Two novel bioactive sulfated guaiane sesquiterpenoid salt alkaloids from the aerial parts of Scorzonera divaricata.

Extracts of the aerial parts of Scorzonera divaricata afforded sulfoscorzonin D (1) and sulfoscorzonin E (2), two novel pyrrolidine inner salt alkaloids with a sulfated guaiane sesquiterpene lactone nucleus, along with 22 known compounds. Especially, sulfoscorzonin D containing a unusual monoterpene moiety is very rare. The structures of new compounds were established using spectroscopic analysis including one- and two-dimensional NMR and HRESIMS. The cytotoxicities of compounds 1-4 and 10 against three tumor cell lines (K562, Hela, and HepG2) were evaluated using the MTT assay. Compounds 2 and 10 exhibited moderate cytotoxic activity. The biological properties of 1-3, 5-8, 10-14, and 16-24, were screened against nine different gram-positive and gram-negative bacteria. Compounds 1, 5-8, 10, and 18, showed potent antibacterial activities.

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Glucozaluzanin C (PubChem CID: 442320); 1β,4α-dihydroxy-5α,6β,7α,11βH-eudermn-12; 6-olide (CID: 11119093); oleanolic acid (CID: 10494); lup-20(29)-ene-3β,28-diol (CID: 72326); (22E)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (CID: 5469431); ergosta-3β,5α, 6β-trialcohol (CID: 44558918); stigma-5-en-3-O-β-glucoside (CID: 5742590); vomifoliol (CID: 12444927); trans-caffeic acid (CID: 689043); trans-p-hydroxy coumaric acid (CID: 637542); 4-hydroxy-3-methoxyphenyl ferulate (CID: 11500646); 7,3',4'-trihydroxyflavonol (CID: 5281614); tricin (ID: 5281702); luteolin (CID: 5280445); diosmetin (CID: 5281612); 5,7-dihydroxy-8-methoxyflavone (CID: 5281703); 5,7-dihydroxy-6-methoxyflavone (CID: 5320315); methyl-3,4-dihydroxy benzoate (CID: 287064); m-hydroxy benzoic acid (CID: 7420); 7-hydroxy-coumarin (CID: 5281426); and scopoletin (CID: 5280460).