Patent Application: US-15646008-A

Abstract:
the invention relates to a reference plant which has been selected to : a ) not express a medicinally active compound or group of compounds ; yet b ) express , at least substantially qualitatively , most other non medicinally active compounds present in a therapeutically active comparator plant . the reference plant can be used to generate a reference extract with a reference chemical profile which resembles that of the comparator plant less the active compound or group of compounds and may thus be used as a placebo or to otherwise test the hypothesis that the active compound or compounds are responsible for an extracts perceived medicinal activity .

Description:
by way of introduction it should be noted that there are many different cannabis sativa varieties and chemotypes . these include both wild type plants and cultivated varieties . the cultivated varieties include plants which have been cultivated as fibre producers ( low thc varieties ); those that have been bred ( illegally ) for recreational use ( high thc ) and more recently medicinal plants which have been selectively bred for their cannabinoid content ( one or more cannabinoids predominate ) and optionally the profile of e . g . entourage compounds . in order to produce plants with the desired characteristics it was necessary to “ knock out ” the expression of cannabinoids in a manner , which did not detrimentally effect the production of e . g . entourage compounds in the medicinal plants . how this was achieved is set out below : because in many countries cannabis cultivation is restricted to fibre hemp cultivars having specified “ low ” levels ( typically below either 0 . 1 or 0 . 3 % w / w of the dry floral tissue ) of thc , several breeding programmes have been devoted to meeting these legal limits . according to a survey of the european commercial fibre cultivars [ 13 ], the cultivars bred at the ukrainian institute of fibre crops ( glukhov , formerly , federal research institute of bast crops ) have the lowest thc contents and the lowest total cannabinoid contents . the cannabinoid breeding programme at this institute started in 1973 . their usual selective breeding methodology consists of family selection within existing cultivars with a high agronomic value and the elimination , before flowering , of plants with relatively high contents [ 14 ] and [ 15 ]. this effort has resulted in a gradual decrease of both thc content and total cannabinoid content . gorshkova et al . [ 16 ] evaluated the densities of sessile and stalked glandular trichomes on the bracteoles of various plants . they found that plants with stalked trichomes had relatively high cannabinoid contents and that their contents were positively correlated with the density of the stalked trichomes . plants that had solely sessile trichomes always had low contents that were uncorrelated with the densities of the sessile trichomes . gorshkova et al . [ 16 ] also mention plants without glandular trichomes that were found to be cannabinoid - free . since then , ukrainian plant breeders have reported several times on the existence of cannabinoid - free breeding materials [ 15 ], [ 17 ] and [ 18 ] pacifico et al . [ 1 , 9 ] analysed individual plants from the ukrainian cultivar uso 31 and found that one third of the individuals contained no cannabinoids . he also found that a minority of the plants (& lt ; 10 %) in a french fibre cultivar , epsilon 68 , were cannabinoid - free . the ukrainian cultivar uso 31 is amongst several varieties of hemp that have been approved for commercial cultivation under subsection 39 ( 1 ) of the industrial hemp regulations in canada for the year 2007 . these cannabinoid free plants are phenotypically and chemotypically different to those developed by the applicant through artificial manipulation and differ from those cannabinoid free plants that have been isolated in nature . ( 1 ) a disrupted morphogenesis of glandular trichomes that , according to sirikantaramas et al . [ 20 ], appear to be essential structures for cannabinoid synthesis , and ( 2 ) a blockage of one or more biochemical pathways that are crucial for the formation of precursors upstream of cbg . the first condition would also seriously affect the synthesis of other secondary metabolites that are produced largely or uniquely in the glandular trichomes . in 1991 , field grown cannabinoid - free plants , resulting from gorshkova et al . [ 16 ] programme were viewed and the bracts and bracteoles of these plants were apparently lacking glandular trichomes . also , the plants did not exude the characteristic cannabis fragrance . this suggests that the volatile mono - and sesquiterpenes were not produced in these plants . such cannabinoid free plants might therefore have been considered unsuitable for the purpose of breeding a cannabinoid free plant with typical entourage compounds . the second condition could also affect metabolites other than cannabinoids , as in the case of an obstruction of the basic pathways of common precursors for different classes of end products . the ipp incorporated , via gpp , into cannabinoids is derived from the dox pathway in the plastids [ 2 ]. monoterpenes , diterpenes , carotenoids , phytol and tetraterpenes are also uniquely synthesised in the plastids and one could therefore conclude that the ipp incorporated in these compounds , as with cannabinoids , is derived from the dox pathway [ 21 ]. sesquiterpenes , sterols and triterpenes are uniquely synthesised in the cytoplasm . presumably they are synthesised from mva derived ipp [ 21 ] and so do not share a fundamental pathway with the terpenoid moiety of cannabinoids . even so , according to evans [ 22 ], there is also evidence for a cooperative involvement of the dox - and the mva pathway in the synthesis of certain compounds , through the migration of ipp from the plastids into the cytoplasm and vice versa . the potentially wider chemical effect of engineering plants with the cannabinoid knockout factor yet which express selected entourage compounds has implications for pharmaceutical cannabis breeding . cannabinoids , and thc in particular , are generally considered as the major pharmaceutically active components of cannabis . nevertheless , according to mcpartland and russo [ 23 ], the terpenoid fraction may modify or enhance the physiological effects of the cannabinoids , providing greater medicinal benefits than the pure cannabinoid compounds alone . as summarized by williamson and whalley [ 24 ], there are indications that the non - cannabinoid ‘ entourage ’ of constituents , such as : modulate the cannabinoid effects and also have medicinal effects by themselves . speroni et al . [ 25 ] reported an anti - inflammatory effect from an extract that was obtained from a cannabinoid - free chemotype . whilst uso - 31 was selected as the source of a “ knockout ” gene to be introduced into pharmaceutical plants the challenge remained of achieving plants which were devoid of cannabinoids but which retained a good profile of selected entourage compounds ( i . e . were broadly speaking comparable to plants grown to produce extracts for pharmaceutical use ). in this regard uso - 31 had a chemical profile , which was not similar to medicinal varieties in that it was lacking both in cannabinoids , and monoterpenes . furthermore , the sesquiterpene profile also differed both quantitatively and qualitatively from that of plants used to produce pharmaceutical extracts . to overcome the problem of creating a reference plant which is , in the case of cannabis sativa , free of cannabinoids but which had a chemical profile of entourage compounds resembling pharmaceutical cannabis , selective breeding programmes were undertaken . a first cross was made between the selected cannabinoid free plant uso - 31 and a plant having a high cannabinoid content of a given cannabinoid , in this case m35 , a high thcv containing plant ( 83 . 4 % by weight of cannabinoids thcv ), and m84 , a high cbd containing plant ( 92 . 4 % by weight of cannabinoids cbd ). the high cannabinoid plants were selected both for their high and specific cannabinoid contents and their vigour . alternatively , a direct cross with a selected pharmaceutical plant could have been made . table 1 , bottom 2 rows , provides details of the cannabinoid composition of these parental clones : of course other strains containing a high percentage of another cannabinoids e . g . thc , cbdv , cbg , cbgv , cbc , cbcv , cbn and cbnv could be used . by “ high ” is meant that the specific cannabinoid predominates and would typically comprise greater than 50 % by weight of the total cannabinoids present , more particularly greater than 60 %, through 70 % and 80 % to most preferably greater than 90 % by weight . the initial cross generated an f1 progeny ( table 2 rows 1 and 2 ) which were then self crossed to generate an f2 progeny from which plants having the desired characteristics ( zero cannabinoid / good entourage compound chemotype profile ) were selected for back crossing to pharmaceutical varieties . the selected zero - cannabinoid plant , uso - 31 , was monoecious . i . e . it has unisexual reproductive units ( flowers , conifer cones , or functionally equivalent structures ) of both sexes appearing on the same plant . in order to self - fertilise uso - 31 and mutually cross female plants , a partial masculinisation was chemically induced . self - fertilisations were performed by isolating plants in paper bags throughout the generative stage . the uso - 31 source plants were evaluated for their drug type habit . inbred seeds from the best individual apparently devoid of cannabinoids and another with only cannabinoid traces were pooled . i ) crosses of low / zero cannabinoid uso - 31 offspring with m35 and m84 twenty - four plants of the 2003 . 8 f 1 ( table 2 , row 2 ) were evaluated . b the uso - 31 pollinators were two plants with very low cannabinoid content and / or true cannabinoid absence . the other pollinators were f 3 lines confirmed to be devoid of cannabinoids . c the underlined ciphers in the f 2 codes indicate the single f 1 individual that was self - fertilised to produce the f 2 generation . the majority of the plants had ‘ normal ’ cannabinoid contents , falling within a gaussian distribution range from 1 . 13 to 4 . 56 %. three plants had only trace amounts of cannabinoids , ranging from approximately 0 . 02 up to 0 . 15 %. similarly , the 19 plants of the 2003 . 17 f 1 comprised a majority of individuals with a cannabinoid content in the range of from 1 . 69 to 13 . 76 %, and two plants with cannabinoid traces of only ca . 0 . 02 %. from both f 1 s , an individual with only trace cannabinoid amounts was self - fertilised to produce an inbred f 2 2003 . 8 . 21 and 2003 . 17 . 19 . both f 2 s comprised plants that were confirmed to be devoid of cannabinoids . the remaining plants , those with cannabinoids present , could be assigned to two categories on the basis of a discontinuity in the cannabinoid content range : a group with low contents ranging from trace amounts up to roughly 0 . 6 %; and a group with higher contents . the newly obtained cannabinoid - free plants designated 2003 . 8 . 21 and 2003 . 17 . 19 f 2 had more branching ( typical of a drug type phenotype and in contrast to that of a fibre type phenotype ), a stronger fragrance ( due to the presence / increase in the terpenes and sesquiterpenes ) and higher trichome density ( determinable on examination ) than the original uso - 31 plants . the cannabinoid - free f 2 individuals with the best drug type plant habit , 2003 . 8 . 21 . 76 and 2003 . 17 . 19 . 67 , were self - fertilised to produce fixed cannabinoid - free f 3 inbred lines ( table 2 , rows 3 - 6 , col 2 ) for use in a backcrossing programme with pharmaceutical production clones m3 ( high thc 97 . 2 %) and m16 ( high cbd 91 . 5 %) ( table 1 , top 2 rows ). backcrosses were performed in order to obtain cannabinoid - free material , more closely resembling ( both qualitatively and quantitatively ) the pharmaceutical production clones by way of their non - cannabinoid profile , particularly those of the entourage compounds . all the clones listed in table 1 were true breeding for their chemotype . ii ) backcrossing of cannabinoid - free lines to pharmaceutical production clones m3 and m16 the cannabinoid - free lines 2003 . 8 . 21 . 76 and 2003 . 17 . 19 . 67 , ( table 2 , column 2 , last 4 rows ) were then back crossed with pharmaceutical production clones m3 and m16 and the resulting f1 &# 39 ; s crossed to generate an f2 progeny . the resulting progeny had their cannabinoid content evaluated as shown in table 3 below . within the f 1 s the cannabinoid contents showed a single gaussian distribution . the f 1 contents were much lower than the parental means and therefore much closer to the cannabinoid - free parent than to the production parent . the f 1 s were well covered with trichomes and were quite fragrant . in respect of the cannabinoid composition , the 2005 . 45 f 1 segregated into two chemotypes : thc predominant plants and mixed cbd / thc plants , in a 1 : 1 ratio . the 2005 . 47 f 1 was uniform and consisted of thc plants , all with a minor proportion of thcv . the 2005 . 48 f 1 was uniform and consisted of cbd / thc plants that also had minor proportions of cbdv and thcv . per f 1 , one individual was selected on the basis of criteria such as ‘ drug type morphology ’ ( e . g . branching ) and minimal monoeciousness to produce back cross generations . these individuals were used for a repeated pollination of m3 or m16 , which is not discussed here . to examine chemotype segregation , the selected f 1 individuals were also self - fertilised to produce large inbred f 2 s . fig1 shows chromatograms of different chemotype segregants from the 2005 . 45 . 13 f 2 . fig1 a is the chromatogram for a zero cannabinoid plant . the different chemotype segregants were microscopically compared . the cannabinoid - free plants of each progeny all had small , grey , dull trichomes of various shapes ( fig2 a ). some were headless ; some were pinhead and shrivelled , either flat , convex or concave . the high content cbd - and / or thc - predominant individuals of each group all had big , round clear heads that sparkled under the lamp ( fig2 b ); the low content plants from each progeny were almost indistinguishable from the cannabinoid - free plants except that there was an occasional small but bright trichome in some ( fig2 c ); and the high content cbg predominant plants from the 2005 . 45 . 13 f 2 had big , round , opaque white heads ( fig2 d ), clearly distinct from the transparent ones occurring on the thc predominant plants of the same progeny . the low content cbg predominant 2005 . 45 . 13 plants did not show opaque white trichome heads and were indistinguishable from the low content thc predominant plants . neither were white trichome heads observed in any of the cannabinoid - free plants of this progeny . as an indication of their vigour , the total above ground dry weights of all the cannabinoid - free - and the high content segregants were assessed . per progeny , per segregant group the weights showed a gaussian distribution . for the 2005 . 45 . 13 , 2005 . 46 . 27 and the 2005 . 47 . 9 progenies the cannabinoid - free individuals on average had a ca . 10 % higher dry weight than the high content individuals . in the 2005 . 48 . 7 progeny however , the average weight of the high content group exceeded that of the cannabinoid - free group by about 10 %. in order to characterize the plants a chemical analysis of both the cannabinoid content , and selected other chemicals , was undertaken as set out below : mature floral clusters were sampled from every individual plant considered in the breeding experiments . sample extraction and gc analysis took place as described by de meijer et al . [ 26 ]. the identities of the detected compounds were confirmed by gc - ms . cannabinoid peak areas were converted into dry weight concentrations using a linear calibration equation obtained with a cbd standard range . the contents of the individual cannabinoids were expressed as weight percentages of the dry sample tissue . the total cannabinoid content was calculated and the weight proportions of the individual cannabinoids in the cannabinoid fraction were used to characterize the cannabinoid composition . each of the six f 2 s listed in table 2 segregated into : in each case , per f 2 , the floral leaves , bracts and bracteoles of all the cannabinoid - free plants were pooled and homogenised , as was the floral fraction of all the plants belonging to the group with high cannabinoid contents . the different bulks from the : 2005 . 45 . 13 ( from m3 - thc ), 2005 . 46 . 27 ( from m16 - cbd ), 2005 . 47 . 9 ( from m3 - thc ) and 2005 . 48 . 7 ( from m16 - cbd ) f 2 the monoterpene and sesquiterpene composition of these essential oils was analysed by gas chromatography with flame ionisation detection ( gc - fid ). the relative amounts of a wide range of entourage compounds in the bulk homogenates of : 2003 . 8 . 21 ( from m84 - cbd ) and 2003 . 17 . 19 ( from m35 thcv ) f 2 s to obtain comparative fingerprints , gc - ms analyses were performed on a hp5890 gas chromatograph , coupled to a vg trio mass spectrometer . the gc was fitted with a zebron fused silica capillary column ( 30 m × 0 . 32 mm inner diameter ) coated with zb - 5 at a film thickness of 0 . 25 μm ( phenomenex ). the oven temperature was programmed from 70 ° c . to 305 ° c . at a rate of 5 ° c ./ min . helium was used as the carrier gas at a pressure of 55 kpa . the injection split ratio was 5 : 1 . gc profiles of terpenoids were generated in the splitless mode with a hp5890 gas chromatograph . the gc was fitted with a zebron fused silica capillary column ( 30 m × 0 . 32 mm inner diameter ) coated with zb - 624 at a film thickness of 0 . 25 μm ( phenomenex ). the oven temperature was held at 40 ° c . for 5 minutes , programmed to 250 ° c . at a rate of 10 ° c ./ min then held at 250 ° c . for 40 minutes . helium was used as the carrier gas at a pressure of 9 . 2 psi . the injection split ratio was 10 : 1 . hplc profiles were obtained using methods specific to a variety of compound classes . all samples were analysed using agilent 1100 series hplc systems ( i ) cannabinoid profiles were generated using a c 18 ( 150 × 4 . 6 mm , 5 μm ) analytical column . the mobile phase consisted of acetonitrile , 0 . 25 % w / v acetic acid and methanol at a flow rate of 1 . 0 ml / min and uv profiles were recorded at 220 nm . ( ii ) carotenoid profiles were generated using a varian polaris c 18 ( 250 × 4 . 6 mm , 5 μm ) analytical column . the mobile phase consisted of acetonitrile : methanol : dichloromethane : water at a flow rate of 1 . 2 ml / min and uv profiles were recorded at 453 nm . ( iii ) chlorophyll profiles were generated using the same column , mobile phase and flow rate described for carotenoids . uv profiles were recorded at 660 nm . ( iv ) non - polar compound profiles ( triglycerides , sterols etc ) were generated by a gradient lc method using a phenomenex luna c 18 ( 2 ) ( 150 × 2 . 0 mm , 5 μm ) analytical column . the mobile phase consisted of solvent a ( acetonitrile : methyl - tert - butyl - ether ( 9 : 1 )) and solvent b ( water ) with the proportion of b decreased linearly from 13 % to 0 % over 30 minutes then held constant for 20 minutes at a flow rate of 1 . 0 ml / min . the flow rate was then increased linearly to 1 . 5 ml / min over 40 minutes and uv profiles were recorded at 215 nm . ( v ) polar compound profiles ( phenolics ) were generated by a gradient lc method using an ace c 18 ( 150 × 4 . 6 mm , 5 μm ) analytical column . the mobile phase consisted of solvent a ( acetonitrile : methanol , 95 : 5 ) and solvent b ( 0 . 25 % w / v acetic acid : methanol , 95 : 5 ). the proportion of b was decreased linearly from 75 % to 15 % over 30 minutes then held constant for 10 minutes at a flow rate of 1 . 0 ml / min and uv profiles were recorded at 285 nm . the yields and compositions of steam - distilled essential oils from bulked cannabinoid - free - and bulked high content segregants of the four f 2 progenies are presented in table 4 below . in three ( 2005 . 46 . 27 , 2005 . 47 . 9 , and 2005 . 48 . 7 ), the cannabinoid - free bulks contained less essential oil than the high content ones . no significant qualitative differences in the essential oil composition were found , only minor quantitative ones , which generally did not show a systematic pattern . the only consistent quantitative difference between the low and high content progeny was difference was found for caryophyllene oxide that in all four progenies , reached a higher proportion in the cannabinoid - free bulks than in the high content bulks . when the zero cannabinoid backcross plants of the invention were compared to control 1 ( the original zero cannabinoid plant which was also devoid of monoterpenes ) and controls 2 and 3 ( the pharmaceutical plants with a high cannabinoid content and a range of entourage compounds ) the following differences were observed : 1 . the volume of oil (%) obtained by steam distillation in the zero cannabinoid plants of the invention was on average 0 . 50 %. by way of comparison control 1 is 0 . 14 %, and the mean of control 2 and 3 was 0 . 52 %. in other words the % oil is representative of the pharmaceutical clones . 2 . the total measured monoterpene fraction in the zero cannabinoid plants of the invention was on average about 76 . by way of comparison control 1 is 0 , and the mean of control 2 and 3 was about 61 . in other words the monoterpene fraction is representative of the pharmaceutical clones . 3 . within the monoterpence fraction in the zero cannabinoid plants of the invention the predominant terpene was myrcene , followed by alpha pinine and beta pinine with smaller amounts of limonine and linalol . whilst quantitatively there were differences compared to the pharmaceutical controls there was , broadly speaking , a qualitative relationship . 4 . the total measured sesquiterpene fraction in the zero cannabinoid plants of the invention was on average about 23 . by way of comparison , control 1 is about 93 , and the mean of controls 2 and 3 was about 39 . in other words the sesquiterpene fraction is much more representative of the pharmaceutical clones than control 1 . 5 . within the sesquiterpene fraction in the zero cannabinoid plants of the invention the predominant sesquiterpene were carophyllene , humulene and carophyllene oxide ( accounting for more than 50 % of the sesquiterpence fraction ). whilst there were differences compared to the pharmaceutical controls ( where quantitatively carophyllene and humulene were again the most significant sesquiterpenes but carophyllene oxide was absent ) there was , broadly speaking a qualitative , if not quantitative relationship between the plants of the invention and the pharmaceutical plants as compared to the starting zero cannabinoid plants which had much higher levels of sesquiterpenes and a wider detectable range of sesquiterpenes . by way of comparison table 5 gives some analytical data on the intermediate plants generated . it is a comparison of the different segregant bulks from 2003 . 8 . 21 and 2003 . 17 . 19 for a variety of compound classes . in general the differences between the entourages of the cannabinoid - free and the high content bulks were only quantitative . limonene was an exception , as it was not detected in the cannabinoid - free bulks whereas a minor presence was found in both of the high content bulks . however , the essential oil data in table 4 does not confirm this finding for the other f 2 s . likewise , table 5 does not show the difference in caryophyllene oxide as it appears in table 4 . both progenies in table 5 had consistently higher levels of four different triglycerides in the cannabinoid - free bulks than the high content bulks . the occurrence of none of the entourage compounds listed in the tables 4 and 5 appears to be critically associated with the presence or absence of cannabinoids . with the reported exception of the triglycerides , the quantitative differences in the entourage compounds does not show a consistent trend between cannabinoid - free - and high content bulks . this is most clearly seen in fig3 , which compares high cannabinoid bulks with cannabinoid free bulks . it also shows an m3 pharmaceutical bulk . what is apparent from a comparison of these extracts is that the profiles between the high content bulk and the cannabinoid free bulk of the segregating plants are very similar and that further more there is substantial similarity to the pharmaceutical extract m3 , particularly at the earlier retention times ( less than 30 minutes ). the cannabinoid - free segregants resulting from backcrosses with high content drug clones had glandular trichomes in normal densities but the trichome heads were dull and much smaller than those of high cannabinoid content sister plants . nevertheless the trichomes of cannabinoid - free segregants appear to be functional metabolic organs , as the chemical comparison of contrasting segregant bulks did not reveal big differences in the content and composition of volatile terpenes , which are also produced in the trichomes . the absence of cannabinoids probably causes the small trichome heads , rather than being a result of them . the abundant presence of apparently functional trichomes on the cannabinoid - free plants rules out that the absence of cannabinoids is due to a disrupted morphogenesis of the glandular trichomes . it thus appears that the cannabinoid knockout factor is not derived from the gland free plants selected by gorshkova et al [ 16 ]. it is more plausible that the absence of cannabinoids is attributable to the blockage of one or more biochemical pathways that are crucial for the formation of precursors upstream of cbg . as the chemical entourage of cannabinoid - free plants is intact , the obstacle is probably not in the mva and dox pathways towards ipp . a blocked mva pathway would not affect cannabinoid synthesis [ 2 ], but it should reduce levels of sesquiterpenes , sterols and triterpenes [ 21 ]. a blockage of the dox pathway would obstruct the synthesis of the terpenoid moiety of cannabinoids [ 2 ] but it should also negatively affect the synthesis of monoterpenes , diterpenes , carotenoids , phytol and tetraterpenes [ 21 ]. an alternative is that the knockout allele encodes a defective form of the enzyme got [ 1 ] that catalyses the condensation of resorcinolic acids ( oa and da ) with gpp into cbg . however , with such a mechanism one would expect an accumulation of the phenolic moieties oa and / or da in the cannabinoid - free segregants . our gc method for cannabinoid analysis detects the decarboxylated forms of both acids but they were observed in none of the cannabinoid - free plants &# 39 ; chromatograms . the most plausible hypothesis for the absence of cannabinoids appears to be a blockage in the polyketide pathway towards the phenolic moieties oa and da . whatever the working mechanism of the cannabinoid knockout factor is , one would expect that a functional synthase dominates a non - functional version , and so it remains obscure as to why the heterozygous genotypes ( o / o ) have such a strongly suppressed cannabinoid synthesis . the essential oil comparison and the chromatographic fingerprinting of contrasting segregant bulks demonstrated that except the cannabinoids , all the monitored compound classes were present in both segregant groups . the relative levels of the compound classes did vary between the contrasting segregant groups but not usually in a systematic way . the quantitative differences between contrasting bulks could be attributable to the fact that in cannabinoid - free plants the trichome heads , as the metabolic centres for a range of end products , are not inflated with cannabinoids . this may change the physical environment in which the reactions occur so that it quantitatively affects the synthesis of entourage compounds . the fact that large amounts of basic cannabinoid precursors are not incorporated may also affect equilibriums of other biosynthetic reactions . a further benefit of the plants of the present invention is that they can be used to create plant extracts containing cannabinoids in quantities / purities , which could not be achieved naturally . such plant extracts providing the benefits arising from the presence of one or more selected entourage compounds . the cannabinoids , which could be introduced to the cannabinoid free extracts , could include one or more natural cannabinoids , synthetic cannabinoids or biosynthetic cannabinoids ( modified natural cannabinoids ). this would produce a “ designer ” plant extract that could be used in clinical trials or as medicines . the benefits of natural or biosynthetic cannabinoids over synthetic cannabinoids lies in the fact that all of the cannabinoids are in the active form as opposed to a racemic mixture . other aspects of the invention will be clear to the skilled artisan and need not be repeated here . each reference cited herein is incorporated by reference in its entirety for the relevant teaching contained therein . the terms and expressions that have been employed are used as terms of description and not of limitation , and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof , it being recognized that various modifications are possible within the scope of the invention . fellermeier m , zenk m h ( 1998 ) prenylation of olivetolate by a hemp transferase yields cannabigerolic acid , the precursor of tetrahydrocannabinol . febs letters 427 : 283 - 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