RNA editing events and expression profiles of mitochondrial protein-coding genes in the endemic and endangered medicinal plant, Corydalis saxicola

Corydalis saxicola, an endangered medicinal plant endemic to karst habitats, is widely used in Traditional Chinese Medicine to treat hepatitis, abdominal pain, bleeding hemorrhoids and other conditions. However, to date, the mitochondrial (mt) genome of C. saxicola has not been reported, which limits our understanding of the genetic and biological mechanisms of C. saxicola. Here, the mt genome of C. saxicola was assembled by combining the Nanopore and Illumina reads. The mt genome of C. saxicola is represented by a circular chromosome which is 587,939 bp in length, with an overall GC content of 46.50%. 40 unique protein-coding genes (PCGs), 22 tRNA genes and three rRNA genes were identified. Codon usage of the PCGs was investigated and 167 simple sequence repeats were identified. Twelve homologous fragments were identified between the mt and ct genomes of C. saxicola, accounting for 1.04% of the entire mt genome. Phylogenetic examination of the mt genomes of C. saxicola and 30 other taxa provided an understanding of their evolutionary relationships. We also predicted 779 RNA editing sites in 40 C. saxicola mt PCGs and successfully validated 506 (65%) of these using PCR amplification and Sanger sequencing. In addition, we transcriptionally profiled 24 core mt PCGs in C. saxicola roots treated with different concentrations of CaCl2, as well as in other organs. These investigations will be useful for effective utilization and molecular breeding, and will also provide a reference for further studies of the genus Corydalis.

Corydalis saxicola Bunting: A Review of Its Traditional Uses, Phytochemistry, Pharmacology, and Clinical Applications

Corydalis saxicola Bunting (CSB), whose common name in Chinese is Yanhuanglian, is a herb in the family Papaveraceae. When applied in traditional Chinese medicine, it is used to treat various diseases including hepatitis, abdominal pain, and bleeding haemorrhoids. In addition, Corydalis saxicola Bunting injection (CSBI) is widely used against acute and chronic hepatitis. This review aims to provide up-to-date information on the botanical distribution, description, traditional uses, phytochemistry, pharmacology, and clinical applications of CSB. A comprehensive review was implemented on studies about CSB from several scientific databases, such as SciFinder, Elsevier, Springer, ACS Publications, Baidu Scholar, CNKI, and Wanfang Data. Phytochemical studies showed that 81 chemical constituents have been isolated and identified from CSB, most of which are alkaloids. This situation indicates that these alkaloids would be the main bioactive substances and that they have antitumour, liver protective, antiviral, and antibacterial pharmacological activities. CSBI can not only treat hepatitis and liver cancer but can also be used in combination with other drugs. However, the relationships between the traditional uses and modern pharmacological actions, the action mechanisms, quality standards, and the material basis need to be implemented in the future. Moreover, the pharmacokinetics of CSBI in vivo and the toxicology should be further investigated.

Highly variable chloroplast genome from two endangered Papaveraceae lithophytes Corydalis tomentella and Corydalis saxicola

The increasingly wide application of chloroplast (cp) genome super-barcode in taxonomy and the recent breakthrough in cp genetic engineering make the development of new cp gene resources urgent and significant. Corydalis is recognized as the most genotypes complicated and taxonomically challenging plant taxa in Papaveraceae. However, there currently are few reports about cp genomes of the genus Corydalis. In this study, we sequenced four complete cp genomes of two endangered lithophytes Corydalis saxicola and Corydalis tomentella in Corydalis, conducted a comparison of these cp genomes among each other as well as with others of Papaveraceae. The cp genomes have a large genome size of 189,029-190,247 bp, possessing a quadripartite structure and with two highly expanded inverted repeat (IR) regions (length: 41,955-42,350 bp). Comparison between the cp genomes of C. tomentella, C. saxicola, and Papaveraceae species, five NADH dehydrogenase-like genes (ndhF, ndhD, ndhL, ndhG, and ndhE) with psaC, rpl32, ccsA, and trnL-UAG normally located in the SSC region have migrated to IRs, resulting in IR expansion and gene duplication. An up to 9 kb inversion involving five genes (rpl23, ycf2, ycf15, trnI-CAU, and trnL-CAA) was found within IR regions. The accD gene was found to be absent and the ycf1 gene has shifted from the IR/SSC border to the SSC region as a single copy. Phylogenetic analysis based on the sequences of common CDS showed that the genus Corydalis is quite distantly related to the other genera of Papaveraceae, it provided a new clue for recent advocacy to establish a separate Fumariaceae family. Our results revealed one special cp genome structure in Papaveraceae, provided a useful resources for classification of the genus Corydalis, and will be valuable for understanding Papaveraceae evolutionary relationships.

Corydalis saxicola Alkaloids Attenuate Cisplatin-Induced Neuropathic Pain by Reducing Loss of IENF and Blocking TRPV1 Activation

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication of cisplatin, which is characterized by intolerable paresthesia, burning, and hyperalgesia, and severely impacts the life quality of patients. However, no clearly potent drug has been found for clinical medication due to its undefined mechanism. Corydalis Saxicola Bunting, a traditional Chinese medicine, has been proven to work well in anti-inflammation, blood circulations improvement, hemostasis, and analgesia. This study was designed to observe the effects of Corydalis saxicola Bunting total alkaloids (CSBTA) on cisplatin-induced neuropathic pain and to explore its potential mechanisms. In this study, the rats received intraperitoneal injection of 2mg/kg cisplatin twice a week for five weeks. Meanwhile, oral administration of low (30mg/kg)-, medium (60mg/kg)- and high (120mg/kg)-dose CSBTA were given daily for five weeks. By using Von-frey hair, heat radiant and -80∘C cold acetone, we found that CSBTA could obviously relieve cisplatin-induced mechanical, heat, and cold hyperalgesia. It has been verified that cisplatin-induced peripheral neuropathy is related to intraepidermal nerve fibers loss and activation of inflammation downstream. Our research found that Tumor necrosis factor-alpha (TNF-α), Interleukin-1beta (IL-1β), and Prostaglandin E2 (PGE2) were significantly increased by 10 intraperitoneal injections of cisplatin, and such pro-inflammation cytokines could be reduced via CSBTA administration. Besides, in the cisplatin model group, the neuronal structures of dorsal root ganglia (DRG) were severely damaged and the loss of intraepidermal nerve fibers occurred; but in the CSBTA administration groups, all above pathological changes were improved. Moreover, CSBTA could normalize the overexpression levels of p-p38 and Transient receptor potential vanilloid receptor (TRPV1) induced by cisplatin in DRG, trigeminal ganglion (TG), spinal cord, and foot of rats. In summary, we considered that CSBTA exerted its therapeutic effects by ameliorating neuronal damages, improving intraepidermal nerve fiber (IENF) loss, and inhibiting inflammation-induced p38 phosphorylation to block TRPV1 activation. These findings were the first to confirm the analgesic effect of CSBTA on CIPN and suggested a novel strategy for treating CIPN in clinic.

Antitumor lignanamides from the aerial parts of Corydalis saxicola

BACKGROUND

Cancer is one of the leading cause of unnatural death globally. There is still a great need for effective anticancer agents from plant sources. Corydalis saxicola Bunting is a medicinal plant that is traditionally used to treat various diseases in southwest China. Previous phytochemical investigations of C. saxicola have focused on isoquinoline alkaloids that have been isolated, which have activity against anti-hepatitis B virus and inhibit DNA topoisomerase I. However, the exploration of other classes of constituents and their bioactivities needs further study.

PURPOSE

The aim of this study was to investigate the antitumor activity of isolated lignanamides as well as their detailed cellular proliferation, suppression, and cytotoxic mechanisms.

METHODS

Herbs were extracted and constituents were purified by chromatographic separation, including silica gel, ODS, MCI, Sephadex LH-20 and Preparative HPLC. The compound structures were elucidated by the use of UV, IR, NMR and MS spectral data. The cytotoxicity effects of all compounds from the MGC-803, HepG2, T24, NCI-H460, Spca-2, and HL-7702 cell lines were studied by MTT assays. The induction of apoptosis by corydalisin C was investigated using acridine orange/ethidium bromide staining, Hoechst 33,258 staining, JC-1 mitochondrial membrane potential staining and flow cytometry.

RESULTS

Three new lignanamides, together with five known analogues, were isolated from the aerial parts of C. saxicola. Corydalisin C possessed the most potent inhibitory effects, with an IC₅₀ value of 8.81 ± 2.05µM against MGC-803 cells. SAR analysis showed that the sterics and chirality of lignanamides play a crucial role in pharmacologically relevant events. The antitumor activity was possibly due to the induction of cell apoptosis. Western blot experiments demonstrated that corydalisin C may induce apoptosis through both intrinsic and extrinsic apoptosis pathways, accompanied by down-regulating the expression of Bcl-2 and FasL in a time-dependent manner.

CONCLUSION

This study provides evidence that a lignanamide from the ethyl acetate extract of whole plants of C. saxicola showing potential in cancer treatment.