Yun-Heng Shen

Two new diterpenoids from Coleus forskohlii.

Two new diterpenoids, forskolins I and J, have been isolated in our further investigation on Coleus forskohlii (Willd.) Briq. collected in Yunnan Province. Their structures have been determined as 1α,6β-diacetoxy-7β,9α-dihydroxy-8,13-epoxylabd-14-en-11-one (1) and 1α,9α-dihydroxy-6β,7β-diacetoxy-8,13-epoxylabd-14-en-11-one (2) by spectral methods (including 1D and 2D NMR techniques).Two new diterpenoids, forskolins I and J, have been isolated in our further investigation on Coleus forskohlii (Willd.) Briq. collected in Yunnan Province. Their structures have been determined as 1alpha,6beta-diacetoxy-7beta,9alpha-dihydroxy-8,13-epoxylabd-14-en-11-one (1) and 1alpha,9alpha-dihydroxy-6beta,7beta-diacetoxy-8,13-epoxylabd-14-en-11-one (2) by spectral methods (including 1D and 2D NMR techniques).

Two new rearranged abietane diterpenoids from tropical Isodon coetsa

Two new rearranged abietane diterpenoids, sincoetsin A (1) and sincoetsin B (2), were isolated from the aerial part of Isodon coetsa (Buth-Ham ex D.Don) Hara collected in Singapore, and their structures were determined by spectroscopic methods, especially 2D NMR techniques.

Coumarins from Coriaria nepalensis.

Two new coumarins (1) and (2), along with seven known coumarins 3–9, were isolated from the leaves and stems of Coriaria nepalensis Wall. The two new compounds were established as 7-hydroxy-6-methoxy-3,8-bis(3-methyl-2-butenyl) coumarin (1) and 7-hydroxy-6-methoxy-3-(3-methyl-2-butenyl) coumarin (2), on the basis of 1D and 2D NMR techniques. The known compounds 3, 6–9 were isolated from this plant for the first time.

Four new coumarin glucosides from the roots of Heracleum rapula

Four new coumarin glucosides, 7-O-[β-D-glucopyranosyl-(1R 2) -β-D-glucopyranosyl]demethylsuberosin (1), 8-O-[β-D-apiofuranosyl-(1R 6) -β-D-glucopyranosyl]-8-hydroxybergapten (2), 8-O-[β-D-apiofuranosyl-(1R 6) -β-D-glucopyranosyl]xanthotoxol (3), and 5-O-[β-D-glucopyranosyl-(1R 6) -β-D-glucopyranosyl]-8-hydroxybergaptol (4), were isolated from the roots of Heracleum rapula. The structures of these compounds were determined on the basis of their 1D NMR, 2D NMR and HRMS spectral data. Their inhibitory effects on rabbit platelet aggregation respectively induced by PAF, AA and APD were tested. Weak to moderate inhibitory activities for each compound were observed.