Phenolic acid glucosides from the seeds of Entada phaseoloides Merill

Chromosome-level genome of Entada phaseoloides provides insights into genome evolution and triterpenoid saponins biosynthesis

As a medicinal herbal plant, Entada phaseoloides has high levels of secondary metabolites, particularly triterpenoid saponins, which are important resources for scientific research and medical applications. However, the lack of a reference genome for this genus has limited research on its evolution and utilization of its medicinal potential. In this study, we report a chromosome-scale genome assembly for E. phaseoloides using Illumina, Nanopore long reads, and high-throughput chromosome conformation capture technology. The assembled reference genome is 456.18 Mb (scaffold N50=30.9 Mb; contig N50=6.34 Mb) with 95.71 % of the sequences anchored onto 14 pseudochromosomes. E. phaseoloides was estimated to diverge from the Leguminosae lineage at approximately 72.0 million years ago. With the integration of transcriptomic and metabolomic data, gene expression patterns and metabolite profiling of E. phaseoloides were determined in different tissues. The pattern of gene expression and metabolic profile of the kernel were distinct from those of other tissues. Furthermore, the evolution of certain gene families involved in the biosynthesis of triterpenoid saponins and terpenes was analyzed and offer new insights into the formation of these two metabolites. Four CYP genes, one UGT gene and related transcription factors were identified as candidate genes contributing to regulation of triterpenoid saponins biosynthesis. As the first high-quality assembled reference genome in the genus Entada, it will not only provide new information for the evolutionary study of this genus and conservation biology of E. phaseoloides but also lay a foundation for the formation and utilization of secondary metabolites in medicinal plants.

Medicinal and edible plants used by the Lhoba people in Medog County, Tibet, China

ETHNOPHARMACOLOGICAL RELEVANCE

The Lhoba people are a small, ancient, tribal ethnic group from the Himalayas and are located in the Tibet Autonomous Region of China. Medog County is rich in biocultural diversity. For a long time, Medog has been almost isolated from the outside world. The Lhoba people, who live in Medog, have maintained a relatively unique lifestyle and have accumulated rich traditional knowledge (TK), especially about medicinal and edible plants. Currently, there is very little documentation of the plants traditionally used by the local Lhoba communities.

AIM OF THE STUDY

Our investigation aimed to (i) document the species of medicinal and food plants used by the Lhoba people in Medog County, Tibet, China; (ii) screen the most important plant taxa for specific medicines, and identify the aliments treated to further contribute to drug and food supplement research; and (iii) examine whether the ethnobotanical knowledge of the Lhoba is similar among different tribes and discuss traditional uses in the health practices and livelihoods of the local communities.

METHODS

Ethnobotanical data were recorded through semi-structured interviews, guided field trips, and quantitative analysis. The informant consensus factor (FIC) was used as a quantitative index.

RESULTS

Ninety-one informants (61 men and 30 women) were interviewed. A total of 75 species, including 37 medicinal plants for 14 categories of diseases and 57 edible plants from six types of food, were recorded. Among the usage types of medicinal plants, the highest FIC values were recorded for antidotes (FIC = 0.98), anthelmintics (FIC = 0.98), and treatments of gastrointestinal problems (FIC = 0.93). The FIC values for different types of edible plants were very similar. The most frequently used medicinal and food plants in the studied communities are Zanthoxylum motuoense, Crassocephalum crepidioides, and Swertia nervosa. According to the comparative study, few differences in the use of wild plants were found. There appeared to be more overlapping species between two Lhoba tribes in Medog, named Mixingba and Miguba, with 46 (61%) common species, compared with the Bo'gaer tribe in Milin, which had only two (2.7%) overlapping species. This might be due to the different geographical environments, vegetation types, and different influences of other ethnic cultures.

CONCLUSIONS

The Lhoba people in Medog County, Tibet, China, have rich TK about the uses of wild plants. However, the TK is seriously threatened due to environmental degradation and acculturation, and it showed signs of being forgotten and abandoned by the younger generation. Therefore, measures are urgently needed to document and protect the TK of the uses of the wild plant resources; and (i) the most frequently used medicinal and/or edible plants; (ii) the plants used to treat the most commonly mentioned diseases; and (iii) the endemic species that are widely used in Medog, which should be assessed for their potential future as food supplements and therapeutic products.

Triterpene saponins with anti-inflammatory activity from the stems of Entada phaseoloides

The phytochemical investigation of the ethanol extract from the stems of Entada phaseoloides (L.) Merr (also called "Guo Gang Long") led to the isolation of eleven triterpene saponins (1-11). Their structures were elucidated by extensive spectroscopic methods including 1D- ((1)H and (13)C) and 2D-NMR ((1)H-(1)H COSY, HSQC, HMBC, HSQC-TOCSY and ROESY) experiments as well as ESIMS analysis and hydrolysis. These saponins comprised entagenic acid as the main aglycon, saccharide moieties at C-3 and C-28, and esterification of C-2 or C-3 hydroxyl group of the terminal β-d-glucopyranose unit with a monoterpenic acid. To further explain the clinical applications of "Guo Gang Long" for its anti-inflammatory effect, the inhibitory activities on the production of NO of the saponins and the related aglycon, entagenic acid (12), were evaluated in vitro. The compounds containing a free hydroxyl at C-3 of aglycon (1 and 4) and entagenic acid showed significant activities against NO production in lipopolysaccharide-stimulated mouse macrophage RAW264.7 cells with IC50 values of 25.08, 20.13 and 23.48 μM, respectively. And the three compounds could also inhibit the release of pro-inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and IL-8.

Two new derivatives of 2, 5-dihydroxyphenylacetic acid from the kernel of Entada phaseoloides

Two new aromatic compounds, butyl 2,5-dihydroxyphenylacetate (1) and butyl 2-O-β-D-glucopyranosyloxy-5-dihydroxyphenylacetate (2), together with three known ones, methyl 2,5-dihydroxyphenylacetate (3), ethyl 2,5-dihydroxyphenylacetate (4) and 2-O-β-D-glucopyranosyloxy-5-hydroxyphenylacetic acid (5), were isolated from the EtOH extract of the kernel of Entada phaseoloides. The structures of the new compounds were elucidated by MS and NMR experiments. Compounds 1, 3 and 4 displayed potent inhibitory activities against HIV-1 replication, with EC₅₀ values of 9.80 μM, 11.70 μM and 9.93 μM, respectively.