The cytotoxicity-guided study of the dichloromethane and ethanol extracts of Thymus mastichina L. using the HCT colon cancer cell line allowed the identification of nine compounds, sakuranetin (1), sterubin (2), oleanolic acid (3), ursolic acid (4), lutein (5), β-sitosterol (6), rosmarinic acid (7), 6hydroxyluteolin-7-O-β-glucopyranoside (8), and 6-hydroxyapigenin-7-O-β-glucopyranoside (9). All compounds were tested for their cytotoxicity against the HCT colon cancer cell line. Compound 4 showed cytotoxicity with GI 50 value of 6.8 µg/mL. A fraction composed of a mixture (1:1) of triterpenoid acids 3 and 4 displayed improved cytotoxicity with a GI 50 of 2.8 g/mL suggesting a synergistic behavior. This is the first report on the chemical constituents of Thymus mastichina L. based on structural assignments by spectroscopic analysis. The presence of these constituents identified by colon cancer cytotoxicity-guided activity indicates that extracts of T. mastichina L. may have a protective effect against colon cancers.

A model optical immunosensor was developed to quantify an antibody present in a sample by measuring the fluorescence of Cyanine-5 conjugated with the antibody, using a competitive and a sandwich immunoreaction configuration, with the antigen immobilised in controlled pore glass beads. At pH 2, 94% of the antigen-antibody complex was dissociated, allowing reutilisation. Photobleaching had no effect on the fluorescence. This model system was used to detect Brucella sp. infection and could quantify anti-Brucella sp. antibodies in ovine serum samples in the range from 0.005 to 0.11 mg ml(-1).

The skin acts as a barrier to environmental insults and provides many vital functions. One of these is to shield DNA from harmful ultraviolet radiation, which is achieved by skin pigmentation arising as melanin is produced and dispersed within the epidermal layer. This is a crucial defence against DNA damage, photo‐ageing and skin cancer. The mechanisms and regulation of melanogenesis and melanin transfer involve extensive crosstalk between melanocytes and keratinocytes in the epidermis, as well as fibroblasts in the dermal layer. Although the predominant mechanism of melanin transfer continues to be debated and several plausible models have been proposed, we and others previously provided evidence for a coupled exo/phagocytosis model. Herein, we performed histology and immunohistochemistry analyses and demonstrated that a newly developed full‐thickness three‐dimensional reconstructed human pigmented skin model and an epidermis‐only model exhibit dispersed pigment throughout keratinocytes in the epidermis. Transmission electron microscopy revealed melanocores between melanocytes and keratinocytes, suggesting that melanin is transferred through coupled exocytosis/phagocytosis of the melanosome core, or melanocore, similar to our previous observations in human skin biopsies. We, therefore, present evidence that our in vitro models of pigmented human skin show epidermal pigmentation comparable to human skin. These findings have a high value for studies of skin pigmentation mechanisms and pigmentary disorders, whilst reducing the reliance on animal models and human skin biopsies.

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