“…In addition, C(2) of a 2-deoxysugar (cymarose (¼ 2,6-dideoxy-3-O-methyl-ribo-hexose), digitoxose (¼ 2,6-dideoxy-ribo-hexose), or diginose (¼ 2,6dideoxy-3-O-methyl-lyxo-hexose) that possesses an a-l-configuration usually appears in the 13 C-NMR spectrum at d(C) ca. 32.0 or less, while that of a b-configured 2deoxysugar normally resonates at a lower field with a d(C) larger than 34.0 [22] [23]. All the sugar units in the steroidal glycosides obtained in this study were thus tentatively established by 1 H-and 13 C-NMR analysis during the initial structure elucidation and were finally determined by optical-rotation analysis of the sugars obtained from their acidic hydrolyzates.…”
Six new polyhydroxypregnane glycosides, namely cynotophyllosides A -F (1 -6), together with five known steroids, were isolated from the roots of Cynanchum otophyllum. Their structures were elucidated by extensive spectroscopic methods (especially 2D-NMR techniques) and acid-catalyzed hydrolysis. Furthermore, high field 1D-and 2D-NMR experiments were employed to elucidate the structure of 8 previously deduced only on the basis of LC/MS data.
“…In addition, C(2) of a 2-deoxysugar (cymarose (¼ 2,6-dideoxy-3-O-methyl-ribo-hexose), digitoxose (¼ 2,6-dideoxy-ribo-hexose), or diginose (¼ 2,6dideoxy-3-O-methyl-lyxo-hexose) that possesses an a-l-configuration usually appears in the 13 C-NMR spectrum at d(C) ca. 32.0 or less, while that of a b-configured 2deoxysugar normally resonates at a lower field with a d(C) larger than 34.0 [22] [23]. All the sugar units in the steroidal glycosides obtained in this study were thus tentatively established by 1 H-and 13 C-NMR analysis during the initial structure elucidation and were finally determined by optical-rotation analysis of the sugars obtained from their acidic hydrolyzates.…”
Six new polyhydroxypregnane glycosides, namely cynotophyllosides A -F (1 -6), together with five known steroids, were isolated from the roots of Cynanchum otophyllum. Their structures were elucidated by extensive spectroscopic methods (especially 2D-NMR techniques) and acid-catalyzed hydrolysis. Furthermore, high field 1D-and 2D-NMR experiments were employed to elucidate the structure of 8 previously deduced only on the basis of LC/MS data.
“…Furthermore, a survey of glycosides from the Asclepiadaceae family reveals that all the β-linked 2,6dideoxysugars have the D-configuration, whereas the α-linked sugars are mostly L-sugars. [13,14] To the 2,6dideoxysugars obtained in this study, most significant differences in the 13 C-NMR data between D-and Lsugars are the shift of C-2, in the L-formed 2deoxysugar it is ca. 32.0 ppm or less, while that of C-2 in the D-formed sugar appears above 34.0 ppm.…”
Seven new polyhydroxypregnane glycosides, named cynotophyllosides P–V, together with three known analogs were isolated from the roots of Cynanchum otophyllum C.K.Schneid. Their structures were elucidated by a variety of spectroscopic techniques, as well as acid‐catalyzed hydrolysis. All isolates were tested for their immunological activities in vitro against Con A‐ and LPS‐induced proliferation of mice splenocytes. Immunoenhancing (for 1, 9) and immunosuppressive (for 2) activities were observed. Furthermore, cynotophylloside R (3) showed immunomodulatory as it enhanced the proliferation of splenocytes in low concentration and suppressed immune cells in concentration more than 1.0 μg/ml.
“…These results were actually inspired by the hypothesis of the biosynthetic pathway of Daphniphyllum alkaloids that is the “premature” involvement of amines in the formation of molecular skeletons, which lead to the structural diversity of Daphniphyllum alkaloids in Daphniphyllum species. The structural diversity of plant natural products derived from the diversity of biosynthetic pathways is also mirrored by other new natural products, such as alkaloids [ 63 – 80 ], terpenoids [ 81 – 113 ], polyphenols [ 114 – 123 ], and steroids [ 124 – 128 ] rooted from the plentiful plant resources in Southwest China. Fig.…”
Section: Mining Novel Phytochemical Structures From Diverse Plants Inmentioning
Xiaojiang Hao, who obtained Master Degree from Kunming Institute of Botany (KIB), Chinese Academy of Sciences (CAS) in 1985, and Doctor in Pharmacy degree in Pharmacy from Institute for Chemical Research, Kyoto University, in 1990, was born in Chongqing in July, 1951. In 1991, he returned to KIB, CAS, as an Associate professor and served as the chair of the Department of Phytochemistry. In 1994, he was promoted to a full professor at the current institute. He served as the Deputy Director of KIB and the Director of Open Laboratory of Phytochemistry from 1995 to 1997, and the Director of KIB from 1997 to 2005. Professor Hao has published more than 450 peer-reviewed SCI papers, which have been cited over 6000 times. He has obtained one PCT patent and 23 patents in China. Due to his tremendous efforts, one candidate drug, phenchlobenpyrrone, has entered the Phase II clinical trail for the treatment of Alzheimer’s disease. Moreover, he won the First Prize of Natural Sciences in Yunnan Province for three times, and Ho Leung Ho Lee Fund Science and Technology Innovation Award in 2017.Graphical Abstract
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