Evaluation of Skin Anti-aging Potential of Citrus reticulata Blanco Peel

Background: The peel of Citrus reticulata Blanco is traditionally used as tonic, stomachic, astringent, and carminative. It is also useful in skin care. Objective: To study the anti-aging potential of alcoholic extracts of C. reticulata Blanco peel using in vitro antioxidant and anti-enzyme assays. Materials and Methods: Plant extracts were obtained by Soxhlation (CR HAE- Hot Alcoholic Extract of Citrus reticulata) and maceration method (CR CAE- Cold Alcoholic Extract of Citrus reticulata). Qualitative and quantitative phytochemical analysis was performed. Further, in vitro antioxidant, anti-enzyme, and gas chromatography-mass spectrometry (GC-MS) analyses were performed. Results: Total phenolic and flavonoid contents of CR HAE were found to be higher than CR CAE. EC50value of CR HAE and CR CAE for 1,1-Diphenyl-2-picrylhydrazyl, Superoxide anion, and 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays were 250.33 ± 40.16 μg/ml and 254.73 ± 15.78 μg/ml, 221.27 ± 11.25 μg/ml and 354.20 ± 23.79 μg/ml, and 59.16 ± 2.17 μg/ml and 59.12 ± 6.21 μg/ml, respectively. Oxygen radical absorbance capacity values for CR HAE and CR CAE were found to be 1243 and 1063 μmoles 6-hydroxy-2,5,7,8-tetra methylchromane-2-carboxylic acid equivalent/g of substance, respectively. Anti-collagenase and anti-elastase activities were evaluated for both CR HAE and CR CAE. EC50values of CR HAE and CR CAE for anti-collagenase and anti-elastase were 329.33 ± 6.38 μg/ml, 466.93 ± 8.04 μg/ml and 3.22 ± 0.24 mg/ml, 5.09 ± 0.30 mg/ml, respectively. CR HAE exhibited stronger anti-collagenase and anti-elastase activity than CR CAE. GC-MS analysis of CR HAE was carried out because CR HAE exhibited higher antioxidant and anti-enzyme potential than CR CAE. Conclusion: C. reticulata peel can be utilized in anti-wrinkle skin care formulations. SUMMARY Skin anti-aging potential of Citrus reticulata Blanco peel was evaluated through In vitro antioxidant and anti-enzyme assays Two types of extraction were performed and extracts were subjected to qualitative and quantitative phytochemical analysis. Extract obtained by Soxhlation (CR HAE) showed higher total phenolic and flavonoid contents than extract obtained by maceration (CR CAE) CR HAE demonstrated strong DPPH and Superoxide free radical scavenging activity whereas, ABTS scavenging activity of both the extracts were found to be similar. Oxygen Radical Absorbance Capacity (ORAC) of CR HAE was found to be more; indicating its strong antioxidant potential In vitro collagenase and elastase enzyme inhibition activities were evaluated for both the extracts and CR HAE showed strong anti-collagenase and anti-elastase potential indicating its anti-aging ability GC-MS analysis of CR HAE revealed the presence of various compounds mainly including Polymethoxyflavones. CR HAE exhibited promising antioxidant and anti-enzymatic activity and can be used as a potent anti-wrinkle agent in anti-aging skin care formulations. Abbreviation Used: ECM: Extracellular matrix, UV: Ultra violet, ROS: Reactive Oxygen Species, MMP: Matrix metalloproteinase, Chc: Clostridium histolyticum collagenase, DPPH: 2, 2-diphenyl-1-picrylhydrazyl, GC-MS: Gas Chromatography- Mass Spectroscopy, RT: Room Temperature, μg GAE/ mg: Microgram Gallic acid equivalent / milligram, W/V: Weight by Volume, μg QE/ mg: Microgram Quercetin equivalent / milligram, CR HAE: Hot Alcoholic Extract of Citrus reticulata Blanco, CR CAE: Cold Alcoholic Extract of Citrus reticulata Blanco, EC50: Half Maximal Effective Concentration, PMS NADH: Phenazine methosulfate nicotinamide adenine dinucleotide, NBT: Nitroblue tetrazolium, DMSO: Dimethyl sulfoxide, APS: Ammonium Persulphate, AAPH: 2,2 -azobis(2-amidino-propane) dihydrochloride, TROLOX: (±) 6-hydroxy-2,5,7,8-tetramethyl chromane-2-carboxylic acid, ORAC: Oxygen Radical Absorbance Capacity, FALGPA: N-[3-(2-Furyl) acryloyl)]-Leu-Gly-Pro-Ala, SANA: Succinyl-Ala-Ala-Ala-p-nitroanilide, Rf: Retardation Factor, MSD: Mass Selective Detector