Two new tirucallane triterpenoids from Aphanamixis grandifolia

Two new tirucallane triterpenoids,2a-ethoxy-2,3-secotirucalla-2,29-epoxy-7-ene-23-oxo-3-oic acid(1)and(23E)-2a-hydroxytirucalla-7,23,25-triene-3-one(2),along with the known 2,3-secotirucalla-2,3;2,29-diepoxy-7-ene-3,23-dione(3),were isolated from the leaves and twigs of Aphanamixis grandifolia.Their structures were elucidated by extensive NMR and MS data,and compound 3 was further confirmed by X-ray crystal diffraction analysis.Antimicrobial activities and insecticidal activities of these three compounds were also evaluated.Compound 1 showed good antimicrobial activity against Staphylococcus aureus with the MIC value of 1.56μg/mL,while compounds 1 and 2 showed insecticidal activity at 100 ppm,with the corrected mortality 79.1%and 60.6%,respectively.

Two New Highly Oxygenated Spirostanol Saponins from Paris polyphylla var.stenophylla

Phytochemical investigation of the rhizomes of Paris polyphylla var.stenophylla led to the isolation of two new highly oxygenated spirostanol saponins,named paristenosides A(1)and B(2),together with seven known compounds.Their structures were established mainly on the base of NMR spectroscopic techniques and mass spectrometry,as well as chemical methods.In addition,the cytotoxicity of the two new saponins was tested.Graphical Abstract Two new highly oxygenated spirostanol saponins,paristenosides A(1)and B(2),were isolated from the rhizomes of Paris polyphylla var.stenophylla.Their structures were established mainly based on NMR spectroscopic techniques and mass spectrometry,as well as chemical methods.

β-Carboline alkaloids from Trigonostemon filipes and Trigonostemon lii

Sixβ-carboline alkaloids including three new ones,trifilines A-C(1-3)were isolated from Trigonostemon filipes,along with a newβ-carboline alkaloid,trigonoine C(7)isolated from Trigonostemon lii.Their structures were elucidated by extensive spectroscopic techniques.Trifilines A(1)and B(2)showed weak anti-HIV-1 activity with EC50 values of 54.61μg/mL and 9.75μg/mL,along with TI(Therapeutic index)values of 1.52 and 1.42,respectively.This is the first time to report the chemical constituents of Trigonostemon filipes.

Five new mexicanolide type limonoids from Heynea trijuga

Five new mexicanolide-type limonoids,heytrijunolides A-E(1-5)were isolated from the branches and leaves of Heynea trijuga.The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis.Compound 3 showed weak cytotoxicity against HL-60,SMMC-7721 and A-549 human tumor cell lines with the IC50 values of 21.88,20.66 and 12.70μM,respectively.

Daphmacrodins A and B, alkaloids from Daphniphyllum macropodum

Two new daphnicyclidin-type Daphniphyllum alkaloids,daphmacrodins A and B(1 and 2)were isolated from the leaves and stems of Daphniphyllum macropodum.Their structures were elucidated by extensive spectroscopic techniques,including 2D NMR spectroscopy and mass spectrometry.The relative configuration of 1 was further confirmed by a single-crystal X-ray diffraction analysis.Their cytotoxic activities against five human cancer cell lines,pesticidal activities against brine shrimp(Artemia salina),and antibacterial activities against five standard bacterial and fungal strains were evaluated.The structure of 1 was successfully transformed to 2 by a chemical method.

Limonoids and triterpenoids from the twigs and leaves of Dysoxylum hainanense

Four new limonoids,dysohainanins A-D(1-4),and two new triterpenoids,dysohainanins E and F(5 and 6),together with seven known ones were isolated from the twigs and leaves of Dysoxylum hainanense Merr.The structures of the new compounds were determined by a variety of spectroscopic methods.The cytotoxic activities of these compounds were evaluated,and the known compound ent-19-nor-4,16,18-trihydroxy-8(14)-pomaren-15-one(13)showed in vitro cytotoxicity against HL-60,A-549,MCF-7,and SW480 cells,with IC50 values of 24.3,28.1,30.7,and 22.5mM,respectively.Compounds 2 and 3 were tested their insecticidal activities using brine shrimp and both of them were inactive.

Chemical Constituents from the Stems of Manihot esculenta

Two new compounds,maniesculentins A(1)and B(6),together with four known ones were isolated from the stems of Manihot esculenta Crantz.The structures of the new compounds were elucidated by extensive spectroscopic methods including NMR spectroscopy and mass spectrometry.The two new compounds(1,6)were assayed for antibacterial activity against four tested bacteria lines.

Nanogeology in China:A review

Nanogeology is a subject that is a combination of geology and nanoscale science,and it has been a frontier field in recent years.It is also a new subject with the features of intersectionality and multidisciplinary. Digging deeper into geological problems and nanoscale phenomena helps better revealing the more essential mechanisms and processes in geological science,which is also an evitable path in the development of geology.In this paper,we elaborate the concept,feature and main subdisciplines,and summarize three stages ofnanogeology development from preliminary research in the 1990s to subject formation in China.After summarizing the researchers'achievements in this field,we illustrate some primary research progresses of nanogeology in China as eight subdiseiplines.On the basis of the above content,we propose the development prospect of nanogeology in China.There are many geologic problems with scientific values and economic benefits,such as research of geologic fundamental problems,resource exploration and development,mechanism study and prediction of geological activities (disasters),mechanism research and management of environmental pollution and others.Nanogeology has a great potential in China to solve all of these problems.As a result,the theories and methods of nanogeology will become enriching and advanced.It offers important theoretical basis and technological methods to deal with major issues concerning the national economy and the people's livelihoods,such as the prediction of geological activities,as well as resource dislribution and its exploration and utilization.

Uncarialines A-E,new alkaloids from Uncaria rhynchophylla and their anticoagulant activity

Uncarialines A-E(1-5),five undescribed monoterpene indole alkaloids,together with five known analogues were obtained from the stems of Uncaria rhynchophylla.Alkaloids 1-3 were unique 3,4-seco-tricyclic alkaloids with a 6/5/10 ring system,while 4 and 5 possessed a rare rearranged scaffold originated from corynantheine-type alkaloids with C-2/C-7 oxidation.Their structures were characterized by a comprehensive analysis of MS,NMR,and ECD.Their effects on blood clotting times of human plasma were evaluated and alkaloid 5 had a slight prolongation effect on both thrombin time and activated partial thromboplastin time(p<0.001).

Five new limonoids isolated from Walsura robusta

Five new toosendanin limonoids with highly oxidative furan ring walsurobustones A-D(1-4),and one new furan ring degraded limonoid walsurobustone E(5)together with one known compound toonapubesic acid B(6)were isolated from the leaves of Walsura robusta.Their structures were elucidated by NMR and MS data.Especially,the absolute configuration of toonapubesic acid B(6)was confirmed by X-ray diffraction study.Compounds 1-6 exhibited good cytotoxicity against the cancer cell lines HL-60,SMMC-7721,A-549,MCF-7,and SW480.

Correction:Uncarialines A-E,new alkaloids from Uncaria rhynchophylla and their anticoagulant activity

Correction:Natural Products and Bioprospecting(2023)13:13 https://doi.org/10.1007/s13659-023-00377-0 Following publication of the original article[1],it was reported that the original version of this article unfortu-nately contained a mistake.Prof.Hong-Ping He is also one of the corresponding authors.The correct corresponding information should read:Hong-Ping He1,*E-mail address:hehongping@yahoo.com Yu Zhang2,*E-mail address:zhangyu@mail.kib.ac.cn The original article[1]has been updated.

Three New C_(21) Steroidal Glycosides from Roots of Cynanchum otophyllum

Objective To investigate the chemical structures of glycosides in the roots of Cynanchum otophyllum（Asclepiadaceae） and to find new glycosides. Methods The total glycosides in the roots of C. olophyllum were separated by silica gel column chromatography. The structures of the resulting compounds were determined by NMR and FAB-MS spectra. Results Three C21 steroidal glycosides were separated. Their structures were determined as caudatin 3-O-（4-O-methyl-β-D-cymaropyranosyl）-（1→4）-ɑ-D-oleandropyranosyl-（1→4）-β-D-glucopyranosyl-（1→4）-ɑ-L-rhamnopyranoside（1）, caudatin 3-O-β-D-digitoxopyranosyl-（1→4）-ɑ-D-oleandropyranosyl-（1→4）-β-Ddiginopyranosyl-（1→4）-β-D-glucopyranoside（2）, and caudatin 3-O-β-D-diginopyranosyl-（1→4）-ɑ-D-oleandropyranosyl-（1→4）-ɑ-D-oleandropyranosyl-（1→4）-β-Dglucopyranoside（3）, respectively. Conclusion Glycosides 1-3 are new compounds.

C_(21) Steroidal Saponins from Cynanchum otophyllum

Objective To study the chemical structures of saponins in the rhizome of Cynanchum otophyllum（Asclepiadaceae）, and to find new compounds. Methods The total saponins of the rhizome were separated by silica gel column chromatography. The chemical structures of obtained compounds were determined by NMR and FAB-MS spectra. Results Three C21 steroidal saponins were separated. Their structures were determined as caudatin 3- O-β-D-glucopyranosyl-（1 →4）-β- D-digitoxopyranosyl-（1 → 4）-β-D-digino- pyranosyl-（1 -4）-α-D-oleandropyranoside （1）, caudatin 3-O-β-D-oleandropyranosyl- （1→4）-α-D-oleandropyranosyl-（1→4）-α-D-oleandropyranoside （2）, and caudatin 3-O- β-D-glucopyranosyl-（1 →4）-α-D-oleandropyranosyl-（1 -4）-β-D-diginopyranosyl-（1→4）- α-D-oleandropyranoside （3）, respectively. Conclusion Saponins 1-3 are new compounds.