CBD - 180/356
CBN - 185/365
CBC - 220/428
d-limonene - 177 / 351
ß-caryophyllene - 119 / 246
ß-myrcene - 168 / 334
a-pinene - 156 / 313
Analytical Chemistry - The area of chemistry concerned with measuring the various aspects of chemicals in a sample. Determining the cannabinoid content of cannabis requires requires application of analytical chemistry.
Know Your Alcohols: Ethanol (CH2OH) is the ONLY consumable alcohol. Poisonous methanol has the chemical formula CH3OH, smells sweet and is often superior to Ethanol for extractions due to it's higher polarity and lower viscosity. Drinking methanol (MeOH) leads to blindness and death. Isopropyl alcohol (IPA) is rubbing alcohol (CH3)2CHOH).
There are endless kinds of alcohols. We can consider water a type of alcohol and water is known to organic chemist as the "Universal Solvent". Most kinds of salts dissolve in water. Cannabinoids are not salts and only barely soluble in cold water, but they are somewhat soluble in alcohol/water mixtures.
How Satellites Spot Cannabis Plants
Satellites can measure differences in the intensity and exact color of light reflected by plants. Each species has a unique signature and satellites can automatically sift through images and flag them for human inspection. Consider also that the same technology could done with infrared data toward buildings despite the invasion of privacy. A warmer building amongst a group of cooler buildings may flag the image, analogous to utilities companies reporting high electricity usage vs. peers.
Glandular trichomes contain most of the cannabinoids and essential oils responsible for therapeutic effect, aroma & flavor.
The information on Cannabis-Science.com is for educational purposes only.
To measure cannabinoid content one must first separate them from a liquid mixture that contains all the other extractable oils. This separation is done by chroma-tography using several milligrams of biomass. Here are three kinds of chromatography, GC, LC and TLC... GC being the best since it can also measure all of the volatile compounds, which includes aroma & flavor molecules such as terpenes, esters and alkanes...
Gas Chromatograph Flowpath
A gas chromatograph is a programmable oven. A thin, hollow glass coil is placed inside. The inside surface of the coil ("column") is lined with various chemicals that attract certain types of molecules. The upstream end of the column terminates at the injector and the downstream end connects at the detector. At all times an inert gas such as nitrogen or helium flows through the system slowly.
A measured amount of liquid solvent extract of cannabis is injected into the injector, which is around 325C. The solvent and all of the oils in the sample flash evaporate into a vapor cloud. The flowing gas through the system carries a portion of the mixed vapor cloud to the column, where everything is adsorbed. The temperature of the programmable oven is gradually increased to a desired setpoint. As the temperature goes up, the different types of molecules that adsorbed onto the glass column start to evaporate one-by-one. Each compound (THC, CBD, etc.) continues traveling in the stream of gas and enters the detector.
Detectors come in many varieties. In this example our GC has two detectors combined: FID/MS - Flame Ionization and Mass Spectrometer. The vapor cloud enters the FID, which is a flame that puts charge on the molecule, and that charge can be measured electronically. The result is a chart called a chromatogram (below). The more volatile, lower boiling molecules came off first and would be represented by the first couple peaks. The compounds with higher boiling points (b.p.) will elute later, represented later in time, farther to the right in the chromatogram.
The MS (mass spectrometry) detector is a device that accepts a side stream of the vapor cloud and bombards the molecules with a beam of electrons. This electron bombardment causes the molecules to break apart into somewhat predictable fragments. By way of gremlins, each fragment proceeds to rapidly pass through a magnetic field that deflects the molecules to one side. The bigger the fragment, the lesser it is affected by the magnet since it has more momentum, so it hits the target sensor in a different place. The amount of deflection is proportional to the mass of the fragment. So, we end up knowing the molecular weight of the pieces, and by adding them up we can determine the weight of the intact molecule, and other information about the structure. This data is compared to a library of pre-existing data to find a match.
Chromatogram (above): Graphic Results of Chromatography - Each peak represents a compound/molecule (i.e. THC, Citral A, CBD, Myrcene)
Headspace GC Chromatogram: Green House Seed Company in Amsterdam - Utilizes a vaporizor-like device to produce the vapor cloud. This chromatogram shows many of the terpenes responsible for flavor, aroma and therapeutic benefit present in the variety called "Arjan's Haze".
LC uses liquid solvents to help separate the mixture, similar to how GC uses heat and gas flow. Both LC and GC absorb all the compounds onto a solid mineral and then strips them off one-by-one. LC often uses a UV detector, sometimes couped with the MS detector. With some types of molecules, when a UV light is shined at them, they will absorb or reflect the light, which can be measured and helps identify them. Intensity of the 'reflected' light can tell how much compound is present.
A 3rd kind of chromatography is TLC...
TLC gives a visual picture, and sometimes measurement, of which compounds are present in an extract. With TLC, the many compounds are individually separated from the extract/mixutre.
First, a dehydrated sample is powdered and mixed with solvent to dissolve many of the chemicals. Solvent choice is key.
Imagine a glass plate (10 x 10cm) that is coated with a thin layer of powdered silica, the same stuff in packets to absorb moisture in food and new shoes. TLC plates are commercially available pre-coated with all kinds of fancy minerals that perform specific separations. Across the plate a pencil line is drawn horizontally, 1cm from the bottom.
From the liquid extract a capillary or needle is used to drip a fraction of a drop onto the line that is drawn on the TLC plate. The droplet will evaporate, leaving behind a dry green spot. Next the TLC plate is placed into a jar with lid, standing vertically. Already in the jar is a specific solvent or solvent mixture. The solvent level must be below pencil line on the TLC plate. The liquid, over time, will be drawn to the top of the plate (capillary action, like a paper towel).
Once the upwardly mobile solvent passes the line, each component gets separated based on how attracted to the silica coating it is. Compounds not attracted to the silica will travel with the solvent to the top of the plate. Compounds that are polar will not, they stay closer to the pencil line, moving more slowly. The result is the compounds/dots getting stretched apart from one another. Ideally, we get individual dots that range between the pencil line and the top of the plate, where the solvent stopped.
In practice, TLC plates must be "developed" in order to see all of the spots. Sometimes shining a UV light on the plate reveals invisible spots.
The position of the spot(s) is compared to reported values, or to known compounds (called 'standards', ex: pure THC) to verify which chemical the spot represents.
TLC Chromatogram - Developed TLC Plate
By Yun Xie |August 26, 2008
Pharmacists and chemists have found another use for the multipurpose cannabis as a source of antibacterial chemicals for multidrug resistant bacteria. Ironically, inhaling cannabis is known to damage the lung's ability to fend off invading pathogens, but the ingredients in cannabis, particularly the cannabinoids, have antiseptic properties. Although scattered research has been conducted since the 1950s, no comprehensive study existed that relates the structure of cannabinoids with antibacterial activity. Giovanni Appendino, Simon Gibbons, and coworkers attempted to remedy that problem by examining the activity of five common cannabinoids and their synthetic derivatives.
"..Five cannabinoids (THC, CBD, CBG, CBC, and CBN) were potent against bacteria. Notably, they performed well against bacteria that were known to be multidrug resistant, like the strains of MRSA that plagued U.K. hospitals. CBD and CBG have the most potential for consumer use because they are nonpsychotropic.
Besides identifying antibacterial capability, the researchers wanted to figure out why these cannabinoids are so good at killing bacteria. They obviously are very effective at specifically targeting some vital process in the bacteria. Unfortunately, even after extensive work at modifying the cannabinoids and comparing their activities, that targeting mechanism remains a mystery. The scientists were able to figure out that the position of the n-pentyl chain (orange) relative to the terpenoid moiety (blue) serves to control lipid affinity.
These cannabinoids are promising enough to warrant rigorous clinical trials. They are applicable as topical antiseptics, biodegradable antibacterial compounds for cosmetics, and systematic antibacterial agents.
J. Nat. Prod., 2008.
Org. Biomol. Chem., 2005, 3, 1116 - 1123
Lumír O. Hanu, Susanna Tchilibon, Datta E. Ponde, Aviva Breuer, Ester Fride and Raphael Mechoulam
(–)-Cannabidiol (CBD) is a major, non psychotropic constituent of cannabis. It has been shown to cause numerous physiological effects of therapeutic importance. We have reported that CBD derivatives in both enantiomeric series are of pharmaceutical interest. Here we describe the syntheses of the major CBD metabolites, (–)-7-hydroxy-CBD and (–)-CBD-7-oic acid and their dimethylheptyl (DMH) homologs, as well as of the corresponding compounds in the enantiomeric (+)-CBD series. The starting materials were the respective CBD enantiomers and their DMH homologs. The binding of these compounds to the CB1 and CB2 cannabinoid receptors are compared. Surprisingly, contrary to the compounds in the (–) series, which do not bind to the receptors, most of the derivatives in the (+) series bind to the CB1 receptor in the low nanomole range. Some of these compounds also bind weakly to the CB2 receptor.
**CS: Nature often produces molecules in multiple geometrical configurations. This study shows that cannabinoid receptors are selective about which type they like to hook-up with. This is extremely common with drugs and very important to pharmacology because each unique geometry can act like a whole other drug. In many cases one geometry will be a valuable and active drug in humans while the other form of the drug is mega-potent or poisonous.
Taxonomy of Cannabis (marijuana) and Humulus (hops)- not
The cannabis scientist should not only consider the genus Cannabis, but the entire botanical family Cannabaceae (aka Cannabidacea), which also contains the genus Humulus that includes the vine called hops. Understanding the terpene profile and biosynthesis in Humulus may provide cannabis breeders with insight regarding flavor/aroma profile manipulation.
Humulus (Hops, as in Hoppy India Pale Ale) is the only other genus besides Cannabis that is found in the family Cannabaceae; the two are genetically similar. Go to your local Homebrew Supplier and get an ounce of hops. A skunky variety such as Saaz will do. Compare the smell and physical similarities of the two Cannabaceae products. Smell familiar? Both have glandular trichomes that exude terpenoid-rich resin. Many of these resins not only add flavor to beer, but their orginal intent was to prevent spoilage via antimicrobial activity. Side-by-side the GC chromatograms from each plant would have many similarities (peaks). Cannabis and Hops each contain some of the same essential oils. For example, each has significant amounts of oils called myrcene and caryophyllene which contribute to their characteristic smells. They are both aromatic terpenes that contribute to the spicy smell in both flowers. Limonene, also present in Cannabaceae, is an oil with citrusy notes, and it happens to also be found in citrus fruits. Perhaps there lies utility in this genetic similarity for developing new flavor/aroma lineage. Attempts to cross-breed and graft the two species have failed. But today, cannabis scientists can influence the biosynthesis of certain compounds with advanced genetic technology. Understanding how the Humulus vine is influenced may provide insight into the nature of cannabis, and vice versa.
Hops: Humulus japonicus seeds
Aroma Chemistry - Random Facts by Terry Acree