Grayanotoxin-XVIII and grayanoside B, a new a-nor-b-homo-ent-kaurene and its glucoside from Leucothoe grayana

Micranthanosides I and II, two novel 1,10-secograyanane diterpenoids and their antinociceptive analogues from the leaves and twigs of Rhododendron micranthum

“…In the acetic acid-induced writhing test, compounds 17 and 19 showed signicant antinociceptive activity at a dose of 3 mg kg À1 and compounds 2, 6 and 32 showed signicant antinociceptive activity at a dose of 10 mg kg À1 . Grayananes and kalmanes such as 17,19,[29][30][31]33 are both antinociceptive and toxic components. In addition, micranthanoside IX (9) and rhodomicranoside F 26showed moderate anti-inammatory activity by reducing LPS-induced NO production in BV2 cells.…”

“…The 1 H and 13 C NMR data of 11 were similar to that of grayanotoxin-XVIII (17) except for signal of an additional sugar moiety. 19 The glucose unit was placed at C-6 as suggested by the HMBC correlations from H-1 0 to C-6. The NOESY correlations of H-3/H 3 -18, H-1/H-6, H-6/H 3 -18, H-1/ H 3 -18, H 3 -17/H-9, and H-9/H-15b indicated that H-1, H-3, and H-6 are a-oriented and H-9 and H 3 -17 are b-oriented.…”

“…The known compounds micranthanoside F (16), 13 grayanotoxin XVIII 17, 19 pierisformosin A (18), 20 6-deoxy-1-epigrayanotoxin XVII (19), 18 grayanotoxin IV 20, 21 grayanoside C (21), 22 grayanotoxin II (22), 23 grayanoside B (23), 19 micranthanosides C (24) and A (25), 13 rhodomicranoside F (26), 14 grayanotoxins I (27), 21 III 28, 24 VII 29, 25 IX 30, 26 and VIII (31), 26 19-sophorosyl kaurenoate (32), 27 kalmanol (33), 28 18446 | RSC Adv., 2019, 9,[18439][18440][18441][18442][18443][18444][18445][18446][18447][18448][18449][18450] This journal is © The Royal Society of Chemistry 2019…”

“…In contrast, in the same assay, ibuprofen inhibited 58.6% of the writhes when administered at a dose of 20 mg kg À1 while morphine inhibited 63.6% of the writhes when administered at a dose of 0.1 mg kg À1 . Compounds 17,19,[29][30][31](grayananes) and 33 (kalmane) produced antinociceptive effects at lower doses while showed toxic reactions at higher doses. Mice given higher doses showed reactions of nausea and convulsion, which is consistent with the clinical symptoms of "zhaoshanbai" poisoning.…”

A case of human poisoning by grayanotoxins following honey ingestion: elucidation of the toxin profile by mass spectrometry

“…In addition to the GrTx, related toxins such as asebotoxins, rhodojaponins, rhodomolleins, kalmitoxins, lyoniatoxins and craiobiotoxins are formed by different substitution of the skeleton (Figure 1 and Table 1). Up to now the occurrence of approximately 60 grayanane-type diterpenoids has been reported (Wood et al 1954;Tallent et al 1957;Hikino et al 1976;Sakakibara et al 1979;El-Naggar et al 1980;Burke & Doskotch 1990;Klocke et al 1991;Wang et al 1998;Zhang et al 2005Zhang et al , 2008Li et al 2013). Due to common structural features of grayanane-type toxins, their nomenclature is often confusing because derivatives are also designated as asebotoxins, rhodojaponine, andromedoto-, andromedol-, lyonia-, kalmia-and pieristoxins (Teuscher & Lindequist 1994).…”