Stilbene Derivatives from the Leaves and Stems of Bletilla striata and their Cytotoxicity and Autophagy Activity

• Published in: Chemistry of natural compounds 2021-05, Vol.57 (3), p.462-467
• Main Authors: Wang, Da-Wei, Wu, Fan, Zhu, Ya-Ning, Liu, Lu, Miao, Dong, Zhou, Min, Wang, Wei-Guang, Hu, Qiu-Fen, Yue, Jian-Bo
• Format: Article
• Language: English
• Subjects: Apoptosis; Autophagy; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cytotoxicity; Fluorescence; Leaves; NMR; Nuclear magnetic resonance; Organic Chemistry; Plant Sciences; Stilbene; Toxicity
• ISSN: 0009-3130; 1573-8388
• DOI: 10.1007/s10600-021-03388-w

Two new compounds ( 1 and 2 ), together with five known ( 3–7 ) stilbene derivatives, were isolated from the leaves and stems of Bletilla striata. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their cytotoxicity against five human tumor cell lines. Compound 1 showed cytotoxicity against SHSY5Y and MCF7 cells with IC 50 values of 2.8 and 2.2 μM. Compound 2 showed cytotoxicity against SHSY5Y and MCF7 cells with IC 50 values of 2.2 and 2.4 μM, respectively. Moreover, compound 1 was found to trigger both apoptosis and autophagy in Hela cells, as indicated by increased cleaved PARP and LC3B, respectively. The enhanced autophagy induced by compound 1 was further confirmed by imaging detection of more autophagosomes (mRFP–GFP–LC3+ puncta) and autolysosomes (mRFP–LC3+ puncta), as well as a low GFP/RFP fluorescence ratio of GFP-LC3-RFP. Signal pathway analysis indicated compound 1 might inhibit mTOR signaling to stimulate autophagy.