title: Polar biophenolics in sweet potato greens extract synergize to inhibit prostate cancer cell proliferation and in vivo tumor growth.
abstract: Polyphenolic phytochemicals present in fruits and vegetables indisputably confer anticancer benefits upon regular consumption. Recently, we demonstrated the growth-inhibitory and apoptosis-inducing properties of polyphenol-rich sweet potato greens extract (SPGE) in cell culture and in vivo prostate cancer xenograft models. However, the bioactive constituents remain elusive. Here, we report a bioactivity-guided fractionation of SPGE based upon differential solvent polarity using chromatographic techniques that led to the identification of a remarkably active polyphenol-enriched fraction, F5, which was ~100-fold more potent than the parent extract as shown by IC50 measurements in human prostate cancer cells. High-performance liquid chromatography-ultraviolet and mass spectrometric analyses of the seven SPGE fractions suggested varying abundance of the major phenols, quinic acid (QA), caffeic acid, its ester chlorogenic acid, and isochlorogenic acids, 4,5-di-CQA, 3,5-di-CQA and 3,4-di-CQA, with a distinct composition of the most active fraction, F5. Subfractionation of F5 resulted in loss of bioactivity, suggesting synergistic interactions among the constituent phytochemicals. Quantitative analyses revealed a ~2.6- and ~3.6-fold enrichment of QA and chlorogenic acid, respectively, in F5 and a definitive ratiometric relationship between the isochlorogenic acids. Daily oral administration of 400mg/kg body wt of F5 inhibited growth and progression of prostate tumor xenografts by ~75% in nude mice, as evidenced by tumor volume measurements and non-invasive real-time bioluminescence imaging. These data generate compelling grounds to further examine the chemopreventive efficacy of the most active fraction of SPGE and suggest its potential usefulness as a dietary supplement for prostate cancer management.
authors: Department of Biology and.
authors: Sushma R
authors: SR
authors: Gundala
authors: Chunhua
authors: C
authors: Yang
authors: N
authors: N
authors: Lakshminarayana
authors: Ghazia
authors: G
authors: Asif
authors: Meenakshi V
authors: MV
authors: Gupta
authors: Shahab
authors: S
authors: Shamsi
authors: Ritu
authors: R
authors: Aneja
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements; D004357:Drug Synergism; D006801:Humans; D027723:Ipomoea batatas / Q000737:chemistry*; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000008:administration & dosage* / Q000737:chemistry; D059808:Polyphenols / Q000008:administration & dosage* / Q000737:chemistry; D011471:Prostatic Neoplasms / Q000178:diet therapy* / Q000473:pathology; D023041:Xenograft Model Antitumor Assays
chemical_list: D010936:Plant Extracts; D059808:Polyphenols