(±)-Acortatarinowins A–F, Norlignan, Neolignan, and Lignan Enantiomers from Acorus tatarinowii

Abstract

Three pairs of new 8-O-4'-type dinorneolignan enantiomers, (±)-acortatarinowins A-C (1a/1b-3a/3b), a pair of new 8-O-4'-type (4a/4b) and a pair of rare C7-C8'-type (5a/5b) neolignan enantiomers, (±)-acortatarinowins D and E, and a pair of new furofuran-type lignan enantiomers, (±)-acortatarinowin F (6a/6b), along with two pairs of known lignan enantiomers (7a/7b and 8a/8b), were obtained from the rhizomes of Acorus tatarinowii. The separation of 1-8 by chiral HPLC using a Daicel IC column led to the isolation of eight pairs of enantiomers, 1a/1b-8a/8b, which had variable enantiomeric excess (ee) values of approximately 66, 71, 63, 60, 0, 38, 48, and 75%, respectively. The structures were elucidated by extensive spectroscopic and chemical methods, and their absolute configurations were determined by a combined analysis of single-crystal X-ray diffraction and a modified Mosher's method, assisted by experimental and calculated electronic circular dichroism data. Among them, compounds 1a, 3a, 6b, 8a, and 8b showed weak inhibitory activities against NO production in activated macrophages with IC50 values ranging from 23.3 to 38.0 μM, respectively.

Constituents and Activities of Acorus tatarinowii

“…And IC 50 values of positive control dexamethasone were 0.8μM. More interestingly, in that study (-)-acortatarinowin F showed inhibitory effect, while (+)-acortatarinowin F was inactive (Lu et al 2015). Among acortatarinowins G~N only acortatarinowin L showed antioxidant activity using DPPH reducing antioxidant power assay with IC 50 value of 16.4±0.22μg/mL, while the IC 50 value of positive control trolox was 3.895±0.38μg/mL (Lu et al 2016).…”

“…Many lignans were isolated and reported with their enantiomers such as (±)-acortatarinowins A~C being reported as pairs of new 8-O-4'-type dinorneolignan enantiomers, (±)-acortatarinowins D and E as pairs of new 8-O-4'-type and rare C7-C8'-type neolignan enantiomers and (±)-acortatarinowin F as a pair of new bisepoxylignan enantiomers obtained along with known compounds (±)-eudesmin (Lu et al 2015). Lu's group also reported other pairs of enantiomers such as (±)-acortatarinowins G~I in which (±)-acortatarinowin G were rare 7,8'-epoxy-8,7'-oxyneolignane (Lu et al 2016).…”

Recent advances in research on lignans and neolignans

“…168 The pair of new 8-O-4 0 -type neolignan enantiomers (AE)-acortatarinowin D (484a/484b) was separated from the ethyl acetate soluble fraction of 95% methanol extract of Acorus tatarinowii Schott by chiral HPLC using a Daicel IC column. 114 Compound 485 was reported from the stem or bark of Ocotea cymosa. 152 Its conguration was tentatively assigned as S based on its positive optical rotation, as for synthetic (S)-virolongin B, a closely related compound even though the magnitude of the rotations differed signicantly.…”

“…149 A pair of rare C7-C8-type neolignan enantiomers trivially named (+)-acortatarinowin E (542a) and (À)-acortatarinowin E (542b) was obtained from the rhizomes of Acorus tatarinowii Schott aer separation using a chiral HPLC column. 114 Five new 8-9 0 linked neolignans, conchigeranals A-E (545-549) were isolated from the whole plant of Alpinia conchigera (Zingiberaceae). 181 However, the relative stereostructures of 547-549 were not determined.…”

Triterpenoid Saponin and Lignan Glycosides from the Traditional Medicine Elaeagnus angustifolia Flowers and Their Cytotoxic Activities

“…Both compounds 2 and 3 produced d-glucose after acid hydrolysis, indicating that the difference between them was the stereochemistry of C-7 and C-8. The large coupling constant between H-7 and H-8 (J = 6.1 Hz) of compounds 2 and 3 indicated they had the same 7,8-threo configuration [14]. Therefore, compounds 2 and 3 are a pair of diastereoisomers, making their aglycones a pair of enantiomers.…”