Pelliolatifolias A-D,Four Undescribed Compounds from Pellionia latifolia Boerl. and Their Nitric Oxide Production Inhibitory Activity

Four undescribed compounds ( 1 – 4 ) named pelliolatifolias A−D together with seven known compounds trans-clovamide ( 5 ), N-trans-caffeoyl-4-hydroxyphenylalanine methyl ester ( 6 ), N-trans-caffeoyl-3,4-dihydroxyphenylalanine methyl ester ( 7 ), luteolin 4’-O-β-D-glucopyrannoside ( 8 ), cis-syringin ( 9 ), trans-syringin ( 10 ), and citroside A ( 11 ) have been isolated from the methanol extract of the Pellionia latifolia leaves. Their chemical structures were elucidated based on extensive analyses of HR-ESI-MS, 1D and 2D NMR, and CD spectra. Compounds 1 – 7 , 9 and 10 showed moderate inhibition of NO production in LPS-activated RAW264.7 cells with their IC₅₀ values ranging from 39.27 to 75.42 μM, compared to that of the positive control compound, dexamethasone, IC₅₀ value of 14.20 μM.     

Four New Stilbene Derivatives Isolated from Gnetum latifolium var. funiculare Markgr. and Their Inhibition of NO Production in LPS-activated RAW264.7 Cells

Gnetum latifolium var. funiculare Markgr. is a medicinal plant and widely distributed in mountainous areas of Vietnam. Phytochemical investigation on the trunks of this plant afforded eight stilbene derivatives ( 1 – 8 ) including for new compounds ( 1 – 4 ). Their structures were determined based on extensive analyses of HR-ESI-MS, 1D and 2D NMR spectra. Among the isolates, compounds 1 – 3 showed moderate NO production inhibition in LPS-activated RAW264.7 cells with the IC₅₀ values ranging from 46.81 to 68.10 μM, compounds 4 and 6 showed weak effects with the IC₅₀ values of 96.57 and 79.46 μM, respectively, compared to that of the positive control compound, dexamethasone (IC₅₀ 14.20 μM).     

Cytotoxic Activity of New Phenolic Compounds from Vietnamese Caesalpinia sappan

Two new phenolic compounds, caesalpiniaphenols G–H (1 and 2), were isolated from Vietnamese Caesalpinia sappan heartwood. The chemical structures were established mainly by extensive spectroscopic studies and chemical evidence. Compounds 1 and 2 showed potent inhibitory activity against HL-60 cancer cell lines with respective IC₅₀ values of 16.7 and 22.5 µg/mL. Treating HL-60 cells with various concentrations of 1 resulted in growth inhibition and the induction of apoptosis.     

Four New Tirucallane Triterpenoids from the Fruits of Melia azedarach and Their Cytotoxic Activities

Four new tirucallane triterpenoids, (21S,23R,24R)‐21,23‐epoxy‐21,24‐dihydroxy‐25‐methoxytirucall‐7‐en‐3‐one ( 2 ), (3S,21S,23R,24S)‐21,23‐epoxy‐21,25‐dimethoxytirucall‐7‐ene‐3,24‐diol ( 8 ), (21S,23R,24R)‐21,23‐epoxy‐24‐hydroxy‐21‐methoxytirucalla‐7,25‐dien‐3‐one ( 11 ), and (21S,23R,24R)‐21,23‐epoxy‐21,24‐dihydroxytirucalla‐7,25‐dien‐3‐one ( 12 ), along with 16 known analogues, 1 , 3  –  7 , 9  –  10 , and 13  –  20 , were isolated from the fruits of Melia azedarach. Their structures were elucidated by spectroscopic methods including 1D‐ and 2D‐NMR techniques and mass spectrometry. These compounds were evaluated for their cytotoxicities against HepG2 (liver), SGC7901 (stomach), K562 (leukemia), and HL60 (leukemia) cancer cell lines. Compound 20 exhibited potent cytotoxicity against HepG2 and SGC7901 cancer cells with the IC₅₀ values of 6.9 and 6.9 μm , respectively.     

Four New C19-Diterpenoid Alkaloids from Aconitum nagarum Stapf

Four new aconitine-type C₁₉-diterpenoid alkaloids, were isolated from the roots of Aconitum nagarum Stapf which were named as nagarutines A–D ( 1–4 ), together with eleven known compounds ( 5–15 ). The structures of the compounds were identified by IR, HR-ESI-MS, 1D and 2D NMR spectra. All compounds were tested for the inhibitory effect on LPS induced NO production in RAW 264.7 macrophages, compound 7 showed moderate anti-inflammatory activity effect and Inhibition rate is about 44.50%.     

New Cardenolide Glycosides from the Seeds of Digitalis purpurea and Their Cytotoxic Activity

A chemical investigation of Digitalis purpurea seeds led to the isolation of three new cardenolide glycosides (1, 8 and 11), together with 12 known cardenolide glycosides (2–7, 9, 10 and 12–15). The structures of 1, 8 and 11 were determined by 1D and 2D NMR spectroscopic analyses and the results of an acid or enzymatic hydrolysis. The cytotoxic activity of the isolated compounds (1–15) against HL-60 leukemia cells was examined. Compounds 2, 9, 11 and 12 showed potent cytotoxicity against HL-60 cells with respective 50% inhibition concentration (IC₅₀) values of 0.060, 0.069, 0.038, and 0.034 µM. Compounds 2, 9 and 11 also exhibited potent cytotoxic activity against HepG2 human liver cancer cells with respective IC₅₀ values of 0.38, 0.79, and 0.71 µM. An investigation of the structure-activity relationship showed that the cytotoxic activity was reduced by the introduction of a hydroxy group at C-16 of the digitoxigenin aglycone, methylation of the C-3' hydroxy group at the fucopyranosyl moiety, and acetylation of the C-3' hydroxy group at the digitoxopyranoyl moiety.     

New Isoprenylated Phenolic Compounds from Morus laevigata

Two new isoprenylated flavonoids, laevigasins A and B ( 1 and 2 , resp.), and one new isoprenylated 2‐arylbenzofuran, leavigasin C ( 3 ), together with eight known compounds, 4 – 11 , were isolated from the twigs of Morus laevigata. Their structures were elucidated by spectroscopic methods. Laevigasin A ( 1 ) showed significant inhibitory effect on α‐glucosidase in vitro. Notabilisin E ( 5 ), taxifolin ( 10 ), and hultenin ( 11 ) inhibited PTP1B phosphatase activity in vitro.     

Isolation and Characterization of Cytotoxic Compounds from Corn

A host-vector system was constructed in Bacillus megaterium strain NK84–0128, an oxetanocin A producer. The replication origin of an endogeneous plasmid, P–4, was used to construct a potential plasmid vector, pSM5, which had a chloramphenicol resistance gene as a selective marker. Plasmid transformation by a protoplast method was used in B. megaterium strain NK84–0128. The maximum transformation frequency attained with the pSM5 plasmid was 2.0 x 10⁴cfu/µg DNA.     

Four New Diterpenoid Alkaloids from the Roots of Aconitum carmichaelii

Aconitum carmichaelii Debeaux is a widely used traditional Chinese medicine and an important source of clinical drugs, of which the parent and lateral roots are known as ‘Chuanwu’ and ‘Fuzi’, respectively. Four new C₁₉‐diterpenoid alkaloids, carmichasines A – D ( 1 – 4 ), were isolated from the roots of Aconitum carmichaelii, together with twelve known compounds ( 5 – 16 ). Their structures were elucidated via spectroscopic analyses, including HR‐ESI‐MS, IR, and NMR. Carmichasine A ( 1 ) is the first natural C₁₉‐diterpenoid alkaloid possessing a cyano group. Most of the diterpenoid alkaloids isolated were C₁₉‐category, which might provide further clues for understanding the chemotaxonomic significance of this plant. The cytotoxicity of the new compounds was also investigated against several human cancer cell lines, including MCF‐7, HCT116, A549, and 786‐0, and none of them showed considerable cytotoxic activity.     

短瓣花中的微量新环肽成分

从中国民间草药短瓣花（Brachystemma calycinum D.Don)干燥根的乙醇提取物中分离得到4个新的微量环八肽,命名为短瓣花环肽A、B、C和D。经光谱分析鉴定。它们的结构分别为cyclo(Pro^1-Phe-Leu-Ala^1-Thr-Pro^2-Ala^2-Gly)(1)、cyclo(Pro^1-Ala-Phe-Trp-Asp-Pro^2-Leu-Gly)(2)、cyclo(Pro^1-Ⅱe-Gly-Pro^2-Val-Ala^1-Ala^2-Tyr)(3)和cyclo(Pro-OMet-Trp-Ⅱe-Gly-Ala-Leu-Asp)(4)。     

Structural Modification of Stilbenoids from Acanthopanax leucorrhizus and Their Cytotoxic Activity

A new cis‐stilbenoid, 1,9‐dihydroxy‐10‐methoxy‐6H‐dibenzo[b,f]oxocin‐6‐one ( 2 ) was isolated from the AcOEt extract of the stem barks of Acanthopanax leucorrhizus, along with three known stilbenoids, 9‐hydroxy‐10‐methoxy‐6H‐dibenzo[b,f]oxocin‐6‐one ( 1 ), 5‐O‐methyl‐(E)‐resveratrol 3‐O‐β‐d ‐glucopyranoside ( 3 ), and (E)‐resveratrol 3‐O‐β‐d ‐xylopyranoside ( 4 ). Two derivatives ( 2a and 2b ) were synthesized by the structural modification of compound 2, which exhibited certain cytotoxic activities against HT‐29 and HeLa cell lines in vitro. All compounds were structurally characterized by comprehensive analysis of their spectroscopic data and comparison with literature information, and evaluated for their cytotoxic activities against three human tumor cell lines (HL‐60, HT‐29, and HeLa) by the standard MTT assay in vitro. The results showed that derivatives 2a and 2b exhibited strong activities than compounds 2 against HT‐29 and HeLa cell lines.     

Cytotoxic xanthene derivatives from Homalium paniculiflorum

Two new xanthene derivatives, homapanicones A (1) and B (2), along with 11 known compounds (3–13), were isolated from the stems of Homalium paniculiflorum. Among them, homapanicones A (1) and B (2) represent the first example of naturally occurring xanthene derivatives with an oxidized aromatic B unit, and the known compounds (3–13) were isolated from this plant for the first time. These structures were established on the basis of extensive spectroscopic methods. Compounds 1 and 2 were tested for their cytotoxicities on HL-60, SMMC-7721, A-549, MCF-7, and SW480 human tumor cell lines. Homapanicones A (1) and B (2) showed cytotoxicities against various human cancer cell lines in the range of IC₅₀ at 4.08–24.14 μM.     

Two New Eudesmane-Type Sesquiterpene from Clonostachys sp. Y6-1and Their Cytotoxic Activity

Two undescribed eudesmane-type sesquiterpenoids together with four known compounds were isolated from Clonostachys sp. Y6-1 associated. Their chemical structures were unambiguously determined by NMR, mass spectrometry, and ¹³C-NMR calculation as well as DP4+ probability analyses. The absolute configurations of compounds 1 and 2 were determined by ECD calculation and X-ray single-crystal diffraction methods. Furthermore, all isolates were evaluated for in vitro cytotoxic activities against MCF-7, HCT-116, MDA-MB-231, and SW620 cancer cells. Among them, bioactivity evaluation of compound 5 revealed that weak activity (IC₅₀=66.55±0.82 μM) against SW620.     

Four New Polyhydroxy Cyclohexanes from the Stems of Fissistigma tientangense

Four undescribed polyhydroxy cyclohexanes, fissoxhydrylenes A–D ( 1–4 ), together with two known biogenetically related polyhydroxy cyclohexanes ( 5 and 6 ) were isolated from the stems of Fissistigma tientangense Tsiang et P. T. Li. Their structures were elucidated by detailed analysis of NMR, HR-ESI-MS, IR, UV and Optical rotations data. The absolute configuration of 1 was confirmed by X-ray crystallographic. The absolute configurations of 2–4 were confirmed by chemical reaction and optical rotations. Compound 4 represent the first example of a no substituent polyhydroxy cyclohexanes from natural products. All isolated compounds were evaluated for their anti-inflammatory activities against the lipopolysaccharide-induced nitric oxide (NO) production in mouse macrophage RAW 264.7 cells in vitro. Compounds 3 and 4 showed inhibitory activities with the IC₅₀ values of 16.63±0.06 μM and 14.38±0.08 μM, respectively.     

Two New Cytotoxic Disulfated Holostane Glycosides from the Sea Cucumber Pentacta quadrangularis

Two new disulfated triterpene glycosides, pentactasides B and C ( 1 and 2 , resp.), were isolated from the sea cucumber Pentacta quadrangularis collected from the South China Sea. Their structures were elucidated by extensive spectral analysis (2D‐NMR and MS) and chemical methods. The compounds 1 and 2 possess the same tetrasaccharide moieties with two sulfated groups, but are different in the side chains of the triterpene aglycone. Pentactasides B and C ( 1 and 2 , resp.) showed significant cytotoxicities (IC₅₀ 0.09–2.30 μM ) against different human tumor cell lines.     

Chemical Constituents of Crinum asiaticum L. var. sinicum Baker and Their Cytotoxic Activities

A phytochemical investigation of the bulbs of Crinum asiaticum L. var. sinicum Baker resulted in the isolation of two new alkaloids, asiaticumines A and B ( 1 and 2 , resp.), together with 21 known compounds, including nine alkaloids, four amides, five phenolic compounds, and three flavonoids. All 23 compounds were isolated for the first time from Crinum asiaticum L. var. sinicum Baker . Their structures were elucidated by spectroscopic methods. In addition, ten alkaloids, 1 – 10 , were evaluated for their cytotoxic activities against human tumor cell lines A549, LOVO, HL‐60, and 6T‐CEM. Compounds 3, 4 , and 7 – 10 selectively showed remarkable inhibition against one or more of the tested cell lines.     

New Minor Cyclic Peptides from Brachystemma calycinum (in English) CHENG

From the ethanol extract of the roots of Brachystemma calycinum D.Don, a Chinese folk herb, four new minor cyclic peptides namely brachystemin A, B, C and D (1-4) have been isolated. Their structures were established as cyclo (Pro¹-Phe-Leu-Ala¹-Thr-Pro²-Ala²-Gly)(1)、cyclo(Pro¹-Ala-Phe-Trp-Asp-Pro²-Leu-Gly)(2)、cyclo (Pro¹-Ile-Gly-Pro²-Val-Ala¹-Ala²-Tyr) (3) and cyclo (Pro-OMet-Trp-Ile-Gly-Ala-Leu-Asp) (T4) respectively by means of extensive spectral methods.     

Alkaloids from Cephalotaxus lanceolata and Their Cytotoxicities

A phytochemical investigation of the branches and leaves of Cephalotaxus lanceolata resulted in the isolation of three new cephalotaxus alkaloids, cephalancetines A, B, and D ( 1, 2 , and 4 , resp.), together with ten known alkaloids, 3 and 5 – 13 . The structures of the alkaloids were elucidated on the basis of spectroscopic analyses, including 1D‐ and 2D‐NMR, and HR‐ESI‐MS, and single‐crystal X‐ray diffraction. All isolated compounds were tested for their cytotoxicities against four human tumor cell lines, A549, HCT116, SK‐BR‐3, and HepG2. Compounds 12 and 13 showed remarkable activities against A549, HCT116, and HepG2 cell lines.