Identification of powdered Chinese herbal medicines by fluorescence microscopy, Part 1: Fluorescent characteristics of mechanical tissues, conducting tissues, and ergastic substances.

The light microscope has been successfully used in identification of Chinese herbal medicines (CHMs) for more than a century. However, positive identification is not always possible. Given the popularity of fluorescence microscopy in bioanalysis, researchers dedicated to finding new ways to identify CHMs more effectively are now turning to fluorescence microscopy for authentication purposes. Some studies on distinguishing confused species from the same genus and on exploring distributions of chemicals in tissues of CHMs by fluorescence microscopy have been reported; however, no systematic investigations on fluorescent characteristics of powdered CHMs have been reported. Here, 46 samples of 16 CHMs were investigated. Specifically, the mechanical tissues including stone cells and fibers, the conducting tissues including three types of vessels, and ergastic substances including crystals of calcium oxalate and secretions, in various powdered CHMs were investigated by both light microscope and fluorescence microscope. The results showed many microscopic features emit fluorescence that makes them easily observed, even against complex backgrounds. Under the fluorescence microscope, different microscopic features from the same powdered CHM or some same features from different powdered CHMs emitted the different fluorescence, making this information very helpful for the authentication of CHMs in powder form. Moreover, secretions with unique chemical profiles from different powdered CHMs showed different fluorescent characteristics. Hence, fluorescence microscopy could be a useful additional method for the authentication of powdered CHMs if the fluorescent characteristics of specific CHMs are known.

[Allergy to asparagus]. / Alergia al espárrago.

Asparagus (Asparagus officinalis) is a widely grown vegetable; together with garlic, the onion and the leek, it belongs to the Liliaceae family. Both delayed cell-mediated reactions and IgE-mediated reactions secondary to asparagus have been described. While the former (allergic contact dermatitis) are a fairly common cause of occupational disease, only a few case-reports of IgE-mediated reactions have been published. IgE-mediated reactions can be further grouped into food allergy and reactions due to cutaneous or respiratory exposure, which is often occupational. Anaphylaxis is the most common clinical picture of food allergy, while contact urticaria, rhinitis and asthma, appearing either isolated or associated, are clinical pictures of the latter. Sensitization to different allergens is the likely cause of the different clinical pictures due to asparagus. Their detection and early diagnosis is of prime importance due to the different prognosis and treatment. In the present article we resume our experience over the last 5 years.