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Raphael Ikan (9 July 1927 - 21 July 2013). Scientist. Professeur of organic chemistry.
In 1938, during the "Stalinist" period, his family managed, rarely, to leave the Soviet Union to visit family members in Palestine. They arrived in Israel as tourists without a resident visa. After extending their stay, World War II broke out and they became permanent residents. In 1943, he started studying at the an evening Gymnasium and worked during the day to help the home economy. He worked in the physical chemistry department of the Hebrew University. The head of the department was Professor Ladislav Prakash. This was during the British Mandate period in Israel and his main occupations were to make mercury interruptors for the British Air Force and to renovate transmission lamps. The connection that was established in those days with the subject of chemistry is that it outlined its way to chemistry studies at the Hebrew University. He was a "defensive" member. He was drafted into the IDF during the War of Independence. After three years of service, he began his studies at the Hebrew University. He did his dissertation under the guidance of Prof. Ernest David Bergman, in the Department of Organic Chemistry. In 1958, he was a postdoctoral fellow in Glasgow, Scotland, at Strathclyde University. He spent more than two years as a researcher at Yale University in the United States, where he researched marine materials, and for many years was invited as a visiting professor at UCLA and UNAM, Mexico, and served as a scientific advisor for chemical research at the Foundation for Research and Initiation. Of the National Research Council And for development near the Prime Minister's Office, which allowed him to take a closer look at research and development areas that were being conducted at that time in Israel and around the world.
Science Education
Prof. Ikan became known for his passion not only for science but for instilling this subject for the younger generation. At the same time as his scientific research and his extensive teaching experience, he assisted with his assistants to lecture and instruct in the science-based youth chemistry lab. The participants actually learned a variety of material that opened up new and interesting science avenues. Many "science-savers" have become prominent students over the years in their achievements in the Faculty of Natural Sciences. Furthermore, Prof. Ican, who at one point was appointed head of the Division of Natural Sciences at the Hebrew University's Student Abroad School, saw the reception of young Jewish scientists from abroad in Israel as a real mission. Indeed, following the courses they took as part of the School of Overseas Students, many of them continued their studies at Israeli universities. To facilitate students from abroad, he prepared a special dictionary in five languages containing terms related to the natural sciences and mathematics.
He was a member of the systems of the following scientific papers: "Looking", "Nearly two thousand", Chemistry in Israel. He also served as a scientific editor and reviewer for encyclopedias, including the "chemistry" of the "science" encyclopedia published by Masada; He also co-authored the values of chemistry with Dr. Vera Weinstein for "General Israeli Encyclopedia," published by "Keter," and also wrote a review of state-of-the-art methods for identifying organic materials together with Dr. Bernard Kramer for the Encyclopedia of Physical Sciences and Technology. He was among the editorial staff of the International Scientific Journal Organic Geochemistry and also wrote two entries in the Hebrew Encyclopedia.
For years he served as editor of "The Chemist in Israel", in the Israeli Chemical Society's Township. He also published Hebrew articles on various chemical and interdisciplinary topics in popular scientific papers such as "Science" and "Knowledge," published by the Weizmann Institute for Publications in the Natural Sciences and Technology.
In 1991, he served as chair of the National Conference on Chemistry that took place during the First Gulf War. It was the only conference not canceled due to the war. In 1996, he chaired the first international conference of sweeteners in Jerusalem, attended by scientists from 15 countries.
Selected Studies
The research carried out in his laboratory over the years has been many and varied, some of them interdisciplinary, dealing with the following topics: Energy - The studies were in shale oil, marine algae and humic substances. Organic geochemistry The studies dealt with biological signs. Insect pheromones such as ants, beetles and beetles and rodents and especially Marion are found, essential oils in Israeli plants. Identification and enrichment of the wine aroma, natural sweeteners, and, as noted above, from the plant Stevia Rabodiana and anticoagulants of blood. All the studies were done in collaboration with renowned scientists from the Faculty of Agriculture, the Department of Zoology, the Dead Sea Works, the Ministry of Agriculture, the Neve Yaar Experimental Station, the Department of Physiology and Pharmacology at Tel Aviv University and the Hematology Department at Ichilov Hospital. Some of the topics explored in his lab were topics for researchers who did their dissertation under his guidance. In addition, there was a scientific collaboration between Prof. Ican and Dr. Pimsmeran of Kun Kane University in Thailand on the study of monotrophs of lipid plants and their potential activity as insecticides. Ican, in collaboration with a team of researchers in his laboratory and botanical garden, researched the stevia plant in the early 1980s. They found that the sweetener is in the leaves and that its sweetness is 250 times greater than sucrose and that it is resistant to acidic conditions and high temperatures and can therefore be used for sweetening beverages, cooking and baking, and today stevia is a healthy substitute for sugar and is sold in almost every supermarket.
Under his guidance, 10 doctoral students and 30 graduate from the natural sciences.
Sweeteners from plants The ongoing search for sugar substitutes has led to the discovery of low caloric synthetic sweeteners such as saccharin and cyclamate which possess high sweetening intensity. They possess, however, an unpleasant aftertaste. It has been reported that the Indian triibes of Paraguay have been using the leaves of a local shrub Stevia rebaudiana for sweetening purposes. In order to explore the possibility of culturing this plant in the Botanical Gardens of the Hebrew University, we discussed the matter with Dr. Michael Avishai and Mr. Yechiel Baras who succeeded in growing it in the botanical garden. We have found that the leaves contained 10-15% of a mixture of sweeteners, stevioside being the major one, its sweetness was 250 higher than sucrose. An American Research and Development Company (headed by Mr. Vary from Los Angeles and Mr. Yosef Tkoa, a local manager) have financed the "sweet project". The agrotechnical know-how of this project was transferred to Mr. Dan Ulman of Kibbutz Geivim (near Ashqelon) who succeeded in culturing the Stevia and the closely-related substances is that it is stable in acidic pH as well as high temperatures, thus making it useful for food and beverage industry and domestic use. A patent application on the isolation of pure stevioside has been submitted to the Israeli Patent Office. A pilot plant scale production of the sweeteners from the dry leaves of Stevia rebaudiana was carried out in the plant of the Casali Institute for Applied Chemistry of the Hebrew University, headed by Eng. Tom Kovari. The research team of the sweet project included Dr. Vera Weinstein, Dr. Bernard Crammer and Mrs. Ora Haber. Recently we have developed together with Prof. Yoram Milner an efficient enzymatic transformation of stevioside into rubusoside which possesses a better taste. This method was also patented via Yissum R & D Company of the Hebrew University. Recently the natural sweetener was sold in natural stores (in the form of tea bags) and was well accepted by the customers. So far no final approval of the Health Authorities has been granted. It seems that soon stevioside will be used by diabetics and the general public worldwide.
Pheromones Pheromones are organic compounds located mainly in special glands of animals and also in plants. They function as simulants of sexual activity. They are being excreted from as special glands in the animal body and thus elicit chemical communication in the individual of the same species. Of special interest are the insect pheromones. The attraction of the bees to their queen is due to the "queen substance" which is isolated in her mandibular glands. Chemical identification of the pheromones and their synthesis may be used for the cradicatioe of agricultural pests by using "sex traps" containing the appropriate pheromones of the particular pest. This species-specific approach is superior to the use of poisonous insecticides which partially penetrate our food chain. In a cooperative research with the team of Prof. Aaron Shulov of the Entomology Department we succeeded in isolating the pheromone of the Khapra beetle. Trogoderma grnarium, which inflicts heavy damage to grains in storage.
In a cooperative research with Prof. Yaacov Ishay from the Department of Pharmacology and Physiology of Tel Aviv University, we have performed a comprehensive research on the social life of the Oriental hornet, Vespa orientalis. We have isolated and identified the queen pheromone from the mandibular glands of the queens, which was different from the queen-substance of the honey bees. Later we succeeded in synthesizing this pheromone, which had similar biological activity as the natural one. The queen hornets were collected in the Ein-Gedi area by a member of the Kibbutz, "the big mustache Charlie". In an exhaustive research, Prof. Ishai and our team have observed unique behavior of the members of the hornet nest especially the strong dependence of the members on the larvae which is capable of producing glucose from proteins (gluconeogenesis). The extraordinary behavior was published by Prof. W.O. Wilson from Harvard University in his excellent book titled "The Insects of the life of Vespa orientalis. This venture was kindly supported by Prof. Alex Polyakoff from the center of Science Teaching of the Hebrew University.
The investigation on the behavioral and physiological aspects of the oriental gerbil. Mariones tristrami, was carried out by Ron Kagan in his Master's and Doctorate theses in the frame of a cooperative research of Profssors Shulov and Yaacov Marder of the Entomology and Zoology departments, respectively, and by my team. The gerbil is known to cause heavy damage to agricultural products and trees. It has been observed that the pheromone is being released by the gerbil from a special ventral sebaceous gland located in the lower part of his abdomen by touching slightly the soil during his motion. This pheromonal trail effects sexually the female. We have isolated , identified and synthesized the multiple pheromone which was biologically identified with the natural product' by using three-choice digital olfactometer.
Organic Geochemistry The special feature and goal of Organic Geochemistry is to isolate organic constituents in the geosphere and thus reveal the fate of organic matter which was buried in marine and terrestrial environment during geological periods of millions of years and its contribution to the formation of fossil fuels. I became interested in this exciting area when I spent a year as a postdoctorate fellow in the Royal College of Science and Technology in Glasgow.
During the years 1972-1974 I was a visiting professor in the Institute of Earth and Space Science, University of California, Los Angeles, department of Geochemistry; headed by Prof. Isaac Kaplan. Our main research topic was a laboratory-simulated thermal process for generating petroleum-like products from a young marine California sediment. We succeeded in isolating various organic constituents which originated from a thermal transformation paths of chlorophyll and other natural molecules which were present in the marine sediment. We have proposed detailed chemical transformations of bio- into geo-organic molecules some of which are present in petroleum. Our research supported the theory that the origin of petroleum is mainly from marine biomass (plankton).
Aroma enrichment of wine. It has been known that monoterpenes and other organic constituents are responsible for the aroma of wine, During our joint research with Prof. Ben-Ami Bravdo, Dr. Oded Shoseyov, Mr. Dany Segal and Prof. Ilan Chet from the Department of Horticulture. Faculty of Agriculture, Rehovot, we realized that monoterpene glycosides are the "hidden" aroma in grapes and wines. The main object of our research was to find a unique enzyme for cleaving the glycoside bond and thus releasing free terpenes. We have isolated a β-glucosidase from Aspergillus niger which cleaved the glycosidic bond even in solutions of high sugar and alcohol concentration. It was immobilized on a polymeric support and is used efficiently for the enrichment of wine aroma. This discovery was patented worldwide and many companies have expressed their interest in this process. This research was supported by BARD.
Optically active terpenes from essential oils. Essential oils are volatile constituents of plants. They are used as flavoring agents in food and as odorants in cosmetics. Our joint research with Dr. Uzi Ravid and Dr. Eli Putievsky from the Newe Ya'ar Agricultural Experiment Station where spice and medicinal plants are grown. Various essential oils were isolated from plants. Terpenes of these oils were isolated and their enantiomeric composition detected by a new method "nuclear magnetic resonance polarimetry". Since the biological activity depends on the optical activity of terpenes, this method will be most useful in industry and in detection of adulteration of these compounds in various food and cosmetic products. Recently a joint research was initiated with Dr. Supance Pimsamarn from Kohn Kaen University, Tailand, on the essential oils of the Labiatae family and their use for insect eradication.
My teaching duties include lectures and laboratory experiments on the chemistry and biosynthesis of natural products. I also initiated a course on organic microchemistry. Both courses are very popular and well accepted by the students. So far 10 Ph.D. and 15 M.Sc students have completed their studies under my supervision.
Other scientific activities
For many years I used to be a consultant to the National Council of Research and Development (NCRD) in the Prime Minister's Office. Thus I had an opportunity to get insight into the chemical and interdisciplinary research topics which were performed in Israel. For several years I was engaged as a scientific head of the Sciences in the School for Overseas Students of the Hebrew University, where two main programs are taught. The One-Year program for American students Four-Year program for students from all countries. In accordance with the request of Mr. Avraham Herman and Prof. Nathan Roteshtreich, I was asked by Prof. Mordechai (Moca) Abir to plan and promote a special science program for the one-year students. For this purpose I "shuttled" in the USA in many universities for promoting the new science program which was accepted enthusiastically by the students. Recently, about 1000 students are studing in the School for Oversease students, about 25% are science students. A few years ago I initiated a special course titled "Science and Technology in Israel for the summer courses of the school of Oversease Students, directed by Mr. Yoel Nesson and his associates. Science Youth
The initiator of the special science courses for youth in the University was Prof. E.D. Bergmann. Following his idea, we conducted lectures and laboratory courses in chemistry for high school students. These enrichment courses are favorably received by the participants. during the summer vocations. American students also participate in these science courses together with the Israelis.
Scientific Publications
Encyclopedias
A 4 volume encyclopedia (in Hebrew) titled "The General Israeli Encyclopedia" was published by Keter Publishing House. The chemistry parts were written by Dr. Vera Weinstein and myself. 2. I have edited a special chapter on Chemistry which was published by Massada (in Hebrew) in the Science series. 3. Together with Dr. Bernard Crammer. I have written a chapter titled Organic Chemistry compound detection" which was published in volume 10 in the 15 volumes "Encyclopedia of Physical Sciences and Technology" by Academic Press. Author of Chemistry in Israel Encyclopedia Books
The following books have been published by Academic Press:
Natural Products, a Laboratory Guide . R. Ikan, 1976, (2nd edition in 1991) Chromatography in Organic microanalysis, R. Ikan, 1982 5 Language Dictionary of Scientific Terms. R. Ikan and Y. Ikan, Academon, 1980 (2nd edition published, R. Ikan, Y. Ikan and V. Weinsteinin 1990). Chemical Lexicon (in Hebrew) R. Ikan and J. Seckbach, Zemora-Bitan Publishers.1991 second edition 1999 Chemistry Today (in Hebrew) by R. Ikan and Y. Ikan , keter Publishing House. 1990). The Maillard Reaction, edited R. Ikan, John Wiley & Sons1996 Naturally Occurring Glycosides, edited R. Ikan, John Wiley & Sons Natural and Laboratory -simulated Thermal Geochemical Processes, Kluver Academic Publishers, 2002 Selected Topics in the Chemistry of Natural Products, edited R. Ikan, World Scientific. 2005 He published 150 scientific publications in international scientific journals and tens of articles in Hebrew in Israeli journals.
Was a member of the Editorial Board of an international journal "Organic Geochemistry" published by Pergamon Press, since 1988.
1995-1988 was the editor of the "Israeli Chemist", a bulletin of the Chemistry Society.
Occasionally published popular science articles (in Hebrew) in local journals such as Mada and Lada'at which were published by the Weizmann Press.
Also was a scientific consultant of the quarterly "Mabat" edited by Dr. Devora Gertz, Mira Mechoulam and Hana Bernholtz and published by the Science Teaching Center of the Hebrew University.
1995-2000 Was in the Editorial Committee of the journal "almost 2000"
1951-1954 Chemistry graduate from the Hebrew University in Jerusalem
1954-1958 Phd in Chemistry
1958-1959 Post Doc, University of Strathclyde, Glasgow, Scotland
1959-1961 Post Doc, Yale University, New Haven, connecticut
1972-1974 Visiting professeur UCLA
1976 UNAM
UCLA1989,1994,1995
Academic rolls in Israel
Since 1960, a member of the Israeli Chemical Society
1991 organizer and chair of the national conference of the Israeli Chemical Society at the Hebrew University
Starting in 1994, a full member of the British Royal Society of Chemistry
Since 1995 Member of the New York Academy of Sciences
1996 Organizer and Chair of the First International Sweeteners Conference in Jerusalem
2001 Chair of the Organizing Committee of the 2nd International Sweeteners Conference in Hiroshima, Japan
Member of the newspaper system 1987-1995
2000 Member of the American Science Encouragement Association
1995-2000 Member of the "almost two thousand" system
From 2002 the "Chemistry with the World" editor in the "Chemistry" quarter
Editor of steroid and carotenoid entries in the Hebrew Encyclopedia.
Editor of Chemical Values in General Israeli Encyclopedia published by "Keter"
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