Bioactive isoquinoline alkaloids from Corydalis saxicola.

Twelve isoquinoline alkaloids including two new nitro-containing tetrahydroprotoberberines, (-)-2,9-dihydroxyl-3,11-dimethoxy-1,10-dinitrotetrahydroprotoberberine (1) and (+)-4-nitroisoapocavidine (2), were isolated from the whole plant of Corydalis saxicola Bunting. The structures of the new compounds were established by spectroscopic analysis and chemical evidence. The inhibitory activity of these isolates against cholinesterase and canine parvovirus were evaluated. Compounds 1 and 1A, (+)-1-nitroapocavidine (5), berberine (8), palmatine (9), dehydrocavidine (10), and sanguinarine (11) showed potent inhibitory activity against acetylcholinesterase with IC(50) values of less than 10 µM, while only compound 1 possessed weak activity against canine parvovirus. Structure-activity studies demonstrated that the nitro substituents at ring A in the tetrahydroprotoberberines led to an increase in the anti-acetylcholinesterase activity.

Cytotoxic amide alkaloids from Piper boehmeriaefolium.

Eight new amide alkaloids (1-8) and 19 known ones were isolated from the whole plant of Piper boehmeriaefolium. Their structures were determined through spectroscopic data analyses. Cytotoxic activity of these amides against human cervical carcinoma HeLa cells was evaluated, and 1-[(9E)-10-(3,4-methylenedioxyphenyl)-9-decenoyl]pyrrolidine (9) exhibited significant inhibitory activity with an IC(50) value of 2.7 µg/mL.

Clerodane diterpenoids and prenylated flavonoids from Dodonaea viscosa.

Repeated column chromatography of the EtOAc-soluble fraction of the aerial parts of Dodonaea viscosa led to the isolation of two new modified clerodanes, methyl dodovisate A (1) and methyl dodovisate B (2), two new prenylated flavonoids, 5,7,4'-trihydroxy-3',5'-di(3-methylbut-2-enyl)-3,6-dimethoxyflavone (10) and 5,7,4'-trihydroxy-3'-(4-hydroxy-3-methylbutyl)-5'-(3-methylbut-2-enyl)-3,6-dimethoxyflavone (11), together with eight known compounds, dodonic acid (3), hautriwaic acid (4), hautriwaic lactone (5), (+)-hardwickiic acid (6), 5alpha-hydroxy-1,2-dehydro-5,10-dihydroprintzianic acid methyl ester (7), strictic acid (8), dodonolide (9), and aliarin (12). The structures of the new compounds were elucidated by spectroscopic data analysis. Compounds 1-9 and 11 were evaluated on larvicidal activity against the fourth-instar larvae of Aedes albopictus and Culex pipens quinquefasciatus.

Primula dongchuanensis (Primulaceae), a new species from northern Yunnan, China.

Primula dongchuanensis Z.K.Wu & Yuan Huang, a new species of Primulaceae from Dongchuan of northern Yunnan, China, is described and illustrated. Both morphological and molecular evidence support P. dongchuanensis as a member of the sect. Proliferae. It is similar to P. aurantiaca W.W.Smith & Forrest, but is distinguished by having unique raceme inflorescences. Its distribution, phenology and conservation status are also provided.

Carboxymethyl flavonoids and a monoterpene glucoside from Selaginella moellendorffii.

A new dihydroflavone, 5-carboxymethyl-7,4'-dihydroxyflavonone (1), and its glucoside 5-carboxymethyl-7,4'-dihydroxyflavonone-7-O-ß-D: -glucopyranoside (2), and one new monoterpene glucoside, (4Z,6E)-2,7-dimethyl-8-hydroxyocta-4,6-dienoic acid 8-O-ß-D: -glucopyranoside (3), were isolated from the whole plants of Selaginella moellendorffii. Their structures were determined by spectroscopic methods and chemical transformation. Compound 2 was evaluated for the ability to enhance glucose consumption in normal and insulin-resistant L6 muscle cells induced by high concentrations of insulin and glucose. Glucose consumption in insulin-resistant cells (but not in normal cells) was increased 15.2 ± 3.3% (p < 0.01) by compound 2 at a concentration of 0.1 µM in the presence of insulin (1 nM).

A piperidine alkaloid and limonoids from Arisaema decipiens, a traditional antitumor herb used by the Dong people.

A new piperidine alkaloid and three known tetranortriterpenoids were isolated from the methanol extracts of the rhizomes of Arisaema decipiens Schott (Araceae) and their chemical structures were identified as (-)-(2R*,3S*,6S*)-N,2-dimethyl-3-hydroxy-6-(9-phenylnonyl) piperidine (1), 6-deacetylnimbin (2), 28-deoxonimbolide (3) and nimbin (4). The N-methylated derivative (1a) of 1 was synthesized. Compound 1 exhibited weak inhibitory activity against the MCF-7 cell line, while compound 1a showed potential inhibitory activity against the MCF-7 cell line with an IC50 value of 4.6 µM and weak inhibitory activity against K562 and SK-OV-3 cells. This plant in genus Arisaema is firstly reported as the source of limonoids that are considered a natural antitumor herbal medicine.

Palhinine A, a novel alkaloid from Palhinhaea cernua.

Palhinine A, a novel C(16)N-type Lycopodium alkaloid with a unique 5/6/6/9 tetracyclic ring system, was isolated from the whole plant of Palhinhaea cernua L. (Lycopodiaceae). Its structure was elucidated by spectroscopic methods, and the absolute configuration was determined by single-crystal X-ray diffraction analysis using the Flack parameter. Palhinine A is reported as the first example of Lycopodium alkaloids of which C-16 is fused to a new ring through a C-16-C-4 lingkage.