Neolignans and Diarylheptanoids with Anti-Inflammatory Activity from the Rhizomes of Alpinia zerumbet.

The dried leaves and rhizomes of Alpinia zerumbet have been traditionally used as food and medicine. Anti-inflammatory activity-guided phytochemical investigation into the rhizomes of A. zerumbet led to the isolation of 17 compounds including 10 neolignans (1-10, 1a, 1b, 2a, 2b, 3a, 3b, 4, and 5 are new compounds) and seven diarylheptanoids (11-17) in which 1-3 were three pairs of enantiomers. 4 was only one enantiomer and 5 was a racemic mixture. Compounds 1a, 1b, 2a, and 2b incorporated an 8',9'-dinorneolignan skeleton, which was rare in the lignan family. The planar structures of these compounds were elucidated by extensive analyses of spectroscopic data. The relative and absolute configurations were determined by the time-dependent density functional theory (TDDFT)-based electronic circular dichroism (ECD) calculation method. The 95% ethanol extract and ethyl acetate extract of A. zerumbet were found to show anti-inflammatory activity against croton oil-induced ear edema in mice with inhibition rates of 20.0 and 47.6% at a dose of 80 mg/kg, respectively. Bioassays showed that compounds 1a, 1b, 2a, 2b, and 12 moderately inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 cells with IC50 values of 3.62, 7.63, 6.51, 5.60, and 8.33 µM, respectively.

Novel nortriterpenoids with new skeletons and limonoids from the fruits of Evodia rutaecarpa and their bioactivities.

Two novel nortriterpenoids together with 7 known compounds were isolated from the fruits of Evodia rutaecarpa. The structures of the new compounds were elucidated by spectroscopic analysis, X-ray, and electronic circular dichroism (ECD) calculations. Compound 1 is the first example of triterpenoid with a 27 (17 â†’ 12)-abeo-five-ring skeleton. In turn, compound 2 possesses a unique C/D/E linear fused ring system and a methyl on C-21. Plausible biogenetic pathway for the new compounds 1 and 2 are also proposed. Compound 1 exhibited significantly antitumor activity against A549 and LoVo cells with IC50 values of 2.0 µM and 1.9 µM, respectively. Colony formation inhibition, cell cycle arrest and cell apoptosis of compound 1 were also evaluated. Compound 2, 6, 7 and 9 showed potent neuroprotective activities against serum-deprivation induced P12 cell damage.

Marine natural products as antifouling molecules - a mini-review (2014-2020).

In the present review, 182 antifouling (AF) natural products from marine microorganisms, algae and marine invertebrates reported from August 2014 to May 2020 are presented. Amongst these compounds, over half were isolated from marine-derived microorganisms, including 70 compounds from fungi and 31 compounds from bacteria. The structure-relationship of some of these compounds is also briefly discussed. Based on the work reported, a general workflow was drafted to refine the procedures for the commercialization of any novel AF compounds. Finally, butenolide, which is considered a potential environmentally friendly antifoulant, is used as a case study to show the procedures involved in AF compound work from the aspect of discovery, structure optimization, toxicity, stability, AF mechanism and coating incorporation, which highlight the current challenges and future perspectives in AF compound research.

Two new stilbenoids from Bletilla striata.

Two new stilbenoids bletilol D (1) and bletilol E (2), together with five known compounds were isolated from Bletilla striata. Three of them (3, 4, and 7) were obtained from this genus for the first time. Their structures were elucidated by spectroscopic methods and comparing with data reported in literatures. The cytotoxic activities of compounds 1-7 against MCF-7 (human breast cancer) and A549 (human lung carcinoma) cell lines were evaluated by MTT assay. Compound 2 showed weak cytotoxicity against MCF-7 and A549 cell lines with IC50 values of 36.32 ± 1.17 and 36.48 ± 1.12 µM, respectively, and 5 exhibited weak cytotoxicity against MCF-7 cell line with IC50 value of 57.09 ± 2.03 µM.