Special Issue "Saffron (Crocus sativus, L.): Omics and Other Techniques in Authenticity, Quality, and Bioactivity Studies".

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L-Theanine: properties, synthesis and isolation from tea.

Theanine is a non-protein amino acid that occurs naturally in the tea plant (Camellia sinensis) and contributes to the favourable taste of tea. It is also associated with effects such as the enhancement of relaxation and the improvement of concentration and learning ability. It is also linked with health benefits including the prevention of certain cancers and cardiovascular disease, the promotion of weight loss and enhanced performance of the immune system. Thus, there has been a significant rise in the demand for theanine. While theanine has been chemically and biologically synthesised, techniques to isolate theanine from natural sources remain an important area of research. In this review article, the properties and health benefits of theanine are summarised and the synthesis and isolation of theanine are reviewed and discussed. Future perspectives for the isolation of theanine from natural sources are also outlined.

Treatment of anxiety and depression: medicinal plants in retrospect.

Anxiety and depression are complex heterogeneous psychiatric disorders and leading causes of disability worldwide. This review summarizes reports on the fundamentals, prevalence, diagnosis, neurobiology, advancement in treatment of these diseases and preclinical assessment of botanicals. This review was conducted through bibliographic investigation of scientific journals, books, electronic sources, unpublished theses and electronic medium such as ScienceDirect and PubMed. A number of the first-line drugs (benzodiazepine, azapirone, antidepressant tricyclics, monoamine oxidase inhibitors, serotonin selective reuptake inhibitors, noradrenaline reuptake inhibitors, serotonin and noradrenaline reuptake inhibitors, etc.) for the treatment of these psychiatric disorders are products of serendipitous discoveries. Inspite of the numerous classes of drugs that are available for the treatment of anxiety and depression, full remission has remained elusive. The emerging clinical cases have shown increasing interests among health practitioners and patients in phytomedicine. The development of anxiolytic and antidepressant drugs of plant origin takes advantage of multidisciplinary approach including but not limited to ethnopharmacological survey (careful investigation of folkloric application of medicinal plant), phytochemical and pharmacological studies. The selection of a suitable plant for a pharmacological study is a basic and very important step. Relevant clues to achieving this step include traditional use, chemical composition, toxicity, randomized selection or a combination of several criteria. Medicinal plants have been and continue to be a rich source of biomolecule with therapeutic values for the treatment of anxiety and depression.