Flavonoids from the roots and rhizomes of Sophora tonkinensis and their in vitro anti-SARS-CoV-2 activity

Acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)had caused a global pandemic since 2019,and posed a serious threat to global health security.Traditional Chinese medicine(TCM)has played an indispensable role in the battle against the epidemic.Many components originated from TCMs were found to inhibit the production of SARS-CoV-23C-like protease(3CLpro)and papain-like protease(PLpro),which are two promising therapeutic targets to inhibit SARS-CoV-2.This study describes a systematic investigation of the roots and rhizomes of Sophora tonkinensis,which results in the characterization of 12 new flavonoids,including seven prenylated flavanones(1−7),one prenylated flavonol(8),two prenylated chalcones(9−10),one isoflavanone(11),and one isoflavan dimer(12),together with 43 known compounds(13−55).Their structures including the absolute configurations were elucidated by comprehensive analysis of MS,1D and 2D NMR data,and time-dependent density functional theory electronic circular dichroism(TDDFT ECD)calculations.Compounds 12 and 51 exhibited inhibitory effects against SARS-CoV-23CLpro with IC_(50) values of 34.89 and 19.88μmol·L^(−1),repectively while compounds 9,43 and 47 exhibited inhibitory effects against PLpro with IC_(50) values of 32.67,79.38,and 16.74μmol·L^(−1),respectively.

Polyoxypregnanes as safe, potent, and specific ABCB1-inhibitory pro-drugs to overcome multidrug resistance in cancer chemotherapy in vitro and in vivo

Multidrug resistance(MDR)mediated by ATP binding cassette subfamily B member 1(ABCB1)is significantly hindering effective cancer chemotherapy.However,currently,no ABCB1-inhibitory drugs have been approved to treat MDR cancer clinically,mainly due to the inhibitor specificity,toxicity,and drug interactions.Here,we reported that three polyoxypregnanes(POPs)as the most abundant constituents of Marsdenia tenacissima(M.tenacissima)were novel ABCB1-modulatory pro-drugs,which underwent intestinal microbiota-mediated biotransformation in vivo to generate active metabolites.The metabolites at non-toxic concentrations restored chemosensitivity in ABCB1-overexpressing cancer cells via inhibiting ABCB1 efflux activity without changing ABCB1 protein expression,which were further identified as specific non-competitive inhibitors of ABCB1 showing multiple binding sites within ABCB1 drug cavity.These POPs did not exhibit ABCB1/drug metabolizing enzymes interplay,and their repeated administration generated predictable pharmacokinetic interaction with paclitaxel without obvious toxicity in vivo.We further showed that these POPs enhanced the accumulation of paclitaxel in tumors and overcame ABCB1-mediated chemoresistance.The results suggested that these POPs had the potential to be developed as safe,potent,and specific pro-drugs to reverse ABCB1-mediated MDR.Our work also provided scientific evidence for the use of M.tenacissima in combinational chemotherapy.

Birhodomolleins D and E, two new dimeric grayanane diterpenes with a 3-O-2＇ linkage from the fruits of Rhododendron pumilum

Two new dimeric diterpenes, birhodomolleins D （1） and E （2）, were characterized from the fruits of Rhododendron pumilum. Their structures featured two grayanane diterpenes dimerized through an oxygen bridge locating at C-3 and C-2＇. They are the first examples of dimeric grayanane diterpenes with a 3-O-2＇ linkage from the Ericaceae family. Their structures were elucidated on the basis of comprehensive analysis of spectroscopic data.

3,4-seco-Isopimarane and 3,4-seco-pimarane diterpenoids from Callicarpa nudiflora

A phytochemical investigation was carried out on the extract of a medicinal plant Callicarpa nudiflora,resulting in the characterization of five new 3,4-seco-isopimarane(1-5)and one new 3,4-seco-pimarane diterpenoid(6),together with four known compounds.The structures of the new compounds were fully elucidated by extensive analysis of MS,1 D and 2 D NMR spectroscopic data,and time-dependent density functional theory(TDDFT)calculation of electronic circular dichroism(ECD)spectra,and DFT calculations for NMR chemical shifts and optical rotations.

Monomeric and dimeric sesquiterpene lactones from Artemisia heptapotamica

One new dimeric(1) and two monomeric sesquiterpene lactones(5 and 13), together with 10 known compounds(2-4, 6-12), were isolated from Artemisia heptapotamica collected in Almaty region of Kazakhstan. All compounds were isolated from this plant for the first time. The structures of the new compounds were mainly achieved by extensive analysis of MS, 1D and 2D NMR spectroscopic data, and ECD spectrum as well. The inhibitory activities of all isolates against activation of NF-κB induced by LPS were assessed on a THP1-Dual cell model. Some of them showed strong inhibitory activity with IC50 values ranging from 2 to 25μmol·L^-1.

Three new carabrane sesquiterpenoid derivatives from the whole plant of Carpesium abrotanoides L.

Dicarabrols B and C(1 and 2),two new carabrane sesquiterpenoid dimers,along with one new carabrane sesquiterpenoid(3)were isolated from the whole plant of Carpesium abrotanoides L.Their full structures were established by extensive analysis of HR-ESI-MS and NMR spectroscopic data,and time-dependent density functional theory(TDDFT)electronic circular dichroism(ECD)calculations.Dicarabrol B possesses a novel C30 skeleton featuring a methylene-tethered bridge between two sesquiterpene moieties,while dicarabrol C presents the unique linkage of a cyclopentane ring in the molecule.Dicarabrol C exhibited potent inhibitory effects on HL−60 cells with an IC50 value of 3.7μmol·L^(−1).

Cytotoxic cassane diterpenoids from the seeds of Caesalpinia sappan

Phytochemical investigation on the seeds of Caesalpinia sappan led to the isolation of five new cassanetype diterpenoids, named 11-oxo-phanginin A（1）, caesalsappanins O–Q（2–4） and phanginin U（5）,together with five known compounds. The structures of the new compounds were elucidated by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. All the new compounds showed moderate cytotoxic effects on human breast cancer MCF-7 and human colon cancer HCT116 cell lines.

Cytotoxic germacrane-type sesquiterpene lactones from the whole plant of Inula cappa

Phytochemical investigation on the whole plant of Inula cappa led to the isolation of two new germacrane-type sesquiterpene lactones,ineupatolides D and E（1 and 2）,together with three known analogs.The structures of the new compounds were established by extensive analysis of 1Dand 2DNMR spectra,as well as MS data.Their absolute configurations were determined by CD spectra.All compounds showed moderate inhibitory effects on A431,A549,BGC-823,HL-60,HT-29,and MCF-7 cancer cell lines with IC50 values ranging from 2.1 to 36.3 μM.

Isocartormin, a novel quinochalcone C-glycoside from Carthamus tinctorius

A new semi-quinonechalcone C-glycoside isocartormin along with cartormin and saf fl omin C were isolated from the water extract of Carthamus tinctorius L. The structure of isocartormin was determined by extensive analysis of HR-MS, 1D-and 2D NMR data, and by comparison with those of cartormin reported previously by our group. Isocartormin was identified as a diastereoisomer of cartormin with a reverse configuration at C-18.

Three new dimeric diterpenes from Rhododendron molle

Birhodomolleins A-C（1-3）,three novel diterpenoids dimerized from two grayanane diterpenes through an oxygen bridge,were isolated from the flowers of Rhododendron molle.Their structures were elucidated by interpretation of their 1D and 2D NMR and other spectroscopic data.Birhodomollein A（1） contains a rare chloro-substitution on one of the grayanane moieties.These are the first examples of dimeric diterpenes from the Ericaceae family.