NEWS
Publications of 2019 – Invited review in NPR
After a while not posting for too many reasons, we start 2020 including the activities of 2019 which have not been mentioned here. The first is the review “Approaches for the isolation and identification of hydrophilic, light-sensitive, volatile and minor natural products”, published in Natural Product Reports. This was an invited review by the guest editors Julia Kubanek (School of Biological Sciences, Georgia Institute of Technology), Hendrik Luesch (College of Pharmacy, University of Florida) and Roger Linington (Department of Chemistry, Simon Fraser University).
The co-authors were all post-doctoral researchers (Afif Monteiro, Juliana Gubiani, Luciane Tonon), PhD students (Ariane Bertonha, Darlon Bernardi, Vitor Freire) and MSc students (Lamonielli Michaliski, Juliano Slivinski and Vitor Venâncio). Collecting the bibliography was somewhat a challenge because in most cases finding articles dealing with water-soluble or hydrophilic and light-sensitive compounds is difficult. In many cases, there are no keywords related to these particular features, what is different for volatile compounds. It was a detective work.
Here is the picture of the original graphical abstract. Alcatrazes island is photographed behind the Petri dish. It is a very beautiful location where we have collected a couple of times in the past.
Preparing the manuscript was truly a team work, that also included a critical revision by Dr. Camila Crnkovic (see the acknowledgments). We very much thank Professors Kubanek, Luesch and Linington for the opportunity in preparing the review for the special issue of NPR on “New methods for isolation and structure determination of natural products”. We also thank the RSC editorial team for the support during the preparation of the review.
We hope the readers will enjoy reading it here.
Professor Koji Nakanishi in Brazil
This post had to be written a while ago.
Professor Koji Nakanishi’s death meant very much to the natural products chemistry community. Needless to say, his achievements are beyond words. Two of the perhaps less-known facts of Professor Nakanishi’s career are worth of mention.
The first is his 1962 book on infrared spectroscopy, with a foreword by Professor Carl Djerassi. I was lucky in finding this book in an Ann Arbor (Michigan) old books bookstore. It is perhaps one of the best books on infrared interpretation ever written.
The book opens with an impressive statement:
“The infrared spectrum (IR) is said to be one of the most characteristic properties of a compound”.
Who would ever think in IR nowawadys representing a specific feature of an organic compound? Professor Nakanishi’s thought has to be placed in a historical context, and represents a truth until today. The fact is that IR data is very often considered of minor importance, and frequently recorded with not much care, even if state-of-art Fourier transform-based instruments are currently available. But the fact is that IR data remains a unique feature for each organic compound. Even if very similar compounds can be hardly differentiated by analysis of IR data, IR spectra of very similar, but not identical, organic compounds are distinct. The structure of sebastianine B, for example, needed a good quality IR spectrum to be completely elucidated in 2001.
The book has extensive and very well organized tables of IR functional groups. A plethora of examples are discussed in detail for relevant IR absoprtions. Very useful for teaching purposes, the book includes a set of 85 problems with answers and all the spectra included are of excellent quality.
The second story is that Professor Nakanishi visited Brazil in 1996. And I was also lucky in meeting and talking to him in person. He came to participate in a meeting to discuss a very challenging endeavour – the proposal to setup the PROBEM program in the Amazon forest, a program to explore the forest chemistry for biodiscovery.
I don’t know the details on how the meeting in Brasilia, Brazil’s capital, was organized. I went as an invited observer. Among many scholars, Professor Nakanishi and Professor Jerry Meinwald were invited as advisors. Since I knew in advance that he was coming, I took with me my copy of Professor Nakanishi’s autobiography, “A Wandering Natural Products Chemist”. He was extremely kind to sign it for me, for which I was very grateful. I remain inspired by him and his achievements. Rest in peace, Professor.
Anti-malarial natural and synthetic bromopyrrole alkaloids
One project whose results were published in 2018 and has not been mentioned here was the discovery of anti-malarial activity of pseudoceratidine and synthetic derivatives. This project started some years ago when a MSc student Ivan Severo started to work on a sample of the sponge Tedania brasiliensis, endemic to Brazil, and isolated pseudoceratidine. Unfortunately Ivan left the group before finishing his MSc dissertation. Afterwards, a new PhD student, Lorena Parra, took the project and developed it with great enthusiasm. Lorena did a very fine and careful isolation work and discovered a series of pseudoceratidine derivatives with varied bromination at the pyrrole groups. She also discovered unprecedented modified pseudoceratidine derivatives that we named tedamides. When the first results of bioassays were available, a new PhD student joined the group, Ariane Bertonha. Ariane had a previous experience on organic synthesis during her MSc degree. We then agreed for her to develop a project on the synthesis of pseudoceratidine derivatives in collaboration with Professor Daniel Romo’s group at Baylor University. Ariane was awarded with a Science without Borders scholarship to spend 11 months at Professor Romo’s group, where she prepared 20 pseudoceratidine derivatives. This collaboration was extremely fruitful after we got the complete results of bioassays performed by Dr. Danilo C. Miguel (on anti-Leishmanial activity, Biology Institute at UNICAMP), Prof. Fernanda Gadelha (on anti-Trypanosoma cruzi activity, Biology Institute at UNICAMP) and Prof. Rafael Guido (on anti-malarial activity, Physics Institute at São Carlos, USP). This was a true interdisciplinary project involving natural products chemistry, synthetic chemistry and biology, thanks to the great team involved. We are particularly grateful to Professor Daniel Romo for hosting Ariane at his group. The results have been reported in a paper published last year in the Journal of Natural Products. If you are interested in the article, please read it and check the Supplementary Material including isolation and synthesis data.
This is Tedania brasiliensis, a beautiful red-pink sponge with large oscula. The photo was taken by our sponge taxonomy collaborator Professor Eduardo Hajdu (Museu Nacional, UFRJ)
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