Three new eudesmanolactones (=eudesmanolides), loloanolide A (1), loloanolide B (2), and 1-O-acetylloloanolide B (3), together with five known compounds, were isolated from the CHCl₃ extract of the aerial parts of Camchaya loloana. Their structures were elucidated on the basis of spectroscopic analysis. This type of eudesmanolactones bearing a 2-(hydroxymethyl)acryloyloxy group at C(8) was discovered for the first time. Compounds 1–3 exhibited cytotoxicity against the HepG2 cell line, with GI₅₀ values of 22.9, 18.1, and 12.8 nmol/ml, respectively.

Introduction – Biosynthesis of terretonin was studied due to the interesting skeleton of this series of sesterterpenoids. Very recently, López-Gresa reported two new sesterterpenoids (terretonins E and F) which are inhibitors of the mammalian mitochondrial respiratory chain. Mass spectrometry (MS), especially tandem mass spectrometry, has been one of the most important physicochemical methods for the identification of trace natural products due to it rapidity, sensitivity and low levels of sample consumption. The potential application prospect and unique skeleton prompted us to study structural characterisation using MS.

Objective – To obtain sufficient information for rapid structural elucidation of this class of compounds using MS.

Methodology – The elemental composition of the product ions was confirmed by low-energy ESI-CID-QTOF-MS/MS analyses. The fragmentation pathways were postulated on the basis of ESI-QTOF-MS/MS/MS and ESI-IT-MSⁿ spectra. Common features and major differences between ESI-QTOF-MS/MS and IT-MSⁿ spectra were compared. For ESI-QTOF-MS/MS/MS experiments, capillary exit voltage was raised to induce in-source dissociation. Ammonium acetate or acetic acid were added into solutions to improve the intensity of [M + H]⁺. The collision energy was optimised to achieve sufficient fragmentation. Some fragmentation pathways were unambiguously proposed by the variety of abundance of fragment ions at different collision energies even without MSⁿ spectra.

Results – Fragmentation pathways of five representative sesterterpenoids were elucidated using ESI-QTOF-MS/MS/MS and ESI-IT-MSⁿ in both positive- and negative-ion mode. The key group of characterising fragmentation profiles was ring B, and these fragmentation patterns are helpful to identify different types of sestertepenoids.

Conclusion – Complementary information obtained from fragmentation experiments of [M + H]⁺ (or [M + NH₄]⁺) and [M − H]⁻ precursor ions is especially valuable for rapid identification of this kind of sesterterpenoid.

Four new alkaloids, brevianamides O–R (1–4, resp.), were isolated from the AcOEt extract of the solid-state fermented rice culture of the fungus Aspergillus versicolor. Their structures were elucidated on the basis of spectroscopic analyses.

Two new depsidones, mollicellins I and J (1 and 2, resp.), and a new chromone, 2-(hydroxymethyl)-6-methylmethyleugenin (3), along with six known compounds, 4–9, were isolated from the ethyl acetate extract of a solid-state fermented culture of Chaetomium brasiliense. Their structures were elucidated based on spectroscopic analysis. Mollicellins I and H (5) exhibited significant growth inhibitory activity against human breast cancer (Bre04), human lung (Lu04), and human neuroma (N04) cell lines with GI₅₀ values between 2.5–8.6 μg/ml.

Two diastereoisomeric decalins, (2S,4aS,5S,6R)- and (2S,4aS,5R,6R)-5-(2-hydroxyethyl)-1,1,4a,6-tetramethyldecalin-2,6-diol (5 and 6) were prepared from the degradation products of oleanolic acid. Starting from 6, (−)-ambrox (4) was synthesized.

Two new iridoids, methyl (+)-rel-(1R,3S,4R,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H-1a,2-dioxacyclopent[cd]indene-4-carboxylate (1) and methyl (+)-rel-(1R,3S,4S,5R,8R,9R)-1,3,4,5,8,9-hexahydro-8-hydroxy-3-methoxy-2H-1a,2-dioxacyclopent[cd]indene-4-carboxylate (2), were isolated from Viburnum cylindricum along with 14 known compounds. Their structures were determined by spectroscopic analyses. This type of iridoids bearing a MeO group at C(3) was discovered for the first time.