AHPA Workshop: In which Elan falls in love with Microscopy all over again
When we started the lab 20 years ago, my main job function was cleaning toilets, paying the bills and whatever else needed to be done that an 18 year old still in school could do. Our founder, Sidney Sudberg had just attended several courses held by the FDA on botanical microscopy, which were mostly based around powders and tea cut materials. It did not include much on the art of cross sectioning. He passed the knowledge on to me for my next role of botanical microscopy.
Another special early character in this story is Roy Upton and The American Herbal Pharmacopoeia. While working with them on early monographs we quickly sprouted an herbarium and the capacity to test more botanicals of relevance to the industry. Roy provided us with reference samples that were authenticated using the original techniques, keying out a whole plant in the field as did our friend Carl Linnaeus, organoleptically, many moons ago. Our job was to return to him images of characteristic microscopic features of plants to augment his monographs.
Over the next decade I spent much of my time immersed in microscopy, and the more proficient I became the more I marveled at what a simple yet remarkably effective tool it is.
About 12 years later I was honored with the opportunity to share my skill with the industry by developing and presenting a two day course on botanical microscopy for The American Herbal Products Association. The course I developed was a crash course in microscopic plant anatomy followed by a 1.5 day deep dive into practical botanical microcopy based on my industry experience of testing mostly powders, sometimes tea cut and rarely whole material.
The first class was at The University of Southern California, which was an amazing beginning to a ‘continental tour’ of the course over subsequent years. Next I taught the course at Rutgers University in New Brunswick New Jersey, then two times at Asheville-Buncombe Technical Community College and most recently at Weber State University in Ogden, Utah, twice.
The most recent course, in June 2017, I co-instructed with Marcelo Pace, Ph.D., Peter Buck postdoctoral fellow, National Museum of Natural History, Smithsonian Institution. This one was most special because it was three days long and contained a module on cross sectioning weaved with in the connective tissue of my normal course outline. Before the course my stance on cross sectioning was that ‘I don’t do it’ because maybe 5% of the materials presented to us for microscopic analysis are in tea cut or powdered form. Cross sections obviously can’t work for materials processed beyond the size needed to produce thin slices. Having spent 3 days co-instructing with Marcelo I acquired a new found respect and affinity for cross sectioning of plants, as well as a new friend.
When I analyze powdered botanicals under the microscope, everything I am looking for (trichomes, epidermal patterns, type of stomata etc.) is mostly discombobulated and floating aimlessly in a chaotic micro flood of clearing reagent. Once the fragments settle, key microscopic features (trichomes, epidermal patterns, type of stomata etc.) can be identified to culminate a positive ID. I really enjoy the puzzle/art of putting these little pieces together to tell the story of Genus and species as well as plant part and adulterant.
With cross sectioning, the art begins from the preparation of the samples. Once they are softened via boiling in various solutions, the hard part is presented where you can either slice the end of your finger off or get a beautiful 2 cell thick cross section of a root. Apply some dye, wash with water and voila! Frozen in time, only a few cells thick, and dyed based on structure and function, is the anatomy of a root or leaf or fruit. It’s really extraordinarily beautiful, and tells us so much about that sample.
As the AHPA newsletter described it: “In order to study the structural organization of the plant body, sections and surface preparations are made so that enough light can be transmitted through the specimen to resolve cell structures under the microscope. Sectioning preserves the structural relationships between individual cells, which provides insights into the plant’s anatomy and identification. Attendees gained hands-on experience with plant sectioning, surface preparation, and microscopic analysis of plant parts and powders. Through these processes, attendees became familiar with the characteristic cellular features of each plant part examined and the basic structures of various tissue types. About 30 of the most widely used botanicals in the herbal and supplement industries were explored. Attendees left the workshop with a better understanding of plant anatomy and the experience necessary to confidently conduct microscopic analysis on botanical materials. Microscopy remains an important tool for both the identification and authentication of botanical materials. Of all the analytical methods, microscopy is one of the most rapid, revealing, cost-effective, and environmentally sound technologies available.”
I’m aware that most people are not as obsessed as I am with this kind of thing, but there is something inspiring about experiencing what I spend so much time doing through a different lens.
Alkemist Labs CEO
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