Front Cover: Nitric Oxide Inhibitory Carbazole Alkaloids from the Folk Medicine Murraya tetramera C.C. Huang (Chem. Biodiversity 11/2020)

Front Cover . Carbazole alkaloids are a group of well‐known natural products possessing a broad range of intriguing pharmacological activities including antioxidant, cytotoxic, analgesic, antimicrobial, antidiarrheal, and anti‐inflammatory effects. Many of the biologically active carbazole alkaloids have been isolated from taxonomically related higher plants of the genera Murraya , Clausena , and Glycosmis from the family Rutaceae, among which, the genus Murraya is the most common plant source of this type of alkaloids. Murraya tetramera C.C. Huang, well‐known as “Qian‐Zhi‐Yan” in Chinese, is a shrub commonly distributed in the southeast of Yunnan Province and the west of Guangxi Province in China. This plant has been traditionally used as folk medicine for treating a series of inflammatory diseases such as coughs, bronchitis, eczema, and acute conjunctivitis. As part of our ongoing search for bioactive carbazoles from Murraya plant, the 95% aqueous ethanol extract of M. tetramera was chemically examined, yielding 19 simple carbazole alkaloids including two new ones (1‐ethoxy‐2‐hydroxy‐3‐methylcarbazole and 1,7‐dimethoxy‐8‐formyl‐2‐hydroxy‐3‐methylcarbazole). In the activity test experiment, most of the isolated compounds showed potent inhibitory activities on NO production in the LPS‐stimulated murine microglial cell line BV‐2, which supplies the evidences for traditional usage of M. tetramera as an anti‐inflammatory agent, as reported by Lyu et al . in their full paper at 10.1002/cbdv.202000490.