Rui-Juan Li

Marsupellins A-F, ent-longipinane-type sesquiterpenoids from the Chinese liverwort Marsupella alpine with acetylcholinesterase inhibitory activity.

Acetylcholinesterase (AChE) inhibitory activity-guided fractionation of the Chinese liverwort Marsupella alpine afforded six new [marsupellins A-F (1-6)] and three known (7-9) ent-longipinane-type sesquiterpenoids. The structures were determined from MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1-9 exhibited moderate to weak AChE inhibitory activity.

Highly Oxygenated ent-Pimarane-Type Diterpenoids from the Chinese Liverwort Pedinophyllum interruptum and Their Allelopathic Activities

Ten highly oxygenated ent-pimarane-type diterpenoids, pedinophyllols A-J (1-10), were isolated from the Chinese liverwort Pedinophyllum interruptum. Their structures were determined by comprehensive analysis of spectroscopic data together with single-crystal X-ray diffraction analysis. The absolute configurations were elucidated by comparison of experimental and theoretically calculated electronic circular dichroism spectra. Allelopathic testing showed that several new diterpenoids inhibited germination of Arabidopsis thaliana seeds.

Hapmnioides A–C, Rearranged Labdane-Type Diterpenoids from the Chinese Liverwort Haplomitrium mnioides

Many exceptional labdane-type diterpenoids have been exclusively found in liverworts, which serve as taxonomic molecules or play important ecological roles in interactions among organisms. Three unprecedented labdane-type diterpenoids hapmnioides A (1), B (2), and C (3) formed through cascade rearrangement from the Chinese liverwort Haplomitrium mnioides are reported. Their structures were established by comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction, and their anti-inflammatory activities were also preliminarily tested.

Cembrane-type diterpenoids from the Chinese liverworts Chandonanthus hirtellus and C. birmensis.

Six new cembrane-type diterpenoids (1-6) were isolated from two species of Chandonanthus: Chandonanones A, B, and D-F (1, 2, and 4-6) were isolated from C. hirtellus, and chandonanones B, C, E, and F (2, 3, 5, and 6) from C. birmensis. Five known diterpenoids, (8E)-4α-acetoxy-12α,13α-epoxycembra-1(15),8-diene (7), isochandonanthone (8), chandonanthone (9), anadensin (10), and 2,10,14-triacetoxy-7,8,18,19-diepoxydolabell-3(E)-ene (11), were also obtained. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). The absolute configurations of compounds 1 and 2 were unequivocally confirmed using single-crystal X-ray diffraction analysis with Cu Kα radiation. Cytotoxicity tests of the isolated diterpenoids against seven cancer cell lines (DU145, PC3, A549, PC12, NCI-H292, NCI-H1299, and A172) revealed that some of the diterpenoids had weak activity.

Terpenoids from the Chinese liverwort Plagiochila pulcherrima and their cytotoxic effects

Three new pimarane-type diterpenoids, 7β,11α-dihydroxypimara-8(14),15-diene (1), 1β,11α-dihydroxypimara-8(14),15-diene (2), and 11α-hydroxypimara-8(14),15-diene (3), five 2,3-secoaromadendrane-type sesquiterpenoids, including a new one, ethyoxyplagiochiline A2 (4), and three known fusicoccane-type diterpenoids were isolated from the Chinese liverwort Plagiochila pulcherrima. Their structures were established on the basis of extensive spectroscopic analysis. Compounds 6 and 7 exhibited moderate inhibitory activity on the proliferation of human cancer cell lines Hela, A172, and H460. Moreover, the cytotoxicity of compound 6 to Hela cells was related to apoptotis as confirmed by DAPI nuclear staining and flow cytometry.

cis-clerodane diterpenes from the liverwort Scapania ciliata.

Chemical investigation of the Chinese liverwort Scapania ciliata led to the isolation of four new cis‐clerodane lactones, named ciliatolides A–D (1–4, resp.), among which compound 1 was found to be a tetranorclerodanoid. Their structures were determined by extensive analysis of spectroscopic data, and, in the case of compound 1, together with a single‐crystal X‐ray diffraction analysis. The absolute configurations were established by analysis of the CD spectra and by quantum‐chemical CD calculations. The cytotoxicities of compounds 1–4 were preliminarily tested against the PC3 and MCF‐7 cell lines.

Four New Kaurane Diterpenoids from the Chinese Liverwort Jungermannia comata Nees.

In our continuing program to find new bioactive compounds from the Chinese liverworts, four new kaurane‐type diterpenoids, (6β)‐kaur‐16‐ene‐6,9‐diol (1), (6β,12β)‐kaur‐16‐ene‐6,9,12‐triol (2), (6β)‐kaur‐16‐ene‐5,6,9‐triol (3), and kaur‐16‐ene‐9,19‐diol (4), have been isolated from the Chinese liverwort Jungermannia comata Nees. Five known kaurane‐type diterpenoids (5 – 9) and four known trachylobane‐type diterpenoids (10 – 13) were also obtained. The structures of the new compounds were established unequivocally on the basis of spectroscopic data. The absolute configuration of compound 1 was established by comparing experimental and calculated electronic circular dichroism spectra.

Chemical and antioxidant responses of the Chinese liverwort Plagiochasma appendiculatum to water-deficit stress

Abstract Chemical and antioxidant responses of the water-deficit tolerant Chinese liverwort, Plagiochasma appendiculatum, to water-deficit stress were investigated in this study. The results showed that water-deficit stress could increase the accumulation of the main bisbibenzyl, riccardin D (RD), and the level of the expression of genes related to production of RD. Activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), soluble protein and malondialdehyde (MDA) content could be used as indicators of the degree of damage to plants under different water-deficit stresses. Among these indicators, SOD played a significant role in defense against water stress when humidity is higher than 40 ± 5% RH (relative humidity), while the activities of POD and CAT were inhibited. However, when humidity is lower than 40 ± 5% RH, POD and CAT activities were accelerated, and if water-deficit reached serious levels (≤ 20 ± 5% RH), POD activity was inhibited, while CAT activity was long-lasting and enhanced; soluble protein and MDA content exhibited the opposite trend. Below 70 ± 5% RH, MDA contents were the highest among all treatments, suggesting that over-wetting is a significant stress for this liverwort. Content of MDA is higher after one week rather than two weeks, suggesting that the liverwort has the ability to eliminate MDA produced by membrane lipid peroxidation. The results of this study provide optimized soil humidities to improve the production of riccardin D in a cultivated liverwort.