'-azino-bis-(3-ethylbenzothiazoline -6-sulphonic acid), AO: Acridine orange,
Analysis of variance, ARE: Antioxidant response elements, BSA: Bovine serum albumin, CAPE: Caffeic acid phenethyl ester, CAT: Catalase, DCFH-DA: 2',7'-dichlorofluorescein diacetate, DMEM: Dulbecco's modified eagle's medium, DMSO: dimethyl sulfoxide, DNA: Deoxyribonucleic acid, DPBS: Dulbecco's phosphate-buffered saline, DPPH: 2,2-diphenyl-1-picryl hydrazyl, ECL: Enhanced chemiluminescence, EDTA: Ethylenediaminetetraacetic acid, ELISA: Enzyme-linked immunosorbent assay, EtBr: Ethidium bromide, FBS: Fetal bovine serum, FE Fraction: Flavonoid-enriched fraction, FRAP: Ferric reducing antioxidant power, GPx: Glutathione peroxidase, GR: Glutathione reductase, GST: Glutathione-S-transferase, GSH: Reduced glutathione, GSSG: Oxidized glutathione, HDF: Human dermal fibroblast adult cells, HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulphonic acid, HRP: Horseradish peroxidase, HO-1: Heme oxygenase-1, HPTLC: High-performance thin layer chromatography, Keap-1: Kelch-like ECH-associated protein-1, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, NaCl: sodium chloride, NFDM: nonfat dry milk, Nrf2: Nuclear factor E2-related factor 2, NQO1: NAD (P) H: Quinine oxidoreductase 1, OH: Hydroxyl ions, PBST: Phosphate-buffered saline with 0.1% tween 20, PCR: Polymerase chain reaction, PMSF: Phenylmethanesulfonyl fluoride, Rf: Retention factor, ROS: Reactive oxygen species, rRNA: Ribosomal ribonucleic acid, SDS: Sodium dodecyl sulfate, SOD: Superoxide dismutase, TLC: Thin layer chromatography, TLC-DPPH: Thin layer chromatography-2,2-diphenyl-1-picryl hydrazyl, UV: Ultraviolet, UV-A: Ultraviolet-A, UV-B: Ultraviolet-B, UV-C: Ultraviolet-C, qPCR: Quantitative polymerase chain reaction.
紫外线B（UV-B）辐射在到达地球的总辐射中占比更小，但会通过形成自由基改变细胞的氧化还原稳态，对脱氧核糖核酸（DNA）和其他生物分子造成广泛损害。在阿育吠陀医学中，黄秋葵已知具有抗糖尿病、降血脂、缓和、解痉、利尿、泻下等功效。
本研究旨在评估黄秋葵中的黄酮类化合物对UV-B诱导的人皮肤成纤维细胞损伤的保护作用。
研究了黄秋葵乙酸乙酯（EA）组分对UV-B诱导的细胞毒性、抗氧化调节、氧化性DNA损伤、细胞内活性氧（ROS）生成、凋亡形态变化以及通过核因子E2相关因子2-抗氧化反应元件（Nrf2-ARE）途径对血红素加氧酶-1（HO-1）基因的调节作用。
富含黄酮类化合物的EA组分具有显著的抗氧化潜力，且含有芦丁。用EA组分（10 - 30μg/ml）预处理细胞可预防UV-B诱导的细胞毒性、内源性酶抗氧化剂的消耗、氧化性DNA损伤、细胞内ROS产生、凋亡变化以及Nrf2和HO-1的过度表达。
我们的研究首次证明，黄秋葵的EA组分可能通过Nrf2-ARE途径以及内源性酶抗氧化系统减轻氧化应激。这些结果表明，黄秋葵中的黄酮类化合物可被视为潜在的UV-B防护剂，也可制成草药防晒霜用于局部应用。
黄秋葵富含黄酮类化合物的乙酸乙酯（EA）组分可保护细胞免受紫外线B（UV-B）诱导的氧化性DNA损伤EA组分可预防UV-B诱导的细胞毒性、内源性酶抗氧化剂的消耗以及细胞内活性氧的产生EA组分可通过Nrf2-ARE途径减轻氧化应激EA组分被发现无遗传毒性并可预防凋亡变化。
黄秋葵中的黄酮类化合物可保护细胞免受紫外线B诱导的损伤它们能够通过Nrf2-ARE途径减轻氧化应激它们无遗传毒性且不具有诱变潜力黄秋葵中的黄酮类化合物可进一步研究并探索其作为防晒霜的局部应用。使用的缩写：ABTS：2,2'-偶氮二（3-乙基苯并噻唑啉-6-磺酸），AO：吖啶橙，方差分析：方差分析，ARE：抗氧化反应元件，BSA：牛血清白蛋白，CAPE：咖啡酸苯乙酯，CAT：过氧化氢酶，DCFH-DA：2',7'-二氯荧光素二乙酸酯，DMEM：杜氏改良伊格尔培养基，DMSO：二甲基亚砜，DNA：脱氧核糖核酸，DPBS：杜氏磷酸盐缓冲盐水，DPPH：2,2-二苯基-1-苦基肼，ECL：增强化学发光，EDTA：乙二胺四乙酸，ELISA：酶联免疫吸附测定，EtBr：溴化乙锭，FBS：胎牛血清，FE组分：富含黄酮类化合物的组分，FRAP：铁还原抗氧化能力，GPx：谷胱甘肽过氧化物酶，GR：谷胱甘肽还原酶，GST：谷胱甘肽-S-转移酶，GSH：还原型谷胱甘肽，GSSG：氧化型谷胱甘肽，HDF：成人人类皮肤成纤维细胞，HEPES：4-（2-羟乙基）-1-哌嗪乙磺酸，HRP：辣根过氧化物酶，HO-1：血红素加氧酶-1，HPTLC：高效薄层色谱，Keap-1： Kelch样ECH相关蛋白-1，MTT：3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐，NaCl：氯化钠，NFDM：脱脂奶粉，Nrf2：核因子E2相关因子2，NQO1：NAD（P）H：奎宁氧化还原酶1，OH：氢氧根离子，PBST：含0.1%吐温20的磷酸盐缓冲盐水，PCR：聚合酶链反应，PMSF：苯甲基磺酰氟，Rf：保留因子，ROS：活性氧，rRNA：核糖体核糖核酸，SDS：十二烷基硫酸钠，SOD：超氧化物歧化酶，TLC：薄层色谱，TLC-DPPH：薄层色谱-2,2-二苯基-1-苦基肼，UV：紫外线，UV-A：紫外线A，UV-B：紫外线B，UV-C：紫外线C，qPCR：定量聚合酶链反应。
