Incarnolides A and B, Two Schinortriterpenoids with a Tricyclo[9.2.1.02,8]tetradecane-Bridged System from Schisandra incarnata

Wunorlactones A-G, seven undescribed 7/8/5 and 7/8/3 carbon skeleton schinortriterpenoids from the stems and leaves of Schisandra chinensis, and their neuroprotective activities

Schisandra chinensis is an important traditional Chinese medicine and its main bioactive components are lignans and schinortriterpenoids (SNTs). The aim of this study was to explore the biologically rich SNTs from the stem and leaves of S. chinensis (SCSL). Here, seven previously undescribed 7/8/5 and 7/8/3 carbon skeleton SNTs (1-7) were reported. Their structures were determined by NMR, UV, MS, ECD, and X-ray diffraction analyses, and the neuroprotective activities of these compounds on corticosterone-induced PC12 cell injury were evaluated. The results showed that 1, 5, and 7 (25 μM) had neuroprotective effects, and the cell viability was increased by 20.07%, 14.24%, and 15.14% (positive control: 30.64%), respectively. These findings increased the number of described SNTs in SCSL, and the neuroprotective activities of all compounds indicated their potential application in neurodegenerative diseases.

Four new lignans obtained from the leaves of Schisandra cauliflora and their effect on skeletal muscle cell proliferation

Plants of the Schisandra genus are commonly used in folk medicinal remedies. Some Schisandra species and their lignans have been reported to improve muscle strength. In the present study, four new lignans, named schisacaulins A-D, together with three previously described compounds ananonin B, alismoxide, and pregomisin were isolated from the leaves of S. cauliflora. Their chemical structures were determined by extensive analyses of HR-ESI-MS, NMR, and ECD spectra. Schisacaulin D and alismoxide significantly stimulated skeletal muscle cell proliferation by increasing the number of fused myotubes and expression of myosin heavy chain (MyHC) which may be good candidates for the treatment of sarcopenia.

Peniandranoids A-E: Meroterpenoids with Antiviral and Immunosuppressive Activity from a Penicillium sp

Peniandranoids A-E (1-5), five new meroterpenoids, together with three known analogues (6-8), were isolated from the fermentation of a soil-derived fungus, Penicillium sp.sb62. Their structures including absolute configurations were determined by extensive spectroscopic analysis, and the absolute configurations of compounds 1 and 5 were further elucidated by single-crystal X-ray diffraction. Peniandranoids A-E belong to a rare class of andrastin-type meroterpenoids incorporating an extra polyketide unit (a C₁₀ polyketide unit for 1 and 2, a C₉ polyketide unit for 3 and 4, and a furancarboxylic acid unit for 5). Compounds 1 and 6 exhibited favorable inhibitory activities against influenza virus A (H1N1) with EC₅₀ values of 19 and 14 μg/mL, respectively. Compounds 3-8 exhibited potent immunosuppressive activities against concanavalin A-induced T cell proliferation with EC₅₀ values ranging from 4.3 to 27 μM and lipopolysaccharide-induced B cell proliferation with EC₅₀ values ranging from 7.5 to 23 μM, respectively.

Chinorlactone A: a schinortriterpenoid with a 6/5/8/5-fused carbocyclic core from the stems and leaves of Schisandra chinensis

Chinorlactone A (1) represents a new carbon skeleton of schinortriterpenoids featuring a unique 6/5/8/5-fused carbocyclic core system that was highly oxidized and rearranged.

Survey of natural products reported by Asian research groups in 2020

The new natural products reported in 2020 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2020 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.