Chemical Constituents from Strychnos Cathayensis

Secostrychnosin ( 1 ), a new secoiridoid, as well as seven compounds never before isolated from nature: 4‐tert‐butyl‐2‐oxazolidinone ( 2 ), 3‐acetoxyindole ( 3 ), indole‐2‐carboxylic acid ( 4 ), benzocaine ( 5 ), 3‐acetylindole ( 6 ), butylparaben ( 7 ) and 2‐hydroxy‐3‐methoxybenzaldehyde ( 8 ), together with fifty other known compounds, have been isolated from the stem of Strychnos cathayensis. These compounds include twenty‐three alkaloids, twelve benzenoids, four steroids, three flavonoids, three iridoids, two triterpenoids, two secoiridoids, two fatty acids, one lignan, one acetophenone, one coumarin, one chromane, one tetraterpenoid, one tannin, and one organic acid. The structures of these compounds were determined by means of spectralanalyses.     

Identification of Five New Minor Constituents from the Whole Plant of Amischotolype hispida

Bioassay‐guided fractionation of the active AcOEt‐soluble layer from the whole plant of Amischotolype hispida resulted in the isolation of four new compounds, i.e., amisbenzoic acid ( 1 ), one butenolide derivative, amisnolide ( 2 ), one chlorin analog, amisphytin ( 3 ), one lignan, amislignol ( 4 ), and one metabolite isolated for the first time from nature, (?)‐glaberide I ( 5 ), along with 20 known compounds, 6 – 25 . Their structures were elucidated on the basis of UV, IR, 1D‐ and 2D‐NMR (¹H,¹H‐COSY, DEPT, HSQC, HMBC), as well as HR‐ESI‐MS, analyses. Among these isolates, palmitic acid ( 13 ) showed an antimycobacterial activity with an MIC value of 20.0 μg/ml against Mycobacterium tuberculosis H37Rv.     

Chemical Constituents of the Endophytic Fungus Hypoxylon sp. 12F0687 Isolated from Taiwanese Ilex formosana

Bioassay‐guided fractionation of an AcOEt‐soluble fraction of the liquid fermentation of an endophytic fungus Hypoxylon sp. BCRC 12F0687 associated with the root of Taiwanese Ilex formosana (Aquifoliaceae) resulted in the isolation of two new compounds, i.e., one benzenoid, hypoxyphenone ( 1 ), and one azaphilone derivative, hypoillexidiol ( 2 ), two metabolites isolated for the first time from natural source, (?)‐(3S)‐3‐hydroxy‐3‐methyloxindole ( 3 ) and (+)‐vermelone ( 4 ), along with twelve previously identified compounds, 5 – 16 . Their structures were determined through in‐depth spectroscopic and mass‐spectrometric analyses. The effects of some isolates on the inhibition of NO and IL‐6 production in lipopolysaccharide‐activated RAW 264.7 murine macrophages were evaluated. Of the isolates, 2 and 3 exhibited potent anti‐NO production activity, with IC₅₀ values of 17.5±1.8 and 24.7±1.6 μM , respectively, compared to that of quercetin, an iNOS inhibitor with an IC₅₀ value of 35.9±1.7 μM . Compounds 2, 4, 5 , and 12 also showed moderate inhibition of IL‐6 production, with IC₅₀ values ranging from 27.2±1.8 to 35.3±5.8 μM . This is the first report on an oxindole metabolite from the genus Hypoxylon.     

Secondary Metabolites from the Endophytic Fungus Xylaria cubensis

Seven new metabolites, including three sesquiterpenoids, 10‐hydroxythujopsene ( 1 ), akotriol ( 2 ), and xylaritriol ( 3 ), one diterpenoid, cubentriol ( 4 ), one aliphatic derivative, akoenic acid ( 5 ), one alkaloid, akodionine ( 6 ), and one isocoumarin, akolitserin ( 7 ), together with seven known compounds, 8 – 14 , were isolated from the AcOEt‐soluble fraction of the fermentation broth of the endophytic fungus Xylaria cubensis, derived from the leaves of Litsea akoensis Hayata (Lauraceae). Their structures were elucidated by spectroscopic analyses, including 1D‐ and 2D‐NMR experiments, and by HR‐ESI‐MS mass spectrometry. Among the isolates, (?)‐(R)‐7‐hydroxymellein showed IL‐6 inhibitory activity with an IC₅₀ value of 9.41 μM .     

Two New Endiandric Acid Analogs,a New Benzopyran,and a New Benzenoid from the Root of Beilschmiedia erythrophloia

Phytochemical investigation of the root of Beilschmiedia erythrophloia led to the isolation and structural elucidation of two new endiandric acid analogs, endiandric acids I and J ( 1 and 2 , resp.), a new benzopyran, dehydrooligandrol methyl ether ( 3 ), and a new benzenoid, farnesylol ( 4 ), together with six known compounds. Their structures were established on the basis of extensive 1D‐ and 2D‐NMR analyses in combination with HR‐MS experiments.     

Bishordeninyl Terpene Alkaloids from Zanthoxylum Integrifoliolum

Examination of the leaves of Zanthoxylum integrifoliolum led to the isolation of a new bishordeninyl alkaloid, integramine, along with alfileramine, α‐allocryptopine, pseudoprotopine and (+)‐sesamin from the tertiary non‐phenolic base fraction. The structures of these compounds were elucidated by spectral evidence.     

Secondary Metabolites from Magnolia kachirachirai

Investigation of the root bark of Magnolia kachirachirai led to the isolation of a new sesquiterpene, kachirachirain ( 1 ), and a new aporphine alkaloid, kachirachiranine ( 2 ), together with 20 known compounds, of which dimethyl 4,4′‐methylenebis(4,1‐phenylene)diurethane ( 3 ) was isolated for the first time from a natural source. Their structures were elucidated by spectroscopic analysis.     

Secondary Metabolites from the Leaves of Litsea lii var. nunkao‐tahangensis

Investigation of the leaves extract of Litsea lii var. nunkao‐tahangensis led to the isolation of five new butanolides, litsealiicolide A ( 1 ), isolitsealiicolide A ( 2 ), litsealiicolide B ( 3 ), isolitsealiicolide B ( 4 ), and isolitsealiicolide C ( 5 ), along with 17 known compounds. Their structures were determined through in‐depth spectroscopic and mass‐spectrometric analyses. Among the isolates, compounds 1 and 2 were cytotoxic against MCF‐7, NCI‐H460, and SF‐268 cell lines in vitro. Compound 5 and isolinderanolide B ( 6 ) showed marginal cytotoxic activity against these three cell lines in vitro.     

Height Uniformity for Algebraic Points on Curves

We recall the main result of L. Caporaso, J. Harris, and B. Mazur's 1997 paper of Uniformity of rational points. It says that the Lang conjecture on the distribution of rational points on varieties of general type implies the uniformity for the numbers of rational points on curves of genus at least 2. In this paper we will investigate its analogue for their heights under the assumption of the Vojta conjecture. Basically, we will show that the Vojta conjecture gives a naturally expected simple uniformity for their heights.