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A fluorescence compound of benzocoumarin typical skeleton was synthesized and its interaction with various metal ions was evaluated. The synthesis was performed via Knoevenagel condensation whereas identification of the product was accomplished by various spectroscopic techniques. The chemo-sensor test against representative metal ions was monitored by fluorescence spectrophotometry. Density Functional Theory calculation (DFT) (Functional/basis set; M06/6-31G (d, p)) was also carried out to clarify the experimental results and to confirm the mechanism of interaction. The 3-oxo-3H-benzo[f]chromene-2-carboxylic acid 1 was obtained as yellow solid with; 60 % chemical yield, melting point; 235.6 - 236.7°C, λmax UV/Visible, λem and Stokes shift (MeOH / nm); 374, 445, and 71 nm, respectively. Structure of the compound was identified based on spectroscopic data and literature comparison. The compound 1 exhibited a chelation quenched fluorescence (CHQF) phenomenon toward Na+ ion selectively, with binding stoichiometry (1:2) and LoD and LoQ of 0.14 and 0.48 mg/L, respectively. Based on DFT calculation, compound 1 chelated Na+ ion through mechanism of oxidative (1:1 equivalent) and reductive (2:1 equivalent) Photoinduced Electron Transfer (PET), correspondingly.

A seco-apotirucallane-type triterpenoid, namely angustifolianin (1), along with three dammarane-type triterpenoids, (20S, 24S)-epoxy-dammarane-3β,25-diol (2), 3-epi-cabraleahydroxylactone (3), and ...

Nine analogues of antioxidant peptide SCAP1 were successfully synthesised using a solid-phase method on a 2-chlorotrytil resin. The compounds were obtained in a range of yields of 7.0–57.8%. The occurrence of aggregation during the synthesis is suspected to be responsible for the poor yields. All peptides were characterized by high-resolution time-of-flight mass spectrometry (HR-TOFMS) and nuclear magnetic resonance (NMR). The antioxidant activities of the SCAP1 analogues as well as SCAP1 were analysed utilising the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay. The results revealed that all of the analysed peptides exhibited moderate antioxidant properties. Moreover, the evaluation of the structure–activity relationship showed that the Asn residue is an important requirement for the antioxidant activity of SCAP1. The replacement of Asn with other amino acid residues (Thr, Pro, Tyr, Trp and Phe) resulted in a decrease in the IC50 values of the peptides. Notably, however, the replacement of the Lys residue with Val marginally increased the activity.

Three new limonoids namely pentandricines B–D (1–3), were isolated from n-hexane extract of the stem bark of Chisocheton pentandrus, along with four known limonoids (4-7). The chemical structures of pentandricines B–D, were fully elucidated based on UV, IR, HR-TOFMS, 1D- and 2D-NMR spectra. Furthermore, compounds 1-7 were evaluated for their cytotoxic activity against MCF-7 breast cancer cells in vitro, with compound 7 (nimonol) showing strongest cytotoxicity activity with an IC50 value of 22.03 ± 0.026 μM.

Four new triterpenoids, namely, chisopaten A-D (1-4), were isolated from the n-hexane extract of the bark of Chisocheton patens Blume. The chemical structures of new compounds were elucidated on the basis of spectroscopic data interpretation. All isolated compounds were evaluated for their cytotoxic activity against MCF-7 breast cancer lines. Chisopaten A and C, showed strongest cytotoxicity activity with IC50 values of 4.01 ± 0.008 and 4.33 ± 0.009 μM, respectively.

A new havanensin-type limonoid, 16β-hydroxydysobinin (1), along with four known limonoids (2–5), have been isolated from the seeds of Chisocheton macrophyllus. The chemical structure of the new compound was determined by referencing spectroscopic data, and by comparison to those related spectra previously reported. Each compound was evaluated for their cytotoxic effects against Michigan Cancer Foundation-7 (MCF-7) breast cancer cells and display no significant activity.

Antimicrobial peptides (AMPs) are interesting compounds owing to their ability to kill several pathogens. In order to identify new AMPs, c-PLAI analogues were synthesized and evaluated together with their linear precursors for their antimicrobial properties against two Gram-positive bacteria ( Staphylococcus aureus and Bacillus cereus ), two Gram-negative bacteria ( Escherichia coli and Klebsiella pneumoniae ), and two fungal strains ( Candida albicans and Trichophyton mentagrophytes ). The new c-PLAI analogues were prepared through a combination of solid- and solution-phase syntheses, as previously employed for the synthesis of c-PLAI. The antimicrobial activity tests showed that the synthetic parent peptide c-PLAI was inactive or weakly active towards the bioindicators employed in the assay. The tests also indicated that cyclic c-PLAI analogues possessed enhanced antimicrobial properties against most of the bacteria and fungi tested. Furthermore, this study revealed that analogues containing cationic lysine residues displayed the highest activity towards most bioindicators. A combination of lysine and aromatic residues yielded analogues with broad-spectrum antimicrobial properties.

Eleven undescribed triterpenoids (pentandrucines A to K) were isolated from the n-hexane extract of the stem bark of Chisocheton pentandrus (Blanco) Merr. These comprised ten undescribed dammarane-type triterpenoids and one undescribed apotirucallane-type triterpenoid. Additionally, two dammarane-type triterpenoids, four apotirucallane-type triterpenoids and two tirucallane-type triterpenoids were also isolated. The chemical structures of pentandrucine A-K, were fully elucidated using 1D and 2D-NMR, and high resolution MS. All of the compounds were evaluated for cytotoxic activity against MCF-7 breast cancer cells in vitro. Melianodiol proved to be the most active with an IC50 of 16.84 μM comparing favourably with Cisplatin (13.2 μM).

A new pregnane-type steroid, 2α-hydroxy-3α-methoxy-5α-pregnane (1), together with three known dammarane-type triterpenoid, 3β-acetyl-20S,24S-epoxy-25-hydroxydammarane (2), 20S,24S-epoxy-3α,25-dihydroxydammarane (3), and eichlerianic acid (4) have been isolated from the stem bark of Aglaia elliptica. The structure s were determined by spectroscopic methods including the 2D-NMR techniques. Compound 1-4 showed moderate cytotoxic activity against P-388 murine leukemia cells .

A new propylcholesterol-type steroid, namely (22E,24S)-24-propylcholest-5en-3α-acetate (1), has been isolated from the stembark of Aglaia angustifolia (Miq.). The structure of 1 was determined on the basis of spectroscopic data including 1D- and 2D-NMR as well as high resolution mass spectroscopy analysis. Compound 1 showed weak activity against the MCF-7 breast cancer cell line.

SCAP1 is a pentapeptide isolated from the hydrolysate of oyster (Saccostrea cucullata), which has antioxidant and anticancer properties. This study aims to find a novel strategy to obtain antioxidant peptide SCAP1 (Leu-Ala-Asn-Ala-Lys) through chemical synthesis. This study reports the first synthesis of SCAP1 through the solid phase peptide synthesis (SPPS) method with Fmoc strategy on 2-chlorotrityl chloride resin. A HATU-HOAt coupling reagent was employed in all amide bond formations and 95% TFA in water was employed to release the desired peptide from the solid support. The crude peptide was purified using successive preparative-RP-MPLC and RP-HPLC to obtain the pure peptide. The synthesized peptide was confirmed by mass spectrometry, showing a correct molecular ion peak at m/z 516.3143 (M+H)+, referring to the desired SCAP1. 1H-NMR spectra of the peptide revealed protons signals consistent to the structure of SCAP1. During the synthesis, the coupling between Ala and Asn(Trt) was not straightforward, which led to a low yield of the final product. The use of Trt-based Asn was not a suitable option, as it could cause aggregation during the synthesis, eventually leading to a poor yield of the final product. SCAP1 was obtained as a white solid with a percent yield of 8.28%.

Exumolides A and B are two cyclodepsipeptides that was previously isolated from marine fungus. Both peptides were synthesized using a combination of solid- and solution-phase method. The linear precursor was synthesized through solid-phase method on 2-chlorotrityl resin with standard Fmoc strategy. The hydroxy acid, (S)-2-hydroxy-4-methylpentanoic acid (Hmp), was prepared from its precursor l -leucine, and attached on the resin with a double-coupling protocol. The depside bond formation that was carried out at the end of the coupling process, was beneficial, particularly, in the blockage of the diketopiperazine formation during Fmoc deprotection. The cyclic product was obtained through HATU-based cyclisation. Exumolides A and B were successfully synthesized with overall yields of 4.12% and 6.39%, respectively.

Four dammarane-type triterpenoid compounds, dammar-24-en-3a-ol ( 1 ), 3- epi -cabraleahydroxy lactone ( 2 ), ( E )-25-hydroperoxydammar-23-en-3b,20-diol ( 3 ), and dammar-24-en-3β,20-diol ( 4 ), were isolated from the methanolic extract of the stembark of Aglaia argentea . Compounds 1 - 4 were isolated for first time from this plant. The structure of isolated compounds were elucidated by spectroscopic methods including one and two-dimensional NMR as well as mass spectrometric analysis. Compounds, 1 - 4 , along with a known synthetic analog, 20-hydroxy-dammar-24-en-3-on ( 5 ), were evaluated their cytotoxic activity against P-388 murine leukemia cells in vitro . The IC 50 values of compounds, 1 - 5 were 9.09 ± 0.10, 68.53 ± 0.08, 5.89 ± 0.08, 22.40 ± 0.11, and 11.53 ± 0.08 µg/mL, respectively. Among the dammarane-type triterpenoids, compounds 1 , 3 , 4 and 5 having opened side chain showed the stronger activity, wheres compound 2 with cyclic side chain showed weak or no activity. In addition, compound 3 showed strongest activity, indicate that hydroperoxy group at side chain increase cytotoxic activity.

Aureobasidins are a family of cyclodepsipeptides have antifungal properties. They were isolated from the black yeast Aureobasidium pullulans R106 and over 30 derivatives have been successfully characterized. There are few publications reporting the total synthesis of aureobasidins. The limited reports of the synthesis of the aureobasidin derivatives are due to the difficult access to the preparations of precursors. The aim of this research is to synthesise a precursor of aureobasidin B, t-butyl (2R)-hydroxyisovalerate (t-Bu-Hiv), that is prepared for the total synthesis of aureobasidin B. The synthesis of AbB is planned to be undertaken by using a solid phase method, so the ester formation between t-Bu-Hiv and the Fmoc-β-hydroxymethylvaline will be carried out in solution phase to form depsidipeptide. The t-butyl group was used as protecting agent that is due to the straightforward elimination of the protecting group from the Fmoc-depsidipeptide. The t-Bu-Hiv acid was prepared from D-valine through diazotisation to form (2R)-acetyloxyisovaleric acid in 62.7% yield. Product of the first step was then protected by t-butyl group by using Boc-anhydride in t-butanol to give t-butil (2R)-acetyloxyisovalerate in 44% yield. In the last step, the acetyloxy group was eliminated by using potassium carbonate in methanol/water to give the desired product, t-Bu-Hiv in 33.5% yield. The t-Bu-Hiv is ready to be combined with Fmoc-β-hydroxymethylvaline to result in depsidipeptide that will be attached to the resin in the total synthesis of AbB. Each stage of this synthesis was controlled by thin layer chromatography and all products were purified by open column chromatography. All the synthesized products were characterized by various spectroscopic techniques, including infrared spectrophotometer, mass spectroscopy (ESI-MS), 1H-NMR and 13C-NMR.

A new 30-nor trijugin-type limonoid, chisotrijugin (1), has been isolated from the bark of Chisocheton cuminganus belong to the Meliaceae family. The chemical structure of 1 was elucidated by spectroscopic techniques such as UV, IR, MS, 1D and 2D NMR.