One new bisabolane sesquiterpene, bisabolan-1,10,11-triol (1), one new norbisabolane sesquiterpene, 12-nor-11-acetoxybisabolen-3,6,7-triol (2), two new naturally occurring monoterpenes, (7S)- and (7R)-1-hydroxy-3-p-menthen-9-oic acids (3 and 4), one new naturally occurring trichodenone, dechlorotrichodenone C (5), one new chlorine-containing trichodenone, 3-hydroxytrichodenone C (6), one new diketopiperazine, methylcordysinin A (7), and one new naturally occurring oxazole derivative, 4-oxazolepropanoic acid (8), were isolated from the culture of a marine brown alga-endophytic strain (cf44-2) of Trichoderma asperellum. Their structures and relative configurations were determined by extensive 1D/2D NMR and mass spectrometric data, and the absolute configurations of 3–6 were assigned by analysis of the ECD spectra aided by quantum chemical computations. Compounds 1, 2, 5, and 6 showed growth inhibition of some marine phytoplankton species and pathogenic bacteria.

In this paper, quaternary ammonium salts of chitosan bearing halogenated acetate, including N,N,N-trimethyl chitosan chloroacetate (TMCSC), N,N,N-trimethyl chitosan dichloroacetate (TMCSDC), N,N,N-trimethyl chitosan trichloroacetate (TMCSTC), and N,N,N-trimethyl chitosan trifluoroacetate (TMCSTF), were prepared via N,N,N-trimethyl chitosan iodide (TMCSI). The obtained chitosan derivatives were characterized by FT-IR, ¹H NMR spectra, ¹³C NMR spectra, and elemental analysis. Their antifungal property against Fusarium oxysporum f. sp. cucumebrium Owen (F. oxysporum f. sp. cucumebrium Owen), Botrytis cinerea (B. cinerea), and Phomopsis asparagi (P. asparagi) were evaluated by hyphal measurement method at concentrations ranging from 0.08 mg/mL to 0.8 mg/mL. Meanwhile, two common bacteria, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were selected as the model Gram-negative and Gram-positive bacteria to evaluate the antibacterial property of the chitosan derivatives by agar well diffusion method. The results showed that TMCSC, TMCSDC, TMCSTC, and TMCSTF had better antifungal and antibacterial activities than chitosan and TMCSI. In particular, a rule showed that the inhibitory activity decreased in the order: TMCSTF > TMCSTC > TMCSDC > TMCSC > TMCSI > chitosan, which was consistent with the electron-withdrawing property of different halogenated acetate. Apparently, the quaternary ammonium salts of chitosan with stronger electron withdrawing ability possessed relatively greater antifungal and antibacterial activities. This experiment provides a potentially feasible method for the further utilization of chitosan in fields of antifungal and antibacterial biomaterials.

Two new antimicrobial bisabolane-type sesquiterpenoid derivatives, ent-aspergoterpenin C (compound 1) and 7-O-methylhydroxysydonic acid (2), and two new butyrolactone-type monoterpenoids, pestalotiolactones C (3) and D (4), along with a known monoterpenoid pestalotiolactone A (5) and four known bisabolane sesquiterpenoids (6−9), were isolated and identified from the deep-sea sediment-derived fungus Aspergillus versicolor SD-330. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and the absolute configurations of the new compounds 1−4 were determined by the combination of NOESY and TDDFT-ECD calculations and X-ray crystallographic analysis. Additionally, we first determined and reported the absolute configuration of the known monoterpenoid pestalotiolactone A (5) through the X-ray crystallographic experiment. All of these isolated compounds were evaluated for antimicrobial activities against human and aquatic pathogenic bacteria. Compounds 1, 2, 6 and 9 exhibited selective inhibitory activities against zoonotic pathogenic bacteria such as Escherichia coli, Edwardsiella tarda, Vibrio anguillarum and V. harveyi, with MIC values ranging from 1.0 to 8.0 μg/mL.

A new epoxy-cadinane sesquiterpene, 4β,5β-epoxycadinan-1β-ol (1), and six known cadinane sesquiterpenes: cadinan-1,4,5-triol (2), 4α,5β-dihydroxycubenol (3), cubenol (4), cadinan-3-ene-1,5-diol (5), cubenol-3-one (6), and torreyol (7), were isolated from a sample of marine brown alga Dictyopteris divaricata collected off the coast of Yantai (China). Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

The quantification of steroid hormones of individual zebrafish (Danio rerio) provides perspective to understand endogenous hormone function. A UPLC–TOF–MS method was developed to provide a reproducible, sensitive, and efficient assay to determine the concentration of steroid hormones, including cortisol, testosterone, androstenedione, 11-deoxycortisol, 11-deoxycorticosterone, and 17-hydroxyprogesterone in whole-body homogenates of each zebrafish. Solid-phase extraction was used to sample matrix clean-up and acquired a recovery from 89.7% to 107.9%. The analytes were separated on an Aquity BEH C18 column using gradient elution. Mass spectrometric analysis was performed by single reaction monitoring (SRM) using positive electrospray ionization mode. The total running time was 6 min, which was greatly shortened compared with a previously reported method. The developed method exhibited excellent linearity for all the analytes, with regression coefficients higher than 0.99. The limit of detection varied between 0.1 and 0.5 ng/L and the limit of quantification was 0.5–1.7 ng/L for all analytes. The precision of the method was assessed on replicate measurements and was found to be in the ranges of 1.9 % to 6.6% and 4.3% to 8.6%, for intra- and inter-day analysis, respectively. This method was validated according to FDA guidance and applied to determine steroid hormone levels in the tissue homogenate of zebrafish acutely treated with caffeine and ethanol.