Obituary – Professor Dr. Meinhart H. Zenk

Professor Dr. Meinhart H. Zenk

On July 5th 2011 Professor Meinhart Hans Zenk, a world-renowned plant biochemist, plant physiologist, pharmacognosist and phytochemist passed away in St. Louis, USA, at the age of 78 years. He was born on February 4, 1933, in the Bavarian town of Donauwörth. His father was a teacher. The Second World War had a severe impact on the Zenk family as neither father nor brother survived.

Meinhart Zenk started his scientific curriculum as a student of biology at the Ludwig Maximilians University in Munich. His academic teachers were the botanists Hermann Merxmüller, Otto Kandler and the biochemist and Nobel laureate Feodor Lynen. These scientists offered orientation and were an example to him throughout the early years of his career. The time he spent in the laboratory of Carl Leopold at Purdue University in West Lafayette, USA, set him on course to a career in plant physiology and plant biochemistry. In the early sixties Leo Brauner, who was head of the Botanical Institute in Munich, paved the way for Meinhart Zenk in helping him to establish a radioisotope laboratory in the attic of his institute.

The research of Meinhart Zenk took place at the interface between chemistry, pharmacy, plant physiology, biochemistry and ecology. In this interdisciplinary field he often raised questions from a biologist's point of view. In addition, he mastered a broad range of biochemical, molecular biological, immunological and chemical techniques which won him much admiration of the international scientific community.

In the early sixties of the past century it was believed that secondary natural compounds were waste products which plants dispose of in vacuoles, a view strongly opposed by Meinhart Zenk. The following years witnessed increasing evidence in favor of his opinion and for an ecological function of natural products. In his research he often employed plant cell suspension cultures to tackle unresolved questions of plant metabolism. Without these experimental systems the investigation of indole and isoquinoline alkaloid biosynthesis and the identification of the respective enzymes would not have been possible. The most intriguing question that Meinhart Zenk left us is how it is possible that both plants and mammals are able to synthesize morphine, where, why and under which circumstances morphine is produced and what role it plays in human physiology.

Meinhart Zenk was strongly convinced of Humboldt's principle of the unity of teaching and research. Working in his group was a challenge. However, he never hesitated to acknowledge a successfully completed piece of work. Whenever he was convinced that one of his associates met with the high scientific standards set by him he did not hesitate to support her or his career. Several of his former PhD students now hold chairs in pharmacy, plant biochemistry and plant physiology.

He was honored by election to learned societies in several countries, decorated with highly prestigious medals of scientific and non-scientific institutions, and honorary doctorates from three continents.

Meinhart Zenk was an outstanding scientist and an eminent personality. His work adds splendour to plant science and pharmacy.

His remains are buried on the old German cemetery in Augusta in the vicinity of St Louis, Missouri, USA. Our thoughts are with his wife Toni Kutchan and his daughters Annabelle and Isabelle.

Birgit Draeger, Halle/Saale, Germany
Eckhard Leistner, Bonn, Germany