Biosynthesis of kratom opioids.

Mitragynine, an analgesic alkaloid from the plant Mitragyna speciosa (kratom), offers a safer alternative to clinical opioids such as morphine, owing to its more favorable side effect profile. Although kratom has been traditionally used for stimulation and pain management in Southeast Asia, the mitragynine biosynthesis pathway has remained elusive. We embarked on a search for mitragynine biosynthetic genes from the transcriptomes of kratom and other members of the Rubiaceae family. We studied their functions in vitro and in vivo. Our investigations led to the identification of several reductases and an enol methyltransferase that forms a new clade within the SABATH methyltransferase family. Furthermore, we discovered a methyltransferase from Hamelia patens (firebush), which catalyzes the final step. With the tryptamine 4-hydroxylase from the psychedelic mushroom Psilocybe cubensis, we accomplished the four-step biosynthesis for mitragynine and its stereoisomer, speciogynine in both yeast and Escherichia coli when supplied with tryptamine and secologanin. Although we have yet to pinpoint the authentic hydroxylase and methyltransferase in kratom, our discovery completes the mitragynine biosynthesis. Through these breakthroughs, we achieved the microbial biosynthesis of kratom opioids for the first time. The remarkable enzyme promiscuity suggests the possibility of generating derivatives and analogs of kratom opioids in heterologous systems.

Differentiation of Mitragyna speciosa, a narcotic plant, from allied Mitragyna species using DNA barcoding-high-resolution melting (Bar-HRM) analysis.

Mitragyna speciosa (Korth.) Havil. [MS], or "kratom" in Thai, is the only narcotic species among the four species of Mitragyna in Thailand, which also include Mitragyna diversifolia (Wall. ex G. Don) Havil. [MD], Mitragyna hirsuta Havil. [MH], and Mitragyna rotundifolia (Roxb.) O. Kuntze [MR]. M. speciosa is a tropical tree belonging to the Rubiaceae family and has been prohibited by law in Thailand. However, it has been extensively covered in national and international news, as its abuse has become more popular. M. speciosa is a narcotic plant and has been used as an opium substitute and traditionally used for the treatment of chronic pain and various illnesses. Due to morphological disparities in the genus, the identification of plants in various forms, including fresh leaves, dried leaf powder, and finished products, is difficult. In this study, DNA barcoding combined with high-resolution melting (Bar-HRM) analysis was performed to differentiate M. speciosa from allied Mitragyna and to assess the capability of Bar-HRM assays to identify M. speciosa in suspected kratom or M. speciosa-containing samples. Bar-HRM analysis of PCR amplicons was based on the ITS2, rbcL, trnH-psbA, and matK DNA barcode regions. The melting profiles of ITS2 amplicons were clearly distinct, which enabled the authentication and differentiation of Mitragyna species from allied species. This study reveals that DNA barcoding coupled with HRM is an efficient tool with which to identify M. speciosa and M. speciosa-containing samples and ensure the safety and quality of traditional Thai herbal medicines.

The Mitragyna speciosa (Kratom) Genome: a resource for data-mining potent pharmaceuticals that impact human health.

Mitragyna speciosa (kratom) produces numerous compounds with pharmaceutical properties including the production of bioactive monoterpene indole and oxindole alkaloids. Using a linked-read approach, a 1,122,519,462 bp draft assembly of M. speciosa "Rifat" was generated with an N50 scaffold size of 1,020,971 bp and an N50 contig size of 70,448 bp that encodes 55,746 genes. Chromosome counting revealed that "Rifat" is a tetraploid with a base chromosome number of 11, which was further corroborated by orthology and syntenic analysis of the genome. Analysis of genes and clusters involved in specialized metabolism revealed genes putatively involved in alkaloid biosynthesis. Access to the genome of M. speciosa will facilitate an improved understanding of alkaloid biosynthesis and accelerate the production of bioactive alkaloids in heterologous hosts.

DNA sequence analyses of blended herbal products including synthetic cannabinoids as designer drugs.

In recent years, various herbal products adulterated with synthetic cannabinoids have been distributed worldwide via the Internet. These herbal products are mostly sold as incense, and advertised as not for human consumption. Although their labels indicate that they contain mixtures of several potentially psychoactive plants, and numerous studies have reported that they contain a variety of synthetic cannabinoids, their exact botanical contents are not always clear. In this study, we investigated the origins of botanical materials in 62 Spice-like herbal products distributed on the illegal drug market in Japan, by DNA sequence analyses and BLAST searches. The nucleotide sequences of four regions were analyzed to identify the origins of each plant species in the herbal mixtures. The sequences of "Damiana" (Turnera diffusa) and Lamiaceae herbs (Mellissa, Mentha and Thymus) were frequently detected in a number of products. However, the sequences of other plant species indicated on the packaging labels were not detected. In a few products, DNA fragments of potent psychotropic plants were found, including marijuana (Cannabis sativa), "Diviner's Sage" (Salvia divinorum) and "Kratom" (Mitragyna speciosa). Their active constituents were also confirmed using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), although these plant names were never indicated on the labels. Most plant species identified in the products were different from the plants indicated on the labels. The plant materials would be used mainly as diluents for the psychoactive synthetic compounds, because no reliable psychoactive effects have been reported for most of the identified plants, with the exception of the psychotropic plants named above.

The botanical origin of kratom (Mitragyna speciosa; Rubiaceae) available as abused drugs in the Japanese markets.

Kratom is the leaves of Mitragyna speciosa (Rubiaceae). Recently, kratom has been sold in street shops or on the Internet in Japan for the purpose of abuse due to its opium-like effects. In this study, we investigated the botanical origin of the commercial kratom products using the internal transcribed spacer (ITS) sequence analysis of rDNA in preparation for future regulation of this product. In addition, a previously reported method to authenticate the plant, utilizing polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was applied to the same products in order to estimate the method's accuracy and utility. The ITS sequence analysis of the commercial kratoms revealed that most of them were derived from M. speciosa or closely related plants, while the others were made from the same tribe plant as M. speciosa. The reported PCR-RFLP method could clearly distinguish kratoms from the other psychoactive plants available in the Japanese markets and also from related plants. The authentication method is considered to be useful for the practical regulation of the plant due to its wide range of application, high accuracy and simplicity.