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Objective: To evaluate antibacterial activity and the bioactive compounds of 50％ hydro-ethanolic extract of Alpinia zerumbet (A. zerumbet) rhizomes. Methods: Eight reference microbial strains including two Gram-positive bacteria [Staphylococcus aureus (ATCC 29213) and Enterococcus faecalis (ATCC 29212)] and six Gram-negative bacteria [Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATTC 700603), Proteus mirabilis (DMST 8212), Salmonella enterica subsp. enterica serovar Vellore. (ATCC 15611), Shigella flexneri (ATCC 12022) and Pseudomonas aeruginosa (ATCC 27853)], were used to test antimicrobial susceptibility by the broth microdilution method. Bioactive compounds were analyzed by using HPLC. Results: The minimum inhibitory concentration values of A. zerumbet extract were 8 mg/mL for Staphylococcus aureus, Escherichia coli and Shigella flexneri and 16 mg/mL for Enterococcus faecalis and the other four Gram-negative bacilli. HPLC chromatograms revealed that the A. zerumbet extract contained hydroxybenzoic acids, hydroxycinnamic acids and flavonoids. Conclusions: The constituents of A. zerumbet rhizomes could be a potential source of antibacterial compounds, warranting further study of A. zerumbet extract.
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Objective: To investigate biomolecular alteration of sesamol on human lung adenocarcinoma (SK-LU-1) cells compared with cisplatin using Fourier transform infrared microscopy (FTIR). Methods: Cytotoxicity of sesamol was investigated against SK-LU-1 cells by using neutral red. DNA fragmentation and the cell cycle analysis were determined by agarose gel electrophoresis and flow cytometry, respectively. The FTIR microscopy technique was applied to explore the changes in cellular biochemical compositions in cells treated with sesamol that the biochemical and biological assays cannot cover. The alkylating property was determined by 4-(4-nitrobenzyl)pyridine assay. Results: Sesamol and cisplatin exerted an antiproliferative effect at 48 h with respective IC50 values of 2.7 and 0.07 mM. Both induced apoptosis by causing DNA damage and accumulation of cell populations at sub-G1. FTIR microscopy and Principle Component Analysis clearly discriminated the sesamol- and cisplatin-treated cells from the untreated cells or control. A significant increase of total lipid content was found in cisplatin-treated cells. Conformational changes in the proteins secondary structure from the α-helix to the β-sheet were found in both sesamol- and cisplatin-treated cells, as well as significant reductions in relative DNA content of both compared to the control were observed, suggesting DNA damage. A shift in the peak position of DNA region provides insight on the DNA interactions. Conclusions: The non-alkylating effect of sesamol based on the nitrobenzyl pyridine assay delineates the non-covalent binding mode of sesamol on DNA. Hydrogen bonding is the binding mode of sesamol on DNA, while for cisplatin it was covalent and hydrogen bonding.
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Objective: To investigate the antimelanogenesis properties of three sesame compounds-sesamol,sesamin and sesamolin via two stages of melanin synthesis vis-`a-vis sunscreen function and enzyme inhibition in melanoma cell line in order to search for alternative depigmenting agents. Methods: Antimelanogenic effects of sesame lignans were assessed in SK-MEL2 compared with the reference depigmenting agents, kojic acid and β-arbutin, in order to evaluate:(a)the sunscreen function of sesamol,sesamin and sesamolin by measurement of UV absorbtion property; (b) the inhibition of tyrosinase activity through mushroom and cellular tyrosinase; and (c) the effect on melanin content and melanogenic protein expression(tyrosinase,TRP-1 and TRP-2)by Western blot analysis;and(d)the toxicity of sesamol,sesamin and sesamolin to cells using cell cytotoxicity assay. Results: The results showed that sesamin, sesamolin and sesamol exerted satisfiable sunscreen function by absorbed UVB at 290 nm.Sesamol exhibited the highest inhibition of mushroom tyrosinase activity, but lipophilic sesamolin exhibited the highest cellular tyrosinase inhibition (IC50of 1.6 μM) followed by sesamin, sesamol, and kojic acid, respectively.The order from high to low inhibition of melanin pigment was detected in the SK-MEL2 treated with sesamolin, sesamin, sesamol, kojic acid, and β-arbutin, respectively.Sesamolin and sesamin successfully inhibited cellular tyrosinase activity and respectively decreased TRP-1/TRP-2 (36%/15%) and TRP-1 levels (16%), thereby inhibiting melanogenesis via antityrosinase activity. No cytotoxicity to SK-MEL2 or Vero (normal) cell lines was observed at the lignan concentrations that exerted an anti-melanogenic effect. Conclusions: Three sesame lignans prevent melanin synthesis through 2 stages: (a) by blocking melanin-induction and(b)by interrupting melanogenic enzyme production.This study provides evidence that sesamol, sesamin and sesamolin are potential for anti-melanogenesis agents.
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Objectives:To evaluate the concentration differences of sulforaphene and sulforaphane at various ages and in different pairs of Raphanus sativus L.var.caudatus with respect to their potential cancer preventive effect on HCT116 colon cancer cells.Methods:FTIR-ATR and GC-MS were used to characterize the isothiocyanates in the plant extracts followed by HPLC for quantification.Antiproliferation and apoptosis induction were determined by using MTT assay and flow cytometry,respectively.Results:The respective rank of anticancer activity ofRaphanus sativus were as follows:vegetative (3 week) ＜ older rosette (4 week) ＜ early-bolting (5 week) ＜ senescence (7 week) ＜ late-bolting (6 week).The low to high concentration of sulforaphene and sulforaphane occurred in the same stage order.Conclusions:The reproductive parts (flower,pod,and dry seed) of Raphanus sativus have the greatest isothiocyanate concentration,evidenced by a sulforaphene concentration higher than the sulforaphane.This result should inform the selection of the most appropriate harvesting stage and plant part for use as a potential chemopreventive agent.