title: A new label-free screen for steroid 5α-reductase inhibitors using LC-MS.
abstract: Steroid 5α-reductase (S5αR) plays an important role in metabolizing testosterone into active androgen dihydrotestosterone (DHT) which is involved in many androgen dependent disorders, such as androgenic alopecia, benign prostatic hyperplasia and acne. The method for screening for S5αR inhibition is key in finding new antagonists. In this study, the label-free S5αR inhibitory assay using LC-MS was developed. S5αR type 1 enzyme was obtained from LNCaP prostate cancer cells. The enzymatic assay was optimised for enzyme-substrate (testosterone) concentration, NADPH-cofactor concentration, solvent tolerance, enzyme activity stability and incubation time. The developed assay was validated by measuring the signal to background ratio (S/B), the signal to noise ratio (S/N), the signal window (SW) and the zeta factor Z' in accordance with published bioassay guidelines. The enzymatic reaction was performed in 96-well plates and DHT formation was determined by LC-MS. S/B, S/N, SW and Z' factor were well above acceptable criteria and the reproducibility was good using Z' factor other 3days and further validated by dutasteride and finasteride inhibition. The method was successfully applied to quantify S5αR inhibitory activity of some Thai herbal extracts. Two plant extracts, Impatiens balsamina L. and Curcuma longa L. showed IC50at 5.4±0.2 and 9.0±1.2μgmL-1and are therefore promising sources of new S5αR inhibitors. The assay has high selectability and reproducibility and suited to medium throughput screening required by phytochemistry.
authors: Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand.
authors: Jukkarin
authors: J
authors: Srivilai
authors: Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand.
authors: Karma
authors: K
authors: Rabgay
authors: Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand.
authors: Nantaka
authors: N
authors: Khorana
authors: Cosmetics and Natural Products Research Center, Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand.
authors: Neti
authors: N
authors: Waranuch
authors: Science Laboratory Centre, Faculty of Science, Naresuan University, Phitsanulok, Thailand.
authors: Nitra
authors: N
authors: Nuengchamnong
authors: Bioscreening Unit, Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok, Thailand. Electronic address: k_ingkaninan@yahoo.com.
authors: Kornkanok
authors: K
authors: Ingkaninan
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D058891:5-alpha Reductase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002853:Chromatography, Liquid / Q000379:methods*; D030024:Curcuma / Q000737:chemistry; D013196:Dihydrotestosterone / Q000378:metabolism; D057075:Enzyme Assays; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D029069:Impatiens / Q000737:chemistry; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D015203:Reproducibility of Results
chemical_list: D058891:5-alpha Reductase Inhibitors; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D013196:Dihydrotestosterone; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase
keywords: Anti-androgen; LC-MS; Label-free 5-alpha reductase inhibitory assay; Steroid 5-alpha reductase