L. A. Mitscher

Bio: L. A. Mitscher is an academic researcher from Ohio State University. The author has contributed to research in topics: Mycobacterium smegmatis & Thalictrum. The author has an hindex of 3, co-authored 3 publications receiving 35 citations.

Antibiotics from higher plants. Thalictrum rugosum. New bisbenzylisoquinoline alkaloids active vs Mycobacterium smegmatis

Abstract: Extracts of Thalictrum rugosum were found to be reproducibly active against mycabacteria, the active agents were isolated, and four were identified to be bisbenzylisoquinoline alkaloids of known and unknown structure.

Identity of RW-47 and venoterpine and determination of their absolute configuration

Abstract: RW-47 und Venoterpin sind identisch. Die absolute Konfiguration ist durch ORD-CD, Vergleiche mitl-(−)-actinidin ableitbar.

Antibiotics from higher plants. Thalictrum rugosum. Thalrugosamine, a new bisbenzylisoquinoline alkaloid active vs mycobacterium smegmatis.

Abstract: Charakterisierung und Strukturaufklärung eines neuen Alkaloides, Thalrugosamin ausThalictrum rugosum.

Antimicrobial Agents from Higher Plants

Abstract: The modern antibiotic era can be said to have opened on February 12, 1941, with the first clinical trial of penicillin. Within a couple of years man had at last, after eons of adventitious searching, a truly effective and safe agent for the treatment of many systemic bacterial infections. This was shortly followed by the introduction of one after another of the major antibiotic substances which remain the mainstay of clinical therapy of infectuous diseases to this date. Intensive screening of fermentation liquors derived from various microbes, principally fungi and streptomycetes, has resulted in literature descriptions of more than 2,000 Individual antibiotics to date, and It has been estimated that more than 20,000 analogs of 6-amino- penicillante acid alone have been made by chemists working tn close collaboration with biochemists and microbiologists. Several of these substances are currently on the market.

Chapter 1 Allelochemical Properties or the Raison D'être of Alkaloids

Abstract: Publisher Summary This chapter provides evidence that alkaloids are not waste products or functionless molecules as formerly assumed, but rather defense compounds employed by plants for survival against herbivores and against microorganisms and competing plants. These molecules were developed during evolution through natural selection in that they fit many important molecular targets, often receptors, of cells, which are seen in molecules that mimic endogenous neurotransmitters. The chapter discusses that microorganisms and herbivores rely on plants as a food source. Since both have survived, there must be mechanisms of adaptations toward the defensive chemistry of plants. Many herbivores have evolved strategies to avoid the extremely toxic plants and prefer the less toxic ones. Many herbivores have potent mechanisms to detoxify xenobiotics, which allow the exploitation of at least the less toxic plants. In insects, many specialists evolved that are adapted to the defense chemicals of their host plant, in that they accumulate these compounds and exploit them for their own defense. Alkaloids function as defense molecules against insect predators in the examples studied, and this is further support for the hypothesis that the same compound also serves for chemical defense in the host plant. It needs more experimental data to understand fully the intricate interconnections between plants, their alkaloids, and herbivores, microorganisms, and other plants.

Antimicrobially Active Alkaloids

Abstract: Plants produce a broad variety of natural products. The data bank NAPRALERT listed about 88,000 natural products in 1988, of which about 16,000 were alkaloids. These so-called secondary metabolites most likely play a role in the interaction of the plant with its environment, e.g., to defend the plant against microorganisms or various predators. In the former case the plant secondary metabolites concerned are expected to have an antimicrobial activity, i.e., the phytoalexins. Phytoalexins are low-molecular-weight compounds, which are synthesized and accumulated in the plant after microbial infection (Paxton, 1981). Among the compounds recognized as phytoalexins are some alkaloids (reviewed by Kuc, 1992; Whitehead and Threlfall, 1992); however, the number of alkaloids that have been shown to possess antimicrobial activity is in fact much larger. There has long been an interest in screening plants and the derived natural products for biological activity, with the aim of producing new drugs. Since ancient times man has been using plants to treat all kinds of diseases. As infectious diseases are easy to diagnose, and the effects of an antibiotic can be observed clearly, it is likely that many traditional medicines have useful biological activity. Screening such plants has indeed shown that the incidence of antimicrobial activity found is much higher than for a random screening (e.g., Dorn-berger and Lieh, 1982; Elmi et al, 1986; Le Grand et al, 1988; Mitscher et al, 1987; Verpoorte et al, 1982b, 1983a). Studies of antimicrobially active plants have resulted in identifying many alkaloids that have such activity.