Eremophilane‐Type Sesquiterpenoids from the Fermentation Broth of Plant Endophytic Fungus Pestalotiopsis photiniae Isolated from the Chinese Podocarpaceae Plant Podocarpus macrophyllus

Two new sesquiterpenoid esters, pestalotiopins B and C ( 1 and 2 , resp.) related to the eremophilane class, together with one known compound, berkleasmin C ( 3 ), were isolated from the fermentation broth of the plant endophytic fungus Pestalotiopsis photiniae. Their structures and relative configurations were elucidated by extensive spectroscopic analysis including 1D‐ and 2D‐NMR (HSQC, HMBC, and NOESY), and MS experiments. Compound 1 has an interesting lactam structure, and this type of sesquiterpenoid with a lactam structure is reported for the first time.     

Essential Oil of Cannabis sativa L: Comparison of Yield and Chemical Composition of 11 Hemp Genotypes

Cannabis sativa L. is an annual species cultivated since antiquity for different purposes. While, in the past, hemp inflorescences were considered crop residues, at present, they are regarded as valuable raw materials with different applications, among which extraction of the essential oil (EO) has gained increasing interest in many fields. The aim of the present study is the evaluation of the yield and the chemical composition of the EO obtained by hydrodistillation from eleven hemp genotypes, cultivated in the same location for two consecutive growing seasons. The composition of the EOs was analyzed by GC–MS, and then subjected to multivariate statistical analysis. Sesquiterpenes represented the main class of compounds in all the EOs, both in their hydrocarbon and oxygenated forms, with relative abundances ranging from 47.1 to 78.5%; the only exception was the Felina 32 sample collected in 2019, in which cannabinoids predominated. Cannabinoids were the second most abundant class of compounds, of which cannabidiol was the main one, with relative abundances between 11.8 and 51.5%. The statistical distribution of the samples, performed on the complete chemical composition of the EOs, evidenced a partition based on the year of cultivation, rather than on the genotype, with the exception of Uso-31. Regarding the extraction yield, a significant variation was evidenced among both the genotypes and the years of cultivation.     

Total synthesis of (-)-diversifolin

First total synthesis of biologically active germacrane-type sesquiterpene (−)-diversifolin has been achieved. The features of the synthesis involve (i) ring-closing metathesis to give a 10-membered carbocycle, (ii) regioselective Mukaiyama aldol reaction of silyl dienol ether with formaldehyde at the α-position, and (iii) lactone transposition of the fully functionalized 11-oxabicyclo[6.2.1]undecane system.     

Sesquiterpenes from Rhizomes of Cyperus rotundus with Cytotoxic Activities on Human Cancer Cells in vitro

Two new sesquiterpenes, cyperusol A₃ ( 1 ) and 3β‐hydroxycyperenoic acid ( 2 ), along with three known sesquiterpenes, britanlin E ( 3 ), 1β,4α‐dihydroxyeudesm‐11‐ene ( 4 ), and 11,12‐dihydroxyeudesm‐4‐en‐3‐one ( 5 ), were isolated from the AcOEt‐soluble fraction of rhizomes of Cyperus rotundus L. The structures of 1 and 2 were elucidated by physical and spectroscopic methods (¹H‐ and ¹³C‐NMR, 2D‐NMR, and MS). All of the isolates, 1 – 5 , were evaluated for their cytotoxic activities against human ovarian cancer cells (A2780) and endometrial adenocarcinoma cells (Ishikawa) using MTT assays.     

Volatile constituents of Amomum maximum Roxb and Amomum microcarpum C. F. Liang & D. Fang: two Zingiberaceae grown in Vietnam

The chemical composition of essential oils obtained from the hydrodistillation of different parts of Amomum maximum Roxb and Amomum muricarpum C. F. Liang & D. Fang (Zingiberaceae) grown in Vietnam are reported. The analysis was performed by means of gas chromatography–flame ionisation detectoorand gas chromatography coupled with mass spectrometry. The major compounds identified in the oils of A. maximum were β-pinene (20.4–40.8%), α-pinene (6.8–15.0%), β-elemene (2.5–12.8%) and β-caryophyllene (2.3–10.3%). Moreover, β-phellandrene (11.6%) was present in the root oil. The main compound identified in all the oil samples of A. muricarpum was α-pinene (24.1–54.7%) and β-pinene (9.2–25.9%). In addition, limonene (7.4%) and δ-3-carene (9.4%) were present in the leaves and stem oils, respectively. However, while β-phellandrene (8.3%) could be seen prominent in the root oil, the fruits contained significant amount of zingiberene (6.3%). The largest amount of τ-muurolol (13.0%) was found in the flower oil.     

Volatolomics of Three South African Helichrysum Species Grown in Pot under Protected Environment

Helichrysum decorum DC, Helichrysum lepidissimum S. Moore, and Helichrysum umbraculigerum are three species traditionally used in the South African medicine. The present work deals with the investigation of the spontaneous emission and the essential oils obtained from these plants cultivated in open field under uniform conditions. Fractions of the volatile organic compounds of the three species were rich in monoterpene hydrocarbons, representing more than 70% of the total composition. Pinene isomers were the most representative compounds: β-pinene in H. decorum (53.0%), and α-pinene in H. lepidissimum (67.9%) and H. umbraculigerum (54.8%). These latter two species evidenced an important amount of sesquiterpene hydrocarbons (SH) especially represented by γ-curcumene (H. lepidissimum) and α- and β-selinene (H. umbraculigerum). On the contrary, in the EOs, sesquiterpenes compounds prevailed, representing more than 64% of the identified fraction to reach more than 82 and 87% in H. umbraculigerum and H. lepidissimum, respectively. Although the chemical classes and their relative abundances were comparable among the three species, the individual compounds of EOs showed large differences. In fact, caryophyllene oxide (26.7%) and γ-curcumene (17.4%) were the main constituents in H. decorum, and H. lepidissimum respectively, while neo-intermedeol (11.2%) and viridiflorol (10.6%) characterized H. umbraculigerum.     

Germacrene A–A Central Intermediate in Sesquiterpene Biosynthesis

This review summarises known sesquiterpenes whose biosyntheses proceed through the intermediate germacrene A. First, the occurrence and biosynthesis of germacrene A in Nature and its peculiar chemistry will be highlighted, followed by a discussion of 6–6 and 5–7 bicyclic compounds and their more complex derivatives. For each compound the absolute configuration, if it is known, and the reasoning for its assignment is presented.     

Phenylpropenol ester and sesquiterpenoids with antimetastatic activities from the whole plants of Chloranthus japonicus

One new phenylpropenol ester (1) and three new lindenane sesquiterpenes (2–4) were isolated from the whole plant of Chloranthus japonicus together with three known lindenane derivatives (5–7). Their structures were determined based on detailed spectroscopic and electronic circular dichroism computational analyses. Compound 4 showed moderate efficacy in inhibiting cell migration, invasion, and vasculogenic mimicry (VM) in human of hepatocarcinoma (HCC) HepG2 cells. Furthermore, compound 4 could alter the expression of the proteins Vimentin, N-cadherin, Snail1 and E-cadherin by down-regulating the expression of Twist1, which indicated that its antimetastatic effect was associated with restraining the epithelial-mesenchymal transition (EMT) in HepG2 cells.     

Terpenoids from Croton regelianus

Two new terpenoids, the bisnorditerpene rel‐(5β,8α,10α)‐8‐hydroxy‐13‐methylpodocarpa‐9(11),13‐diene‐3,12‐dione ( 1 ) and the guaiane sesquiterpene rel‐(1R,4S,6R,7S,8aR)‐decahydro‐1‐(hydroxymethyl)‐4,9,9‐trimethyl‐4,7‐(epoxymethano)azulen‐6‐ol ( 2 ), together with seven known compounds, were isolated from Croton regelianus var. matosii. The structures of the isolated compounds were determined by HR‐ESI‐TOF and a combination of 1D‐ and 2D‐NMR experiments.