O’Shaughnessy’s • Winter 2015/16 —15— Appendino’s Advice to Cannabinoid Researchers: Consider ‘New Targets, Chemistry, and Plant Sources’ By Ryan Lee and O’S News Service “Natural Selection Works Like a Tinkerer...” The International Cannabinoid Research monoterpenes (limonene, pinene, linalool, Society held its 24th annual meeting at a terpinolene, et al). lakeside hotel in Baveno, Italy, in June The 15-carbon sesquiterpenes such as 2014. ICRS members are mainly —but beta-caryophyllene, differ from the mono- not exclusively— university-connected terpenes by the incorporation of an extra biochemists and pharmacologists investi- isoprene unit. (β is the Greek letter beta.) gating how things work at the sub-cellular level. When Cannabis is dried, stored Baveno is a resort town on big, beauti- for periods of time, or made into ful Lake Maggioro, with the Alps visible extracts, the monoterpenes are gen- to the north. There were four days of talks erally first to evaporate. The sesqui- describing recent studies, and sessions at which investigators answered questions terpenes like β-caryophyllene are about their findings as summarized on more likely to remain. posters. When the ICRS was founded in 1990, Monoterpenes are more volatile —they its original name was “International Can- evaporate at lower temperatures— so when nabis Research Society.” In 1995 —after Cannabis is dried, or stored for periods of the body’s own cannabinoid receptor sys- time, or made into extracts, the monoter- tem had been discovered and elucidated by penes are generally first to evaporate. The ICRS members— the group changed the sesquiterpenes like β-caryophyllene are C-word in its name to “Cannabinoid.” As more likely to remain. pharmacologist Dale Deutsch explained in β-caryophyllene seems like the Cannabis plant’s own perfect key for nature’s CB2 1998, “The field is moving away from the LEAVES THAT RESEMBLE CANNABIS SATIVA are (top row, left to right): Acer japonicus, Ac- lock. Plants use β-caryophyllene to defend plant.” onitum vulparia, Geranium pratense. Bottom row, left to right: Hibiscus cannabinum, themselves against predators. Some spe- The 2014 ICRS meeting marked the re- Vitex agnus-castus, Cannabis sativa. Graphic from “Plantes interdites. Une histoire cies up-regulate specific terpenes when turn of the plant to the forefront of the field. des plantes politiquement incorrectes,” by Jean-Michel Groult. Appendino quoted attacked by herbivores to render the plant Neurologist Ethan Russo was serving as the French scientist Francois Jacob in connection with this slide:: “Natural selection less palatable to the attacking insect. ICRS president (the job is held for a year), works like a tinkerer who does not know exactly what he is going to produce, but In a beautiful demonstration of the web and he invited the Italian natural product uses whatever he finds around him to produce some kind of workable object. None of that Mother Nature has created, these same chemist Giovanni Appendino to give the the material at the tinkerer’s disposal has a precise and definite function. Each can terpenes have been shown to recruit para- featured talk at the meeting in Baveno. be used in different ways. Novelty comes from previously unseen association of old sitic bugs that themselves attack the herbi- Appendino, a professor at the Università material. To create is to recombine.” del Piemonte Orientale, noted proudly that vores that are eating the plant! he is from Carmagnola, a northern Italian reminded his ICRS audience. also impede legitimate scientific research. town renowned for its fiber hemp variety In the course of screening more than 200 After two years of bureaucratic red tape, The drive to breed high-yielding of the same name. varieties of fiber hemp, Appendino and Appendino was only able to obtain a small varieties of corn for intensive Appendino first published research in the colleagues have found significant quanti- vial of extract from the plant. Being unable cannabinoid field in 2002, when he was co- ties of obscure compounds whose medical to obtain seeds themselves has limited his commercial agriculture sacri- author of a paper on “Noladin ether —a pu- potential he considers “worthy of investi- ability to investigate the biosynthetic path- ficed the ability of the plant to tative endocannabinoid.” (The lead authors gation.” ways by which Helichrysum produces can- produce β-caryophyllene . were Raphael Mechoulam and Vincenzo nabinoids. DiMarzo.) But Appendino’s “relationship Cannabinoids are not unique to Appendino discovered that cannabinoid- Appendino recounted how the wild, an- with cannabis as fiber hemp” goes much like compounds are made by plants “apart Cannabis —they have been found cestral relative of corn, teosinte, grown by further back: “My grandfather was grow- from the normal cannabinoid biosynthetic the Mayan and Incan farmers in pre-Euro- ing it and the odor of hemp retting tanks in other plants. route. There is a new pathway that starts pean Central and South America, produced was filling the air around Carmagnola dur- from an aromatic acid.” Referred to as the significant amounts of β-caryophyllene ing the Fall.” He touched briefly on canniprene, the “Helichrysum cannabinoids,” these com- before modern breeders selected towards cannflavins, cannabinoid esters, and “ses- pounds also have been detected in liver- high yielding corn with an increased sugar By defining cannabinoids as qui-CBG,” which Appendino’s group iso- wort. content. The drive to breed high-yielding lated from a fiber hemp variety. drugs that work at the CB1 and Helichrysum is used in African ethno- varieties of corn for intensive commer- Appendino has encountered a hemp vari- pharmacology, Appendino explains, “like cial agriculture sacrificed the ability of the CB2 receptors, researchers may ety containing two percent canniprene —a hemp, to make fumes in ritual ceremonies” plant to produce β-caryophyllene . Cannabis be overlooking beneficial com- compound he called “the version and that a “psychotropic effect... similar to That β-caryophyllene binds specifically of resveratrol” (a beneficial compound cannabinoids,” might ensue. to the CB2 receptor (which is found main- pounds in Cannabis that work by present in red grapes). other mechanisms. ly outside the central nervous system) was From others varieties Beta-caryophyllene reported by Jürg Gertsch at the 2007 ICRS he isolated the prenyl- Terpenoids, the largest class of naturally Researchers have focused almost ex- meeting. ated version of cannab- occurring compounds on the planet, are clusively on THC, CBD, CBC (canna- igerol —meaning CBG the chemicals that give plants their unique bichromene) and CBG (cannabigerol, pre- The CB2 receptor attached to a prenyl group (illustration at smells and flavors. Found in high concen- cursor to the other three), Appendino said, The CB2 receptor has yet to be success- left). There is no reason, Appendino said, trations in many culinary herbs and spices, while not investigating the therapeutic po- fully exploited by the pharmaceutical that marijuana should not also produce the terpenes not only provide flavor and scent, tential of related molecules present in Can- industry, Appendino said. “If drug dis- prenylated version of THC —which would they are also important signaling chemi- nabis —and other plants as well. covery is a sea, then CB2 is a rock that is have distinct biological activity. cals that plants use to communicate with Similarly, by defining cannabinoids as surrounded by shipwrecked-projects,” he insects. drugs that work at the CB1 and CB2 recep- Cannabinoids not unique to Cannabis commented poetically. Terpenes are synthesized by the plant tors, researchers may be overlooking ben- Cannabinoids are not unique to cannabis Pharmaceutical companies have spent from five-carbon isoprene units, two of eficial compounds in Cannabis that work —they have been found in other plants. which come together in specialized cel- continued on next page by other mechanisms. “Nature has varied Appendino reported that a large amount of lular compartments to form the 10-carbon on the cannabinoid structure,” Appendino CBG and its carboxylic precursor had been isolated from a specific He- lichrysum variety found only in South Africa. Studying how Helichrysum makes “non-cannabis” CBG and its related compounds has been difficult for Ap- pendino and his colleagues, alpha-pinene beta-pinene limonene βeta caryophylllene because strict South African TERPENOIDS are categorized in terms of how many 5-carbon bio-piracy laws prohibit the units they contain. Three molecules at left are monoter- collection and export of na- penes —each contains 10 carbon atoms. Larger molecule tive species or their seeds. at right, β-caryophyllene, is a sesquiterpene with 15 carbon HELICHRYSUM UMBRACULIGERUM, a daisy na- These laws, designed to atoms. Because β-caryophyllene is heavier than the mono- tive to South Africa, produces cannabigerol prevent foreign corporate terpenes, it evaporates less readily and is often present in TEOSINTE, THE ANCESTOR OF CORN was tiny but (CBG). It was identified by Ferdinand Bohl- exploitation of the country’s relatively large amounts in dried Cannabis. (But not all rich in beta-caryophyllene. The cob in this mann and Evelynn Hoffmann in 1978. unique genetic resources, Cannabis produces large amounts of β-caryophyllene.) photo is two inches tall. —16—O’Shaughnessy’s • Winter 2015/16 ICRS from previous page large sums investigating proprietary synthetic CB2- selective compounds that end up showing little clinical effi- cacy. “But β-caryophyllene is a special lottery ticket,” said Appendino. β-caryophyllene is known to be anti-inflammatory and easy on the stomach lining. A special lottery ticket, indeed! So grind some black pepper on your next salad, and order CANNABIGEROL (CBG, top left) is the compound in Cannabis from which other plant cannabi- those Echinacea and mari- noids are synthesized. Molecule at bottom left is sesqui-CBG, which has been identified in fi- gold seeds now —they all ber hemp It consists of CBG plus a five-carbon pentyl tail (at right in illustration).