Two Novel Flavonoids and Cytotoxicity Evaluation from Cryptocarya yunnanensis

Abstract

Two new flavonoids, cryunchalcone (1) and cryptoyunnanone I (2), were isolated from the leaves and twigs of Cryptocarya yunnanensis. Their structures were elucidated by the detailed spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Cryunchalcone (1) is a biflavonoid constructed by a dihydrochalcone coupled with a chalcone through an unprecedented C‐2′′−C‐6 linkage. Cryptoyunnanone I (2) is a unique complex flavanone bearing a phenylpropanoid moiety.

The Genus Cryptocarya: A Review on Phytochemistry and Pharmacological Activities

“…After repeating silica gel CCs, Sephadex LH‐20, and semipreparative HPLC, nine new complex flavanones cryptometcones A–I ( 267 – 275 ) were purified from the 95 % ethanol extract of C. metcalfiana leaf and twig [93] . In the same manner, the chemical structures of other complexes cryptoyunanone A–I ( 276 – 284 ), nine new compounds were detected in C. yunnanesis leaf and twig, were elucidately by NMR and single‐crystal X‐ray crystal analyses [3,79] . Usman et al also isolated and structurally analysed a new flavanone 7‐hydroxy‐5,6‐dimethoxyflavanone ( 288 ) from C. costata bark [87] .…”

“…Flavonoids type flavanones are a chemical class of naturally occurring flavones that are available in this genus. For Table 1 and Figure 4, a list of eighty‐one compounds 227 – 297 were summarized, as well their resource included C. chartacea , C. chinensis , C. chingii , C. concinna , C. costata , C. infectoria , C. impressinervia , C. konishii , C. kurzii , C. metcalfiana , C. maclurei , C. obovata , C. rubra , C. strictifolia , and C. yunnanesis [3–6,37,66,71,79,83,86–94] . Pinocembrin ( 296 ) was likely to be the main compound in this group.…”

“…[93] In the same manner, the chemical structures of other complexes cryptoyunanone A -I (276 -284), nine new compounds were detected in C. yunnanesis leaf and twig, were elucidately by NMR and single-crystal X-ray crystal analyses. [3,79] Usman et al also isolated and structurally analysed a new flavanone 7-hydroxy-5,6dimethoxyflavanone (288) from C. costata bark. [87] In the search for cytotoxic agents from medicinal plants, four new complex flavanones kurziflavolactones A -D (290 -293) were determined to appear in the ethanol extract of C. kurzii leaf.…”

“…Chalcones and C. yunnanesis [3,5,66,70,81,82,[85][86][87][88][89][90][91][92] (Figure 4). Cryptocaryone (298), which was first obtained from the hexane extract of C. bourdilloni root as yellow crystallines, was structurally established as a new chalcone.…”

“…Cryptocarya is a genus of 350 evergreen plants belonging to the family Lauraceae, and is widely distributed in the tropics and subtropics except for central Africa [2,3] . This genus is renowned for containing diverse secondary metabolites, such as alkaloids, α‐pyrones, and flavonoids [4–9] .…”