Offline Two-Dimensional RP/RPLC Method to Separate Components in Dracaena cochinchinensis (Lour.) S.C.Chen Xylem Containing Resin

Two-dimensional liquid chromatography with reversed phase in both dimensions: A review

Two-dimensional liquid chromatography (2D-LC), and in particular comprehensive two-dimensional liquid chromatography (LC×LC), offers increased peak capacity, resolution and selectivity compared to one-dimensional liquid chromatography. It is commonly accepted that the technique produces the best results when the separation mechanisms in the two dimensions are completely orthogonal; however, the use of similar separation mechanisms in both dimensions has been gaining popularity as it helps avoid difficulties related to mobile phase incompatibility and poor column efficiency. The remarkable advantages of using reversed phase in both dimensions (RPLC×RPLC) over other separation mechanisms made it a promising technique in the separation of complex samples. This review discusses some physical and practical considerations in method development for 2D-LC involving the use of RP in both dimensions. In addition, an extensive overview is presented of different applications that relied on RPLC×RPLC and 2D-LC with reversed phase column combinations to separate components of complex samples in different fields including food analysis, natural product analysis, environmental analysis, proteomics, lipidomics and metabolomics.

Terpenoid profiles of resin in the genus Dracaena are species specific

Dragon's blood is the colloquial name for the red resin produced by tree species in the genus Dracaena (Asparagaceae), and the resin is directly involved in plant defensive mechanisms against pathogen and herbivore attack. It is also widely used in traditional folk medicine due to its antiviral, antimicrobial and antitumor activities. In the present work, a method using solid phase microextraction combined with two-dimensional gas chromatography with time-of-flight mass spectrometric detection was developed for the analysis of resin from five Dracaena species, namely Dracaena cinnabari Balf. f., D. serrulata Baker, D. ombet Heuglin ex Kotschy & Peyr., D. draco subsp. draco, and D. draco subsp. ajgal. Twenty terpenoid components in the resins of the five species were identified after comparative study of the volatile metabolite profiles. Monoterpenes were found to be species specific, and the observed differences might be further investigated as a possible means of identifying chemotaxonomic markers. In addition, for the first time, we describe the terpenoid volatile profiles of D. ombet and D. serrulata resins.

Phenolic constituents, pharmacological activities, quality control, and metabolism of Dracaena species: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Dragon's blood (Chinese name: Xuejie), which comprises red resins obtained from several plants (27 species from 4 families), is drawing worldwide interests in medicinal applications owing to its broad pharmacological spectrum such as promoting blood circulation, regenerating muscle, relieving swelling and pain, maintaining hemostasis, etc. AIM OF THE STUDY: This work aims to evaluate current research progress on phenolic constituents, pharmacological activities, quality control, and metabolism of six Dracaena plants, namely, Dracaena cochinchinensis (Lour.) S.C.Chen, D. cambodiana Pierre ex Gagnep., D. cinnabari Balf. f., D. draco (L.) L., D. loureiroi Gagnep., and D. schizantha Baker, figure out the shortcomings of existing studies, and provide meaningful guidelines for future investigations.

METHODS

Extensive database retrieval, such as SciFinder, PubMed, CNKI, ChemSpider, etc., was performed by using the keywords "Dracaena," "dragon's blood," as well as the Latin names of the six Dracaena species. In addition, relevant textbooks, patents, reviews, and documents were also employed to ensure sufficient information is collected.

RESULTS

Flavonoids and their oligomers are the primary chemical clusters distributed in Dracaena plants. Pharmacological activities including analgesic, anti-inflammatory, antibacterial, hypolipidemic, hypoglycemic, and cytotoxic effects; bi-directional regulation effects on hemorheology; and cardiovascular and cerebrovascular effects have been disclosed by modern pharmacological evaluations. The chemical and metabolic profiles after oral administration of dragon's blood extract were preliminarily characterized. However, some of the pharmacological investigations reported only elementary methodologies and unreliable findings, and even worse, some important aspects were questionable or missing in these articles.

CONCLUSIONS

Dragon's blood is a valuable source of bioactive compounds, mainly flavonoids and their oligomers. Its potential therapeutic effects on different diseases are attractive, such as the notable effect on cardiovascular diseases. In future studies, there is an urgent need to test the effect of this extract on appropriate cell lines and animal models to analyze its ethnopharmacological applications; moreover, "composition-effect correlation" methods and omics technologies are demanded for identifying the effective material basis and therapeutic mechanisms before entering into clinical trials. Moreover, attention should be paid to the chemical profiling and quality evaluation of this precious herbal medicine.

A comparative study on volatile metabolites profile of Dracaena cochinchinensis (Lour.) S.C. Chen xylem with and without resin using GC-MS

Dragon's blood is a famous traditional Chinese medicine produced from source plants under bio- or abio-stress. Dracaena cochinchinensis (Lour.) S.C. Chen xylem (DX) is one of the most important sources of the medicine. In this work, a GC-MS method was developed for analysis of the n-hexane extracts of DX with resin (DXR) and without resin (DXW). The repeatability of the method was also investigated for a metabolite comparative study of the different xylems. About 80 components were detected, 26 of which were identified in both DXR and DXN. Three sesquiterpenes (τ-cadinol, τ-muurolon and α-cadinol) were first discovered in Dracaena cochinchinensis (Lour.) S.C. Chen. The chromatographs of the two plant materials were compared and differences of compounds were found. It showed that phytosterols showed a dramatic rise in content, and sesquiterpenes were found to be synthesized in DXR.

Dragon's blood dropping pills have protective effects on focal cerebral ischemia rats model

Dragon's blood is a bright red resin obtained from Dracaena cochinchinensis (Lour.) S.C.Chen (Yunnan, China). As a traditional Chinese medicinal herb, it has great traditional medicinal value and is used for wound healing and to stop bleeding. Its main biological activity comes from phenolic compounds. In this study, phenolic compounds were made into dropping pills and their protective effects were examined by establishing focal cerebral ischemia rats model used method of Middle Cerebral Artery Occlusion (MCAO), and by investigating indexes of neurological scores, infarct volume, cerebral index, cerebral water content and oxidation stress. Compared to model group, high, middle and low groups of Dragon's blood dropping pills could improve the neurological function significantly (p<0.01) and reduce cerebral infarct volume of focal cerebral ischemia rats remarkably (p<0.05-0.01). Meanwhile, each group could alleviate cerebral water content and cerebral index (p<0.05-0.01) and regulate oxidative stress of focal cerebral ischemia rats obviously (p<0.05-0.01). Activities of middle group corresponded with that treated with positive control drug. The results obtained here showed that Dragon's blood dropping pills had protective effects on focal cerebral ischemia rats.

Separation and identification of flavonoids from complex samples using off-line two-dimensional liquid chromatography tandem mass spectrometry

In this study, a LC-based identification strategy was proposed and off-line two-dimensional liquid chromatography was developed for the separation and identification of flavonoids from complex samples. The highly orthogonal separation system was composed of a CD column, an OEG column and an XTerra C(18) column. The CD column was employed for the first dimensional separation and the OEG column and XTerra C(18) column were used for the second dimensional separation in parallel. A mixture of six traditional Chinese medicines was used as a complex sample in testing this method. Unknown peaks were identified by matching their retention times and accurate mass molecular weights with those of references. The identification efficacy of parallel unidimensional liquid chromatography and off-line two-dimensional liquid chromatography was compared, and the latter was demonstrated to be more efficient for the identification of target compounds-especially co-eluted compounds or minor compounds from complex samples.