Indole Alkaloids and Chromones from the Stem Bark of Cassia alata and Their Antiviral Activities

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 10; p. 3129
• Main Authors: Yang, Pei-Song, Dai, Jia-Meng, Gu, Xue-Jiao, Xiong, Wen, Huang, De-Quan, Qiu, Shi-Yu, Zheng, Jun-Na, Li, Yong, Yang, Feng-Xian, Zhou, Min
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.05.2022; MDPI
• Subjects: Alkaloids; Alkaloids - pharmacology; anti-rotavirus activities; anti-TMV activities; Antiviral agents; Antiviral Agents - chemistry; Bark; Biological properties; Carbon; Cassia - chemistry; Cassia alata; Chromatography; chromones; Chromones - chemistry; Column chromatography; Drug development; Drug screening; High performance liquid chromatography; Hydrocarbons; Indole Alkaloids; Indoles; Liquid chromatography; Metabolites; NMR; Nuclear magnetic resonance; Plant Bark; Rotavirus; Senna Plant; Silica; Silica gel; Skin diseases; Substitution reactions; Tobacco; Tobacco Mosaic Virus; Viruses; anti-TMV activities; indole alkaloids; anti-rotavirus activities; chromones; Cassia alata
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27103129

The (Leguminosae) genus has attracted a lot of attention as a prolific source of alkaloids and chromones with diverse structures and biological properties. The aim of this study is to screen the antiviral compounds from . The extract of the stem bark of this plant was separated using silica gel, MCI, ODS C18, and Sephadex LH-20 column chromatography, as well as semi-preparative HPLC. As a result, three new indole alkaloids, alataindoleins A-C (1-3); one new chromone, alatachromone A (4); and a new dimeric chromone-indole alkaloid, alataindolein D (5) were isolated. Their structures were determined by means of HRESIMS and extensive 1D and 2D NMR spectroscopic studies. Interestingly, alataindolein D (5) represents a new type of dimeric alkaloid with an unusual N-2-C-16' linkage, which is biogenetically derived from a chromone and an indole alkaloid via an intermolecular nucleophilic substitution reaction. Compounds 1-5 were tested for their anti-tobacco mosaic virus (TMV) and anti-rotavirus activities, and the results showed that compounds 2-4 showed high anti-TMV activities with inhibition rates of 44.4%, 66.5%, and 52.3%, respectively. These rates were higher than those of the positive control (with inhibition rate of 32.8%). Compounds 1 and 5 also showed potential anti-TMV activities with inhibition rates of 26.5% and 31.8%, respectively. In addition, compounds 1-5 exhibited potential anti-rotavirus activities with therapeutic index (TI) values in the range of 9.75~15.3. The successful isolation and structure identification of the above new compounds provided materials for the screening of antivirus drugs, and contributed to the development and utilization of .