Natascha Techen

DNA barcoding of medicinal plant material for identification.

Because of the increasing demand for herbal remedies and for authentication of the source material, it is vital to provide a single database containing information about authentic plant materials and their potential adulterants. The database should provide DNA barcodes for data retrieval and similarity search. In order to obtain such barcodes, several molecular methods have been applied to develop markers that aid with the authentication and identification of medicinal plant materials. In this review, we discuss the genomic regions and molecular methods selected to provide barcodes, available databases and the potential future of barcoding using next generation sequencing.

Molecular analyses of the Chinese herb Leigongteng (Tripterygium wilfordii Hook.f.).

Tripterygium wilfordii Hook.f., known as Leigongteng (Thunder God Vine) in traditional Chinese medicine, has attracted much attention for its applications in relieving autoimmune disorders such as rheumatoid arthritis and systemic lupus erythematosus, and for treating cancer. Molecular analyses of the ITS and 5S rDNA sequences indicate that T. hypoglaucum and T. doianum are not distinct from T. wilfordii, while T. regelii should be recognized as a separate species. The results also demonstrate potential value of rDNA sequence data in forensic detection of adulterants derived from Celastrus angulatus in commercial samples of Leigongteng.

DNA Barcoding for the Identification of Botanicals in Herbal Medicine and Dietary Supplements: Strengths and Limitations

In the past decades, the use of traditional medicine has increased globally, leading to a booming herbal medicine and dietary supplement industry. The increased popularity of herbal products has led to a rise in demand for botanical raw materials. Accurate identification of medicinal herbs is a legal requirement in most countries and prerequisite for delivering a quality product that meets consumer expectations. Traditional identification methods include botanical taxonomy, macroscopic and microscopic examination, and chemical methods. Advances in the identification of biological species using DNA-based techniques have led to the development of a DNA marker-based platform for authentication of plant materials. DNA barcoding, in particular, has been proposed as a means to identify herbal ingredients and to detect adulteration. However, general barcoding techniques using universal primers have been shown to provide mixed results with regard to data accuracy. Further technological advances such as mini-barcodes, digital polymerase chain reaction, and next generation sequencing provide additional tools for the authentication of herbs, and may be successful in identifying processed ingredients used in finished herbal products. This review gives an overview on the strengths and limitations of DNA barcoding techniques for botanical ingredient identification. Based on the available information, we do not recommend the use of universal primers for DNA barcoding of processed plant material as a sole means of species identification, but suggest an approach combining DNA-based methods using genus- or species-specific primers, chemical analysis, and microscopic and macroscopic methods for the successful authentication of botanical ingredients used in the herbal dietary supplement industry.

Assessment of the genetic stability of micropropagated plants of Cannabis sativa by ISSR markers.

Inter-simple sequence repeat (ISSR) markers were used to evaluate the genetic stability of the micropropagated plants of Cannabis sativa over 30 passages in culture and hardening in soil for 8 months. A total of 15 ISSR primers resulted in 115 distinct and reproducible bands. All the ISSR profiles from micropropagated plants were monomorphic and comparable to mother plants, confirming the genetic stability among clones and mother plants. Chemical analysis of cannabinoids, using gas chromatography/flame ionization detection (GC/FID), was done to further confirm whether the qualitative and quantitative differences in the major secondary metabolites exist between the mother plant and micropropagated plants. Six major cannabinoids - Delta(9)-THC, THCV, CBD, CBC, CBG, and CBN - were identified and compared with the mother plant. Our results clearly showed a similar cannabinoid profile and insignificant differences in THC content between the two types of plants. These results suggest that the micropropagation protocol developed by us for rapid IN VITRO multiplication is appropriate and applicable for clonal mass propagation of C. SATIVA.

Optimized construction of microsatellite-enriched libraries

The construction of microsatellite‐enriched libraries is an indispensable tool to search for molecular markers as complete genome sequences are still not available for the majority of species of interest. Numerous protocols are available in the literature for the construction of these libraries; however, sometimes their low efficiency or lack of optimization in the protocols can restrict their efficacy. We have designed and tested various adapters and ligation methods; we also tested oligo‐repeat combinations and hybridization temperatures, and created libraries with this new protocol for four organisms: Ipomoea batatas (L.) Lam, Chionanthus retusus Lindley & Paxton, Rotylenchulus reniformis Linford & Olivera and Puccinia kuehnii W. Krüger. The number of microsatellites detected for these species ranged from 2494 to 3919 per Mb of nonredundant sequence, that was 0.86 and 1.53 microsatellites per contig, with 37–66% of di‐nucleotide motifs and 21–49% of tri‐ to octa‐nucleotide repeats combined. A simplified protocol is provided for the successful generation of SSR‐enriched libraries.

Detection of Illicium anisatum as adulterant of Illicium verum.

Chinese Star anise, Illicium verum Hook, is a well known spice in many cultures and has also been used to treat infant colic. Recent publications report that Chinese Star anise might be adulterated with the toxic Japanese Star anise, Illicium anisatum L. We have developed a molecular method that helps with the detection of I. anisatum as adulterant of I. verum. We PCR-amplified the internal transcribed spacer (ITS) region and analyzed it with the endonucleases PSTI and BFMI. Based on fragment length polymorphisms (RFLP), we were able to detect and distinguish between I. anisatum and other Illicium species in powdered samples.

Cardiocrinum seeds as a replacement for Aristolochia fruits in treating cough

AIM OF THE STUDY The antitussive Chinese herb Madouling derived from Aristolochia species is banned due to aristolochic acid-induced nephropathy. A substitute is found dispensed as Madouling in Taiwan. This study aims to determine the source plant and verify the antitussive properties of the Madouling substitute used in Taiwan. MATERIALS AND METHODS Forensically informative nucleotide sequencing (FINS) approach based on the trnL-trnF and psbA-trnH regions was applied to facilitate identification of the genuine species and substitute. The antitussive effect of both genuine Madouling and the substitute were evaluated in guinea pigs. RESULTS FINS approach based on the trnL-trnF and psbA-trnH regions readily identified the sample of Madouling in Taiwan to the seeds of Cardiocrinum giganteum var. yunnanense. Ethanol extracts of the substitute showed significant antitussive properties in guinea pigs. CONCLUSION Cardiocrinum seeds may have potential as a replacement of Aristolochia fruits.

Antifungal activity of extracts from endophytic fungi associated with Smallanthus maintained in vitro as autotrophic cultures and as pot plants in the greenhouse.

The endophytic fungal assemblages associated with Smallanthus sonchifolius (Poepp.) H. Rob. and Smallanthus uvedalius (L.) Mack. ex Small growing in vitro autotrophic cultures and in the greenhouse were identified and evaluated for their ability to produce bioactive compounds. A total of 25 isolates were recovered that were genetically closely related to species of the genera Bionectria , Cladosporium , Colletotrichum , Fusarium , Gibberella , Hypocrea , Lecythophora , Nigrospora , Plectosphaerella , and Trichoderma . The endophytic assemblages of S. sonchifolius presented a greater diversity than the group isolated from S. uvedalius and demonstrated the presence of dominant generalist fungi. Extracts of all fungi were screened against the fungal plant pathogens. Ten extracts (41.6%) displayed antifungal activities; some of them had a broad antifungal activity. The phylotypes Lecythophora sp. 1, Lecythophora sp. 2, and Fusarium oxysporum were isolated from in vitro autotrophic cultures and displayed antifungal activity. The presence of bioactive endophytic fungi within S. sonchifolius and S. uvedalius suggests an ecological advantage against pathogenic attacks. This study revealed reduced numbers of endophytes in association with both Smallanthus species in controlled cultivation conditions compared with the endophytic communities of hosts collected in the wild environments. Even as reduced endophytic communities, these fungi continue to provide chemical protection for the host.

NMR fingerprinting for analysis of hoodia species and hoodia dietary products.

Hoodia gordonii, a succulent plant growing in African arid regions, is used as a botanical dietary supplement for weight loss. The increasing concerns on the quality and safety of Hoodia products call for the needs of more science-based information, as well as objective and efficient tools for inspection. In the present study, NMR fingerprinting and multivariate analysis techniques were applied for the identification, discrimination, and quality analysis of Hoodia plant materials and commercial products. Four Hoodia species, namely H. gordonii (five authenticated samples), H. currorii (one authenticated sample), H. parviflora (three authenticated samples), and H. rushii (one authenticated sample), were investigated; the chemicals and characteristic spectral signals that made most contributions for their differentiations were revealed. With the aid of NMR fingerprint analysis, ten Hoodia products sold on the dietary supplement market were assessed for their chemical composition and quality. The study demonstrated that the NMR fingerprinting approach could be a promising and efficient tool for the authentication of botanicals.

Genetic identification of female Cannabis sativa plants at early developmental stage.

Sequence-characterized amplified region (SCAR) markers were used to identify female plants at an early developmental stage in four different varieties of Cannabis sativa. Using the cetyl trimethylammonium bromide (CTAB) method, DNA was isolated from two-week-old plants of three drug-type varieties (Terbag W1, Terbag K2, and Terbag MX) and one fiber-type variety (Terbag Fedora A7) of C. sativa grown under controlled environmental conditions through seeds. Attempts to use MADC2 (male-associated DNA from Cannabis sativa) primers as a marker to identify the sex of Cannabis sativa plants were successful. Amplification of genomic DNA using MADC2-F and MADC2-R primers produced two distinct fragments, one with a size of approximately 450 bp for female plants and one for male plants with a size of approximately 300 bp. After harvesting the tissues for DNA extraction, plants were subjected to a flowering photoperiod (i.e., 12-h light cycle), and the appearance of flowers was compared with the DNA analysis. The results of the molecular analysis were found to be concordant with the appearance of male or female flowers. The results of this study represent a quick and reliable technique for the identification of sex in Cannabis plants using SCAR markers at a very early developmental stage.