Search Results (6)

The plant mitochondrial genome has become a current research hotspot as an independent genetic model. Nevertheless, mitochondrial genome information for most Dendrobium species remains unknown. In this study, the assembly of mitochondrial genome of Dendrobium nobile Lindl.,1830 and Dendrobium denneanum Kerr., 1933 was conducted through the application of second- and third-generation sequencing technologies, with the mitochondrial genome of D. denneanum Kerr. being reported first. The results revealed that the mitochondrial genomes of the two species possessed a multi-chromosome circular structure. Their total lengths were 641,414 bp and 558,760 bp, consisting of 21 and 19 contigs, respectively. A total of 67 and 72 genes, 993 and 1491 repeat sequences, and 549 and 553 RNA editing sites were identified. Gene loss was observed. A total of 26 and 36 homologous fragments were detected between the mitochondrial and the chloroplast genome, accounting for 5.09% and 4.93% of the total lengths, respectively, indicating intracellular gene transfer. Synteny and phylogenetic analyses revealed that the two species shared extensive collinear regions and clustered together in a distinct clade of the phylogenetic tree, indicating a close sister relationship. These findings enrich the mitochondrial genome database and provide valuable insights to guide future research on species identification and molecular evolution of the genus Dendrobium. Full article

Dendrobium denneanum Kerr, Dendrobium denneanum Kerr, an orchid in the food-medicine homology catalog, is traditionally used for stomach-nourishing, yin-tonifying, and immunity-enhancing. While its preventive effect on acute gastric ulcers is confirmed, variations among genuine producing areas remain underexplored. This study comparatively analyzed components of D. denneanum from 22 habitats and their polysaccharides’ (DDP) anti-inflammatory/antioxidant activities. Results showed habitat-dependent active components: total sugar (20–51.49%), crude polysaccharide yield (0.29–1.76%), and total phenol (~3%). In vitro, all extracts exhibited dose-dependent scavenging of DPPH (IC₅₀: 0.99–2.11 mg/mL), ABTS (0.61–1.62 mg/mL), and hydroxyl radicals (1.02–2.18 mg/mL), with Habitats 5 and 7 showing the strongest activity. GPC, ion chromatography, and FT-IR revealed DDP had a 5–11 kDa molecular weight, dominated by glucose (49.67–84.73%), plus mannose (8.29–12.25%) and galactose (0.96–16.41%), with shared hydroxyl (3400 cm⁻¹) and β-glycosidic bond (890 cm⁻¹) features. In ethanol-induced gastric ulcer rats, DDP exerted dose-dependent protection: low doses (100 mg/kg/d) reduced ulcer index, increased SOD/GSH-Px (1.5–1.8-fold), decreased MDA (30–35%), and elevated PGE₂; high doses (400 mg/kg/d) further inhibited serum TNF-α/IL-6 (25–40%) and improved histopathology. Conclusion: Despite habitat-dependent component variations, DDP maintains consistent structures. This study first confirms DDP protects gastric mucosa via antioxidant-anti-inflammatory synergism, supporting its development as a natural gastroprotectant. Future work may focus on standardized cultivation and clinical translation. Full article

Dendrobium denneanum is an important medicinal and ornamental plant. Its ornamental and medicinal values are affected by its vegetative growth conditions and chemical composition accumulation. This study adopted an orthogonal experimental design to treat D. denneanum with nine different levels of nitrogen (N), potassium (K), and phosphorus (P). The morphological indicators of the plant were positively correlated with the nitrogen concentration. The polysaccharide content was the highest at 1500 mg·L⁻¹ nitrogen and 3000 mg·L⁻¹ phosphorous and was 26.84% greater than the control. The flavonoid content increased by 36.2% at 500 mg·L⁻¹ nitrogen, 2000 mg·L⁻¹ phosphorous, and 300 mg·L⁻¹ potassium. Principal component score analysis showed that nitrogen had the most significant impact on the various indicators of D. denneanum, followed by phosphorus and potassium. The comprehensive score showed that the T9 treatment (N: 1500 mg·L⁻¹, P: 3000 mg·L⁻¹, K: 500 mg·L⁻¹) had the strongest effect on D. denneanum. Transcriptional analysis showed that compared with the control, the T9 treatment led to 2277 differentially expressed genes (1230 upregulated and 1047 downregulated). This includes fifteen genes enriched in the MAPK signaling pathway, five genes in phenylpropanoid biosynthesis, and two genes in flavonoid biosynthesis. These genes may be involved in regulating plant growth and the biosynthesis of polysaccharides and flavonoids. This study provides guidance for the optimal use of N, P, and K in the cultivation of D. denneanum. Full article

Xylariales are common endophytes of Dendrobium. However, xylarialean species resolution remains difficult without sequence data and poor sporulation on artificial media and asexual descriptions for only several species and old type material. The surface-sterilized and morph-molecular methods were used for fungal isolation and identification. A total of forty-seven strains were identified as twenty-three species belonging to Apiosporaceae, Hypoxylaceae, Induratiaceae, and Xylariaceae. Five new species—Annulohypoxylon moniliformis, Apiospora dendrobii, Hypoxylon endophyticum, H. officinalis and Nemania dendrobii were discovered. Three tentative new species were speculated in Xylaria. Thirteen known fungal species from Hypoxylon, Nemania, Nigrospora, and Xylaria were also identified. Another two strains were only identified at the genus and family level (Induratia sp., Hypoxylaceae sp.). This study recorded 12 new hosts for xylarialean endophytes. This is the first report of Xylariales species as endophytes from Dendrobium aurantiacum var. denneanum, D. cariniferum, D. harveyanum, D. hercoglossum, D. moniliforme, and D. moschatum. Dendrobium is associated with abundant xylarialean taxa, especially species of Hypoxylon and Xylaria. We recommend the use of oat agar with low concentrations to induce sporulation of Xylaria strains. Full article

A new 8,4¢-oxyneolignane glucoside 1 has been isolated from the stems of Dendrobium aurantiacum var. denneanum together with six known phenolic glucosides 2-7. The structure of the new compound, including its absolute configuration, was determined by spectroscopic and chemical methods as (–)-(7S,8R,7¢E)-4-hydroxy-3,3¢,5,5¢-tetramethoxy-8,4¢-oxyneolign-7¢-ene-7,9,9¢-triol 7,9¢-bis-O-β-D-glucopyranoside (1). In the in vitro assays, compound 1 and (-)-syringaresinol-4,4¢-bis-O-β-D-glucopyranoside (2) showed evident activity against glutamate-induced neurotoxicity in PC12 cells. Shashenoside I (4) showed a selective cytotoxic activity with the IC₅₀ value of 4.17 μM against the acute myeloid leukemia cell line MV4-11, while it was inactive against 10 other human tumor cell lines. Full article

The water-soluble crude polysaccharide (DDP) obtained from the aqueous extracts of the stem of Dendrobium denneanum through hot water extraction followed by ethanol precipitation, was found to have an average molecular weight (Mw) of about 484.7 kDa. Monosaccharide analysis revealed that DDP was composed of arabinose, xylose, mannose, glucose and galactose in a molar ratio of 1.00:2.66:8.92:34.20:10.16. The investigation of antioxidant activity both in vitro and in vivo showed that DDP is a potential antioxidant. Full article