Mulinane-type diterpenoids from Azorella compacta display antiplasmodial activity

Two mulinane-type diterpenoids were isolated from Azorella compacta; namely 20-hydroxymulin-11,13-dienyl acetate and 13,14-dihydroxymulin-11-en-20-oic acid. The structures were elucidated by analysis of their spectroscopic data. These compounds, as well as three previously isolated diterpenes, were evaluated as potential in vivo growth inhibitors of Plasmodium berghei NK 65 on infected mice at an intraperitoneal dose of 10 mg/kg/day. Sixty percent and forty-two percent growth inhibition were obtained with 17-acetoxymulin-11,13-dien-20-oic acid and 13, 14-dihydroxymulin-11-en-20-oic acid, respectively.     

neo-Clerodane diterpenoids from Baccharis flabellata

Three diterpenoid derivatives were isolated from the acetone extract of Baccharis flabellata. Their structures were elucidated as 2,19;15,16-diepoxy-neo-clerodan-3,13(16),14-trien-18-oic acid, 15,16-epoxy-5,10-seco-clerodan-1(10),2,4,13(16),14-pentaen-18,19-olide and 15,16-epoxy-neo-clerodan-1,3,13(16),14-tetraen-18,19-olide through spectroscopic analyses.     

3-Methylbutanoyl and 3-methylbut-2-enoyl disaccharides from green coffee beans (Coffea arabica)

The aerial parts of Teucrium oliverianum yielded two neo-clerodane diterpenoids, teucrolin F and G, together with the known teucrolin E. The previously proposed structure for teucrolin E was revised so that it contains a tetrahydrofuran ring instead of an oxetane ring. This was based on analysis of the NMR spectroscopic data of its diacetate, including its NOE spectra. In addition, the structural assignments of the new diterpenoids were based on 1H and 13C NMR spectroscopic studies, mainly 2D NMR experiments, including homonuclear and heteronuclear correlations.     

Chemical Constituents from the Whole Plant of Gaultheria itoana Hayata

Two new diterpenoids, 14,18‐dihydroxyabieta‐8,11,13‐trien‐7‐one ( 1 ) and 13‐acetyl‐14,18‐dihydroxy‐podocarpa‐8,11,13‐triene ( 2 ), together with eight known compounds, i.e., gaultheric acid ( 3 ), vanillic acid ( 4 ), 4‐hydroxybenzoic acid ( 5 ), cinnamic acid ( 6 ), stearic acid ( 7 ), palmitic acid ( 8 ), β‐sitosterol ( 9 ), and stigmasterol ( 10 ), were isolated from the MeOH extract of the whole plant of Gaultheria itoana Hayata (Ericaceae). The structures of the new constituents were elucidated by spectroscopic methods (UV, IR, and 1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). Among them, 1 and 2 were demonstrated to exhibit significant cytotoxic activity against the LNCaP cell line.     

Chemical Constituents from the Stems of Excoecaria acertiflia

Six new compounds, including two diterpenoids excocarinols F and G ( 1 and 2 , resp.), two carotane (daucane) sesquiterpenoids excoecafolinols A and B ( 3 and 4 , resp.), one lignanoid compound, excoecanol A ( 5 ), and one simple phenol, excoecanol B ( 6 ), together with 17 known compounds, were isolated from the BuOH extract of Excoecaria acerifolia Didr . stems. Their structures were elucidated through the analysis of the spectroscopic data. The AChE‐inhibitory activities of 17 compounds were evaluated and revealed that four of them possessed moderate inhibitory activities against AChE.     

Composition and Bioactivity of Lipophilic Metabolites from Needles and Twigs of Korean and Siberian Pines (Pinus koraiensis Siebold & Zucc. and Pinus sibirica Du Tour)

Lipophilic extractive metabolites in different parts of the shoot system (needles and defoliated twigs) of Korean pine, Pinus koraiensis, and Siberian pine, Pinus sibirica, were studied by GC/MS. Korean pine needles comprised mainly bornyl p‐coumarate, heterocyclic 15‐O‐functionalized labdane type acids (lambertianic acid), 10‐nonacosanol, sterols and their esters. While Siberian pine needles contained less bornyl p‐coumarate, lambertianic acid, sterols and their esters, but were richer in other 15‐O‐functionalized labdane type acids. The major components of the twig extract of P. koraiensis were lambertianic acid, abietane and isopimarane type acids, cembrane type alcohols, 8‐O‐functionalized labdanoids, sterols, sterol esters, and acylglycerols. The same extract of P. sibirica differed in larger amounts of other 15‐O‐functionalized labdane type acids and pinolenic acid glycerides, but in less quantities of cembranoids and 8‐O‐functionalized labdanoids. The labdane type pinusolic acid was detected for the first time in Korean pine. P. koraiensis was found to be unique in the genus for an ability to synthesize phyllocladane diterpenoids. The content of bound Δ⁵‐unsaturated polymethylene‐interrupted fatty acids in the twig extracts of the both pines was similar or superior to that in their seed oil. Among the pines’ metabolites tested isocembrol was strongest in inhibition of both α‐glucosidase (IC₅₀ 2.9 μg/ml) and NO production in activated macrophages (IC₅₀ 3.6 μg/ml).     

New Bioactive Macrocyclic Diterpenoids from Euphorbia helioscopia

Three new macrocyclic diterpenoids, euphoscopoids A – C ( 1 – 3 ), including two new jatrophanes and a new lathyrane, were isolated from the whole plant of Euphorbia helioscopia. Their structures were elucidated by spectroscopic methods. Antifeedant and cytotoxic activities of these isolates were evaluated. All compounds showed significant antifeedant activity against a generalist plant‐feeding insect, Helicoverpa armigera, with EC₅₀ values ranging from 2.05 to 4.34 μg/cm². In addition, compound 2 showed moderate cytotoxicity against tumor cell lines NCI‐H1975, HepG2, and MCF‐2, while compounds 1 and 3 were not active at 80 μm . The results suggested not only the defensive function of macrocyclic diterpenoids in E. helioscopia against insect herbivores, but also their potential applications as new natural insect antifeedants.     

The Chemical Constituents from Podocarpus brevifolius

Ten compounds were isolated from the barks and leaves of Podocarpus brevifolius (Podocarpaceae) for the first time. They are identified as isokaurene (1), △9- isoclextropimaric acid (2), isoginkgetin (3), sciadopitysin (4), amentoflavone-4′,4″′, 7, 7″-tetramethylether (5), sequoyitol (6), β-sitosterol (7), daucosterol (8), β-sitosterone (9), and 3β, 6β-dihydroxy-stigmast-4-ene (10) by means of spectral analysis, comparison of physio-chemical data and throgh chemical method.     

Two new ent-kaurane diterpenoids from Wedelia trilobata (L.) Hitchc

Two new ent-kaurane diterpenoids, 16α,17,19-trihydroxy-18-nor-ent-kauran-4β-ol (1) and 17-chloro-16β-hydroxy-ent-kauran-19-oic acid (2) were isolated from the whole plant of Wedelia trilobata, together with five known ones (3–7). Their structures were elucidated on the basis of extensive spectroscopic analyses, including NMR and MS techniques. Compound 1 is an 18-nor-ent-kaurane type diterpenoid which is rare in nature, and compound 2 is the first chlorine-containing ent-kaurane diterpenoid so far isolated from plant family of Asteraceae. Known compound 4 was obtained from the genus Wedelia for the first time. Compounds 4–6 selectively showed in vitro antibacterial activity against three assayed Gram-(+) bacteria, especially 5 and 6 which showed the antibacterial activity against Staphylococcus aureus with MIC values (3.125–6.25 μg/mL) comparable to reference compound Kanamycin (MIC 3.125 μg/mL). Compounds 4–6 further displayed significant antibacterial activity against Gram-(−) bacterium Shigella dysenteriae with MIC value 3.125–12.5 μg/mL.     

Phytochemical and Biological Studies of Chloranthus Medicinal Plants

The plants of genus Chloranthus have been investigated in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up‐to‐date overview on the chemistry and bioactivity of the compounds isolated, mainly sesquiterpenoids and diterpenoids, from the genus Chloranthus over the past few decades.