Isolation, Characterization, and Anticancer Evaluation of Alkaloids from (Rubiaceae).

The dimeric (-)-calycanthine (), the hexameric (+)-oleoidine (), the heptameric (+)-caledonine (), the octameric (+)-eumatanine (), and a tricyclic pyrroloquinoline alkaloid, eumatricine (), are alkaloids isolated from the leaves of ; compounds and are novel, previously uncharacterized alkaloids. Preliminary anticancer assays, including MTT, cell count, and clonogenic assays, revealed potent inhibition of cell growth and colony formation by compounds against seven carcinoma cell lines (including breast, colorectal, lung, and glioblastoma multiforme cell lines). The GI values of compounds ranged from 0.

Promorphinan and bisaporphine alkaloids from Alseodaphne peduncularis.

Five previously undescribed benzylisoquinoline alkaloids were isolated from the leaves and stem-bark of Alseodaphne peduncularis. Among these, alseodaphnine (1) was characterized as a tetracyclic rearranged promorphinan alkaloid. Alseodaphnilarines A, B, and C (2-4) were identified as promorphinan-amine conjugates, while alseodaphnidine (5) represents a bisaporphine alkaloid.

Preparation and Preliminary Structure-Activity Relationship Studies of Schwarzinicine A Analogs as Vasorelaxant Agents.

Schwarzinicines A-D, a series of alkaloids recently discovered from , exhibit pronounced vasorelaxant activity in rat isolated aorta. Building on this finding, a concise synthesis of schwarzinicines A and B has been reported, allowing further investigations into their biological properties. Herein, a preliminary exploration of the chemical space surrounding the structure of schwarzinicine A () was carried out aiming to identify structural features that are essential for vasorelaxant activity.

Quinoline, Indole, and Isogranatanine Alkaloids from Malayan .

Nine new alkaloids, eugeniinalines A-H (-) and (+)-eburnamenine -oxide (), comprising one quinoline, six indole, and two isogranatanine alkaloids, were isolated from the stem-bark extract of the Malayan . The structures and absolute configurations of these alkaloids were established based on the analysis of the spectroscopic data, GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray diffraction analysis. Eugeniinaline A () represents a new pentacyclic quinoline alkaloid with a 6/6/5/6/7 ring system.

A comprehensive review on the chemical constituents, sesquiterpenoid biosynthesis and biological activities of Sarcandra glabra.

Sarcandra glabra (Thunb.) Nakai is a perennial evergreen herb categorised within the Sarcandra Gardner genus under the Chloranthaceae family. Indigenous to tropical and subtropical regions of East Asia and India, this species is extensively distributed across China, particularly in the southern regions (Sichuan, Yunnan, and Jiangxi).

Pentacyclic and hexacyclic cucurbitacins from Elaeocarpuspetiolatus.

Four undescribed cucurbitacins, designated as petiolaticins A-D, and four known cucurbitacins were isolated from the bark and leaves of Elaeocarpus petiolatus (Jack) Wall. Their chemical structures were elucidated based on detailed analyses of the NMR and MS data. The absolute configuration of petiolaticin A was also determined by X-ray diffraction analysis.

Monomeric, Dimeric, and Trimeric Tropane Alkaloids from .

Seven new tropane alkaloids, including five monomeric (-), one dimeric (), and one trimeric () 3α-nortropane ester, along with two known monomeric nortropane alkaloids ( and ), were isolated from the leaves and bark of . Their structures, including the absolute configuration of the enantiomeric pair of (±)-, were elucidated by comprehensive spectroscopic analyses. Alkaloids and showed cytotoxicity toward human pancreatic cancer cell lines (AsPC-1, BxPC3, PANC-1, and SW1990).

Concise synthesis of the vasorelaxant alkaloids schwarzinicines A and B.

A concise synthesis of the 1,4-diarylbutanoid-phenethylamine alkaloids, schwarzinicines A () and B (), recently isolated from , is reported. Key steps include a Claisen condensation to assemble the 1,4-diaryl-2-butanone intermediate, followed by a reductive amination to furnish the core skeleton of the target compounds. The overall synthetic yields of and were 9.

Alstoscholactine and Alstolaxepine, Monoterpenoid Indole Alkaloids with γ-Lactone-Bridged Cycloheptane and Oxepane Moieties from Alstonia scholaris.

Two new monoterpenoid indole alkaloids, alstoscholactine (1) and alstolaxepine (2), were isolated from Alstonia scholaris. Compound 1 represents a rearranged stemmadenine alkaloid with an unprecedented C-6-C-19 connectivity, whereas compound 2 represents a 6,7- seco-angustilobine B-type alkaloid incorporating a rare γ-lactone-bridged oxepane ring system. Their structures and absolute configurations were determined by spectroscopic analyses.

Unusual phenethylamine-containing alkaloids from Elaeocarpus tectorius.

From the leaves of Elaeocarpus tectorius (Lour.) Poir. four previously undescribed phenethylamine-containing alkaloids were isolated, namely, tectoricine, possessing an unprecedented isoquinuclidinone ring system incorporating a phenethylamine moiety, tectoraline, representing a rare alkamide incorporating two phenethylamine moieties, and tectoramidines A and B, representing the first naturally occurring trimeric and dimeric phenethylamine alkaloids incorporating an amidine function.

A Bis-benzopyrroloisoquinoline Alkaloid Incorporating a Cyclobutane Core and a Chlorophenanthroindolizidine Alkaloid with Cytotoxic Activity from Ficus fistulosa var. tengerensis.

Tengerensine (1), isolated as a racemate and constituted from a pair of bis-benzopyrroloisoquinoline enantiomers, and tengechlorenine (2), purified as a scalemic mixture and constituted from a pair of chlorinated phenanthroindolizidine enantiomers, were isolated from the leaves of Ficus fistulosa var. tengerensis, along with three other known alkaloids. The structures of 1 and 2 were determined by spectroscopic data interpretation and X-ray diffraction analysis.