Effects of prescribed fire on canopy foliar chemistry and suitability for an insect herbivore

We assessed the effects of a prescribed fire on the phytochemical characteristics and vigor of overstory chestnut oak, scarlet oak, and red maple, and measured the impact of potential changes on herbivore fitness. We compared foliar carbohydrates, tannins, nutrients, and fiber concentrations in foliage from burned and non-burned forest canopies. There were significant differences in most foliar characteristics between tree species. Total non-structural carbohydrate concentrations in scarlet oak and red maple foliage, and calcium levels in red maple foliage, were significantly lower in burned plots, but other phytochemical characteristics were largely unaffected by burning. Tree growth also varied with species. Burning increased chestnut oak relative growth, decreased scarlet oak growth, and had no affect on red maple growth. Scarlet oak and red maple foliage from burned and non-burned forest canopies were assayed for gypsy moth performance. Caterpillars fed foliage from scarlet oak, the preferred host, grew larger and developed more rapidly than did those fed red maple foliage. There were no significant burn treatment differences in caterpillar development within either tree species, suggesting that managers using prescribed fire to promote oak regeneration need not worry about enhancing forest stand susceptibility to gypsy moth. However, the fire in this study was of low to moderate intensity; more intense fires may alter foliar palatability.     

From classical taxonomy to genome and metabolome: towards comprehensive quality standards for medicinal herb raw materials and extracts

Fundamental to herbal medicine quality is the use of 'authentic' medicinal herb species. Species, however, 'represent more or less arbitrary and subjective man-made units'. Against this background, we discuss, with illustrative examples, the importance of defining species boundaries by accommodating both the fixed (shared) diagnostic and varying (within-species) traits in medicinal herb populations. We emphasize the role of taxonomy, floristic information and genomic profiling in authenticating medicinal herb species, in addition to the need to include within species phytochemical profile variations while developing herbal extract identification protocols. We outline the application of species-specific genomic and phytochemical markers, chemoprofiling and chemometrics as additional tools to develop qualifying herbal extract references. We list the diagnostic traits available subsequent to each step during the medicinal herb extract manufacturing process and delineate limits to qualification of extract references.     

艾草的化学成分和药理作用研究进展

艾草为我国传统的中草药,其应用在我国有着悠久的历史和广泛的影响。早在明代李时珍的《本草纲目》中就有记载,称其为“草医”。对艾草的理化性质、提取方法、主要的化学成分、药理学作用和应用进行国内外文献研究总结。艾草主要的化学成分为挥发油类、黄酮类和糖类,具有抑菌、抗虫、抗氧化和提高动物生产性能的作用,开发出了具有抑菌、增强免疫力等功效的产品。基于目前的文献研究,提出仍需深入研究艾草调控的信号转导通路、艾草的药物代谢动力学参数、艾草的安全性评价以及药物间的相互作用等。该综述以期为艾草的药理机制研究和提高艾草的应用价值提供全面的数据支撑。     

边缘学科与植物次生代谢物质的利用

植物生态学和植物分类学分别向化学或植物化学渗透形成植物化学生态和植物化学分类学。认识植物以次生代谢物为媒介与昆虫、植物与微生物之间的化学生态方面的相关性,有利开发大量有用的天然产品,例如天然防腐剂和天然抑菌剂。在植物化学分类学中,用来作为分类标志的特征性成分往往是植物次生代谢物质。了解这些化合物的分布,可能寻找到相关的植物资源,例如调味剂和增香剂。     

Morphological, histochemical and phytochemical investigation of the genus Hypericum of the Central Italy

Eight entities of the genus Hypericum that spontaneously grow on the Central Italy (Appennino Umbro-Marchigiano) have been studied under the morphological, histochemical and phytochemical aspects. From the morphological standpoint, they differ in the shape and size of flowers and leaves and in the dimension and distribution of the secretory structures through the various parts of the plant. It has been possible, with the histochemical and phytochemical studies, to localize and identify some secondary metabolites inside the secretory structures.