Structures and biological evaluation of phenylpropanoid derivatives from Dendrobium Sonia

Chiral resolution of furofuran lignans and their derivatives from the stems of Dendrobium 'Sonia'

Five new furofuran lignans and their derivatives, (-)-glaberide I 4-O-β-D-glucopyranoside (1a), (+)-glaberide I 4-O-β-D-glucopyranoside (1b), (+)-glaberide I 7'-ethoxy-4-O-β-D-glucopyranoside (2a), (-)-glaberide I 7'-ethoxy-4-O-β-D-glucopyranoside (2b), and (-)-isoeucommin A (3b), along with fifteen known analogs were isolated from the stems of Dendrobium 'Sonia'. These compounds were classified into ten pairs of enantiomers or diastereoisomers via chiral resolution, and their structures were determined based on extensive spectroscopic data. Their absolute configurations were determined by hydrolysis, comparison of experimental and calculated electronic circular dichroism (ECD) data, and single-crystal X-ray diffraction analysis. The isolates were evaluated for their ability to inhibit nitric oxide (NO) production in RAW264.7 cells. Among them, syringaresinol (5) exhibited prominent inhibition activity, with an IC50 value of 28.4 ± 3.0 μmol·L-1, and there was a slight difference between 5a, 5b and the racemic mixture 5.

Phenylpropanoid Derivatives from the Tuber of Asparagus cochinchinensis with Anti-Inflammatory Activities

Three undescribed phenylpropanoid derivatives, including two new bibenzyl constituents (1-2), one new stilbene constituent (3), together with five known compounds stilbostemin F (4), dihydropinosylvin (5), 2-(4-hydroxyphenyl)ethyl benzoate (6), 1-(4-hydroxybenzoyl)ethanone (7), and 4-hydroxy-3-prenylbenzoic acid (8), were isolated from the tuber of Asparagus cochinchinensis. The structures of 1-8 were elucidated according to UV, IR, HRMS, 1D and 2D-NMR methods together with the published literature. All of the isolated compounds were assessed for anti-inflammatory activity by acting on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells in vitro. The results showed that compounds 2 and 5 were found to inhibit the production of nitric oxide (NO) with the IC₅₀ value of 21.7 and 35.8 µM, respectively. In addition, further studies found that compound 2 demonstrated concentration-dependent suppression of the protein expression of iNOS and exerted anti-inflammatory activity via the NF-κB signalling pathway. The present data suggest that phenylpropanoid derivatives from the tuber of A. cochinchinensis might be used as a potential source of natural anti-inflammatory agents.

Structures and Anti-Inflammatory Evaluation of Phenylpropanoid Derivatives from the Aerial Parts of Dioscorea polystachya

Seven undescribed phenylpropanoid constituents, including three new bibenzyl derivatives (1–3) along with four new benzofuran stilbene derivatives (4–7), were isolated from the aerial parts of Dioscorea polystachya. The structures of these compounds were elucidated using a combination of spectroscopic analyses, including UV, IR, HRESIMS, 1D, and 2D NMR. Further, all the compounds were evaluated on the anti-inflammatory activity for their inhibition of nitric oxide (NO) production by RAW 264.7 macrophages cells, and some of them (1–3 and 6) displayed inhibitory activity with IC₅₀ values in the range of 9.3–32.3 μM. Moreover, compound 3 decreased the expression of iNOS in Western blot analysis, suggesting compound 3 is mediated via the suppression of an LPS-induced NF-κB inflammasome pathway.

Traditional Uses and Pharmacologically Active Constituents of Dendrobium Plants for Dermatological Disorders: A Review

Dendrobium Sw. is one of the largest genera in the orchidaceous family and includes 900-2000 species. Among them, more than 80 Dendrobium species have been reported in China. However, there are only six Dendrobium species, namely, D. bigibbum var. superbum (syn. D. phalaenopsis), D. chrysanthum, D. fimbriatum, D. loddigesii, D. nobile, and D. officinale (syn. D. candidum), listed in the New Inventory of Existing Cosmetic Ingredients in China Launched. Artificial planting of Dendrobium species has been a great success in China. To better utilize Dendrobium resources for medicinal and cosmetic purposes, we summarize their traditional uses and pharmacologically active compounds for treating dermatological disorders in this review. "Orchidaceae", "Dendrobium", "traditional use", "ethnobotany", "dermatological disorder", and "skin disease" were used as search terms to screen the literature. Cited references were collected between 1970 and 2020 from the Web of Science, China National Knowledge Internet (CNKI), SciFinder, Google Scholar, and Chinese books. From the search, it was found that there are 22 Dendrobium species with traditional uses in dermatological disorders, and 131 compounds from Dendrobium plants have been reported to possess anti-inflammatory, antimicrobial, antioxidant, antiaging, anti-psoriasis, and tyrosinase-inhibitory activities, implying that Dendrobium plants are important resources for the discovery of active compounds and the development of new drugs and cosmetics. D. crepidatum, D. denneanum, D. loddigesii, D. nobile, and D. officinale have been extensively studied. More research on other Dendrobium species is needed. The major active compounds found in Dendrobium species are phenanthrenes, alkaloids, flavonoids, phenylpropanoids, and lignans. Several compounds, such as loddigesiinol A, (S)-5-methoxy-2,4,7,9-tetrahydroxy-9,10-dihydrophenanthrene, (S)-4-methoxy-2,5,7,9-tetrahydroxy-9,10-dihydrophenanthrene, 2,5-dihydroxy-4-methoxy-phenanthrene 2-O-β-D-glucopyranoside, (9R)-1,2,5,9-tetrahydroxy-9,10-dihydrophenanthrene 5-O-β-D-glucopyranoside, (+)-homocrepidine A, and vicenin 2, have significant anti-inflammatory activities and inhibit nitric oxide (NO) production with IC50 values less than 5 μM, and these compounds are worthy of further study.

Antidiabetic and antimicrobial flavonoids from the twigs and roots of Erythrina subumbrans (Hassk.) Merr

The phytochemical investigation of the twig and root extracts of Erythrina subumbrans (Hassk.) Merr. (Fabaceae) resulted in the isolation and identification of a new pterocarpan, erythrinocarpan (1), along with 27 known compounds (2-28). All isolated compounds were evaluated for their antidiabetic, antimicrobial, and anti-inflammatory properties. Compounds 3, 8, 9, and 22 had α-glucosidase inhibitory activity with IC50 values of 13.4 ± 0.05, 24.5 ± 0.13, 29.0 ± 0.05, and 12.8 ± 0.14 μM, respectively, while compound 2 inhibited α-amylase activity with an IC50 value of 67.6 ± 1.12 μM. Compounds 22 and 24 inhibited glycation activity with the IC50 values of 36.9 ± 0.62 and 40.5 ± 0.37 μM, respectively. From cell-based assays, compound 27 showed the highest ability to induce glucose consumption (IC50 29.1 ± 0.86 μM) and glucose uptake (2.8-fold), and to inhibit nitric oxide (NO) production (IC50 52.5 ± 0.56 μM) without cell toxicity. Furthermore, compound 9 showed antimicrobial activities against Gram-positive bacteria and fungi with MIC values ranging from 2-4 μg/mL.